Optimize use of recycled aggregate in high-durability structural concrete: an experimental study

Op imize use o Recycled Agg ega e in High-
Du abili y S uc u al Conc e e: an
Expe imen al S udy
Ca la Te esa Vin imilla Molina
ADVERTIMENT La consul a d’aques a esi queda condicionada a l’accep ació de les següen s
condicions d'ús: La di usió d’aques a esi pe mi jà del eposi o i ins i ucional UPCommons
(h p://upcommons.upc.edu/ esis) i el eposi o i coope a iu TDX ( h p : / / w w w . d x . c a / ) ha
es a au o i zada pels i ula s dels d e s de p opie a in el·lec ual únicamen pe a usos p i a s
emma ca s en ac i i a s d’in es igació i docència. No s’au o i za la se a ep oducció amb inali a s
de luc e ni la se a di usió i posada a disposició des d’un lloc aliè al se ei UPCommons o TDX. No
s’au o i za la p esen ació del seu con ingu en una ines a o ma c aliè a UPCommons ( aming).
Aques a ese a de d e s a ec a an al esum de p esen ació de la esi com als seus con ingu s. En
la u ili zació o ci a de pa s de la esi és obliga indica el nom de la pe sona au o a.
ADVERTENCIA La consul a de es a esis queda condicionada a la acep ación de las siguien es
condiciones de uso: La di usión de es a esis po medio del eposi o io ins i ucional UPCommons
(h p://upcommons.upc.edu/ esis) y el eposi o io coope a i o TDR (h p://www. dx.ca /?locale-
a ibu e=es) ha sido au o izada po los i ula es de los de echos de p opiedad in elec ual
únicamen e pa a usos p i ados enma cados en ac i idades de in es igación y docencia. No se
au o iza su ep oducción con inalidades de luc o ni su di usión y pues a a disposición desde un
si io ajeno al se icio UPCommons No se au o iza la p esen ación de su con enido en una en ana
o ma co ajeno a UPCommons ( aming). Es a ese a de de echos a ec a an o al esumen de
p esen ación de la esis como a sus con enidos. En la u ilización o ci a de pa es de la esis es
obligado indica el nomb e de la pe sona au o a.
WARNING On ha ing consul ed his hesis you’ e accep ing he ollowing use condi ions: Sp eading
his hesis by he ins i u ional eposi o y UPCommons (h p://upcommons.upc.edu/ esis) and he
coope a i e eposi o y TDX (h p://www. dx.ca /?locale- a ibu e=en) has been au ho ized by he
i ula o he in ellec ual p ope y igh s only o p i a e uses placed in in es iga ion and eaching
ac i i ies. Rep oduc ion wi h luc a i e aims is no au ho ized nei he i s sp eading no a ailabili y
om a si e o eign o he UPCommons se ice. In oducing i s con en in a window o ame o eign
o he UPCommons se ice is no au ho ized ( aming). These igh s a ec o he p esen a ion
summa y o he hesis as well as o i s con en s. In he using o ci a ion o pa s o he hesis i ’s
obliged o indica e he name o he au ho .
Op imize use o Recycled Agg ega e in High-
Du abili y S uc u al Conc e e: An Expe imen al
S udy
Doc o al Thesis submi ed in ul ilmen o he equi emen s o he
Deg ee o Doc o o Philosophy in Cons uc ion Enginee ing
by
Ca la Te esa Vin imilla Molina
Thesis Ad iso s
D a. Mi en E xebe ia la añaga
Thesis by compendium o publica ions
Uni e si a Poli ècnica de Ca alunya, UPC Ba celonaTech
Depa men o Ci il and En i onmen al Enginee ing
Ba celona, Ma ch 2025
Op imización del uso de á idos eciclados en
ho migones es uc u ales de al a du abilidad:
Es udio expe imen al
Doc o al Thesis submi ed in ul ilmen o he equi emen s o he
Deg ee o Doc o o Philosophy in Cons uc ion Enginee ing
by
Ca la Te esa Vin imilla Molina
Thesis Ad iso s
D a. Mi en E xebe ia la añaga
Thesis by compendium o publica ions
Uni e si a Poli ècnica de Ca alunya, UPC Ba celonaTech
Depa men o Ci il and En i onmen al Enginee ing
Ba celona, Ma ch 2025
i
"You may encoun e many de ea s, bu you mus no be de ea ed. In ac , i may be
necessa y o encoun e he de ea s, so you can know who you a e, wha you can ise om,
how you can s ill come ou o i ."
- Maya Angelou

ii
iii
Abs ac
Cu en ly, he cons uc ion indus y aces he challenge o adop ing mo e sus ainable
p ac ices, wi h he use o ecycled agg ega es in s uc u al conc e e p oduc ion
eme ging as a key s a egy. This doc o al esea ch e alua es he iabili y and e icacy
o s uc u al conc e e inco po a ing high olumes o ine and coa se ecycled
agg ega es, speci ically ecycled conc e e agg ega es (RCA- ype A) and mixed ecycled
agg ega es (MRA- ype B). The ecycled agg ega e conc e es we e subjec ed o
exposu e condi ions anging om XC1 o XC4 classes, ex ending o mo e se e e
en i onmen al condi ions such as XS1.
The s udy was conduc ed in se e al expe imen al phases. In he i s phase, he physical,
chemical, and mechanical cha ac e is ics o ecycled agg ega es we e e alua ed. All
conc e e mix u es we e designed wi h a comp essi e s eng h o 30/37 MPa and a
cemen , CEM II A/L 42.5R, con en o 300 kg/m³. The second phase in ol ed a
comp ehensi e analysis o he physical, mechanical, and du abili y p ope ies o
conc e e mix u es wi h a ying p opo ions o RCA- ype A and MRA- ype B, using
e ec i e wa e –cemen a ios o 0.48 and 0.52. This phase aimed o de e mine he
maximum eplacemen pe cen age o ecycled agg ega es ha could be inco po a ed
wi hou comp omising he mechanical pe o mance o he conc e e. Resul s con i med
he easibili y o in eg a ing up o 60% coa se RCA (CRCA) and 20% ine RCA
(FRCA) in s uc u al conc e e mix u es, achie ing mechanical p ope ies compa able o
na u al agg ega e conc e e (NAC). The analysis was ex ended o he use o MRA- ype
B, alida ing good mechanical pe o mance wi h up o 40% coa se MRA (CMRA) and
15% ine MRA (FMRA) wi hou comp omising s uc u al pe o mance.
The hi d and ou h phases expanded he s udy, ocusing on he e ec s on conc e e
du abili y using he limi s es ablished in p e ious phases. Recycled agg ega e conc e e
(RAC) and NAC mix u es we e p oduced wi h simila comp essi e s eng hs using
e ec i e wa e –cemen a ios o 0.47 and 0.51, espec i ely. These phases u ilized
di e en cemen ypes, such as CEM II A/L 42.5 R, CEM II A/S 42.5 N/SRC, and CEM
III/B 42.5 N-LH/SR, o e alua e d ying sh inkage, chlo ide pe meabili y, and
accele a ed ca bona ion o he a ious mix u es and he in luence o cemen ype. A e
alida ing hose mix u es wi h up o 50% CRCA and 20% FRCA main ain hei
s uc u al in eg i y unde condi ions suscep ible o ca bona ion and chlo ide-induced
co osion, in he inal phase, wi h addi ional s udies on na u al ca bona ion and chlo ide
p o iles, he conc e e p oduced up o 60% CRCA and 20% FRCA was alida ed.
The indings o his esea ch indica e ha conc e e mix u es wi h high pe cen ages o
ecycled agg ega es, RCA and MRA, no only mee cu en egula o y s anda ds bu , in
some cases, exhibi enhanced p ope ies compa ed o hose o NAC. These esul s
i
suppo hei applica ion in s uc u es wi h ex ended se ice li e expec a ions.
Fu he mo e, i is concluded ha ecycled conc e e exhibi s p ope ies simila o NAC
when wo king wi h he same comp essi e s eng hs. This doc o al wo k unde sco es he
sus ainabili y o ecycled conc e e as a iable al e na i e, p omo ing en i onmen ally
esponsible cons uc ion p ac ices wi hou comp omising s uc u al in eg i y in
demanding en i onmen s.
Keywo ds: coa se and ine ecycled agg ega es, ecycled conc e e agg ega es (RCA- ype
A), mixed ecycled agg ega es (MRA- ype B), supplemen a y cemen i ious ma e ials,
CEM IIAL, CEM IIAS, CEM IIIB, mechanical p ope ies, d ying sh inkage, conc e e
du abili y, ca bona ion, chlo ide pene a ion.
Resumen
La indus ia de la cons ucción en en a ac ualmen e el desa ío de adop a p ác icas más
sos enibles, des acándose el uso de á idos eciclados en la p oducción de ho migón
es uc u al como una es a egia cla e. Es a in es igación doc o al e alúa la iabilidad
y e icacia del ho migón es uc u al que inco po a ele ados olúmenes de á idos
eciclados inos y g uesos, especí icamen e á idos eciclados de ho migón (RCA- ipo
A) y á idos mix os eciclados (MRA- ipo B). Los ho migones eciclados some idos a
condiciones de exposición que aba can desde las clases XC1 a XC4, ex endiéndose a
condiciones ambien ales más se e as como XS1.
El es udio se desa olló en a ias ases expe imen ales. En la p ime a ase, se e alua on
las ca ac e ís icas ísicas, químicas y mecánicas de los á idos eciclados. Todas las
mezclas de ho migón se diseña on con una esis encia a comp esión de 30/37 MPa y un
con enido de cemen o CEM II A/L 42.5R de 300 kg/m³. La segunda ase in oluc ó un
análisis exhaus i o de las p opiedades ísicas, mecánicas y de du abilidad de las mezclas
de ho migón con p opo ciones a iables de RCA- ipo A y MRA- ipo B, u ilizando
elaciones agua-cemen o e ec i as de 0.48 y 0.52. Es a ase u o como obje i o
de e mina el po cen aje máximo de eemplazo de á idos eciclados que pod ía
inco po a se sin comp ome e el endimien o mecánico del ho migón. Los esul ados
con i ma on la iabilidad de in eg a has a un 60% de RCA g ueso (CRCA) y un 20%
de RCA ino (FRCA) en mezclas de ho migón es uc u al, log ando p opiedades
mecánicas compa ables a las del ho migón con á idos na u ales (NAC). El análisis se
ex endió al uso de MRA- ipo B, alidando un buen endimien o mecánico con has a un
40% de MRA g ueso (CMRA) y un 15% de MRA ino (FMRA), sin comp ome e el
desempeño es uc u al.
La e ce a y cua a ases amplia on el es udio, cen ándose en los e ec os sob e la
du abilidad del ho migón u ilizando los lími es es ablecidos en ases an e io es. Se
p oduje on mezclas de ho migón con á idos eciclados (RAC) y NAC con esis encias
a comp esión simila es, u ilizando elaciones agua-cemen o e ec i as de 0.47 y 0.51.
Es as ases emplea on di e en es ipos de cemen o, como CEM II A/L 42.5 R, CEM II
A/S 42.5 N/SRC y CEM III/B 42.5 N-LH/SR, pa a e alua la e acción po secado, la
pe meabilidad a clo u os y la ca bona ación acele ada de las di e sas mezclas, así como
la in luencia del ipo de cemen o. T as alida que las mezclas con has a un 50% de
CRCA y un 20% de FRCA man ienen su in eg idad es uc u al bajo condiciones
suscep ibles a ca bona ación y co osión inducida po clo u os en la ase inal, con
es udios adicionales sob e ca bona ación na u al y pe iles de clo u os, se alidó el
ho migón p oducido con has a un 60% de CRCA y un 20% de FRCA.
xii

xiii
CONTENT:
Abs ac ……………………………………………………………………………………….iii
Resumen ………………………………………………………………………………………..
Resum ………………………………………………………………………………………. ii
Acknowledgmen s ...................................................................................................................ix
Con ibu ions ............................................................................................................................ x
1. Chap e 1. In oduc ion. ......................................................................................... 1
1.1. Resea ch Scope ......................................................................................................... 1
1.2. Objec i e ................................................................................................................... 2
1.3. Mo i a ion ................................................................................................................ 4
1.4. Hypo hesis ................................................................................................................ 4
1.5. S uc u e o he hesis................................................................................................ 4
2. Chap e 2. S a e o he a ...................................................................................... 7
2.1. Backg ound .............................................................................................................. 7
2.2. Recycled Conc e e Agg ega e (RCA-Type A) .......................................................... 7
2.3. Mixed Recycled Agg ega e (MRA-Type B) ............................................................ 14
3. Chap e 3. Ma e ials and Tes p ocedu e. ........................................................... 18
3.1. In oduc ion ............................................................................................................ 18
3.2. Ma e ials ................................................................................................................. 19
3.2.1. Cemen and Chemical admix u es ........................................................................... 19
3.2.2. Na u al Agg ega es ................................................................................................. 20
3.2.3. Recycled conc e e Agg ega es- Type A .................................................................. 21
3.2.4. Mixed ecycled Agg ega es- Type B ....................................................................... 23
3.3. Tes p ocedu e ........................................................................................................ 25
4. Chap e 4. Fine and coa se ecycled agg ega es-Type A in conc e e p oduc ion.
……………………………………………………………………………………….30
4.1. Objec i e ................................................................................................................. 31
4.2. Conc e e p oduc ion ................................................................................................ 31
4.3. Resul s and discussion ............................................................................................ 34
4.3.1. Physical p ope ies .................................................................................................. 34
4.3.2. Mechanical p ope ies ............................................................................................. 35
4.3.2.1 Comp essi e s eng h .............................................................................................. 35
4.3.2.2 Spli ing ensile s eng h ......................................................................................... 38
xi
4.3.2.3 Elas ic modulus ....................................................................................................... 40
4.3.3. D ying sh inkage ..................................................................................................... 42
4.3.4. Du abili y p ope ies. .............................................................................................. 47
4.3.4.1 So p i i y ................................................................................................................ 47
4.3.4.2 Wa e pene a ion unde p essu e ............................................................................ 49
4.4. Conclusions ............................................................................................................ 50
5. Chap e 5. Du abili y o S uc u al Conc e e wi h Recycled Agg ega es Type A:
E alua ion in Phase 1. ........................................................................................................... 52
5.1. Objec i e ................................................................................................................. 53
5.2. Conc e e p oduc ion ................................................................................................ 53
5.3. Resul s .................................................................................................................... 55
5.3.1. Comp essi e s eng h .............................................................................................. 55
5.3.2. D ying Sh inkage .................................................................................................... 58
5.3.3. Chlo ide Ion Pene a ion ......................................................................................... 63
5.3.4. Ca bona ion Resis ance ........................................................................................... 65
5.4. Conclusions ............................................................................................................ 68
6. Chap e 6. Du abili y o S uc u al Conc e e wi h Recycled Agg ega es Type A:
Analysis in Phase 2. .............................................................................................................. 70
6.1. Objec i e ................................................................................................................. 72
6.2. Conc e e p oduc ion and es p ocedu es ................................................................. 71
6.2.1. Conc e e p oduc ion ................................................................................................ 71
6.3. Resul s and Discussion............................................................................................ 73
6.3.1. Comp essi e s eng h .............................................................................................. 73
6.3.2. D ying Sh inkage .................................................................................................... 76
6.3.3. Chlo ide Ion Pene a ion ......................................................................................... 80
6.3.4. Chlo ide Pene a ion Dep h ..................................................................................... 82
6.3.5. Ca bona ion Resis ance ........................................................................................... 86
6.3.6. Accele a ed Ca bona ion ......................................................................................... 86
6.3.7. Na u al Ca bona ion Resis ance .............................................................................. 88
6.3.8. Kna s Kna THEO ................................................................................................. 91
6.3.9. Ca bona ion Analysis a 50 and 100 yea s ............................................................... 92
6.4. Conclusions ............................................................................................................ 94
7. Chap e 7. Fine and coa se ecycled agg ega es-Type B in conc e e p oduc ion.
……………………………………………………………………………………….97
x
7.1. Objec i e ................................................................................................................. 98
7.2. Conc e e p oduc ion ................................................................................................ 98
7.3. Resul s and discussion ........................................................................................... 101
7.3.1. Physical p ope ies ................................................................................................. 101
7.3.2. Mechanical p ope ies ........................................................................................... 103
7.3.2.1 Comp essi e s eng h ............................................................................................ 103
7.3.2.2 Spli ing ensile s eng h ....................................................................................... 107
7.3.2.3 Elas ic modulus ..................................................................................................... 109
7.3.3. D ying sh inkage .................................................................................................... 112
7.3.4. Du abili y p ope ies .............................................................................................. 117
7.3.4.1 So p i i y ............................................................................................................... 117
7.3.4.2 Wa e pene a ion unde p essu e. .......................................................................... 119
7.4. Conclusions .......................................................................................................... 120
8. Chap e 8.Gene al conclusions and u u e esea ch lines. ............................... 122
8.1 Gene al conclusions. ............................................................................................. 122
8.2 Fu u e Resea ch Lines ........................................................................................... 127
9. Re e ences ............................................................................................................ 128
x i
FIGURES:
Figu e 3. 1 Image o all he ac ions: aw agg ega es ............................................................. 20
Figu e 3. 2 Agg ega e pa icle size dis ibu ion ...................................................................... 20
Figu e 3. 3 Image o all he ac ions: ecycled agg ega es ..................................................... 21
Figu e 3. 4 Image o all agg ega e ac ions: Mixed ecycled agg ega e (MRA) ................... 23
Figu e 3. 5 Agg ega e pa icle size dis ibu ion ...................................................................... 24
Figu e 3. 6 Comp ehensi e F amewo k o Physical, Mechanical, and Du abili y Tes ing o
Recycled Agg ega e Conc e e ................................................................................................ 29
Figu e 4. 1 Wa e Abso p ion in a) Phase 1 (e ec i e w/c a io 0.48) and b) Phase 2 (e ec i e
w/c a io 0.52) ........................................................................................................................ 35
Figu e 4. 2 Rela i e comp essi e s eng h a 28 days in a) Phase 1 and b) Phase 2. ................ 37
Figu e 4. 3 Ra io o he expe imen al alue o espec o nume al alue o spli ing ensile
s eng h and modulus o elas ici y a) phase 1 and b) phase 2. ................................................. 40
Figu e 4. 4 D ying sh inkage de elopmen in phase 1 a) d ying sh inkage CRCA1; b) d ying
sh inkage CRCA1&FRCA1; c) mass loss CRCA1; d) mass loss CRCA1&FRCA1..................... 43
Figu e 4. 5 D ying sh inkage de elopmen in phase 2 a) d ying sh inkage CRCA2; b) d ying
sh inkage CRCA1&FRCA2; c) mass loss CRCA2; d) mass loss CRCA1&FRCA2 ................... 44
Figu e 4. 6 Rela i e a io o sh inkage a 91 days a) Phase 1 (e ec i e w/c a io o 0.48) b) Phase
2 (e ec i e w/c a io o 0.52) ................................................................................................. 45
Figu e 4. 7 Analysis o sh inkage es ima ion, he a io o expe imen al esul s/nume ical
es ima ion ollowing SC-BOE and EC-02 o he conc e es p oduced in Phase 1. .................. 47
Figu e 4. 8 So p i i y alues a 28 days in a) Phase 1 and b) Phase 2 ..................................... 48
Figu e 4. 9 Wa e pene a ion unde p essu e in Phase 1 and Phase 2. .................................... 50
Figu e 5. 1 Rela i e comp essi e s eng h a all conc e e ages p oduced wi h cemen s: a) ype
CEM IIAL; b) ype CEM IIAS; c) ype CEM III-B ................................................................ 57
Figu e 5. 2 D ying sh inkage de elopmen a 91 days: a) CEM II/AL, b) CEM II/AS, c) CEM
III/B ....................................................................................................................................... 58
Figu e 5. 3 Mass loss de elopmen a 91 days: a) CEM II/AL, b) CEM II/AS, CEM III/B. .... 59
Figu e 5. 4 Sh inkage es ima ion analysis depic ed h ough a ios o a) expe imen al esul s/
nume ical es ima ion SC-BOE and b) expe imen al esul s/nume ical es ima ion EC-02 ....... 61
Figu e 5. 5 The a io o chlo ide ion pene abili y (de e mined in cha ge pass) o all conc e es
wi h espec o maximum alue o 4000 Coulombs: a) 28 days and b) 56 days ...................... 64
Figu e 6. 1 Rela i e comp essi e s eng h a all conc e e ages wi h cemen s: a) Type CEM II/AL,
b) Type CEM II/AS, c) Type CEM III/B ................................................................................ 75
Figu e 6. 2 D ying sh inkage alue de elopmen and mass loss a 91 days and hei s anda d
de ia ion: (a) and (d) CEM II/AL, (b) and (e) CEM II/AS, (c) and ( ) CEM III/B. ................ 77
x ii
Figu e 6. 3 Sh inkage es ima ion (a) expe imen al esul s/nume ical es ima ion (SC-BOE); (b)
expe imen al esul s/nume ical es ima ion (EC-02). ............................................................... 79
Figu e 6. 4 The a io o chlo ide ion pene abili y (de e mined in cha ge passed) o all conc e es
conce ning maximum alue o 4000 Coulombs: a) 28 days and b) 56 days ........................... 81
Figu e 6. 5 Chlo ide con en pe cemen weigh (%) a di e en dep hs o samples: (a) CEM
II/AL, (b) CEM II/AS, (c) CEM III/B. ................................................................................... 82
Figu e 6. 6 Ra io o he non-s eady-s a e di usion coe icien s (Dnss) o RACs wi h espec o
NAC-0.51. .............................................................................................................................. 86
Figu e 6. 7 Ra io o he RAC Kacc o he NAC-0.51 Kacc. .................................................... 87
Figu e 6. 8 En i onmen al condi ions o na u al ca bona ion. ............................................... 89
Figu e 6. 9 Ra io o he RAC Kna o he NAC-0.51 Kna . ..................................................... 90
Figu e 6. 10 Visual compa ison o he ca bona ion dep h in na u al (1 yea ) and accele a ed
condi ions (91 days) o conc e es wi h di e en cemen ypes. .............................................. 92
Figu e 6. 11 Compa ison o he ca bona ion dep h ela i e o exposu e class XC3 o all
conc e es (a) 50 yea s, (b) 100 yea s. ...................................................................................... 94
Figu e 7. 1 Wa e abso p ion (WA) and Accessible po osi y in (a) Phase 1 (e ec i e w/c a io =
0.48) and (b) Phase 2 (e ec i e w/c a io = 0.52) ........................................................... 103
Figu e 7. 2 Rela i e comp essi e s eng h a day 28: (a) Phase 1 (e ec i e w/c = 0.48) and (b)
Phase 2 (e ec i e w/c = 0.52) ...................................................................................... 105
Figu e 7. 3 Comp essi e s eng h a io s To al w/c a io ................................................ 106
Figu e 7. 4 Ra io o he expe imen al alue o he heo e ical alue o he spli ing ensile
s eng h: (a) Phase 1 (e ec i e w/c = 0.48) and (b) Phase 2 (e ec i e w/c = 0.52)............. 109
Figu e 7. 5 Analysis o modulus o elas ici y es ima ion: (a) Ra io o expe imen al
alue/ heo e ical SC-BOE (b) Ra io o expe imen al/ heo e ical EC-02 ............................ 111
Figu e 7. 6 D ying sh inkage alues in Phase 1: (a) D ying sh inkage MRCA1&FMRA1, (b) Mass
loss MRCA1&FMRA1 ................................................................................................... 113
Figu e 7. 7 Rela i e sh inkage a io a day 91: (a) Phase 1 (e ec i e w/c = 0.48) and (b) Phase
2 (e ec i e w/c = 0.52) ................................................................................................ 113
Figu e 7. 8 D ying sh inkage alue in Phase 2: (a) MRCA2 & FMRA2 d ying sh inkage (b)
MRCA2 & FMRA2 mass loss ........................................................................................ 114
Figu e 7. 9 Analysis o sh inkage es ima ion and he a io o expe imen al esul s o heo e ical
es ima es, pe SC-BOE and EC-02, o conc e es p oduced in Phase 1 .............................. 117
Figu e 7. 10 So p i i y alues a day 28: (a) Phase 1 (e ec i e w/c = 0.48) and (b) Phase 2
(e ec i e w/c = 0.52) ................................................................................................... 118
Figu e 7. 11 Rela ionship be ween So p i i y and WA capaci y. ........................................ 119
Figu e 7. 12 Wa e pene a ion unde p essu e: (a) Phase 1 (e ec i e w/c = 0.48) and (b) Phase
2 (e ec i e w/c = 0.52) ............................................................................................... 120

x iii
TABLES:
Table I. 1 Summa y o Publica ions and Scien i ic Con ibu ions ......................................... x
Table 2. 1 Legisla ion on he use o ecycled conc e es agg ega es. ...................................... 9
Table 2. 2 Legisla ion on he use o mixed ecycled agg ega es. .........................................15
Table 3. 1 Composi ion o admix u es as a pe cen age o he o al weigh ........................... 19
Table 3. 2 Composi ion o cemen as a pe cen age o he o al weigh . ............................... 19
Table 3. 3 P ope ies o na u al agg ega es s udied ........................................................... 21
Table 3. 4 Cons i uen s o ype A CRCA-2 (8/20 mm) agg ega es .................................... 22
Table 3. 5 P ope ies o na u al and ype A RCA agg ega es s udied. ................................. 22
Table 3. 6 Clasi ica ion o Type B CMRA-2 (8/20 mm) agg ega es. .................................. 24
Table 3. 7 Physical, mechanical and chemical p ope ies o NA and MRA specimens. ........ 25
Table 3. 8 Conc e e p ope ies analyzed .......................................................................... 26
Table 4. 1 Mix p opo ions o Phase 1 conc e e. All he conc e es we e p oduced wi h an
e ec i e wa e /cemen a io o 0.48. ............................................................................... 32
Table 4. 2 Mix p opo ions o Phase 2 conc e e. All he conc e es we e p oduced wi h an
e ec i e wa e /cemen a io o 0.52 ................................................................................ 33
Table 4. 3 Physical p ope ies o conc e es p oduced in he labo a o y ............................... 34
Table 4. 4 Comp essi e s eng h in all conc e es. ............................................................. 36
Table 4. 5 Spli ing Tensile s eng h and Modulus o elas ici y .......................................... 39
Table 5. 1 Mix p opo ions o conc e es we e p oduced wi h CEM IIAL, CEM IIAS and CEM
IIIB ............................................................................................................................. 54
Table 5. 2 Comp essi e s eng h and i s s anda d de ia ion (be ween b acke s alues) in all
p oduced conc e es. ...................................................................................................... 55
Table 5. 3 Chlo ide ion pene abili y and he s anda d de ia ion (desc ibed in b acke s)
de e mined in Cha ge pass in coulombs. ......................................................................... 63
Table 5. 4 Ca bona ion dep h, hei s anda d de ia ion, and he accele a ed and heo ical na u al
ca bona ion coe icien o all conc e es ........................................................................... 65
Table 5. 5 Ca bona ion dep h a e li espan o 50 and 100 yea s. ....................................... 67
Table 6. 1 Mix p opo ions o conc e es we e p oduced wi h CEM II/AL, CEM II/AS and CEM
III/B ............................................................................................................................ 72
Table 6. 2 Comp essi e s eng h and i s s anda d de ia ion ( alues in b acke s) in all o he
p oduced conc e e. ........................................................................................................ 73
Table 6. 3 Chlo ide ion pene abili y and s anda d de ia ion as de e mined in cha ge passed in
coulombs. .................................................................................................................... 80
Table 6. 4 Chlo ide concen a ion a he conc e e su ace (Cs) and non-s eady s a e di usion
coe icien (Dnss). ........................................................................................................ 84
xix
Table 6. 5 Ca bona ion dep h and accele a ed ca bona ion coe icien o all conc e e .......... 85
Table 6. 6 Ca bona ion dep h and na u al ca bona ion coe icien o all conc e e ................ 90
Table 6. 7 Rela ionship be ween Na u al Ca bona ion and Accele a ed Ca bona ion in Conc e es
wi h NA and RCA ........................................................................................................ 91
Table 6. 8 Ca bona ion dep h a e li espan o 50 and 100 yea s. ....................................... 93
Table 7. 1 Mix p opo ions o he Phase 1 conc e es. All conc e es we e p oduced wi h an
e ec i e wa e - o-cemen a io o 0.48 ......................................................................... 100
Table 7. 2 Mix p opo ions o he Phase 2 conc e es. All conc e es we e p oduced wi h an
e ec i e wa e - o-cemen a io o 0.52. ......................................................................... 100
Table 7. 3 Physical p ope ies o conc e es p oduced in he labo a o y. ............................ 102
Table 7. 4 Comp essi e s eng h o all conc e es p oduced (inc ease in comp essi e s eng h in
%) ............................................................................................................................. 104
Table 7. 5 Spli ing ensile s eng h and modulus o elas ici y (MRAC/NAC a io) ............ 108
xx
Chap e 1
1
1. Chap e 1. In oduc ion
1.1. Resea ch Scope
The cons uc ion indus y aces signi ican sus ainabili y challenges, exace ba ed by he
in ensi e consump ion o na u al esou ces, subs an ial CO₂ emissions, and he ex ensi e gene a ion
o cons uc ion and demoli ion was e (CDW), which impac s he en i e li ecycle o building
ma e ials om p oduc ion o disposal. These challenges a e d i en by inc easing u baniza ion and
cons uc ion ac i i ies demanding as amoun s o sand and g a el—non- enewable esou ces whose
o e exploi a ion has led o se e e en i onmen al issues. Mo eo e , go e nmen es ic ions on
esou ce ex ac ion a e c ea ing supply sho ages and escala ing ma e ial cos s, unde sco ing he
u gen need o mo e sus ainable al e na i es [1,2].
Conc e e manu ac u ing, which p edominan ly uses cemen and na u al agg ega es, signi ican ly
con ibu es o esou ce deple ion, pollu ion, and a high ca bon oo p in , highligh ing he c i ical
need o sus ainable p ac ices wi hin he sec o [3,4]. Cemen , as he p ima y binding ma e ial,
cons i u es app oxima ely 13% o conc e e’s weigh and ypically 10–15% o he o al olume o a
conc e e p oduc [5,6], wi h agg ega es comp ising 70 o 80% o he olume o conc e e. The
educ ion o o dina y Po land cemen con en and he eplacemen o na u al agg ega es wi h
ecycled agg ega es in conc e e p oduc ion ep esen inno a i e echnologies ha ha e ga ne ed
conside able in e es in he cons uc ion indus y, pa icula ly due o he g owing ocus on
sus ainabili y [1,3].
While he use o coa se ecycled conc e e agg ega e (CRCA) has been ex ensi ely explo ed and
ecommended in a ious coun ies due o i s bene i s in s uc u al conc e e p oduc ion, he
in eg a ion o ine ecycled conc e e agg ega e (FRCA) has been limi ed. This limi a ion is a ibu ed
o he ad e se e ec s ha FRCA can ha e on he p ope ies o bo h esh and ha dened conc e e,
which ha e es ic ed i s use in s uc u al applica ions [7–9]. Despi e he known challenges
associa ed wi h ecycled agg ega es, he e a e issues such as a iabili y in composi ion and
pe o mance ypically lowe han ha o na u al agg ega es due o issues like mic o-c acks and old
mo a adhesion [2]. Eu ope, and pa icula ly Spain, shows a subs an ial o al consump ion o na u al
agg ega es; app oxima ely 2.7 billion onnes annually ac oss Eu ope and 136.9 million onnes in
Spain speci ically o cons uc ion pu poses [10]. Howe e , he u iliza ion o ecycled agg ega es
emains limi ed, eaching only 3.5 million onnes in 2021 [11]. In esponse, he e is an inc easing
in e es wi hin he indus y in employing bo h ine and coa se ecycled conc e e agg ega es (RCA)
and mixed ecycled agg ega es (MRA) in conc e e p oduc ion [12,13], which is c ucial o educing
he en i onmen al impac o CDW, which cons i u es abou one- hi d o o al was e gene a ed in he
Eu opean Union [14,15]. Recycling CDW can p e en 1.4 imes he emissions o disposal scena ios
and sa e up o 85 imes he ene gy consump ion [16].
Chap e 2
8
Spain, as OFICEMEN [23] and ANEHOP [24] s a ed 14.93 million ons o cemen and 25.8 million
m3 o conc e e we e consumed in 2021. Addi ionally, ANEFA [25] desc ibed ha o al na u al
agg ega e (NA) consump ion o cons uc ion eached 136.9 million ons o e he same pe iod.
Fu he mo e, in 2018, o he equi alen o 2277 million ons o cons uc ion and demoli ion was e
(CDW) accoun ed 35.4 % o o al was e gene a ed in he EU [26,27]. The e o e, i is impe a i e o
educe he olume o na u al esou ces consumed and inc ease he use o ecycled agg ega es
p oduced om ea ed CDW.
The guidelines o he Eu opean Commission [28] encou age assuming a ci cula and sus ainable
model inco po a ing was e in o p oduc ion p ocesses o educe aw ma e ial and o e -exploi a ion.
In addi ion, many ins i u ions a e de eloping an EU-wide sus ainable policy o ackle clima e change
[17]. P ojec s in F ance, such as RECYBETON [18] and he Pa is P o ocol [19], ha e de eloped
ecommenda ions o he use o ecycled conc e es agg ega es (RCA) in s uc u al and non-s uc u al
conc e es. Al hough he use o RCA in s uc u al conc e e p oduc ion has a posi i e en i onmen al
impac [29,30], ecycled agg ega e conc e e (RAC) mus mee all s uc u al conc e e code
equi emen s o ensu e i s sa e y and du abili y as a s uc u al ma e ial [31].
RCA, p oduced by c ushing o iginal conc e e, has highe po osi y, lowe densi y, mo e ab asion
loss, and mo e c ushabili y han NA due o i s a ached mo a . RCAs made using e en high-quali y
RCA, always exhibi a ia ion in esh and ha dened p ope ies compa ed o NAC [29,31–37].
Adhe ed mo a a ached o RCA a ec s he mechanical and du abili y p ope ies o RAC [38–40].
The p oduc ion o RAC wi h coa se RCA (CRCA) has been b oadly s udied [33,41–44].
Howe e , i is known ha be ween 30 % and 50 % o he RCA p oduced in he ecycling p ocess a e
ine agg ega es (FRCA) [45]. Plaza e al.[46] concluded ha using CRCA and FRCA ins ead o NA
no only educes CO2 emission in conc e e manu ac u e bu also mi iga es en i onmen al impac s
caused by s ockpiling was e. The e o e, he demand on using FRCA in conc e e s uc u es is high,
bu in compa ison o ine NA s ic e quali y con ol is necessa y [47]. In addi ion, he lack o well-
de eloped quali y con ol guidelines limi s i s wide use. Due o he g owing need o in oduce FRCA
and inc ease he eplacemen pe cen ages o CRCA, some coun ies ha e enac ed legisla ion
limi ing he use o RCA.
Table 2. 1 shows, acco ding o di e en s anda ds, he limi a ions o he ype A- RCA o be used
in s uc u al conc e e. Type A-RCAs a e classi ied acco ding o size (CRCA and FRCA) and
physical p ope ies (densi y and abso p ion). The maximum pe cen age allowed o be eplaced o
na u al agg ega es o conc e e p oduc ion and conc e es s eng h a e also desc ibed. The Spanish
S uc u al Conc e e Code (SC-BOE) [20] allows o a maximum o 20% eplacemen o CRCA o
conc e e wi h a s eng h class o C40/50. The s uc u al conc e e s anda ds o Belgium, I aly,
Po ugal, F ance and Swi ze land allow he use o di e en pe cen ages o CRAC in a speci ic ype
o conc e e [26,48]. The UK s anda d limi s bo h CRCA and FRCA ac ions o 20% o conc e e
class C40/50 p oduc ion. The s anda d equi emen s in China, Japan, and Denma k accep conc e e
p oduc ion wi h 100% CRCA and FRCA when RAC achie ed speci ic ha dened s a e p ope ies, and
he RCA was also o a high quali y [26,48]. Acco ding o UNE EN 206 (Fu u e changes) [18,49],
he use o FRCA oge he wi h CRCA will be allowed in conc e e p oduc ion, gi en speci ic

Chap e 2
9
limi a ions on exposu e classes. The Eu ocode 2 (EC-02) [50] allows o up o 40% eplacemen o
he o al olume o agg ega es using Type-A (FRCA and CRCA) ecycled agg ega es.
Table 2. 1 Legisla ion on he use o ecycled conc e es agg ega es.[18,20,48,49]
Coun y
Agg ega e
ype A
Max.
eplacemen
(%)
F ac ion
S eng h
class
Densi y
(kg/m3)
Abso p io
n (%)
S uc u al Conc e e Code
(SC-BOE)
RCA
20
CRCA
C40/50
-
7
Belgium PTV 406–
2003/ NBN B 15–001
RCA
50,30,20*
C30/37
2100
9
I alyNTC-2008
RCA 1
RCA 2
30
60
15
CRCA
C30/37
C25/30
C45/55
-
-
Po ugal LNEC - E471
RCA 1
25
CRCA
C40/50
2200
7
F anceNP 15-545
RCA 1
60.30,20
CRCA
No limi
-
-
RCA 2
40,15
-
Swi ze landMB -2030
RCA 1
100
CRCA
Ou doo ≥
25/30
-
-
China GB/T-2573
RCA-Type1
100
CRCA
No limi
2450
3
RCA-Type2
30
CRCA
C40/50
2350
5
RCA-Type3
30
CRCA
C25/30
2250
8
RCA-Type1
100
FRCA
C40/50
2450
3
RCA-Type2
30
FRCA
C25/30
2350
5
Uni ed KingdomBS 8500-
2
RCA
20
CRCA+
FRCA
C40/50
2200
-
Japan JIS-5021/ JIS-5022
RCA-HQ
100
CRCA+
FRCA
C45/55
2500
3(C)
3.5(F)
RCA-MQ
100
CRCA+
FRCA
C35/45
2300(C)
2200(F)
5(C)
7(F)
Denma k DS 2426/DCA
No.34
RCA 1
100
CRCA
C40/50
2200
n.a
RCA 2
100
CRCA+
FRCA
C40/50
2200
n.a
UNE EN 206
RCA
50,30
CRCA
No limi
-
-
UNE EN 206
(Fu u e changes)
RCA
60,50,40,30
CRCA
No limi
-
-
30,20,10
FRCA
-
-
The Eu ocode 2 (EC-02)
RCA
401
CRCA+
FRCA
No limi
-
-
1Replacemen o he o al olume o agg ega es
No es: The alues a e o RCA ( ecycled conc e e agg ega e). HQ: high quali y. MQ medium quali y.
All o he s anda ds lis ed in he able apply o s uc u al conc e e. *Replacemen a io by exposu e class
Chap e 2
10
Due o he g ea e amoun o old mo a and esidual cemen pa icles in FRCA in compa ison
o CRCA, some hesi a ion pe sis s ega ding he simul aneous inco po a ion o FRCA in s uc u al
conc e e applica ions [44,51]. Fu he mo e, FRCA has a much highe wa e abso p ion capaci y (6–
12 %) han na u al sand (0.5–2.7 %) [37]. Despi e hese weaknesses, he un-hyd a ed cemen o he
o iginal conc e e a ailable in RCA may play a posi i e ole in i s use in s uc u al conc e e.
Addi ionally, he speci ic su ace o RCA agg ega es imp o es he binde / ecycled agg ega e
in e ace [52,53].
CRCA and FRCA (Type-A ecycled conc e e agg ega e) exhibi s highe po osi y han na u al
agg ega es (NAs) due o adhe ed mo a and mic o-c acks ha o m du ing c ushing. Thus, he wa e
abso p ion capaci y inc eases, a ec ing he amoun o wa e a ailable o mixing. This can lead o
issues ela ed o he loss o he conc e e’s wo kabili y in i s esh s a e and a decline in he mechanical
and du abili y p ope ies in he long e m [47,54,55]. RAC conc e e is ypically associa ed wi h lowe
wo kabili y han NAC conc e e o he same composi ion [56]. A e an exhaus i e e iew and
analysis o he wo kabili y o RAC p oduced wi h FRCA, Nedeljko ić e al. [57] concluded ha
esea che s had o e ed many easonable explana ions o he complex low beha iou o RAC
h ough a combina ion o expe imen s and heo ies. Howe e , hey desc ibed no uni e sal app oach
o ob aining and main aining sa is ac o y wo kabili y o mo a s/conc e es wi h FRCA.
Unde s anding he di e ences be ween na u al agg ega e conc e e (NAC) and RAC is he basic
p emise o u he s udying he beha iou o RAC ma e ials and s uc u es [58].
I is gene ally belie ed ha he comp essi e s eng h o RAC dec eases as he amoun o RCA
eplacemen inc eases [59], which makes conc e e mo e po ous and less dense [60]. Howe e , RAC
p oduced using up o 30 % CRCA and 20 % FRCA has achie ed simila comp essi e s eng h as
NAC [51,61]. Gao and Wang [62] desc ibed a comp essi e s eng h dec ease when a highe
pe cen age o FRCA was employed in conc e e p oduc ion. Some esea che s sugges ha conc e e
p oduced using up o 30 % FRCA as a eplacemen o na u al sand achie es adequa e p ope ies
[63,64]. Lei e and San ana [53] de e mined ha conc e es p oduced wi h 20 % and 40 % FRCA and
100 % coa se NA achie ed a simila comp essi e s eng h o 41.3 MPa and 39.5 MPa, espec i ely.
Se e al esea che s ha e also desc ibed ha conc e es p oduced wi h up o 50 % FRCA achie ed
adequa e p ope ies [44,65]. In addi ion, Sim and Pa k [66] de e mined ha RAC p oduced wi h up
o 60 % FRCA in subs i u ion o na u al sand and 100 % CRCA could achie e a comp essi e design
s eng h o 40 MPa. Howe e , using 100 % FRCA caused a s eng h dec ease o 33 %, which was
simila o esul s ob ained by o he esea che s [46,57,64,67]. Ne e heless, acco ding o Be edjem
e al. [68], conc e e p oduced wi h 100 % CRCA and FRCA achie ed a comp essi e s eng h o o e
25 MPa.
Howe e , he ensile s eng h o conc e e p oduced wi h CRCA and FRCA can be imp o ed,
wi h espec o NAC, due o he imp o emen o he in e ace ansi ion zone in conc e es con aining
RCA [46]. In con as , some esea che s [53,59,62,69] ha e epo ed ha he spli ing ensile s eng h
dec eases when FRCA is employed and ha he d op inc eases wi h a highe pe cen age o FRCA.
The elas ic modulus o RAC is lowe han ha o NAC and dec eases as he RCA eplacemen
pe cen age inc eases due o he inc eased amoun o a ached mo a [41,70]. Chen e al. [71]
de e mined ha RAC p oduced wi h 20 % o 100 % CRCA and na u al i e sand su e ed a dec ease
Chap e 2
11
in modulus elas ici y o 10.8 % o 16.4 %. Acco ding o Bendime ad e al. [31], he use o 30 % FRCA
and na u al g a els achie ed a simila alue o he elas ic modulus as conc e e p oduced wi h a
100 % eplacemen o CRCA.
The du abili y o RAC is in luenced by he in e ac ion be ween wo main ac o s. On he one
hand, he imp o emen in he in e acial ansi ion zone (ITZ) be ween he RCA pa icles and he
new mo a can con ibu e o inc eased du abili y. On he o he hand, he highe po osi y o RCA
ends o inc ease he o al po osi y o he conc e e, which may educe i s du abili y. Whe he he
e ec s o an imp o ed ITZ o inc eased po osi y p edomina e will explain he enhanced o
diminished du abili y pe o mance o RAC compa ed wi h NAC [72]. Fu he mo e, a ia ions in he
wa e - o-cemen a io and he ype o cemen used signi ican ly impac he du abili y o RAC.
Limi ed in es iga ions ha e been ca ied ou s udying he du abili y cha ac e is ics o conc e e
made wi h ine ecycled conc e e agg ega e (FRCA) and coa se ecycled conc e e agg ega e (CRCA)
[40,46,51,64,68]. Howe e , i is known ha , in gene al, he du abili y o RAC is lowe han he
du abili y o NAC conc e e because du abili y is in luenced by he connec i i y o he po ous
ne wo k, wa e con en he ype o supplemen a y cemen i ious ma e ials (SCM) used
[40,44,68,73,74].
The po osi y o RAC ises wi h an inc ease in he eplacemen a io o RCA, and i inc eases
e en mo e when FRCA is employed [75]. Acco ding o Limbachiya [76], he e is a sligh e ec in
du abili y when he RCA eplacemen o NA < 30 %. Howe e , he use o CRCA and FRCA
inc eased he abso p ion capaci y o conc e e [59]. Acco ding o Co eia e al. [7], he wa e capilla y
abso p ion capaci y o RAC was g ea e han NAC, and i was signi ican ly highe when CRCA and
FRCA we e used [8]. Zhao e al. [77] e iewed key du abili y indices and es ing me hods,
emphasizing he impo ance o chlo ide di usion and eeze- haw esis ance. Simila ly, Bu e al.
[78] in es iga ed he e ec s o ecycled ine agg ega es on pe meabili y and ca bona ion esis ance,
unde sco ing ha adjus men s o he wa e –cemen a io can enhance he du abili y o RAC. The
co osion o ein o cemen is a majo and complex pa hology a ec ing ein o ced conc e e s uc u es
[79]. The ein o ced conc e e used in ma ine in as uc u es such as b idges and pie s is ulne able
o chlo ide-induced co osion, which sho ens i s se ice li e [80,81]. Seawa e chlo ides pene a e
he conc e e, causing signi ican damage when le els exceed a c i ical h eshold, which is measu ed
using chlo ide p o iles a a ious dep hs [82].
Mo eo e , SCMs such as blas u nace slag (BFS) can enhance he sus ainabili y o RAC by
lowe ing ca bon dioxide emissions and p omo ing ci cula economy bene i s, po en ially o se ing
some o RAC's du abili y limi a ions by imp o ing i s o e all en i onmen al impac [83,84].
The use o s uc u al RAC in chlo ide-con aining en i onmen s has spa ked deba e among
esea che s [12]. Some au ho s indica e ha he inc ease in RCA con en could lead o a highe
di usion o chlo ides in RAC due o i s high po osi y [85,86]. Howe e , some s udies ha e also
demons a ed ha by educing he amoun o adhe ed cemen mo a s, he esis ance o RAC o
chlo ide ion pene a ion can be imp o ed, pa icula ly when RCA o igina es om highe -s eng h
conc e e [87]. The pene a ion o chlo ide ions is a majo con ibu o o he co osion o s eel
ein o cemen s. The esul s o nume ous s udies [9,44,88–91] conduc ed on his opic ha e e ealed
Chap e 2
12
he ollowing: he di usion coe icien o chlo ide ions exhibi s a linea inc ease wi h he
p opo ional inc ease o ecycled agg ega e use; FRCA in luences mo e han he CRCA in conc e e
di usion coe icien s; and, simila o NAC, chlo ide ion mig a ion can be educed by dec easing he
wa e - o-binde a io o inco po a ing SCM such as ly ash, silica ume o blas u nace slag (BFS)
[44]. Ki hika and Singh e al. [92] obse ed ha using up o 30% FRCA demons a ed an
imp o emen in esis ance o chlo ide pene a ion compa ed wi h NAC. Acco ding o Li e al. [85],
ollowing he ASTM C1202 classi ica ion, while he conc e e p oduced wi h up o 50% o RCA
achie ed low chlo ide ion pene abili y, he RAC p oduced wi h a highe pe cen age han 50% was
classi ied wi h medium pene abili y, consequen ly needing he use o SCM o imp o e he esis ance
o chlo ide ion pene a ion. As con i med, BFS cemen enhances chlo ide pene a ion esis ance in
conc e e due o i s abili y o immobilize chlo ide ions [93,94]. This enhancemen is achie ed h ough
physical and chemical mechanisms, h ough chlo ide ion adso p ion on he C-S-H su ace [93] and
he o ma ion o F iedel's sal due o he highe alumina e con en in he BFS cemen [93,94].
Resea che s [72,95] ha e indica ed ha he in luence o RCA on chlo ide pene a ion esis ance is
signi ican ly lowe han ha o ac o s such as he w/ a io and he use o SCMs.
Ca bona ion in conc e e is a c i ical phenomenon ha signi ican ly a ec s he du abili y and
li espan o conc e e s uc u es. Ca bona ion in conc e e is a physicochemical p ocess in which CO2
pene a es he cemen pas e and eac s wi h Po landi e, o ming calci e and educing he conc e e
pH om 13 o 8-9. The ca bona ion a e is in luenced by he pe meabili y and mois u e con en o
he conc e e [40,44]. As a esul o ca bona ion, s eel ein o cemen loses i s p o ec ion, and
co osion begins when adequa e oxygen and wa e le els a e p esen [44].
Ex ensi e esea ch has been conduc ed on he ca bona ion esis ance analysis o RAC
[79,88,96,97]. Acco ding o he li e a u e [9,79,98,99], he ca bona ion dep h o RAC inc eases wi h
he le el o na u al agg ega e eplacemen . Di e en ac o s can in luence he ca bona ion dep h o
he RAC. These ac o s include he eplacemen a io o ecycled agg ega es, he o igin and quali y
o he RCA, he c ushing echnique employed o RCA p oduc ion, he cemen ype and quan i y
used in conc e e p oduc ion, he cu ing p ocess, and he use o supe plas icise s o educe he wa e -
cemen a io [44,74,99]. Conclusions ega ding he impac o RCA on he ca bona ion esis ance o
conc e e can be ambiguous and con lic ing. Acco ding o Ped o e al. [100], he ca bona ion dep h
inc eases as he conc e e's comp essi e s eng h dec eases. Ce ain esea che s [73,99] ha e a gued
ha RAC mix u es p oduced wi h coa se CRCA exhibi simila o e en highe ca bona ion esis ance
han NAC due o aged adhe ed mo a . Zeng e al. [101] sugges ed ha he op imal eplacemen
pe cen age o na u al agg ega es (NAs) wi h RCA is 50%, which p e en s a dec ease in ca bona ion
esis ance. E xebe ia e al. [97] also eached a simila conclusion when employing a 50%
eplacemen o unca bona ed CRCA. Lo i e al. [89] ound ha RAC p oduced wi h up o 50% coa se
RCA me he cu en Eu opean s anda ds, hus suppo ing i s use in s uc u al applica ion when up
o 50% o CRCA is employed in conc e e p oduc ion. E angelis a and B i o e al. [9] no ed ha
conc e e p oduced wi h he o al eplacemen o ine NA wi h FRCA showed low ca bona ion
esis ance. Howe e , he use o up o 30% FRCA and he use o SCM ( ly ash) wi h a highe
pe cen age o FRCA esul ed in adequa e p ope ies o s uc u al conc e e. In addi ion, despi e
RCA’s highe po osi y, he adhe ed mo a p o ides addi ional eac i e con en agains CO2, which
Chap e 2
13
can enhance ca bona ion esis ance [102]. Howe e , Ped o e al. [103] de e mined ha when he
quali y o mo a adhe ed o RCA was lowe han ha o a new cemen pas e, he ca bona ion a e
inc eased as highe p opo ions o RCA we e used o eplace na u al agg ega es. Howe e , mo e
in es iga ion is needed o e alua e he in luence o FRCA ecycled agg ega es on ca bona ion
esis ance and, in gene al, on conc e e du abili y.
Fu he mo e, i was also demons a ed [76,79,104,105] ha RAC using up o 50% CRCA, wi h a
educ ion in he e ec i e wa e –cemen a io wi hou inc easing cemen amoun , could achie e he
same s eng h and ca bona ion dep hs as NAC, using supe plas icize s o p ese e wo kabili y.
Mo eo e , wi h simila comp essi e s eng h o ha o NAC, RAC showed lowe ca bona ion han
NAC when 20–50% eplacemen was applied [106].
In o de o e alua e he ca bona ion a e o conc e e, besides conside ing i s wa e - o-cemen
a io and comp essi e s eng h, he employed cemen ype and addi i es, such as ly ash o slag,
mus be conside ed [107–110].
Fu he mo e, he se ice li e o conc e e s uc u es agains ca bona ion s ongly depends on he
ype o cemen used in conc e e p oduc ion [110,111]. The ca bona ion dep h o conc e e mix u es
p oduced using SCM was highe due o he educ ion o Po landi e du ing cemen hyd a ion,
educing Ca a ailabili y [109,111] and, consequen ly, causing less esis ance o ca bona ion. Al hough
SCMs educe alkali ese e usually leads o a educ ion in po e size, hey can dec ease he
pe meabili y o cemen i ious ma ices [112]. Howe e , ca bona ion no only lowe s he o e all pH
bu may also esul in he coa sening o he po e s uc u e, po en ially diminishing i s du abili y and
suscep ibili y o a ious o ms o deg ada ion, including chemical and physical a acks [109].
Consequen ly, he ca bona ion conc e e's se ice li e dec eases as mo e SCM is used o eplace
clinke [110,113,114]. Howe e , using limi ed mine al admix u es in RAC p oduc ion can imp o e
ca bona ion esis ance. The RCA p oduced using CEM IIAS achie ed a highe ca bona ion
esis ance han ha p oduced wi h CEM IIAL due o he addi ion o a ailable CaO in he slag cemen .
In addi ion, he use o up o 50% o CRCA had li le in luence on he ca bona ion dep h [115].
In addi ion, he highe d ying sh inkage alue o ecycled agg ega e conc e e (RAC) han ha o
na u al agg ega e conc e e (NAC) is due o he p esence o adhe ed mo a and po ous ma e ial in
RCA [116]. The sh inkage alue also depends on a ious ac o s, including he comp essi e s eng h,
en i onmen al condi ions, and he p ope ies o cemen and addi ions [117]. Ea ly s age sh inkage is
pa icula ly c i ical as i con ibu es subs an ially o he inal sh inkage magni ude, ele a ing he isk
o c acking in he la e s ages o conc e e’s li ecycle [118,119]. Fu he mo e, he sh inkage inc eases
when a highe pe cen age o RCA is employed [120–122]. Gonzalez and E xebe ia [123] s udied he
d ying sh inkage o RACs p oduced using CRCA wi h di e en o igins. They concluded ha he
CRCA p oduced om a lowe -s eng h pa en conc e e achie ed he highes d ying s eng h
alue.Resea ch by Domingo-Cabo e al. [124] e ealed ha RAC RAC) exhibi s d ying sh inkage
simila o na u al agg ega e conc e e (NAC) when using a 20% eplacemen a io o ecycled
conc e e agg ega es (RCA). Howe e , wi h inc easing eplacemen a ios o 50% and 100%, d ying
sh inkage in RAC inc eases by 20% and 70% espec i ely. Acco ding o Zhang e al. [125], he o al
eplacemen o NA wi h RCA ( ine and coa se) inc eased he d ying sh inkage by mo e han 100 %

Chap e 2
14
(102.0 %–116.9 %). The inc ease in he RAC sh inkage alue is due o he high wa e abso p ion o
RCAs, which a e po ous and con ain old cemen pas e [44]. Vin imilla and E xebe ia [126]
de e mined ha all conc e es wi h up o 60% CRCA achie ed sh inkage alues simila o NAC. In
addi ion, hey concluded ha he use o FRCA inc eased he sh inkage alue when compa ed o
conc e e made only wi h CRCA. Ne e heless, he conc e es p oduced wi h up o 60% CRCA and
20% FRCA also ob ained adequa e alues anging up o -800µε, ollowing Ame ican Conc e e
Ins i u e (ACI) s anda ds [122]. Simsek e al. [127] conduc ed a s udy o e alua e he in luence o
using 20%, 40%, 60%, 80%, and 100% FRCA o CRCA in he subs i u ion o na u al agg ega es.
They concluded ha a e 90 days, he RAC wi h up o 20% FRCA achie ed adequa e p ope ies.
Mo eo e , se e al ecen s udies [126,128] ha e con i med he exis ence o a sligh in luence o
FRCA on s uc u al conc e e pe o mance, howe e no being de imen al and consequen ly
echnically iable o hei use. Recen s udies con i med he easibili y o using FRCA in s uc u al
conc e e wi h a minimal impac on o e all pe o mance [126,128].
The ype o cemen used in conc e e p oduc ion also in luences he d ying sh inkage alue. I
has been de e mined ha conc e es p oduced using Po land clinke -based cemen ha e e y high
s eng h, inc eases he hyd a ion hea and as a consequence, leads o highe d ying sh inkage [129].
In con as , he ea ly-s age sh inkage caused in SCM cemen signi ican ly con ibu es o inal
sh inkage, aising he isk o conc e e c acking in la e s ages [118,119].
2.3. Mixed Recycled Agg ega e (MRA-Type B)
In esponse o sus ainabili y conce ns, he cons uc ion indus y has de eloped a s ing in e es
in using ine and coa se mixed ecycled agg ega es (MRA) in he p oduc ion o conc e e [12,13].
Cons uc ion and demoli ion was e (CDW), a majo sou ce o ecycled agg ega e (RA), cons i u es
app oxima ely one- hi d o he o al was e gene a ed in he Eu opean Union [14,15]. Howe e , RA
consump ion in Spain is limi ed, eaching only 3.5 million onnes in 2021 [11]. The use o MRA in
cons uc ion is c i ical o lowe ing he en i onmen al impac o CDW [15], as 70% o he olume o
CDW is classi ied as mixed CDW- he p ima y aw ma e ial used o p oduce MRA [11]. Acco ding
o EN 933-11, ype B MRAs consis o mason y-based ma e ial, wi h ce amic pa icles comp ising
less han 30% by mass and Po land cemen -based agmen s comp ising less han 90% by mass [15].
Cu en esea ch indica es ha mos Eu opean coun ies ha e no enac ed legisla ion egula ing
he use o MRA in s uc u al conc e e. Consequen ly, MRA is p ima ily used o low-u ili y
pu poses, such as landscaping and pa ing [26]. This si ua ion can be explained by inadequa e
s anda ds o speci ica ions, as well as a lack o in-se ice e idence, insu icien inancial incen i es
and go e nmen suppo , and he no ion ha conc e e made wi h RA has less desi able p ope ies
han NA conc e e (NAC) [26,130].
The use o MRA in s uc u al conc e e design needs o be add essed in na ional and in e na ional
conc e e codes and s anda ds (Table 2. 2). Design egula ions ha e been es ablished o non-
s uc u al conc e e in he C20/25 o C30/37 s eng h classes, and he cu en egula ions pe mi he
use o 5% o 50% coa se MRA (CMRA) and up o 20% ine MRA (FMRA) in eplacemen o na u al
Chap e 2
15
agg ega es, depending on he quali y, design s eng h, and exposu e class. DIN 4226-100 [130]
s ipula es limi s o 15% o wa e abso p ion capaci y and 0.5% o he composi ion o con aminan s
in ype B MRA. To al eplacemen o coa se NA is pe mi ed only in non-s uc u al conc e e in
Swi ze land and Denma k, while a 100% eplacemen a io −wi h a design s eng h o C25/30− in
s uc u al applica ions is allowed in Aus alia, and eplacemen is limi ed o 35% in C30/37 conc e e
in Ge many. Fu u e UNE EN 206 speci ica ions [131] will allow FMRA in combina ion wi h CMRA,
subjec o speci ic limi a ions pe exposu e class. The Spanish s uc u al conc e e code (SC-BOE)
[20] does no pe mi he use o MRA- ype B
Table 2. 2 Legisla ion on he use o mixed ecycled agg ega es. [26,46,132,133]
Coun y
Agg ega e
Type B
Max.
eplacemen
(%)
F ac ion
S eng h
class
Densi y
(kg/m3)
Abso p ion
(%)
UNE EN 206/EN 12620
MRA
50,30*
Coa se
C30/37
≥1700
-
Belgium PTV 406–2003/
NBN B 15–001
MRA-Type B
20
Coa se
C20/25
(N.S)
1900
≥1600
9
≤ 18
Po ugal LNEC - E471
MRA
20
Coa se
C35/45
≥2000
7
RILEM
RMA
20
Coa se
No Limi
≥2400
≤ 3
F anceNP 15-545
MRA
30,5
Coa se
No limi
-
-
Ge manyDIN 4226-101,
DA S b
MRA-Type B
35,25*
Coa se
C30/37
≥2000
≤ 15
Aus aliaAS 1141.62/HB
155:2022
MRA (Class
1B)
100
Coa se
C25/30
≥1800
≤ 8
Swi ze landMB -2030
MRA
100
Coa se
(N.S)
Ou doo ≥
25/30
n.a
n.a
No way (NS EN
12620:2008) RESIBA
(2002)
RMA
≥1500
≤ 20
Denma k DS 2426/DCA
No.34
MRA
100
20
Coa se
Fine
C20/25
(N.S)
≥1800
n.a
B azil (NBR 15.116)
MRA
20
Coa se/
Fine
(N.S)
n.a
n.a
≤ 12
≤ 17
Japan (JIS A 5021, JIS A
5022, JIS A5023)
RMA
n.a
Coa se
(N.S)
n.a
≤ 7
Low quali y
Fine
(N.S)
n.a
≤ 13
UNE EN 206
(Fu u e changes)
MRA
40,30,25,20,
15*
15,10,5*
Coa se
Fine
C30/37
-
-
N.S.: non-s uc u al * Replacemen a io pe exposu e class. n.a: No A ailable
Chap e 2
16
Ce amic pa icles and he a ached mo a in cemen pas e cons i u e he p ima y ac o s ha
de e mine he wa e abso p ion (WA) capaci y o MRAs. The high WA o MRA makes i di icul
o con ol he e ec i e wa e - o-cemen a io in cemen pas e [134,135] and he wo kabili y o
conc e e. Se e al esea che s [41,136] desc ibed ha he e ec i e abso p ion capaci y o RAs is
a ound 70% o hei abso p ion capaci y, equi ing ha amoun o wa e be added o he mixe a
conc e e p oduc ion. Mo eo e , E xebe ia e al. [41] ecommend using RA wi h high humidi y (a
70−80% o hei abso p ion capaci y) o con ol he e ec i e wa e -cemen a io, wo kabili y and
ha dened p ope ies.
Se e al s udies ha e in es iga ed he impac o using MRA in eplacemen o NA on he physical,
mechanical and du abili y p ope ies o ecycled agg ega e conc e e (RAC) [15,55,137–141].
Acco ding o Can e o e al. [142], he e ec i e po osi y o conc e e p oduced wi h MRA (MRAC)
inc eases linea ly wi h an inc ease in he con en a io o he CMRA in he conc e e; NAC achie ed
7.5% po osi y, while MRAC p oduced using 20% and 100% CMRA achie ed 9.5% and 15.7%
e ec i e po osi y, espec i ely. Mas e al. [143], Can e o e al. [144] and E xebe ia and Vegas [145]
epo ha MRAC can achie e up o 26% highe WA capaci y han NAC.
Se e al s udies ha e de e mined ha MRAC can achie e mechanical p ope ies (e.g.,
comp essi e s eng h and lexu al s eng h) and du abili y p ope ies simila o hose o NAC
[137,146,147]. Can e o e al. [148] epo ed ha conc e e wi h up o 50% CMRA achie ed
comp essi e and lexu al s eng h simila o ha o NAC; howe e , a 7% dec ease was obse ed
when 100% CMRA was employed. Medina e al. [149] obse ed ha conc e e p oduced wi h 25%
and 50% CMRA achie ed a 15–20% lowe s eng h han NAC and hus concluded ha up o 50%
CMRA is accep able o housing cons uc ion. None heless, i is ecommended ha he eplacemen
a e o CMRA, when used in building s uc u es, should no exceed 30% [146,150]. The cu en
li e a u e sugges s ha signi ican educ ions in s eng h p ope ies a e highly p e alen when
inco po a ing ine RAs in o conc e e [151]. Mo ales e al. [152] demons a e ha hollow conc e e
blocks p oduced wi h 50% and 100% MRA (0/8mm) achie e 27.03% and 42.65% lowe comp essi e
s eng h han con en ional blocks. Meng, Wei, and Yang [150] epo ha MRAC p oduced wi h
100% ine and coa se MRA, using di e en w/c a ios, achie ed a 50% lowe comp essi e s eng h
and 24.8% o 55.5% lowe ensile s eng h han NAC a 28 days o cu ing. Fine ac ions con ain
highe cemen mo a amoun s han coa se ac ions, which yields much highe WA, esul ing in
conc e e wi h lowe s eng h [51] and poo e du abili y pe o mance [55] when p oduced wi h he
same e ec i e w/c a io. Consequen ly, he use o ecycled sand ob ained om CDW is gene ally
no pe mi ed in he p oduc ion o s uc u al cemen i ious ma e ials in mos coun ies [55]. Howe e ,
se e al esea che s [126,148] ha e shown ha highly du able s uc u al conc e e can be achie ed i
a limi ed pe cen age o cleaned coa se and ine ecycled conc e e agg ega e (RCA) and MRA a e
used.
The du abili y p ope ies o RAC decline as he pe cen age o RA employed inc eases due o he
high WA capaci y o RA [51,153]. Se e al s udies ha e also ound ha he wa e pene a ion dep h
inc eases linea ly wi h an inc ease in he MRA eplacemen a io [126,142,144,154]. In con as ,
B a o e al. [155] epo ha conc e e p oduced wi h 10–100% ine o coa se MRA achie es a 21–
52.6% lowe so p i i y alue han NAC.
Chap e 2
17
In addi ion, he adhe ed cemen pas es and ce amic pa icles in RAs can lead o excessi e c eep
and d ying sh inkage le els in conc e e [55]. Gaya e e al. [156] pe o med an analysis o he
sh inkage cha ac e is ics o conc e es comp ised o a ying pe cen ages (20%, 35%, 50%, 70%, and
100%) o coa se and ine ecycled b ick agg ega e (RBA). They concluded ha he sh inkage o his
RAC was highe han ha o he o he RACs due o i s high WA capaci y and he low modulus o
elas ici y o he RBA. Fu he mo e, he conc e e wi h 35% RBA was adequa e o s uc u al
pu poses. Howe e , he use o 100% RBA p oduced an inc ease in he sh inkage alue om 45% o
100% is-à- is NAC, depending on he wa e dosage in he mixes. Vin imilla and E xebe ia [105]
alida ed he sh inkage alues o conc e e p oduced o s uc u al pu poses wi h simul aneous
subs i u ion o up o 50–60% coa se ecycled conc e e agg ega es (CRCA) and 10–20% FRCA,
which ha e 11–56% highe sh inkage alues han NAC. In con as , B a o e al. [157] no e ha
al hough he inco po a ion o MRA in o conc e e inc eases he o al sh inkage, a consensus is ye o
be eached on he ex en o he inc ease. In conclusion, using coa se and ine MRA in he p oduc ion
o conc e e suppo s sus ainable cons uc ion p ac ices.
This s udy aims o de e mine he maximum pe cen age o CMRA and FMRA o p oducing
s uc u al conc e e − wi h a cha ac e is ic comp essi e s eng h o 30 MPa (C30/37)− ha is sui able
o exposu e o XC1 o XC4 en i onmen s, in which ca bona ion-induced co osion may occu due
o he le el o humidi y in such en i onmen s. Two expe imen al phases we e conduc ed: Phase 1
and Phase 2. In Phase 1, all he conc e es we e p oduced wi h an e ec i e w/c a io o 0.48, while
an e ec i e w/c a io o 0.52 was employed in Phase 2; 300 kg o cemen was used in bo h phases.
In Phase 1, 20%, 30%, 50% and 100% CMRA, in combina ion wi h 5%, 10%, 15% and 25% FMRA,
we e used in eplacemen o NA. In Phase 2, due o a high w/c a io, lowe MRA pe cen ages o
20%, 30%, 40% and 50% CMRA, in combina ion wi h 5%, 10% and 15% FMRA, we e employed in
eplacemen o NA in p oducing he conc e es. NAC was also p oduced in hese wo phases. The
physical, mechanical, and du abili y p ope ies o he MRACs p oduced we e de e mined
expe imen ally and compa ed o he co esponding alues achie ed by he NAC. In addi ion, he
c i e ia s ipula ed in Eu ocode 2 [50] and SC-BOE [20] we e used o alida e he s uc u al MRACs
p oduced.
Chap e 3
24
0
20
40
60
80
100
0.01 0.1 1 10 100
Pe cen age passing (%)
Sie e size (mm)
FNA (0/4)
CNA-1 (4/10)
CNA-2 (8/20)
FMRA (0/4)
CMRA-1 (2/10)
CMRA-2 (8/20)
Uppe limi
Lowe Limi
Figu e 3. 5 Agg ega e pa icle size dis ibu ion
The MRA componen s, cha ac e ised by he CMRA-2 ac ion, mee EN 933-11 speci ica ions
(Table 3. 6). Pe he EN 206 s anda d, he MRA used in his s udy we e ca ego ised as ype B (RC50,
RCU70, Rb30-, Ra5-, FL2- and XRg2-). Based on his classi ica ion, he combina ion conc e e (RC)
and na u al s one (Ru) componen s exceeded 50%, while he ce amic con en was below 30%.
Table 3. 6 Classi ica ion o Type B CMRA-2 (8/20 mm) agg ega es.
Type
Conc e e, conc e e
p oduc s, mo a
(Rc)
Unbound mo a ,
na u e s one (Ru)
Manso y
(Rb)
Asphal
(Ra)
Glass
(Rg)
O he
(x)
CRCA-2
43.43%
24.31%
28.38%
2.24%
0.19%
1.46%
EN 12620
Rc+Ru >50%
≤ 30%
≤ 5%
≤ 2%
The physical, chemical and mechanical p ope ies o he MRA employed in p oducing he
conc e e a e desc ibed in Table 3. 7. The ob ained alues we e ca ego ised ollowing EN 12690
speci ica ions. All he p ope ies achie ed he limi s es ablished in he SC-BOE [20] (Table 3. 7),
excep he WA o CMRA, which was highe han 7%. Howe e , he a e age WA capaci y o he
combined NA and CMRA (used in conc e e p oduc ion) emains below he 7% h eshold equi ed
by egula ions.

Chap e 3
25
Table 3. 7 Physical, mechanical and chemical p ope ies o NA and MRA specimens.
P ope y (s anda d)
Speci ica ion
FMRA
CMRA-1
CMRA-2
SC-BOE
(0/4)
(2/10)
(8/20)
Densi y (kg/dm3)
EN 1097-6[162]
2.28
2.15
2.08
≥1.7*
Wa e Abso p ion (%)
EN 1097-6[162]
6.67
8.75
9
<7
Humidi y (%)
6.31
6.44
4. 86
Fines equi alen (%)
EN 933-8[163]
95.5
>70
Los Ángeles coe icien (w %)
EN 1097-2[163]
39.15
<40
Flakiness índex (w %)
EN 933-3[164]
9.72
<35
*P ope y de ined in EN 206
The MRA specimens exhibi ed in e io pe o mance, lowe densi y and highe po osi y and WA
han he NA specimens (Table 3. 7). These limi a ions can be a ibu ed o he adhe ed mo a and
ce amic pa icles in MRA [51,126,142,169]. The d y densi y o he di e en ac ions o ype B
agg ega es was be ween 2.02 kg/dm3 and 2.26 kg/dm3, which is simila o he alues epo ed in
p e ious s udies [170]. Howe e , his ange o alues is g ea e han he 1.7 kg/dm3 s ipula ed o
ype B agg ega es pe UNE EN 206. The MRA was cha ac e ised by a no mal densi y exceeding 2.0
kg/dm³, making i sui able o use in conc e e.
The WA cha ac e is ics o CMRA in pa icula , FMRA a e commonly documen ed as c i ical
indica o s ha impac he p ope ies o RAC [171]. Al hough CMRA ypically exhibi s a WA capaci y
anging om 4.49% o 10% [12,148,171], FMRA can achie e a WA capaci y o 5.6% o 20%
[150,159]. In his s udy, he WA capaci y o he Type B MRA ac ions anged om 6.61% o 9%.
Saiz Ma inez e al. [170] also analysed MRA specimens wi h WA capaci ies o be ween 4.65% and
8.75%. The WA capaci y o he CMRA in his s udy was highe han he 7% h eshold es ablished
by he SC-BOE [20] o RCA, while FMRA demons a ed he lowes WA capaci y among he MRA
specimens.
MRA agg ega es in his s udy achie ed accep able sand equi alen , Los Angeles coe icien and
lakiness index alues o conc e e p oduc ion. Fu he mo e, he le els o he soluble chlo ide and
sul a e ions emained below he maximum alues s ipula ed by he SC-BOE (Table 3. 7) [20], which
esul ed om he wa e washing o he CDW a he ecycling plan . In addi ion, all MRA ac ions
we e u ilized wi h ele a ed mois u e con en .
3.3. Tes p ocedu e
In all p oduced conc e es, he p ope ies de e mined we e physical (densi y and abso p ion),
mechanical (comp essi e and spli ing ensile s eng h, and modulus o elas ici y), plas ic and d ying
sh inkage, and du abili y (capilla y wa e abso p ion and wa e pene a ion unde p essu e, chlo ide
pe meabili y, chlo ide p o ile, accele a ed, and na u al ca bona ion esis ance). Table 3. 8 lis s all o
Chap e 3
26
he es s conduc ed, wi h de ailed desc ip ions o he ypes and numbe o specimens employed in
each es , as well as he age o es ing and he speci ica ions ollowed, and he es used in each
chap e .
Table 3. 8 Conc e e p ope ies analyzed
P ope y
S anda d
Tes age
(days)
Specimens
Specimen size
(mm)
Cha pe
F esh s a e
Slump
4,5,6,7
Ha dened s a e
Densi y and Abso p ion
EN 12390-7
28
3
100x100x100
4,7
Comp esi e s eng h
EN 12390-3
7,28,56
9
100x100x100
4,5,6,7
Spli ing Tensile s eng h
EN 12390-6
28
3
h=200; ϕ =100
4,7
Elas ic modulus
EN 12390-13
28
2
h=200; ϕ =100
4,7
D ying Sh inkage
EN 12390-16
1-91
2
75x75x280
4,5,6,7
So p i i y-Capilla y wa e
abso p ion
EN ISO 12148
28
3
100x100x100
4,7
Wa e Pene a ion
EN 12390-8
28
3
h=200; ϕ =100
4,7
Chlo ide Pe meabili y
ASTM C1202
28,56
2
h=50; ϕ =100
5,6
Chlo ide P o ile
EN 12390-11
90
2
100x100x100
6
Acele a ed Ca bona ion
Resis ance
EN 12390-12
90
2
100x100x300
5,6
Na u al Ca bona ion
Resis ance
UNE 83993-1
360
2
100x100x400
6
The measu emen o plas ic sh inkage s ain was ca ied ou by eco ding leng h changes e e y
minu e o 12 hou s a e cas ing he conc e e. LVDTs we e ins alled on he mold, secu ed o a s eel
pla e in di ec con ac wi h a ee-mo ing Te lon pla e, ensu ing p ecise measu emen o linea leng h
changes. The es specimens, consis ing o wo squa e p isms (400 × 100 × 100 mm) cas in s eel
moulds, we e main ained unde con olled condi ions a 23 ± 2°C and 50 ± 5% ela i e humidi y
h oughou he es ing pe iod. The LVDTs we e connec ed o a da a acquisi ion sys em o con inuously
eco d he da a. Fo he ha dened conc e e es s, all samples we e s o ed in a humidi y chambe a 20
± 2°C wi h a ela i e humidi y o ≥ 95% un il he es ing day.
• The conc e e’s comp essi e s eng h was de e mined using a 3000-kN capaci y loading
machine. The comp essi e s eng h was de e mined a 7, 28, and 56 days ollowing he UNE-
EN 12390-3 [172] speci ica ions. Fo each es ing age, h ee cubic specimens measu ing 100 x
100 x 100 mm we e u ilized.
Chap e 3
27
• Spli ing Tensile s eng h and Elas ic modulus we e de e mined a 28 days o cu ing on
cylind ical samples wi h a diame e o 100 mm and a heigh o 200 mm ollowing he EN
12390-6 and EN 12390-13 speci ica ions, espec i ely.
• The d ying sh inkage o all he p oduced conc e es was de e mined ollowing he EN 12390-
16 [173] speci ica ion. Each conc e e mix u e used wo specimens o 75 × 75 × 280 mm. A e
a 24 h cas ing, hey we e demoulded. Thei ini ial leng hs and weigh s we e measu ed and he
wo specimens o each conc e e we e placed in a con olled clima ic chambe ( empe a u e o
20 ± 2℃ and ela i e humidi y o 50 ± 5%). Leng h and weigh measu emen s we e eco ded
a in e als o 1, 7, 14, 28, 56 and 91 days.
• The capilla y wa e abso p ion (including so p i i y) was assessed using 100 × 100 × 100 mm
cubic specimens ollowing he ISO 15148:2002(E) speci ica ion. In o de o ca y ou he es ,
he bo om aces o specimens we e subme ged in 5 mm wa e ( he la e al su aces we e
imp egna ed wi h impe meable esin). The cumula i e wa e abso bed by he specimen was
eco ded a di e en ime in e als up o 48 h. So p i i y is he slope o he eg ession cu e o
he quan i y o wa e abso bed by a uni su ace a ea e sus he squa e oo o he elapsed ime
om he ini ial ins an ( =0 min) o 120 min. The desc ibed esul s a e he a e age o h ee
measu emen s.
• Wa e pene a ion dep h unde p essu e was de e mined in cylind ical samples wi h a diame e
o 100 mm and a heigh o 100 mm ollowing EN 12390-8. Once he specimen was placed in
he appa a us, a wa e p essu e o 500 ± 50 kPa was applied o he ci cula su ace o 72 ± 2
h. A e wa ds, he specimen was spli in hal along a plane pe pendicula o he su ace on
which he wa e p essu e had been applied, and he dep h o pene a ion was measu ed.
• The chlo ide pe meabili y in he conc e e was assessed ollowing he ASTM C1202 [174]
"S anda d Tes Me hod o Elec ical Indica ion o Conc e es Abili y o Resis Chlo ide Ion
Pene a ion". Two cylind ical conc e e samples o 200 mm in leng h we e employed o each
mix u e, and om hose, wo discs specimens o 100 mm in diame e and 50 mm in hickness
we e ob ained. Two-disc specimens, one o each sample, we e used o de e mine he conc e e's
chlo ide ion pene a ion a e 28 and 56 days o cu ing. The chlo ide pene abili y o p oduced
conc e es was quan i ied by measu ing he o al cha ge (in Coulombs) passed du ing a 6-hou
es ing pe iod. A po en ial di e ence o 60 V was applied ac oss each side o he specimen,
which was imme sed, one side in solu ions con aining sodium hyd oxide (NaOH) and he o he
side in sodium chlo ide (NaCl).
• The chlo ide p o ile was de e mined by analyzing he chlo ide con en a di e en dep hs
ac oss eigh laye s (0–1 mm, 1–3 mm, 3–5 mm, 5–7 mm, 7–10 mm, 10–13 mm, 13–16 mm, and
16–20 mm) in he conc e e specimens. Cubic specimens measu ing 100 × 100 × 100 mm we e
p epa ed ollowing he EN 12390-11 s anda d. A e cu ing, he specimens we e exposed o a
3% NaCl solu ion o 91 days unde con olled condi ions a 23 ± 2°C and 50 ± 5% ela i e
humidi y. The chlo ide concen a ion in each laye was measu ed using i a ion wi h a 0.02N
sil e ni a e solu ion.
Chap e 3
28
• The accele a ed ca bona ion me hod ollowing he UNE-EN 12390-12 [175] speci ica ion was
employed in o de o assess he ca bona ion esis ance o p oduced conc e e mix u es. Each
conc e e mix u e used wo p isma ic 100 x 100 x 300 mm samples. All conc e e specimens
unde wen a cu ing p ocess in a humidi y chambe o 28 days, ollowed by a 14-day p e-
condi ioning pe iod unde labo a o y condi ions (CO2 concen a ion o 425 ppm, 20 ± 2°C,
and 50-55% ela i e humidi y, RH). Subsequen ly, he samples we e s o ed in a chambe wi h
an en i onmen consis ing o 3% CO2, 57% HR and a 20°C. The ca bona ion dep h o each
specimen was measu ed a speci ic in e als o 0, 14, 28, 56, 70, and 91 days o exposu e o
he chambe . In o de o de e mine he ca bona ion dep h, a solu ion con aining
phenolph halein indica o was applied o he eshly ac u ed su ace o he conc e e. The
solu ion con ained 1 g o phenolph halein dissol ed in 70 g o e hanol and 30 g o wa e
ollowing he UNE-EN 14630 [176] speci ica ion.
• The na u al ca bona ion esis ance was e alua ed using wo p isma ic specimens wi h
dimensions o 100 × 100 × 400 mm, measu ed a in e als o 0, 30, 90, 180, and 365 days
ollowing he UNE 83993 s anda d. The specimens we e ini ially cu ed o 4 days in a humidi y
chambe and subsequen ly s o ed in a sui able plas ic box placed in an ou doo en i onmen o
allow na u al exposu e o ca bona ion condi ions. The dep h o ca bona ion was assessed using
a solu ion p epa ed wi h 1 g o phenolph halein, 70 g o e hanol, and 30 g o wa e , as speci ied
in he UNE-EN 14630 [176] s anda d
In all expe imen al phases, conc e e mix u es we e p oduced in a e ical axle mixe . The
ma e ials we e always added manually in he same o de : i s , he agg ega es ( om coa se o ine ),
and a e hey we e mixed o 30 seconds, he cemen was added. While he solid componen s we e
mixing o 1 min, wa e was added, ollowed by chemical admix u es. The comple e mix u e was hen
mixed o 1 min mo e. Once he conc e e was p oduced, conc e e specimens we e ab ica ed a e he
slump es was de e mined. The conc e e specimens we e kep in moulds o 24 h. A e demoulding,
hey we e s o ed in he humidi y oom a 20 ± 2 ℃ wi h ela i e humidi y ≥ 95 % un il 1 h be o e
es ing ime. All he es elemen s we e kep in he same condi ions be o e es ing.
Chap e 3
29
Figu e 3. 6 Comp ehensi e F amewo k o Physical, Mechanical, and Du abili y Tes ing o Recycled Agg ega es.

Chap e 4
30
4. Chap e 4. Fine and coa se ecycled
agg ega es-Type A in conc e e p oduc ion
Limi ing he maximum ine and coa se ecycled
agg ega es-Type A used in s uc u al conc e e
Au ho s:
Ca la Vin imilla, Mi en E xebe ia
Jou nal:
Cons uc ion and Building Ma e ials
Publica ion Da e:
Volume 380, 30 May 2023, 131273
DOI:
h ps://doi.o g/10.1016/j.conbuildma .2023.131273
ABSTRACT
The manu ac u e o conc e e using ecycled conc e e agg ega es (RCA) is an al e na i e used o
educe he exploi a ion o na u al esou ces and land illing o cons uc ion was e. This pape
discusses he sui abili y o p oducing s uc u al conc e e o be exposed o an XC1-XC4 en i onmen
employing di e en pe cen ages o ine RCA (FRCA) and coa se RCA (CRCA) classi ied as ype
A. Two expe imen al phases we e conduc ed in which 300 kg o cemen /m3 and an e ec i e
wa e :cemen a io o 0.48 (Phase 1) and 0.52 (Phase 2) we e employed wi h di e en pe cen ages
o he CRCA and FRCA agg ega es. The ypes o p ope ies de e mined we e physical (densi y,
abso p ion, accessible po ous), mechanical (comp essi e, spli ing ensile s eng h, modulus o
elas ici y), sh inkage, and du abili y (so p i i y, wa e pene a ion). A e exhaus ing analyses o he
expe imen al alues and s uc u al code equi emen s, he success ul use o a simul aneous
combina ion o up o 60 % CRCA and 30 % o FRCA was de ined in Phase 1. In addi ion, he use o
50 % CRCA and 20 % o FRCA we e de ined in Phase 2.
Keywo ds: Coa se and ine ecycled agg ega es; s uc u al ecycled agg ega e conc e e, physical
and mechanical p ope ies, d ying sh inkage, so p i i y.
Chap e 4
31
4.1. Objec i e
In he p esen esea ch wo k, he physical, mechanical, d ying sh inkage and du abili y (so p i i y
and wa e pene a ion) p ope ies o conc e es made wi h CRCA and FRCA we e de e mined. The
main goal was o de ine he maximum pe cen ages o CRCA and FRCA usable o s uc u al conc e e
p oduc ion wi h a cha ac e is ic comp essi e s eng h o 30 MPa (C30/37) o be exposed o XC1 o
XC4 en i onmen s, co osion induced by ca bona ion can happen due o humidi y p esence. Whe e
exposu e condi ions a e: XC1 is d y o pe manen ly we ; XC2 is we , a ely d y; XC3 is mode a e
humidi y; and XC4 is cyclic we and d y. Two expe imen al phases we e conduc ed. In Phase 1, all o
he conc e e mix u es (NAC, conc e es p oduced using only CRCA and conc e es made wi h CRCA
and FRCA) we e p oduced wi h 300 kg o cemen and an e ec i e wa e : cemen (w/c) a io o 0.48.
The pe cen ages o 20 %, 30 %, 50 % and 100 % CRCA we e used o conc e e p oduc ion. In
addi ion, di e en pe cen ages o FRCA we e included (conc e es wi h low CRCA we e p oduced
wi h a low % o FRCA), up o 100 % FRCA in conc e es made wi h 100 % CRCA. Phase 2 conc e es
we e p oduced using 300 kg o cemen and an e ec i e w/c a io o 0.52. Due o he highe w/c a io,
he ecycled conc e es we e p oduced using up o 60 % CRCA (including 20 %, 30 % and 50 %). In
addi ion, up o 50 % FRCA was used as eplacemen o na u al sand, oge he wi h CRCA. The
ob ained alues o he measu ed p ope ies o med he basis o he maximum pe cen ages o CRCA
and FRCA we e de ined o s uc u al conc e e p oduc ion in conc e es p oduced wi h di e en w/c
a ios.
4.2. Conc e e p oduc ion
All he conc e e mix u es we e designed o be exposed o XC1–XC4 en i onmen s [20], which
equi e a minimum cha ac e is ic design s eng h ( ck) o 30 MPa (C30/37). Two conc e e p oduc ion
phases (Phase 1 and Phase 2) we e conduc ed using he e ec i e w/c a ios o 0.48 and 0.52,
espec i ely. In bo h phases, 300 kg o cemen /m3 and di e en pe cen ages o CRCA and FRCA
ac ions we e employed.
Table 4. 1 shows he conc e e mix u es p oduced in Phase 1. NAC was designa ed as NAC1. In
addi ion, he conc e es p oduced using only CRCA we e designa ed as RAC-CX1, whe e X was 20 %,
30 %, 50 % o 100 % o he eplacemen a io (in olume) o NAs coa se agg ega e. Fu he mo e, he
conc e es p oduced wi h FRCA and CRCA we e designa ed RAC-CX-FY1, whe e Y was he
pe cen age o FRCA employed in he eplacemen o NAs sand. The FRCA used was om 0 % o
100 % as eplacemen o na u al sand. As shown in Table 4. 1, he con en ional conc e e (NAC1) was
designed wi h a o al w/c a io o 0.525, and i s e ec i e w/c a io was calcula ed and main ained
cons an in all he p oduced conc e es. All conc e es we e p oduced using an e ec i e w/c a io o 0.48
and 300 kg o cemen /m3. The e ec i e wa e ( ee wa e ) is he wa e amoun eac ed wi h cemen .
In o de o calcula e he e ec i e wa e alue, i he agg ega es we e o e sa u a ed ( he FRCA was
used in ha condi ion), he wa e eleased om agg ega es had o be conside ed ee wa e . Howe e ,
when he agg ega es we e humid bu no sa u a ed, hei e ec i e wa e abso p ion capaci y had o be
conside ed. The e ec i e abso p ion capaci y was conside ed he wa e amoun abso bed by he
agg ega es in 30 min. While he e ec i e abso p ion capaci ies o ine and coa se NAs we e 70 % and
Chap e 4
32
20 %, espec i ely, o hei o al abso p ion capaci ies, he FRCA and CRCA agg ega es’ e ec i e
abso p ion capaci ies we e 100 % and 70 %, espec i ely, o hei o al abso p ion capaci y. Howe e ,
he FRCA was used in an o e sa u a ed condi ion. Consequen ly, he o al wa e in conc e e was
calcula ed by he sum he e ec i e wa e and he wa e inside he agg ega es (humidi y plus e ec i ely
abso bed wa e ). As shown in Table 4. 1, he o al w/c a io was highe wi h inc easing olumes o
RCA used in conc e e p oduc ion. The o al wa e alues we e consis en wi h o he s udies ha
employed up o 100 % o CRCA and FRCA in conc e e p oduc ion [46,68].
In Phase 1, he RCA eplacemen pe cen ages we e de e mined based on Eu opean egula ions
and he esul s o o he esea che s [15,26,46,48]. The conc e es RAC-C201, RAC-C301, RAC-C501
and RAC-C1001 we e p oduced acco ding o he Spanish S uc u al Conc e e code (SC-BOE) [20],
UNE EN 206, NF EN 1260 2003 and RILEM. Fo he simul aneous use o bo h CRCA and FRCA
ac ions, he RECYBETON [177] p oposal was ollowed in c ea ing he mix u es C60-F201, C60-
F301 and C50-F201. In addi ion, he C50-F501, C100-F201 and C100-F1001 conc e e mix u es we e
p oduced based on Danish legisla ion, which allows o he use o agg ega es p o ided ha hei
densi y is no less han 2220 kg/m3[48].
Table 4. 1 Mix p opo ions o Phase 1 conc e e. All he conc e es we e p oduced wi h an e ec i e wa e /cemen a io o
0.48.
Cemen
To al
Wa e
FNA
FRCA
CNA
1
CRCA
1
CNA
2
CRCA
2
S
P
Slump
Mix
(Kg)
(Kg)
(Kg)
(Kg)
(Kg)
(Kg)
(Kg)
(Kg)
(%)
(%)
(mm)
NAC1
300
157.5
994
-
247
-
831
-
1.5
-
100
RAC-C201
300
167.7
994
-
198
41
665
143
1.9
-
140
RAC-C301
300
172.8
994
-
173
62
582
215
1.9
-
150
RAC-C501
300
182.4
952
-
144
121
416
358
1.2
0.4
200
RAC-C1001
300
213.5
849
-
-
414
-
626
1.2
0.4
100
RAC-C50-F201
300
190.0
762
163
144
121
416
358
1.2
1.5
180
RAC-C50-F501
300
203.4
476
407
144
121
416
358
1.2
1.5
200
RAC-C60-F201
300
194.8
762
163
115
145
333
429
1.2
1.5
200
RAC-C60-F301
300
199.3
667
244
115
145
333
429
1.2
1.5
160
RAC-C100-F201
300
222.6
679
145.
-
626
-
626
1.2
1.7
200
RAC-C100-F1001
300
254.0
-
721
-
414
-
626
1.2
1.7
150
The NAC1, RAC-C201 and RAC-C301 conc e es we e p oduced using only he S admix u e.
Howe e , he conc e es p oduced wi h a highe pe cen age o RCA mo e S admix u e we e needed o
achie e simila wo kabili y. Consequen ly, in o de o main ain he wo kabili y wi h a lowe isk o
seg ega ion, he S admix u e amoun was educed, and P (mul i unc ional) admix u e was employed
in all o he o he conc e es.
Chap e 4
33
The consis encies o all conc e es we e de e mined ollowing he EN 12350-2 speci ica ion. All
he conc e es achie ed a slump alue o 150–200 mm excep NAC1 and RAC-C1001. The NAC1
conc e e was p oduced wi h he lowes S admix u e amoun and achie ed a 100 mm slump. In addi ion,
he RAC-C1001 needed a highe amoun o P admix u e. Howe e , i was e i ied ha all o he
conc e es had adequa e luid-liquid consis ency wi h he 1.20 % S and 1.5 % P admix u e.
Table 4. 2 shows he conc e e mix u es p oduced in Phase 2. In his case, he NAC2 was p oduced
using a o al w/c a io o 0.55. In addi ion, all he conc e e mix u es we e p oduced wi h an e ec i e
w/c a io o 0.52 and 300 kg o cemen /m3. Due o he use o a highe w/c a io han ha employed in
Phase 1, and in o de o con ol he o al wa e amoun in conc e e, a maximum o 60 % o CRCA
(RAC-C602) and 50 % o FRCA (RAC-CX-F502) we e employed o conc e e p oduc ion.
Fu he mo e, he C20-F52 and C30-F102 conc e e mix u es, made wi h low pe cen ages o CRCA and
FRCA, we e ab ica ed o analyse he in luence o FRCA on conc e e p ope ies.
Table 4. 2 Mix p opo ions o Phase 2 conc e e. All he conc e es we e p oduced wi h an e ec i e wa e /cemen a io
o 0.52
Cemen
To al,
Wa e
FNA
FRCA
CNA
1
CRCA
1
CNA
2
CRCA
2
S
P
Slump
Mix
(Kg)
(Kg)
(Kg)
(Kg)
(Kg)
(Kg)
(Kg)
(Kg)
(%)
(%)
(mm)
NAC2
300
165
981.2
-
242.9
-
815.4
0.00
1.0
1.2
160
RAC-C202
300
173.9
981.2
-
194.3
43.1
652.3
147.4
0.7
1.0
180
RAC-C302
300
179.1
981.2
-
170.0
64.4
570.8
219.1
0.7
1.0
160
RAC-C502
300
190.8
940.3
-
141.7
125.2
407.7
370.1
1.0
1.2
160
RAC-C602
300
195.9
940.3
-
113.3
150.3
326.2
444.5
1.0
1.2
170
RAC-C20-F52
300
176.9
932.2
41.6
194.3
43.1
652.3
147.4
0.7
1.0
200
RAC-C30-F102
300
183.7
883.1
84.4
170.0
64.4
570.8
219.1
0.7
1.0
90
RAC-C50-F202
300
199.6
752.3
159.5
141.7
125.2
407.7
370.1
1.0
1.2
160
RAC-C50-F502
300
212.8
470.2
398.8
141.7
125.2
407.7
370.1
1.0
1.2
160
RAC-C60-F202
300
204.7
752.3
159.5
113.3
150.3
326.2
444.5
1.0
1.2
180
RAC-C60-F302
300
209.1
658.2
239.3
113.3
150.3
326.2
444.5
1.0
1.2
170
In o de o main ain wo kabili y wi h a lowe isk o seg ega ion, all he conc e e mix u es, we e
p oduced using S admix u e and P (mul i unc ional). As a esul , all he conc e es, excep o RAC-
C30-F102, had adequa e luid-liquid consis ency wi h he 0.7–1.0 % S and 1.0–1.2 % P admix u e. I
was de e mined ha he RAC-C30-F102 would equi e mo e amoun o admix u es due o he high
humidi y o CRCA and o e sa u a ed FRCA. In addi ion, no ele an loss o wo kabili y was shown
in conc e es p oduced using FRCA.
Chap e 4
40
c m=0.3· ck2/3
Eq.4 (4)
Figu e 4. 3 shows he a io o he expe imen al alue wi h espec o he nume ical ( heo e ical)
alue ob ained by each conc e e p oduced. In Phase 1 (Figu e 4. 3-a), i was obse ed ha he
nume ical me hod (Eq.4 [4]) accu a ely es ima ed he expe imen ally ob ained ensile s eng h alues
o NAC1, RAC-C201 and RAC-C301 conc e es. In addi ion, he nume ical alue was simila , wi h a
di e ence o a ound 5 %, wi h espec o he expe imen al alues in all he RAC conc e es excep
RAC-C1001 and RAC-C100-F1001.
In Phase 2 (Figu e 4. 3-b), all he ob ained esul s we e abo e he do ed line (i.e. he heo e ical
me hod unde es ima ed he expe imen ally ob ained alues) excep o RAC-C502, RAC-C60-F202
and RAC-C60-F302. The use o ecycled agg ega es in conc e e, ega dless o he ac ion used, did
no cause signi ican dec eases in ensile s eng h. The e o e, he o mula speci ied in he s uc u al
conc e e code was alida ed as help ul o es ima ing he ensile s eng h o conc e e con aining RCA.
0,6
0,7
0,8
0,9
1,0
1,1
1,2
1,3
1,4
Ra io Expe imen al alue/nume ical
(SC-BOE) alue
Spli ing Tensile S eng h (Expe imen al/Theo ical BOE)
Elas ic Modulus(Expe imen al/Theo ical BOE)
0,6
0,7
0,8
0,9
1,0
1,1
1,2
1,3
1,4
Ra io Expe iemn al alue/nume ical
(SC-BOE) alue
Spli ing Tensile S eng h (Expe imen al/Theo ical BOE)
Elas ic Modulus(Expe imen al/Theo ical BOE)
a)
b)
Figu e 4. 3 Ra io o he expe imen al alue o espec o nume al alue o spli ing ensile s eng h and modulus o
elas ici y a) phase 1 and b) phase 2.
4.3.2.3 Elas ic modulus
The elas ic modulus alues o he p oduced conc e es a e p o ided in Table 4. 5. All o he RACs
achie ed a lowe modulus elas ici y alue han he NACs. In addi ion, he alue was lowe when highe
pe cen ages o RCA we e employed. Howe e , he RAC p oduced in Phase 1 (wi h a lowe w/c a io)
achie ed a highe dec ease wi h espec o NAC han did he RAC p oduced in Phase 2.
In Phase 1, conc e e p oduced wi h 20 %, 30 %, 50 % and 100 % CRCA ob ained 11.5 %,12.3 %,
15.2 % and 24.9 % lowe modulus alues, espec i ely, han NAC1. O he esea che s [51] ound

Chap e 4
41
simila alues o 14 % and 21 % educ ions when conc e es we e p oduced wi h 50 % and 100 %
CRCA eplacemen a ios. Dimi iou e al. [191] also epo ed a 12–33 % educ ion in conc e e made
wi h 100 % CRCA. In addi ion, when he RAC was p oduced wi h up o 30 % FRCA, he modulus o
elas ici y was educed o less han 5 % wi h espec o he co esponding conc e e p oduced using only
CRCA. Howe e , in he conc e es p oduced wi h 50 % and 100 % FRCA, he modulus o elas ici y
dec eased 7.4 % and 14.9 %, espec i ely, wi h espec o he co esponding CRCA conc e e. O he
esea che s also ound ha eplacing 30 % CRCA and FRCA dec eased he elas ic modulus o conc e e
[192]. Mo eo e , se e al esea che s co obo a ed he nega i e in luence o using high pe cen ages o
FRCA in he alue o modulus o elas ici y [51,193]. Dimi iou e al. [191] epo ed a educ ion o up
o 27 % o modulus elas ici y when conc e e was p oduced wi h 100 % CRCA and 25 % FRCA. The
g ea e po osi y, pas e olume and de o mabili y o RAC in compa ison o NAC con ibu ed o lowe
modulus o elas ici y alues [57,106,194,195].
In Phase 2, all o he RAC p oduced using only CRCA achie ed simila alues. Mo eo e , he e
was no a ia ion in he modulus o elas ici y alue when he conc e e was made using 5 % and 10 %
FRCA, compa ed o he co esponding conc e e p oduced wi h CRCA. Howe e , he mixes p oduced
wi h a g ea e han 20 % FRCA eplacemen a io showed conside able dec eases in modulus o
elas ici y. The RAC-C50-F502 and RAC-C60-F302 conc e es had 17.8 % and 22.4 % lowe modulus
o elas ici y han NAC2.
In compa ing he Phase 1 and Phase 2 alues, while he NAC1 conc e e achie ed a highe
modulus han he NAC2, he conc e es p oduced using he same pe cen ages o CRCA and FCRA in
phase 2 achie ed simila modulus elas ici y alues o hose in phase 1.
Acco ding o he s uc u al conc e e code [20], he modulus elas ici y o NAC conc e e can be
es ima ed ollowing Eq.4 (5). Conside ing ha he NAC (30/37) conc e e should ha e a minimum cm
o 38 MPa, i s modulus elas ici y should be 33 GPa. Conside ing his alue, he RAC-C1001, RAC-
C100-F201, RAC-C100-F1001 and RAC-A-C60-F302 conc e es achie ed alues ha we e oo low and,
consequen ly, had oo high s ain.
Ecm=22∗( cm
10)0.3
Eq.4 (5)
whe e Ecm is he elas ic modulus o he conc e e and cm is he mean comp essi e s eng h.
Fu he mo e, Figu e 4. 3 shows he a ios o he expe imen al and nume ical (Eq.4 [5]) modulus
elas ici y alues o each p oduced conc e e. In Phase 1 (Figu e 4. 3-a), i was obse ed ha nume ical
es ima ion (using Eq.4 [5]) o modulus elas ici y was simila o he alues ob ained expe imen ally
when conc e e was made wi h up o 50 % CRCA and na u al sand. In con as , wi h conc e es p oduced
using ine agg ega es, he nume ical me hod o e es ima ed he expe imen al alues ( he ob ained a ios
we e below he d opped line), wi h he expe imen al alue 8 % lowe han he nume ical alue.
Chap e 4
42
Howe e , he di e ence be ween expe imen al and nume ical alues was much g ea e when 100 %
CRCA was employed wi h na u al o FRCA agg ega es. In con as , in Phase 2, he nume ical me hod
(Eq.4 [5]) adequa ely es ima ed he modulus elas ici y o RAC, excep o RAC-C60-302, which
expe imen ally achie ed a low alue. Consequen ly, i can be concluded ha al hough he SC-BOE
de ines he Eq.4 (5) o a conc e e p oduced wi h a maximum 20 % CRCA, i adequa ely es ima es he
alues o conc e es p oduced wi h up o 60 % CRCA and 20 % FRCA.
Acco ding o Figu e 4. 3, he in luence o he ecycled agg ega es on he educ ion o he modulus
o elas ici y alue wi h espec o heo e ical alue was g ea e in Phase 1 han in Phase 2 (due o a
lowe w/c a io and highe s eng h). Consequen ly, he es ima ion o mula app oxima es be e wi h
lowe s eng h conc e es (Phase 2). Howe e , as men ioned, he nume ical es ima ion was good in all
conc e es p oduced using up o 50–60 % CRCA and up o 20 % FRCA, aking in o accoun bo h
phases.
4.3.3. D ying sh inkage
Figu e 4. 4 illus a es he d ying sh inkage (µƐ) and mass loss (%) alues up o 91 days o all
conc e e mix u es p oduced in Phase 1. The ob ained es esul s e ealed ha conc e e wi h a highe
pe cen age o RCA su e ed mo e sh inkage. In addi ion, he use o FRCA signi ican ly inc eased
sh inkage. These inc eases occu mainly in he ea ly ages, ending o s abilize o e ime [51].
Figu e 4. 4-a shows ha all he conc e es p oduced using only CRCA achie ed simila sh inkage
alues as NAC1 excep RAC-C1001, which achie ed conside ably mo e sh inkage (59.9 %) a 91 days.
The RAC-C201, RAC-C301 and RAC-C501 conc e es su e ed 7.7 % mo e sh inkage han NAC1.
Figu e 4. 4-b shows ha he use o FRCA in conc e e p oduc ion inc eased he d ying sh inkage alue.
The RAC-C50-F201 and RAC-C60-F201 inc eased in 13.7% and 16.5%, espec i ely, wi h espec o
NAC1. Howe e , using 30% o FRCA, he RAC-C60-F301 achie ed a 39.1% highe sh inkage alue
han NAC1. In addi ion, he use o 50% o FRCA conside ably inc eased he sh inkage alue. The
RAC-C50-F501 eached a 60.2% g ea e alue han NAC1. Fu he mo e, he RAC-C100-F1001
conc e es achie ed 99.3 % mo e sh inkage han NAC1 a 91 days. Based on hese esul s, i can be
concluded ha he sh inkage inc eased when he eplacemen alue o FRCA was g ea e han 30%,
oge he wi h 60% o CRCA. The ob ained esul s we e in acco dance wi h he esul s ob ained by
o he au ho s [186].
Figu e 4. 4-c shows ha while NAC1 los 2.2 % o mass, conc e e mix u es up o 30 % CRCA
and wi h 50 % CRCA achie ed a mass loss o 2.7 % and 3.5 %, espec i ely, a e 91 days o d ying
es exposu e. Howe e , simila o sh inkage alues, in mix u es p oduced using up o 60 % CRCA
and 30 % FRCA, he weigh losses inc eased up o 3.6 % (see Figu e 4. 4-d). In addi ion, he RAC-
C100-201 and RAC-C100-1001 conc e es su e ed a mass loss o 4.4 % and 5.4 %, espec i ely. O he
esea che s ob ained simila esul s and obse ed ha eplacing 15% and 30 % CRCA caused a mass
loss o 2,0% and 2.5 % wi h d ying sh inkage alues o -550 and -790 µm/m espec i ely [196]. In
addi ion, he conc e es p oduced wi h 20 %, 50 % and 100 % CRCA had maximum loss alues o
1.3 %, 1.9 % and 2.1 %, espec i ely, wi h d ying sh inkage anging om -311 o -717 µm/m [123].
Chap e 4
43
Acco ding o E xebe ia e al. [183], o al eplacemen o bo h ac ions caused a mass loss o 4.2 %
wi h all d ying sh inkage alues we e −1000 µm/m. A clea end was obse ed showing ha mass
loss inc eased as he pe cen age o ecycled agg ega es inc eased.
a)
b)
c)
d)
Figu e 4. 4 D ying sh inkage de elopmen in phase 1 a) d ying sh inkage CRCA1; b) d ying sh inkage CRCA1&FRCA1;
c) mass loss CRCA1; d) mass loss CRCA1&FRCA1
Figu e 4. 5 shows he d ying sh inkage and mass loss (%) ob ained by conc e es p oduced in
Phase 2. The RAC in Phase 2 ob ained a g ea e sh inkage alue han did NAC2. Figu e 4. 5-a and
Figu e 4. 5-b illus a e ha all he conc e e p oduced in Phase 2 achie ed sh inkage alues lowe han
420 µm/m, which is a good alue acco ding o ACI [122]. This de e mines ha con en ional conc e e’s
ypical d ying sh inkage alues a e −200 o −800 when a high w/c a io is used.
Chap e 4
44
Al hough Phase 2 conc e e mix u es we e p oduced using a highe w/c a io han Phase 1, he
sh inkage alues ob ained in Phase 2 conc e es we e lowe . This was because he clima ic oom
condi ion a ied a li le wi h ex e io en i onmen al condi ions. The Phase 1 conc e es we e
manu ac u ed in he sp ing and summe mon hs, and he a e age clima ic oom condi ions we e 22 ℃
and 51 % ela i e humidi y. In con as , he Phase 2 conc e es we e manu ac u ed in he au umn and
win e mon hs, when he a e age clima ic oom condi ions we e 19 ℃ and 53 % ela i e humidi y, so
a lowe empe a u e and highe humidi y han in Phase 1.
a)
b)
c)
d)
Figu e 4. 5 D ying sh inkage de elopmen in phase 2 a) d ying sh inkage CRCA2; b) d ying sh inkage CRCA1&FRCA2;
c) mass loss CRCA2; d) mass loss CRCA1&FRCA2
Figu e 4. 5-c and Figu e 4. 5-d show he mass loss o conc e e specimens submi ed o he d ying
p ocess. While he NAC2 conc e e achie ed a mass loss o 3.0 %, all he RACs p oduced wi h CRCA
achie ed a mass loss o 3.5 % a e 91 days. Simila o Phase 1, conc e e wi h up o 20 % FRCA
main ained he mass loss achie ed by conc e e p oduced wi h only CRCA. Howe e , conc e e
p oduced wi h 30 % FRCA eached a 5 % mass loss. These alues a e simila o hose ound by o he
esea che s [123,183].
Chap e 4
45
The mass loss pe cen ages on Phase 2 conc e e we e highe han Phase 1 conc e e, while he
sh inkage alues achie ed we e lowe . Howe e , as Medjigbodo e al. [197] desc ibed, he mass loss
depended on he ee wa e amoun (i was highe in phase 2), which did no di ec ly in luence in
sh inkage alues. In addi ion, due o a highe humidi y alue in he chambe o phase 2 conc e es,
hei dec easing in e nal ela i e humidi y was lowe , su e ing lowe capilla y s ess and lowe
sh inkage han ha in phase 1 conc e e.
Figu e 4. 6 shows he a io be ween he sh inkage alue o each o he conc e es p oduced wi h
espec o NAC in Phase 1 (Figu e 4. 6-a) and Phase 2 (Figu e 4. 6-b) expe imen al phases. I was
clea ly obse ed ha he sh inkage RAC/NAC a io alue o Phase 1 conc e es was lowe han ha o
Phase 2 conc e es when hey we e p oduced wi h he same amoun o ecycled agg ega es, p obably
due o a highe o al wa e amoun in phase 2.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Ra io sh inkage all conc e e/NAC1
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Ra io sh inkage all conc e e/NAC₂
a)
b)
Figu e 4. 6 Rela i e a io o sh inkage a 91 days a) Phase 1 (e ec i e w/c a io o 0.48) b) Phase 2 (e ec i e w/c a io o
0.52)
In Phase 2, unlike in phase 1, he use o up o 60% o CRCA inc eased he sh inkage alue wi h
espec o con en ional conc e e, NAC2 (see Figu e 4. 6-b). While he RAC-C202 conc e e ob ained a
23 % highe sh inkage alue han ha o NAC2, he RAC-C302, RAC-C502, and RAC-C602 conc e es
eached an inc ease o up o 39.7 %. Mo eo e , he use o up o 20 % o FRCA achie ed a low ise in
sh inkage alue wi h espec o hose ob ained by conc e es using only CRCA. Howe e , he sh inkage
inc eased up o 71.9 % wi h espec o NAC2 when 30 % o mo e FRCA was employed in conc e e
p oduc ion oge he wi h CRCA. Howe e , as p e iously men ioned, he o al d ying sh inkage alues
ob ained by all conc e es p oduced in Phase 2 we e low.
As p e iously demons a ed, he use o ecycled agg ega e inc eases he sh inkage alue o
conc e e due o he p esence o old cemen pas e in CRCA and FRCA and, consequen ly, equi es a
highe quan i y o wa e [47].

Chap e 4
46
In o de o e i y he sh inkage es ima ion alue nume ically in compa ison o he expe imen ally
ob ained da a, he S uc u al Conc e e Code (SC-BOE) [20] and Eu ocode 2: EN 1992-1-1 (EC-02)
[198] we e conside ed.
Acco ding o SC-BOE, he d ying sh inkage is es ima ed nume ically using Eq.4 (6):
εcd( )=( − s)
( − s)+0.04√ho3.kh.εcd,0
Eq.4 (6)
whe e: is he conc e e age in days (91 days); s s is he conc e e age when i was exposed o
d ying condi ions (1 day); h0 is he no ion size equal o 2Ac/u, whe e Ac (5625 mm2) is he conc e e
c oss-sec ional a ea and u (300 mm) is he pe ime e o he sec ion exposed o d ying; kh is he
coe icien ( aking he alue o 1.00), which depends on he a e age hickness h0; and εcd,0 is he ini ial
d ying sh inkage o conc e e in mm/m (Eq.4 [7]).
εcd,0=0.85[(220+210.αds1)exp(−αds2 cm
cmo)].10−6.1.55[1−(HR
HRo)3]
Eq.4 (7)
whe e cm is he a e age comp essi e s eng h (N/mm2) in cylind ical specimens;
cm0 = 10 N/mm2; αds1 is a coe icien ha depends on he ype o cemen , which is 6 o R cemen
class; αds2 is a coe icien ha depends on he ype o cemen , which is 0.11 o R cemen class; HR is
he ela i e humidi y o he en i onmen ; and HR0 = 100 %.
Acco ding o Eu ocode 2: EN 1992-1-1 (EC-02) [198], he d ying sh inkage is nume ically
es ima ed wi h Eq.4 (8):
εcds( − s)=[(220+210.αds)exp(−0.012𝑓𝑐𝑚,28)].10−6.1.55
[
1−
(
RH
99.( 35
𝑓𝑐𝑚,28)3≤99
)
3
]
.[ (𝑡−𝑡𝑠)
0.035∗ℎ𝑛2+(𝑡−𝑡𝑠)]0.5𝑛𝑠ℎ𝑅𝐴
Eq.4 (8)
whe e αds is a coe icien ha depends on he ype o cemen , which is 6 o R class cemen ; RH
is he ela i e humidi y o he en i onmen ; s is he age o he conc e e a he beginning o d ying (1
day); is he ime elapsed since conc e e cas ing (i.e. conc e e age, which was 91 days); hn: is he
no ion size = 2 Ac/u, whe e Ac is he conc e e c oss-sec ional a ea and u is he pe ime e exposed o
Chap e 4
47
d ying; shRA is a ac o when RCA is employed in conc e e p oduc ion be ween 0.20 < αRA  0.40
(shRA = 1+0.8 αRA, whe e αRA is a a io be ween he quan i y o FRCA and CRCA and he o al
quan i y o agg ega es, ine and coa se agg ega es, employed).
Acco ding o EC-02, ecycled agg ega es may be used in no mal conc e e p oduc ion wi hou any
pa icula consen i done in acco dance wi h he p o isions o ype A ecycled agg ega e as de ined
in EN 206.
Figu e 4. 7 shows he a ios be ween expe imen ally ob ained sh inkage da a wi h espec o he
nume ically ob ained alues (SC-BOE and EC-02) o all o he conc e es p oduced in Phase 1. The
alues ob ained in Phase 2 we e no analysed because, due o he low empe a u e and ela i e humidi y
o he clima e oom, he ob ained alues we e lowe han he expec ed ones. Figu e 4. 7 shows ha he
EC-02 [198] es ima ion me hod, which conside ed he RCA in luence using he ac o shRA,
adequa ely es ima ed he alues o all o he conc e es. Howe e , SC-BOE [20] me hods
unde es ima e he RAC sh inkage alue because i is only ega ded as applicable o NAC and RAC-
C20. Howe e , i adequa ely es ima ed he beha iou o conc e e p oduced using up o 60 % CRCA
and 20 % FRCA because hey ha e limi ed in luence on d ying sh inkage alues.
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
1,8
2,0
Ra io Expe imen al alue/ nume ical
es ima ion
SC-BOE EC-02
Figu e 4. 7 Analysis o sh inkage es ima ion, he a io o expe imen al esul s/nume ical es ima ion ollowing SC-BOE
and EC-02 o he conc e es p oduced in Phase 1.
4.3.4. Du abili y p ope ies.
4.3.4.1 So p i i y
Figu e 4. 8 displays he capilla y abso p ion alues ob ained o e ime o he conc e es p oduced
in Phase 1 and Phase 2. In addi ion, Table 4. 3 shows he so p i i y alues o each o he p oduced
conc e es. All o he RACs achie ed highe alues han he NACs.
Chap e 4
48
In Phase 1, he conc e es p oduced using 20 % o 100 % o he CRCA in subs i u ion o coa se
agg ega es ob ained alues o 30.2 % o 39.6 %, a highe so p i i y alue han ha o NAC1. In Phase
2, due o he conc e e p oduc ion ha e highe w/c a ios han Phase 1, he CRCA in luence on so p i i y
was lowe . Consequen ly, he conc e es made using 20 % o 30 % CRCA had so p i i y alues ha
only inc eased by 10 % as compa ed o NAC2. In addi ion, he conc e es p oduced wi h 50 % and 60 %
CRCA achie ed so p i i y alues up o 28.3 % g ea e han NAC2. Simila ly, Ped o and B i o [51]
ob ained so p i i y alues o RAC conc e es p oduced wi h 100 % CRCA and na u al sand and
achie ed comp essi e s eng hs ha we e 46.9–59.4 % highe han he NAC. In addi ion, o he
esea che s [59,180] ha e desc ibed so p i i y inc eases wi h RAC ha we e lowe when he conc e es
we e p oduced wi h a highe w/c a io, eaching an inc ease o 22 % and 37 % when conc e es we e
p oduced wi h a 100 % CRCA eplacemen a io.
The conc e e also employing FRCA achie ed a highe so p i i y alue han ha p oduced only
wi h CRCA (see Figu e 4. 8-a and Figu e 4. 8-b). In Phase 1, he conc e e made wi h 50 % CRCA and
20 % o 50 % FRCA inc eased by 62.5 % and 103.7 %, espec i ely, as compa ed o NAC1. In
addi ion, hey achie ed so p i i y alues o 0.0466 mm/min0.5 and 0.0493 mm/min0.5, espec i ely. In
Phase 2, al hough he RAC-C50-F202 and RAC-C50-F502 conc e es had lowe inc eases wi h espec
o NAC2 (43.5 % and 74 %), hey achie ed so p i i y alues o 0.0557 mm/min0.5 and
0.0676 mm/min0.5, espec i ely. O he esea che s [51] also ound ha conc e e p oduced wi h 50 %
FRCA and CRCA su e ed inc eases o up o 72 % wi h espec o NAC. Howe e , i should be no ed
ha RAC-C60-F202 and RAC-C60-F302 achie ed adequa e pe o mance wi h so p i i y alues o
0.0429 mm/min0.5 and 0.0438 mm/min0.5, espec i ely.
In e ms o he compa ison o Phase 1 and Phase 2 alues, all o he conc e es p oduced using
CRCA in Phase 1 achie ed lowe so p i i y alues han NAC2. The use o FRCA inc eased he
so p i i y alue. The Phase 1 conc e es achie ed lowe so p i i y alues han he co esponding
conc e es in Phase 2.
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
0 2 4 6 8 10 12
Capila y Absop ion (mm)
Time (min0.5)
NAC₁RAC-C20₁
RAC-C30₁RAC-C50₁
RAC-C100₁RAC-C50-F20₁
RAC-C50-F50₁RAC-C60-F20₁
RAC-C60-F30₁RAC-C100-F20₁
RAC-C100-F100₁
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
0 2 4 6 8 10 12
Capila y Absop ion (mm)
Time (min0.5)
NAC₂RAC-C20₂
RAC-C30₂RAC-C50₂
RAC-C60₂RAC-C20-F5₂
RAC-C30-F10₂RAC-C50-F20₂
RAC-C50-F50₂RAC-C60-F20₂
RAC-C60-F30₂
a)
b)
Figu e 4. 8 So p i i y alues a 28 days in a) Phase 1 and b) Phase 2
Chap e 4
49
Acco ding o se e al esea che s [199], conc e e wi h a so p i i y alue lowe han 0.10 mm/min0.5
is conside ed du able. Howe e , o he esea che s [200] p oposed lowe ing ha alue o
0.05 mm/min0.5 o easons o sa e y. Ped o and B i o [51] exp essed ha he quali y o conc e e is low
i he so p i i y alue is highe han 0.2 mm/min0.5, medium i he coe icien is be ween
0.2 mm/min0.5 and 0.1 mm/min0.5, and good i he coe icien is lowe han 0.1 mm/min0.5. Acco ding
o hose c i e ia, i can be concluded ha all o he conc e es in Phase 1 and Phase 2 we e in he high
quali y and du able ange. Howe e , conside ing a mo e es ic i e condi ion o 0.05 mm/min0.5, in
Phase 1, he RCA-C60-F301 would de ine he limi , and he RCA-C50-F20 would be he limi , in Phase
2.
4.3.4.2 Wa e pene a ion unde p essu e
Figu e 4. 9 displays he wa e pene a ion alues ob ained o conc e es p oduced in Phase 1 and
Phase 2. Acco ding o he S uc u al Conc e e Code (SC-BOE) [20], he a e age (Da) and maximum
(Dmax) wa e pene a ion unde p essu e should be lowe han 30 mm and 50 mm, espec i ely, o
agg essi e exposu e classes o conc e e. Consequen ly, he ob ained esul s show ha all o he mixes,
ega dless o he pe cen age and ype o RCA used in conc e e p oduc ion, me he equi emen s
es ablished by he S uc u al Conc e e Code (SC-BOE).
In Phase 1, he conc e es p oduced using only CRCA as eplacemen o NAs achie ed an a e age
wa e pene a ion alue o abou 8.0 mm. In addi ion, he maximum wa e pene a ion alues we e
13 mm. When he ine ac ion was used in conc e e p oduc ion, he a e age (Da) wa e pene a ion
dep h alues o all he conc e es emained simila o ha o he NAC1. Howe e , he Dmax inc eased o
22 %, 16 % and 26 % in RAC-C50-F501, in RAC-C100-F201 and RAC-C100-F1001, espec i ely, as
compa ed o NAC1. The esul s ob ained in his esea ch we e lowe han hose ound by Kapoo and
Singh [201], who obse ed ha ecycled conc e es manu ac u ed wi h 100 % CRCA inc eased wa e
pene a ion by 30 %.
In Phase 2, he a e age and maximum wa e pene a ions anged om 8.03 mm o 13.70 mm and
12.25 mm o 22 mm, espec i ely. The highe wa e pene a ion was obse ed wi h RAC-C50-F502,
RAC-C60-F202 and RAC-C60-F302, wi h a ia ions o 29.4 %, 31.4 % and 72.5 %, espec i ely,
compa ed o NAC2. As a gene al ule, he g ea e he AR subs i u ion in a mix u e, he g ea e he
wa e pene a ion [144]. Howe e , he wa e pene a ion unde p essu e p ope y seems o be mo e
in luenced by he e ec i e w/c a io [183,202] and no by he RCA used, causing doub ega ding an
e ec i e du abili y p ope y.
In e ms o compa ing Phase 1 and Phase 2 alues, he NACs (NAC1 and NAC2) achie ed simila
alues. In addi ion, he ecycled conc e es p oduced in Phase 1 (using an e ec i e w/c a io o 0.48)
ha used up o 60 % CRCA oge he wi h up o 30 % FRCA achie ed alues simila o NAC.
Chap e 5
56
Table 5. 2 shows ha he RAC achie ed 18% lowe comp essi e s eng h han ha o NAC-0.47
(all conc e es we e made using he same e ec i e wa e -cemen a io o 0.47). Howe e , he RAC
achie ed simila s eng h o NAC-0.51 conc e e, which was made wi h an e ec i e wa e -cemen a io
o 0.51 (see Figu e 5. 1). These indings highligh he in luence o ecycled agg ega es on he
mechanical p ope ies o conc e e and emphasise he impo ance o adjus ing he wa e - o-cemen a io
o achie e compa able comp essi e s eng h o ha o NAC.
Al hough all he RACs had he same e ec i e wa e -cemen a io, RACs manu ac u ed wi h ype
CEM IIAL cemen exhibi ed sligh ly lowe comp essi e s eng h han hose ob ained wi h ype CEM
IIAS and ype CEM IIIB cemen . This di e ence could be a ibu ed o en i onmen al empe a u e:
he RACs made wi h CEM IIAL we e p oduced in sp ing/summe , while he o he s we e p oduced in
au umn/win e [204]. These ac o s could in luence he se ing and cu ing p ocess o he conc e e,
di ec ly a ec ing i s inal s eng h.
Figu e 5. 1 a-c desc ibes he a io o comp essi e s eng h alue ob ained by each conc e e wi h
espec o ha o NAC-0.51 a 7, 28 and 56 days. In gene al, NAC-0.47 achie ed be ween 3% and
17% highe s eng h han NAC-0.51 conc e e a di e en ages.
(a) CEM-IIAL
(b) CEM-IIAS
0
0,2
0,4
0,6
0,8
1
1,2
NAC₀₄₇ RAC-C50 RAC-C50-F10 RAC-C50-F20
Ra io comp esi es engh all
conc e es/NAC0,51
7 days 28 days
56 days NAC₀₅₁
0
0,2
0,4
0,6
0,8
1
1,2
NAC₀₄₇ RAC-C50 RAC-C50-F10 RAC-C50-F20
Ra io comp esi es engh all
conc e es/NAC0,51
7 days 28 days
56 days NAC₀₅₁

Chap e 5
57
(c) ) CEM-IIIB
Figu e 5. 1 Rela i e comp essi e s eng h a all conc e e ages p oduced wi h cemen s: a) ype CEM IIAL; b) ype CEM
IIAS; c) ype CEM III-B
Figu e 5. 1-a desc ibes he a io when he conc e es we e p oduced using he cemen CEM IIAL.
While he RAC-C50 and RAC-C50-F10 achie ed simila alues o NAC-0.51 a any age, he RAC-
C50-F20 ob ained a dec ease o up o 8.5% a 56 days. Figu e 5. 1-b shows he esul s ob ained o
conc e e p oduced wi h CEM IIAS. All he RAC, including he RAC-C50-F20, achie ed a simila
s eng h o he NAC-0.51 conc e e. Simila ly, Figu e 5. 1-c shows ha RAC made wi h CEM IIIB
cemen achie ed a sligh ly highe s eng h han NAC-0.51. The esul s (Figu e 5. 1) show ha he
di e en subs i u ion le els o RCA (50% CRCA and up o 20% FRCA) did no ha e a signi ican
de imen al impac on comp essi e s eng h. In addi ion, as disco e ed in p e ious wo k [126], i was
e i ied ha he conc e e p oduced wi h 50% CRCA and 20% FRCA (RAC-C50-F20) achie ed simila
comp essi e s eng h o conc e e con aining only CRCA (RAC-C50) and NAC when he RAC and
NAC we e made wi h an e ec i e wa e -cemen a io o 0.47 and 0.52, espec i ely.
Gao and Wang [62] epo ed ha conc e e p oduced wi h a highe pe cen age o FRCA caused
a educ ion o he comp essi e s eng h alue. Howe e , se e al esea che s sugges ed ha
inco po a ing 30% FRCA as a eplacemen o na u al sand could s ill achie e sa is ac o y p ope ies
[63,64]. E angelis a and B i o [63] and Ped o and B i o [51] also con i med he use o up o 30%
FRCA o s uc u al conc e e p oduc ion.
Acco ding o he esul s, he NAC and RAC conc e e (p oduced wi h 50% CRCA and up o 20%
FRCA) achie ed simila comp essi e s eng h when an e ec i e wa e -cemen a io o 0.51 and 0.47
was used in conc e e p oduc ion, espec i ely. They all achie ed a sui ably designed comp essi e
s eng h o C30/37 o s uc u al applica ions.
0,0
0,2
0,4
0,6
0,8
1,0
1,2
NAC₀₄₇ RAC-C50 RAC-C50-F10 RAC-C50-F20
Ra io comp esi es engh all
conc e es/NAC 051
7 days 28 days
56 days NAC₀₅₁
Chap e 5
58
5.3.2. D ying Sh inkage
Figu e 5. 2 a–c and Figu e 5. 3 a–c illus a es he d ying sh inkage (µƐ) and mass loss (%) alues,
espec i ely, o e 91 days o he NAC-0.51 and RAC conc e es p oduced using cemen CEM IIAL
(a), CEM IIAS (b) and CEM IIIB (c).
(a)
(b)
(c)
Figu e 5. 2 D ying sh inkage de elopmen a 91 days: a) CEM II/AL, b) CEM II/AS, c) CEM III/B
Chap e 5
59
(a)
(b)
(c)
Figu e 5. 3 Mass loss de elopmen a 91 days: a) CEM II/AL, b) CEM II/AS, CEM III/B.
Acco ding o sh inkage alues, he conc e es p oduced wi h CEM IIAL achie ed a d ying
sh inkage alue be ween -496.8 and -562.7 µm/m a 91 days (see Figu e 5. 2-a). The RAC-C50
conc e e achie ed a 7.3% highe d ying sh inkage alue han ha o he NAC. Fu he mo e, he RAC-
C50-F20 conc e e achie ed a 13.3% highe d ying sh inkage han NAC conc e e ( he RAC-C50-F10
conc e e was no es ed).
Acco ding o he esul s ob ained om he conc e es p oduced using CEM IIAS (see Figu e 5.
2-b), he ob ained sh inkage alues we e be ween -318.82 and -496.52 µm/m. Figu e 5. 2-b shows ha
RAC-C50 and RAC-C50-F10 had simila d ying sh inkage alues which we e 18% and 16%,
Chap e 5
60
espec i ely, highe han NAC-0.51. Mo eo e , he RAC-C50-F20 conc e e had 56% highe d ying
sh inkage han NAC-0.51.
In acco dance wi h he esul s ob ained om he conc e es p oduced wi h CEM IIIB (see Figu e
5. 2-c), all he conc e es achie ed simila d ying sh inkage alues, be ween -437.3 and -489.6 µm/m.
Figu e 5. 2-c shows ha RAC-50 only exceeds 3% o he alue ob ained by NAC-0.51 conc e e, while
RAC-C50-10 and RAC-C50-20 we e 11% and 12% highe han NAC-0.51, espec i ely. The use o
RAC educed s i ness caused by he amoun o adhe ed mo a in he ecycled agg ega e
[126,205,206]. This p ope y is closely associa ed wi h he modulus o elas ici y, which is he p incipal
mechanical indica o o ma e ial s i ness [205]. Vin imilla and E xebe ia [126] de e mined ha RAC
conc e e p oduced using CEM IIAL wi h 50% CRCA and 20% FRCA achie ed a 19% lowe modulus
elas ici y and a 14% highe d ying sh inkage alue han hose o NAC. Bendime ad e al. [31]
con i med ha he inc ease in d ying sh inkage was associa ed wi h a dec ease in modulus. Acco ding
o he achie ed esul s, FRCA s ongly in luenced and inc eased he sh inkage alue, consequen ly,
he conc e e p oduced wi h 20% FRCA eached he highes sh inkage alue ega dless o he ob ained
comp essi e s eng h, as all he conc e es exhibi ed simila comp essi e s eng h. Despi e his inc ease
in sh inkage, all he alues we e conside ed accep able acco ding o ACI [122], which s a es ha he
ypical d ying sh inkage alues o NAC ange om -200 o -800 when a high wa e -cemen a io is
employed. In addi ion, in gene al, RAC p esen s de ia ions simila o hose NAC, bu be ween hem
showed a mode a e dispe se in mos cases.
Du ing he i s ou days o cu ing wi hin a d ying chambe , he conc e es p oduced wi h lowe
clinke (CEM IIIB cemen , see Figu e 5. 2-c) achie ed he highes sh inkage alue. D ying sh inkage
mainly occu s du ing he ea ly ages and ends o s abilise o e ime [51] . Howe e , his beha iou is
mo e appa en when SCM is employed as a conc e e binde [118,119]. The NAC-0.51 p oduced wi h
CEM IIIB, CEM IIAL and CEM IIAS cemen eached -200 µm/m, -170 µm/m and -110 µm/m,
espec i ely. In addi ion, he sh inkage alue inc eased as he pe cen age o RCA used inc eased. The
RAC-C50-F20 p oduced wi h CEM IIIB cemen achie ed a d ying sh inkage alue o -280 µm/m in
he i s ou days o d ying. Howe e , as men ioned abo e, he sh inkage alues s abilised o e 28
days.
Figu e 5. 3 a-c show he mass loss (in %) o each conc e e p oduced wi h CEM IIAL, CEM IIAS
and CEM IIIB, espec i ely. The h ee NAC-0.51 mixes achie ed a simila mass loss o 2.2%, 2.3%,
and 1.9%, espec i ely. As expec ed, he conc e e mass loss inc eased as he pe cen age o ecycled
agg ega es ose. Simila ly, o he d ying sh inkage alue, he RAC-C50-F20 p oduced wi h CEM
IIAL achie ed he highes mass loss wi h 3.5%, ollowed by he RAC-C50-F20 p oduced wi h CEM
IIAS and las ly, CEM IIIB wi h a mass loss o 3.1% and 2.86%, espec i ely (see Figu e 5. 3). These
alues a e consis en wi h he esul s ound by o he esea che s [126,207,208].
In all cases, highe d ying sh inkage was closely associa ed wi h a highe mass loss when
compa ing conc e es ha employed he same ype o cemen . All con ol conc e es exhibi ed an
a e age mass loss o app oxima ely 2%, while he inco po a ion o ine and coa se ecycled agg ega es
esul ed in an inc emen o app oxima ely 3% o 3.5%.
Chap e 5
61
The o mula ions p o ided by he S uc u al Conc e e Code (SC-BOE) [20] and he Eu ocode 2:
EN 1992-1-1 (EC-02) [198] we e used o p edic d ying sh inkage in RAC conc e es. The calcula ion
me hod used was desc ibed in a p e ious pape [126].
In o de o de e mine he sh inkage alue ollowing he S uc u al Conc e e Code (SC-BOE)
[20], he ollowing ac o s should be conside ed: he comp essi e s eng h a 28 days; conc e e
specimen size; ambien RH; and he ype o cemen ( he CEM IIAL was conside ed high ea ly s eng h
(Class CR); he CEM II/AS; and CEM IIIB cemen s we e conside ed o dina y ea ly s eng h (Class
CN)). Howe e , i mus be no ed ha he SC-BOE does no conside he use o RCA.
Howe e , he use o RCA o es ima e he sh inkage alue is conside ed in Eu ocode 2: EN 1992-
1-1 (EC-02) [198]. The in luence o CRCA and FRCA was calcula ed by applying a speci ic ac o
(shRA) in he o mula o de e mine he d ying sh inkage o RAC. The shRA is desc ibed
as 1+0.8 αRA, whe e αRA ep esen s he a io be ween he ecycled agg ega es quan i y (CRCA and
FRCA) and he o al quan i y o agg ega es (coa se and ine agg ega es) employed. This ac o
(shRA) is applied when he RCA is employed in eplacemen o 20-40% o NAs (0.20 < αRA  0.40)
[126,198]. In his esea ch wo k, he αRA ac o s was de ined by 0.27, 0.31, and 0.36 o he RAC-
C50, RAC-C50-F10, and RAC-C50-F20 conc e es, espec i ely.
To demons a e he e ec i eness o he codes in p edic ing d ying sh inkage in conc e e, Figu e
5. 4 illus a es he a io be ween he expe imen ally ob ained d ying sh inkage alue o each conc e e
and he alue de e mined using he ollowing s anda ds: a) S uc u al Conc e e Code (SC-BOE) and
b) Eu ocode 2: EN 1992-1-1 (EC-02).
0
0.2
0.4
0.6
0.8
1
1.2
1.4
NAC₀₅₁ RAC-C50 RAC-C50-F10 RAC-C50-F20
Ra io D ying sh inkage s ain all
conc es/SC-BOE
CEM II/AL CEM II/AS
CEM III/B SC-BOE
(SC-BOE)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
NAC₀₅₁ RAC-C50 RAC-C50-F10 RAC-C50-F20
Ra io D ying sh inkage s ain all
conc e es/EC-02
CEM II/AL CEM II/AS
CEM III/B EC-O2
(EC-02)
(a)
(b)
Figu e 5. 4 Sh inkage es ima ion analysis depic ed h ough a ios o a) expe imen al esul s/ nume ical es ima ion SC-
BOE and b) expe imen al esul s/nume ical es ima ion EC-02

Chap e 5
62
Acco ding o Figu e 5. 4-a, he Spanish S uc u al Conc e e Code (SC-BOE) is no exac in he
es ima ion o NAC-0.51 conc e e's sh inkage alue. I has been obse ed ha he conc e e p oduced
wi h CEM IIAL and CEM IIAS cemen s achie ed a 10-15% lowe sh inkage alue han he alue
es ima ed by SC-BOE. Howe e , he conc e e p oduced wi h CEM IIIB cemen achie ed a 15% highe
sh inkage alue han ha o he alue es ima ed o SC-BOE cemen . Al hough he ype o cemen was
conside ed in he d ying sh inkage calcula ion o he SC-BOE, i was no conside ed in a highe ea ly
sh inkage caused by high BFS con en cemen (CEM IIIB), which can in luence o al d ying sh inkage
[118,119]. Mo eo e , he comp essi e s eng h a 28 days is he p ima y pa ame e conside ed in SC-
BOE es ima ion; his p o ed o be simila in all NAC-0.51 conc e es. Howe e , as Figu e 5. 4-a
indica es mo e pa ame e s besides he comp essi e s eng h should be conside ed. Re illa-Cues a
[129] sugges ed ha a pa ial co ec ion coe icien should be used o e e y change in conc e e
composi ion, including aspec s such as he ype o conc e e ( ib a ed, high-pe o mance, o sel -
compac ing), he con en o RA, he ma u i y o he RA, and he addi ion o an al e na i e binde .
The SC-BOE adequa ely es ima es he sh inkage alues o RAC-C50 and RAC-C50-F20
conc e es made wi h CEM IIAL as well as he RAC-C50 and RAC-C50-F10 conc e e made wi h CEM
IIAS as he use o RCA sligh ly inc eased he sh inkage alue o conc e es. Howe e , he RCA-C50-
F20 made wi h CEM IIAS achie ed a 38% highe sh inkage alue han he alue es ima ed by SC-
BOE. The SC-BOE es ima ed adequa ely he sh inkage alue o RCA-C50-F20 made wi h CEM IIAL
as i achie ed a lowe s eng h han any conc e e p oduced wi h his cemen . Consequen ly, i can be
s a ed ha he SC-BOE can adequa ely es ima e he d ying sh inkage o conc e e p oduced wi h 50%
CRCA and up o 10% FRCA. Howe e , i es ima es a lowe sh inkage a e han he alue ob ained
expe imen ally when 50% CRCA and 20% FRCA a e employed in conc e e p oduc ion.
In addi ion, all he conc e es made using CEM IIIB eached a highe sh inkage a e han
es ima ed by SC-BOE. Se e al esea che s ha e epo ed ha he code es ima ions could c ea e a ±
30% dispe sion in he esul s [54,129]. Mo eo e , his di e ence inc eased when ecycled agg ega es
we e used. As men ioned p e iously, conc e e wi h a high BFS con en exhibi s highe ea ly sh inkage,
which can in luence o al d ying sh inkage [118,119]. Fu he mo e, he specimens we e placed in a
clima ic chambe a e a sho pe iod o cu ing (a e 1 day o cas ing) [118], which also in luenced
he inc ease in expe imen ally ob ained sh inkage alues.
Figu e 5. 4-b desc ibes he a io be ween he expe imen al esul s and he alues de e mined by
EC-02. The alues es ima ed by EC-02 o conc e e p oduced wi h CEM IIAL and CEM IIAS we e
highe han hose ob ained expe imen ally. Howe e , simila o SC-BOE, he NAC-0.51 conc e e
p oduced using CEM IIIB, EC-02 es ima ed a lowe sh inkage alue han i achie ed expe imen ally.
Mo eo e , as men ioned abo e, EC-02 conside s sh inkage inc ease as a ac o due o he use o
ecycled agg ega es. Consequen ly, he EC-02 p edic ion o RAC d ying sh inkage is mo e accu a e
o he expe imen al esul s han he alues ob ained by he SC-BOE.
Chap e 5
63
5.3.3. Chlo ide Ion Pene a ion
Table 5. 3 desc ibes he chlo ide ion pene abili y alues and hei s anda d de ia ion ( alues
gi en be ween b acke s) o p oduced conc e e mix u es measu ed a 28 and 56 days o cu ing. The
ASTMC1202 es classi ied he chlo ide ion pene abili y as low (1000-2000 Coulomb), mode a e
(2000-4000 Coulomb), and high (> 4000 Coulombs o o al passed cha ge) [209]. This esea ch ound
ha chlo ide ion pene abili y a ied signi ican ly acco ding o he ype o cemen used, as se e al
esea che s ha e s a ed [113,210–212]. In addi ion, a di ec co ela ion was obse ed be ween he
pe cen age o ecycled agg ega e eplacemen a io and chlo ide ion pene abili y. This is a ac also
de ined in p e ious esea ch wo ks [9,40].
Table 5. 3 Chlo ide ion pene abili y and he s anda d de ia ion (desc ibed in b acke s) de e mined in Cha ge pass in
coulombs.
3
IIAL
IIAS
IIIB
(Coulombs)
Δ (%)
(Coulombs)
Δ
(%)
(Coulombs)
Δ
(%)
28d
56d
28d
56d
28d
56d
NAC-0.51
5314(2)
4096(271)
23
2897(111)
1976(129)
32
674(15)
501(12)
26
RAC-C50
4479(441)
4065(71)
9
2535(136)
1962(80)
23
610(9.0)
503(8)
18
RAC-C50-F10
6038(596)
4448(97)
26
3130(58)
2293(5)
27
626(16)
531(15)
15
RAC-C50-F20
6401(569)
4944(178)
23
4515(91)
2866(66)
37
740(40)
532(18)
28
() S anda d de ia ion. Δ (inc ease o esis ance)
Figu e 5. 5 shows he a io be ween he cha ge passed om each conc e e p oduced wi h espec
o 4000 coulombs ( he maximum alue conside ed a mode a e co osion isk conc e e). Figu e 5. 5 a,b
desc ibe he da a a 28 and 56 days, espec i ely. Figu e 5. 5-a shows ha all conc e es manu ac u ed
wi h CEM IIAL exhibi high alues o chlo ide ion pene a ion. The addi ion o BFS o cemen educed
he ion pene abili y o he conc e e as Kopecký and Balázs e al. [212], s a ed.
Chap e 5
64
(a)
(b)
Figu e 5. 5 The a io o chlo ide ion pene abili y (de e mined in cha ge pass) o all conc e es wi h espec o maximum
alue o 4000 Coulombs: a) 28 days and b) 56 days
Based on he in luence o RCA use, he RAC-C50 achie ed lowe chlo ide ion pene abili y han
ha o NAC, independen o cemen ype. Howe e , i mus be men ioned ha he RAC-C50 and NAC-
0.51 we e p oduced wi h e ec i e wa e -cemen a ios o 0.47 and 0.51, espec i ely. In ag eemen
wi h he s udy conduc ed by Kopeckó and Balázs e al. [212], i was shown ha an inc ease in he w/c
a io leads o an inc ease in he dep h o chlo ide pene a ion, while keeping he same cemen con en
cons an . Mo eo e , when FRCA was employed o conc e e p oduc ion, and mo e e iden ly wi h he
use o 20% FRCA in he eplacemen o na u al sand, he chlo ide ion pene abili y inc eased. In
addi ion, his was mo e e iden when cemen wi hou BSF (CEMII AL) o low BSF (CEM IIAS) was
used o conc e e p oduc ion. The high po osi y and mic oc acks o he old mo a a e p esen on he
RCA su ace, esul ing in he inc eased pe meabili y o chlo ide ions [209,213].
Resea che s ha e demons a ed ha RAC exhibi s mo e capilla y channels han NAC, hese a e
p ima ily a ibu ed o he in oduc ion o in e acial ansi ion zones (ITZs) be ween na u al
agg ega es and old cemen mo a s, as well as he p esence o mic oc acks in he RCA [40,87].
Howe e , E xebe ia e al. [214] ha e demons a ed ha he o al cha ge passed alue o all conc e es
mixed using CEM IIIB cemen wi h di e en pe cen ages o ecycled mixed agg ega es ( olumes o
0%, 25%, 50% and 100%) anged om 800 o 1400 coulombs. The au ho s ha e also demons a ed
ha an adequa e cemen ype was necessa y o inc ease chlo ide ion pene a ion esis ance in conc e e
p oduc ion. Sim and Pa k [91] concluded ha he inco po a ion o FRCA had a minimal impac on
chlo ide ion pene a ion. They obse ed ha he ype o cemen used had a mo e signi ican in luence
on conc e es pe o mance han he quan i y o ecycled agg ega es. In addi ion, Table 5. 3 shows ha
he s anda d de ia ion o conc e es p oduced wi h CEM IIAL was highe han ha p oduced wi h he
CEM IIAS. In addi ion, he conc e es p oduced wi h CEM IIIB achie ed he lowes de ia ion s anda d.
These indings highligh a iabili y in conc e e p ope ies due o di e en cemen ypes. No ably, CEM
0
0.25
0.5
0.75
1
1.25
1.5
1.75
NAC₀₅₁ RAC-C50 RAC-C50-F10 RAC-C50-F20
Ra io Chlo ide Ion Pene a ion all
conc e es/4000(ASTMC1202)
CEM-IIAL CEM-IIAS
CEM-IIIB ASTMC1202 (High)
ASTMC1202(Low) ASTMC1202( Mode a e)
MODERATE
HIGH
LOW
0
0.25
0.5
0.75
1
1.25
1.5
1.75
NAC₀₅₁ RAC-C50 RAC-C50-F10 RAC-C50-F20
Ra io Chlo ide Ion Pene a ion all
conc e es/4000(ASTMC1202)
CEM-IIAL CEM-IIAS
CEM-IIIB ASTMC1202 (High)
ASTMC1202(Low) ASTMC1202( Mode a e)
HIGH
MODERATE
LOW
Chap e 5
65
IIAL and CEM IIAS exhibi ed ela i ely high s anda d de ia ions, howe e , o ensu e accu a e alues,
mo e han wo should be used.
A e a cu ing pe iod o 56 days (see Figu e 5. 5-b), he chlo ide pene a ion esis ance inc eased
in all he conc e es. Howe e , all he conc e es p oduced using CEM IIAL, including NAC, s ill had
e y high chlo ide ion pene abili y alues. This ac can be a ibu ed o he limes one base o CEM
IIAL conc e e [215] which had highe chlo ide ion pe meabili y han hose mixes wi h a highe
eplacemen o SCM [215,216]. As a consequence, i was concluded ha CEM IIAL cemen was
unsui able o de ined applica ion due o i s limi ed abili y o esis chlo ide ion pene a ion. The
ob ained esul s o chlo ide pene abili y in his wo k we e sligh ly lowe han hose de e mined by
E xebe ia and Cas illo [217], in which he conc e e p oduced wi h 50% coa se RCA and he same
ype o cemen wi h e ec i e wa e -cemen a io o 0.50 and a cemen con en 350 kg/m3 ob ained
8799 C a 28 days and 6377 C a 56 days. In conc e e p oduced using CEM IIAS, an imp o emen in
chlo ide ion pene a ion esis ance was obse ed om 28 o 56 days, wi h a ange be ween 23% and
37% in all samples. This ac demons a es ha all conc e e mix u es achie ed a mode a e le el o
esis ance in e ms o chlo ide ion pene a ion. In addi ion, all he conc e es p oduced using ype CEM
IIIB cemen had low chlo ide pe meabili y a 28 and 56 days, independen ly o he pe cen age o RCA
employed. As men ioned abo e, BFS cemen enhances chlo ide pene a ion esis ance in conc e e due
o i s abili y o immobilize chlo ide ions [93,94].
5.3.4. Ca bona ion Resis ance
Table 5. 4 summa ises he ca bona ion dep h (in mm) and i s s anda d de ia ion (be ween
b acke s), which was de e mined by es ing each p oduced conc e e a e 91 days o exposu e o 3%
CO2, 57% RH and 20ºC. Al hough he NAC-0.51 conc e es achie ed he lowes ca bona ion dep hs
(in each ype o cemen conc e es), he RAC-C50 and RAC-C50-F10 conc e es eached simila alues
o ha o NAC-0.51 conc e e, wi h he excep ion o he RAC-C50-F10 conc e e p oduced wi h CEM
IIAL, which had a 12.9% highe ca bona ion dep h han he co esponding NAC-0.51. Acco ding o
Guo e al. [40], he RAC and NAC achie ed simila esis ance and ca bona ion dep h when he RAC
was p oduced wi h a lowe w/c a io.
Table 5. 4 Ca bona ion dep h, hei s anda d de ia ion, and he accele a ed and heo ical na u al ca bona ion coe icien
o all conc e es
Conc e e ypes
Ca bona ion dep h(mm) a 90 days
Ca bona ion coe icien
kacc (mm/day0.5)
kna THEO (mm/yea 0.5)
II AL
II AS
III B
II AL
II AS
III B
II AL
II AS
III B
NAC-0.51
7.7(0.1)
6.0(0.1)
12.0(0.4)
0.81
0.65
1.22
1.84
1.48
2.79
RAC-C50
8.0(0.4)
6.1(0.2)
12.1(0.2)
0.84
0.68
1.27
1.9
1.55
2.89
RAC-C50-F10
8.7(0.2)
6.3(0)
12.1(0.1)
0.97
0.68
1.28
2.19
1.55
2.92
RAC-C50-F20
9.8(0.0
7.2(0.2)
12.9(0.1)
1.04
0.78
1.39
2.37
1.77
3.16
Chap e 6
72
he conc e e was de e mined by combining e ec i e wa e and he wa e wi hin he agg ega es
(humidi y plus he amoun o e ec i ely abso bed wa e ).
Table 6. 1 shows he mix p opo ions o he p oduced conc e es; combina ions o 50% and 60%
CRCA wi h 0%, 10% and 20% FRCA we e used. The desc ibed mix u es we e p oduced using h ee
ypes o cemen (CEM II/AL, CEM II/AS and CEM III/B). As men ioned abo e, hese subs i u ion
le els we e alida ed in a p e ious s udy by Vin imilla and E xebe ia e al. [126] o s uc u al
conc e e use.
Table 6. 1 Mix p opo ions o conc e es we e p oduced wi h CEM II/AL, CEM II/AS and CEM III/B
Ma e ials
Conc e e ypes
(kg)
NAC-
0.51
NAC-
0.47
RAC-
C50
RAC-C50-
F10
RAC-
C50-F20
RCA-
C60
RCA-
C60-F10
RCA-
C60-F20
Cemen
300
300
300
300
300
300
300
300
To al wa e
165
150
175.8
179.5
182.3
180.8
184.34
187.48
CNA 1
354.5
360.1
180.5
180.5
180.5
144.4
144.4
144.4
CNA 2
723.68
737.2
369.3
369.3
369.3
295.5
295.5
295.5
FNA
954.1
971.9
1014.2
875.7
778.4
973
875.7
778.4
CRCA 1
-
-
165.8
165.2
165.6
198.9
198.6
199.7
CRCA 2
-
-
338.8
339.1
337.2
406.0
406.1
404.2
FRCA
-
-
-
87.1
174.1
-
87.1
174.1
P (%)
1/0.7 1
1
1/0.6 1
1/0.5 1
1/0.3 1
1/0.3 1
1/0.3 1
1/0.3 1
S (%)
1
1
1/1.5 1
1/1.5 1
1/1.5 1
1/1.5 1
1/1.5 1
1/1.5 1
e ec i e w/c
0.51
0.47
0.47
0.47
0.47
0.47
0.47
0.47
Slump-IIAS (mm)
175
145
150
155
150
175
155
160
Slump-IIIB (mm)
175
160
135
150
150
140
150
125
Slump-IIAL (mm)
175
150
190
200
195
180
210
195
1 Plas icize con en u ilized in CEM II/AL
Table 6. 1 shows he slump alues (de e mined acco ding o he EN 12350-2 [203] speci ica ion)
o he p oduced conc e es. The conc e es made wi h CEM II/AL exhibi ed a liquid consis ency, and a
g ea e amoun o supe plas icize (P) was used han in he co esponding conc e e p oduced wi h IIAS
and IIIB cemen . In o de o con ol he consis ency, he conc e es p oduced wi h IIAS and IIIB we e
p oduced using a lowe supe plas icize con en and a sligh ly highe plas icize con en (1% S and 1%
P), achie ing a luid consis ency, as de ined by he S uc u al Conc e e Code (SC-BOE) [20]. The
conc e e p oduced wi h ype IIIB cemen achie ed a lowe slump alue han he co esponding
conc e e p oduced using IIAS, wi h he same amoun o admix u es. In addi ion, he conc e e p oduced
using FRCA achie ed a simila o highe slump alue han ha o he conc e e p oduced using only
CRCA.

Chap e 6
73
The conc e e mix u es we e p epa ed in a e ical axis mixe , and he agg ega es we e added i s
in o de o size. They we e mixed o 1 min, a e which cemen , ollowed by wa e and chemical
admix u es, was added while he mixing p ocess con inued. A e mixing o an addi ional minu e, he
conc e e specimens we e manually compac ed and co e ed wi h plas ic o 24-h o cu ing.
Subsequen ly, he specimens we e demolded and s o ed a 20 ± 2 °C wi h a ela i e humidi y o ≥ 95%
un il 1 h be o e es ing. All o he es elemen s we e kep in he same condi ions.
6.3. Resul s and Discussion
6.3.1. Comp essi e s eng h
The comp essi e s eng h alues ( cm, cub100) and hei s anda d de ia ions o cubic conc e e
specimens (100 × 100 × 100 mm) a e p esen ed in Table 6. 2. The specimens, designed o exposu e
classes XC1–XC4 and XS1 wi h s eng h class C30/37, mus mee he minimum cha ac e is ic and
a e age s eng h alues o 30 MPa and 38 MPa, espec i ely, o cylind ical specimens (150 × 300
mm), acco ding o he S uc u al Conc e e Code (SC-BOE) [20]. Acco ding o he di e ences in
geome ies and s ess dis ibu ions be ween cubes and cylinde s, Vin imilla and E xebe ia e al. [126]
de e mined, in compliance wi h SC-BOE [20],[184], ha he minimum a e age comp essi e s eng h
o 100 mm cubes ( cm,cub100) should be 46 MPa a 28 days.
In addi ion, he s anda d de ia ions we e accep able, wi h a highe dispe sion a 7 days ha
dec eased by 28 and 56 days, indica ing eliable measu emen s.
Table 6. 2 Comp essi e s eng h and i s s anda d de ia ion ( alues in b acke s) in all o he p oduced conc e e.
Conc e e
Re e ence
IIAL
IIAS
IIIB
7d
28d
56d
7d
28d
56d
7d
28d
56d
NAC-0.47
52.5(1.3)
62.9(1.3)
65.5(1.0)
54.5(1.3)
69.8(1)
71.3(1.9)
53.1(0.8)
67.2(0.4)
69.9(0.9)
NAC-0.51
45.2(2.0)
56.2(1.6)
58.8(1.0)
54.1(2.0)
59.2(0.5)
64.7(0.2)
51.5(0.1)
57.2(1.2)
59.9(0.9)
RAC-C50
48.6(2.5)
57.3(1.0)
59.9(1.7)
53.9(2.5)
59.2(2.3)
62.8(1.2)
53.7(0.3)
61.4(3.0)
62.0(1.0)
RAC-C50-F10
46.9(1.8)
56.3(1.5)
57.5(0.3)
52.4(1.8)
59.7(1.3)
59.9(0.2)
53.4(2.8)
60.6(1.7)
61.6(0.7)
RAC-C50-F20
44.9(2.4)
52.7(0.3)
53.8(0.4)
50.2(2.4)
60.7(0)
63.7(1.2)
53.6(1.5)
62.8(1.4)
62.9(1.3)
RAC-C60
46,3(0.1)
54.8(0.8)
58.8(0.3)
51.6(1.2)
60.2(0.9)
60.9(0.2)
50.7(0.9)
58.8(0.6)
59(0.1)
RAC-C60-F10
43.5(0.6)
54.7(1.0)
56.1(0.0)
49.8(0.5)
59.2(0.4)
62.2(0.3)
48.2(1.6)
58.2(2.0)
64.3(1.9)
RAC-C60-F20
44.1(0.6)
54.6(0.8)
54.8(0.1)
45.1(0.9)
58.7(0.8)
61.7(2.0)
47.5(1.2)
61.4(0.5)
64.1(0.9)
Comp essi e s eng h alues o 100 mm cube specimens. () S anda d de ia ion
The comp essi e s eng h o RACs was 18% lowe han ha o NAC-0.47, e en hough bo h
we e p oduced wi h he same e ec i e wa e –cemen a io o 0.47, as shown in Table 6. 2. Howe e ,
RAC’s comp essi e s eng h was compa able o ha o NAC-0.51, which had a highe e ec i e
Chap e 6
74
wa e –cemen a io o 0.51 (see Figu e 6. 1). These esul s illus a e he need o adjus he wa e –
cemen a io o a ain comp essi e s eng h simila o ha o NAC-0.51 due o he signi ican impac
o ecycled agg ega es on conc e e’s mechanical p ope ies. As p e iously demons a ed [41,105],
due o he highe po osi y and Los Angeles coe icien (weake pa icles) o he RCA han hose o
NA, he RAC p oduced wi h 50% CRCA could achie e simila mechanical p ope ies o hose o
NAC when p oduced wi h a lowe wa e −cemen a io. The comp essi e s eng h o RACs is
in luenced by he p opo ion o CRCA and FRCA employed in conc e e p oduc ion [221–223]. Fo
ins ance, mixes wi h 50% CRCA (RAC-C50) gene ally exhibi be e pe o mance han hose wi h
60% CRCA (RAC-C60), due o he in e io mechanical quali y o he CRCA and po en ial
weaknesses in he old in e acial ansi ion zone (ITZ) o adhe ed mo a [221,224]. The RAC
p oduced using 10% FRCA achie ed accep able s eng h, likely owing o he enhanced compac ion
and imp o ed bonding o he ine ac ion wi h he cemen pas e [126,190]. This e ec was
pa icula ly p onounced when RACs we e p oduced using CEM III/B and CEM II/AS cemen s,
which enhance ma ix densi ica ion and chemical bonding due o hei SCMs [112] and he p esence
o Po land cemen mo a in FRCA.
Table 6. 2 demons a es ha he RACs made wi h CEM II/AL cemen ob ained a sligh ly lowe
comp essi e s eng h han hose made wi h CEM II/AS and CEM III/B cemen s despi e ha ing he
same wa e −cemen a io. This di e ence is a ibu ed o he seasonal p oduc ion pe iods; RACs wi h
CEM II/AL we e p oduced in sp ing/summe , whe eas he o he s we e manu ac u ed in
au umn/win e , impac ing he se ing and cu ing p ocesses o he conc e e [204].
Figu e 6. 1 a–c illus a e he comp essi e s eng h a ios o each RAC ela i e o con en ional
conc e e (NAC-0.51) a 7, 28, and 56 days. In addi ion, NAC-0.47 achie ed a 3% o 17% highe
s eng h han NAC-0.51 a a ious ages.
(a) CEM II/AL 42.5 R
(b) CEM II/AS 42.5 N/SRC
Chap e 6
75
(c) CEM III/B 42.5 N-LH/SR
Figu e 6. 1 Rela i e comp essi e s eng h a all conc e e ages wi h cemen s: a) Type CEM II/AL, b) Type CEM II/AS, c)
Type CEM III/B
Figu e 6. 1a (conc e e p oduced using IIAL cemen ) shows ha RAC-C50, RAC-C50-F10, and
RAC-C60 achie ed simila alues o NAC-0.51 a all ages, while RAC-C50-F20 showed a dec ease
o up o 8.5% a 56 days. Addi ionally, RAC-C60-F10 and RAC-C60-F20 exhibi ed educed ea ly
comp essi e s eng h (7 days), bu his di e ence was lowe a 56 days, achie ing a 7% lowe s eng h
han NAC-0.51. Figu e 6. 1b shows he esul s o conc e es p oduced wi h CEM II/AS cemen . The
conc e es p oduced using 10–20% FRCA ob ained a sligh ly lowe s eng h a 7 days; howe e , a 28
days, all RACs, including RAC-C60-F20, achie ed simila s eng h o NAC-0.51. A 56 days, he
comp essi e s eng h o all RACs was be ween 3% and 7.5% lowe . All o he RAC p oduced using
IIIB cemen achie ed a simila o highe s eng h han ha o NAC-0.51 a 28 and 56 days (see Figu e
6. 1c). A 7 days, he conc e es p oduced using 60% CRCA and ine agg ega es (10%, 20%) showed
lowe comp essi e s eng h han NAC-0.51.
Fu he mo e, as disco e ed in p e ious s udies [105,126], he RAC-C50-F20 conc e e (p oduced wi h
50% CRCA and 20% FRCA) achie ed simila s eng h o RAC-C50 (using na u al sand) and NAC-
0.51. Howe e , se e al esea che s [51,62–64] ha e sugges ed ha inco po a ing up o 30% FRCA as
a eplacemen o na u al sand could s ill achie e sa is ac o y p ope ies. As men ioned, all o he
RACs p oduced, including RAC-C60-F20, wi h an e ec i e w/c a io o 0.47, achie ed a simila
s eng h o NAC-0.51 a 28 days. Al hough he inclusion o FRCA sligh ly educed he ea ly s eng h,
which was p obably due o he highe wa e amoun caused by he highe WA capaci y (old mo a
was he main componen [225,226]) and weake bonding o he ine ecycled agg ega es [51,88,221],
his e ec was mi iga ed as he conc e e ma u ed, eaching comp essi e s eng hs compa able o ha
o con en ional conc e e (NAC-0.51) a 56 days. All mix u es achie ed a comp essi e s eng h o
C30/37, which is sui able o s uc u al applica ions.
Chap e 6
76
6.3.2. D ying Sh inkage
Figu e 6. 2 a–c,d– illus a es he alues o d ying sh inkage (µƐ) and mass loss (%) o e 91 days
o NAC-0.51 and he RACs p oduced using CEM II/AL, II/AS, and III/B. In addi ion, he s anda d
de ia ion o he sh inkage alues a e desc ibed by he e ical lines.
−4.0
−3.0
−2.0
−1.0
0.0
0 7 14 21 28 35 42 49 56 63 70 77 84 91
Mass Loss (%)
Time (days)
NAC-0.51 RAC-C50-F20
RAC-C50 RAC-C60-F20
a)
d)
CEM II /AL 42.5 R
−4.0
−3.0
−2.0
−1.0
0.0
0 7 14 21 28 35 42 49 56 63 70 77 84 91
Mass Loss (%)
Time (days)
NAC-0.51 RAC-C50 RAC-C50-F10
RAC-C50-F20 RAC-C60 RAC-C60-F10
RAC-C60-F20
b)
e)
CEM II /AS-42.5
Chap e 6
77
−4.0
−3.0
−2.0
−1.0
0.0
0 7 14 21 28 35 42 49 56 63 70 77 84 91
Mass Loss (%)
Time (days)
NAC-0.51 RAC-C50 RAC-C50-F10
RAC-C50-F20 RAC-C60 RAC-C60-F10
RAC-C60-F20
c)
)
CEM III/B-42.5
Figu e 6. 2 D ying sh inkage alue de elopmen and mass loss a 91 days and hei s anda d de ia ion: (a) and (d) CEM
II/AL, (b) and (e) CEM II/AS, (c) and ( ) CEM III/B.
All conc e es p oduced using CEM II/AL (see Figu e 6. 2a) achie ed simila sh inkage alues
( om −496.8 o −576.7 µm/m) a 91 days. The use o FRCA sligh ly inc eased he sh inkage alue;
he RAC-C50-F20 and RAC-C60-F20 conc e es exhibi ed 13.3% and 16.1% highe d ying sh inkage,
espec i ely, han ha o NAC-0,51, while he RAC-C50 conc e e showed a 7.3% highe d ying
sh inkage han ha o NAC-051 ( he RAC-C50-F10, RAC-C60, and RAC-C60-F10 conc e es we e
no es ed).
The conc e es p oduced using CEM II/AS (Figu e 6. 2b) achie ed sh inkage alues be ween
−318.8 and −501.2 µm/m. The RACs wi h up o 60% CRCA and 10% FRCA ob ained be ween 15.8%
and 19.7% highe d ying sh inkage alues han NAC-0.51. In addi ion, he RAC-C50-F20 and RAC-
C60-F20 conc e es had simila beha io s, wi h sh inkage alues up o 57.2% highe han ha o NAC-
0.51. Howe e , he alues ob ained in he RACs we e lowe han hose ob ained in conc e es p oduced
using IIAL.
All o he conc e es p oduced wi h CEM III/B (Figu e 6. 2c) ob ained simila d ying sh inkage
alues anging om −437.3 o −534 µm/m. RAC-C50 and RAC-C60 achie ed 3% and 5% highe
sh inkage alues, espec i ely, han NAC-0.51. The use o FRCA inc eased he sh inkage alue o
conc e e, while RAC-C50-F10, RAC-C50-F20, and RAC-C60-F10 showed 11%, 12%, and 13.4%
highe sh inkage alues han ha o NAC-0.51, and RAC-C60-F20 ob ained a 22.1% highe sh inkage
alue han ha o NAC-0.51.
All sh inkage alues measu ed o he RACs we e wi hin he accep able limi s acco ding o he
guidelines o he Ame ican Conc e e Ins i u e (ACI) [122], which s ipula e an ul ima e sh inkage s ain

Chap e 6
78
o −780 o −800 μm/m, es ablishing his ange as he h eshold o d ying sh inkage in con en ional
conc e e when a high w/c a io is used. Du ing he i s ou days o cu ing, conc e es wi h lowe
clinke con en (CEM III/B) exhibi ed he highes sh inkage alues (Figu e 6. 2c). NAC-0.51 wi h
CEM III/B, CEM II/AL, and CEM II/AS eached −200 µm/m, −170 µm/m, and −110 µm/m,
espec i ely, a 4 days, and i was s abilized o e 28 days. Ea ly age d ying sh inkage ends o s abilize
o e ime, especially wi h an SCM as a binde [51,105,118,119]. The sh inkage alue inc eased wi h
highe RCA con en , wi h simila de ia ions o hose o NAC, hough wi h mode a e a ia ions in mos
cases.
Figu e 6. 2d– illus a es he mass loss pe cen ages o he p oduced conc e e mixes. The NAC-
0.51 mixes showed mass losses o 2.2% wi h CEM II/AL, 2.3% wi h CEM II/AS, and 1.9% wi h CEM
III/B. As expec ed, he mass loss was g ea e in mixes wi h a highe con en o RCA (as a consequence
o a highe o al wa e amoun ). The RACs p oduced using CEM II/AL achie ed a mass loss o up o
3.5%, he CEM II/AS mixes ob ained alues be ween 2.8% and 3.8%, and he CEM III/B mixes
ob ained mass losses om 2.86% o 3.4%. These esul s align wi h hose o p io s udies
[105,126,159,208,227], con i ming ha g ea e d ying sh inkage co ela es wi h inc eased mass loss
ac oss simila cemen ypes.
In o de o alida e he d ying sh inkage alue p edic ion acco ding o codes, he S uc u al
Conc e e Code (SC-BOE) [20] and Eu ocode 2: EN 1992-1-1 (EC-02) [50] we e used o p edic d ying
sh inkage in RACs, as desc ibed in a p e ious s udy [126]. SC-BOE [20] does no conside he use o
RCA. Howe e , ac o s such as he comp essi e s eng h a 28 days, conc e e specimen size, ambien
RH, and cemen ype a e conside ed. CEM IIAL was classi ied as ha ing a high ea ly s eng h (Class
CR), while CEM II/AS and CEM III/B we e classi ied as ha ing an o dina y ea ly s eng h (Class CN).
Eu ocode 2 (EC-02) [50] conside s RCA o es ima e sh inkage. The in luence o CRCA and FRCA
was calcula ed using a ac o (ηshRA) in he o mula o he d ying sh inkage o RAC, de ined as 1 +
0.8 αRA, whe e αRA is he a io o ecycled agg ega es (CRCA and FRCA) o o al agg ega es. This
ac o is applied when he RCA eplaces 20–40% o he NAs (0.20 < αRA ≤ 0.40) [50,126]. In his
s udy, he αRA alues we e 0.27, 0.31, and 0.36 o he RAC-C50, RAC-C50-F10, and RAC-C50-F20
conc e es, espec i ely, while o he RAC-C60, RAC-C60-F10, and RAC-C60-F20 conc e es, he
alues we e 0.32, 0.37 and 0.42. Figu e 6. 3 illus a es he a io be ween he expe imen ally ob ained
d ying sh inkage alue o each conc e e and he alue de e mined using he o mula ions p o ided by
a) he S uc u al Conc e e Code (SC-BOE) [20] and b) Eu ocode 2: EN 1992-1-1 (EC-02) [50].
Chap e 6
79
a) SC-BOE
b) EC-02
Figu e 6. 3 Sh inkage es ima ion (a) expe imen al esul s/nume ical es ima ion (SC-BOE); (b) expe imen al
esul s/nume ical es ima ion (EC-02).
Acco ding o Figu e 6a, SC-BOE [20] does no accu a ely es ima e he sh inkage alue o NAC-
0.51 conc e e. In o de o es ima e he sh inkage alue, he pa ame e s o he comp essi e s eng h a
28 days (as he p ima y pa ame e ) and he ype o cemen we e conside ed. Howe e , i was obse ed
ha , al hough he ype o cemen is conside ed, SC-BOE does no adequa ely assess he sh inkage o
CEM III/B conc e e due o a high ea ly sh inkage caused by he high BFS con en in he cemen ,
signi ican ly in luencing he o al d ying sh inkage [118,119]. NAC-0.51 p oduced wi h CEM III/B
cemen had a 15% highe sh inkage alue han ha es ima ed using SC-BOE [20]. In addi ion, NAC-
0.51 p oduced wi h he CEM II/AL and CEM II/AS cemen s ob ained 9% and 15% lowe sh inkage
alues, espec i ely, han hose calcula ed using he SC-BOE [20].
SC-BOE accu a ely es ima es he sh inkage o he RAC p oduced using up o 60% CRCA and
10% FRCA wi h CEM II/AL and CEM II/AS. Howe e , he RAC-C60-F20 conc e e made wi h CEM
II/AL and CEM II/AS achie ed 6% and 35% highe sh inkage alues, espec i ely, han he alue
es ima ed using he code. In addi ion, all conc e e mix u es p oduced wi h CEM III/B achie ed highe
sh inkage alues han hose es ima ed wi h SC-BOE. Resea che s ha e epo ed ha SC-BOE
es ima ions can ha e a ±30% dispe sion, and hey a e inc eased in RACs [117,228]. The highe ea ly
sh inkage o conc e e p oduced using a high BFS con en in luences he o al sh inkage [118,119].
This highligh s he need o conside o he ac o s o sh inkage es ima ion, such as en i onmen al
condi ions, cemen ypes and p ope ies, ypes o agg ega es, and mine al addi ions [117].
Figu e 6. 3b shows he a io be ween he expe imen al esul s and he EC-02 es ima es. EC-02
o e es ima ed he sh inkage alues o he NAC-0.51 and RAC conc e es p oduced using CEM II/AL
and CEM II/AS. Simila ly o SC-BOE, EC-02 unde es ima ed he sh inkage alue o NAC-0.51 made
wi h CEM III/B. Howe e , EC-02 accu a ely p edic ed sh inkage o he RAC wi h CEM III/B. EC-
02 conside s an inc ease in sh inkage due o ecycled agg ega es, making i s p edic ions mo e accu a e
han hose o SC-BOE o d ying sh inkage in RACs.
Chap e 6
80
6.3.3. Chlo ide Ion Pene a ion
The ASTMC1202 es ca ego izes chlo ide ion pene abili y in o low (1000–2000 Coulombs),
mode a e (2000–4000 Coulombs), and high (>4000 Coulombs) le els [229]. Table 6. 3 p esen s he
a e age chlo ide ion pene abili y o he conc e e mix u es a 28 and 56 days o cu ing. This s udy
con i ms ha chlo ide ion pene abili y signi ican ly a ies wi h he ype o cemen used, which is
consis en wi h p e ious indings [113,210–212], whe e a conc e e p oduced wi h IIAL achie ed
highe pe meabili y han IIAS conc e es and IIIB conc e es, which achie ed he lowes pe meabili y.
In addi ion, he da a in Table 6. 3 e eal ha conc e es made wi h CEM II/AL displayed highe
a iabili y, as measu ed wi h he s anda d de ia ion, compa ed wi h hose wi h CEM II/AS, while
CEM III/B mix u es showed he lowes a iabili y.
Mo eo e , a di ec co ela ion was ound be ween he RCA eplacemen a io and chlo ide ion
pene abili y, as epo ed in ea lie s udies [9,40,51]. Conc e e p oduced wi h highe pe cen ages o
RCA achie ed a highe chlo ide pe meabili y when he same ype o cemen was used. Howe e , due
o he lowe e ec i e wa e −cemen a io employed in RAC compa ed wi h NAC-0.51 (all wi h simila
comp essi e s eng h), RAC-C50 and e en he conc e e p oduced wi h a highe pe cen age o RCA
achie ed highe chlo ide ion pene a ion esis ance han he co esponding NAC-0.51 conc e e.
Fu he mo e, he e ec o FRCA on chlo ide pene a ion was mo e e iden han ha o CRCA due o
he highe amoun o adhe ed mo a in FRCA [40]. In addi ion, NAC-0.47, which was p oduced wi h
a o al wa e −cemen a io o 0.50 as equi ed o he XS1 en i onmen , exhibi ed he highes chlo ide
ion pe meabili y esis ance.
Table 6. 3 Chlo ide ion pene abili y and s anda d de ia ion as de e mined in cha ge passed in coulombs.
IIAL
IIAS
IIIB
Conc e e
Types
(Coulombs)
∆
(%)
(Coulombs)
∆
(%)
(Coulombs)
∆ (%)
28d
56d
28d
56d
28d
56d
NAC-0.47
4451(194)
3971(94)
11
2145(281)
1766(44)
18
530(2)
408(5)
23
NAC-0.51
5314(2)
4096(271)
23
2897(111)
1976(129)
32
674(15)
501(12)
26
RAC-C50
4479(441)
4065(71)
9
2535(136)
1962(80)
23
610(9)
503(8)
18
RAC-C50-F10
6038(596)
4448(97)
26
3130(58)
2293(5)
27
626(16)
531(15)
15
RAC-C50-F20
6401(569)
4944(178)
23
4515(91)
2866(66)
37
740(40)
532(18)
28
RAC-C60
5726(250)
5140(636)
10
2648(71)
2329(28)
12
651(4)
570(4)
12
RAC-C60-F10
6009(197)
5454(33)
9
3425(78)
2736(64)
20
707(44)
668(14)
6
RAC-C60-F20
6549(567)
6048(43)
8
4696(17)
3239(119)
31
843(69)
767(3)
9
S anda d de ia ion ( alues a e gi en in b acke s)
Table 6. 4 a,b depic s he a io be ween he cha ge passed by each conc e e mix wi h espec o
4000 Coulombs ( he h eshold o mode a e co osion isk) a 28 and 56 days, espec i ely. Figu e 6.
Chap e 6
81
4a indica es ha all conc e es made wi h CEM II/AL exhibi high chlo ide ion pene a ion. The
inco po a ion o BFS in o he cemen educed he conc e e’s ion pene abili y [212]. Al hough he
in luence o RCA usage was e iden , RAC-C50 (p oduced wi h an e ec i e w/c a io o 0.47)
demons a ed lowe chlo ide ion pene abili y han NAC (p oduced wi h an e ec i e w/c a io o 0.51),
ega dless o he cemen ype used, as epo ed by Kopecký and Balázs e al. [212]. Fu he mo e, when
FRCA was used, pa icula ly wi h a 20% eplacemen o na u al sand, he chlo ide ion pene abili y
inc eased, mainly when cemen wi hou BFS (CEM II/AL) o wi h low BFS con en (CEM II/AS) was
employed. E angelis a and de B i o e al. [9] obse ed ha conc e e p oduced using FRCA exhibi ed
lowe esis ance o chlo ide ions han NAC. This is a ibu ed o he high po osi y and high olume o
adhe ed mo a in he FRCA, which enhance he pe meabili y o chlo ide ions [213,229].
a) 28 Days
b) 56 Days
Figu e 6. 4 The a io o chlo ide ion pene abili y (de e mined in cha ge passed) o all conc e es conce ning maximum
alue o 4000 Coulombs: a) 28 days and b) 56 days
Figu e 6. 4 also shows ha he RAC p oduced using cemen wi h a g ea e amoun o GGBS
achie ed he highes chlo ide ion pene a ion esis ance. E xebe ia e al. [214] epo ed ha conc e es
mixed wi h CEM III/B cemen and a ying ecycled agg ega e con en s (0%, 25%, 50%, 100%) passed
cha ges be ween 800 and 1400 Coulombs, which was ca ego ized as low chlo ide ion pene abili y.
Simila ly, Sim and Pa k [91] no ed a minimal impac o FRCA on chlo ide ion pene a ion.
A 56 days o cu ing (Figu e 6. 4b), he chlo ide ion pene a ion esis ance o he p oduced
conc e es inc eased. Howe e , he conc e es made using CEM II/AL main ained ele a ed le els o
chlo ide ion pene abili y. This heigh ened pe meabili y is p ima ily a ibu ed o he limes one con en
in he CEM II/AL conc e e, which acili a es g ea e chlo ide ion mig a ion compa ed wi h ha in
mixes u ilizing highe supplemen a y cemen i ious ma e ial (SCM) subs i u ion [215,216]. The
chlo ide pene abili y alues obse ed in his s udy we e ma ginally lowe han hose epo ed by
E xebe ia and Cas illo [217], whe e conc e e composed o 50% coa se RCA and iden ical cemen —
main aining an e ec i e wa e −cemen a io o 0.50 and a cemen con en o 350 kg/m³—demons a ed
chlo ide alues o 8799 Coulombs a 28 days and 6377 Coulombs a 56 days. In con as , 4 shows ha
Chap e 6
88
The RAC-C50 conc e es achie ed less han a 3% inc ease in Kacc compa ed wi h NAC-0.51 in
e e y cemen ype. The RAC-C60 conc e es also showed a simila o sligh ly supe io ca bona ion a e
o ha o NAC-0.51, excep o he conc e e p oduced wi h IIAS, which achie ed 20% highe Kacc
han ha o NAC-0.51. These ends a e consis en wi h indings om p io esea ch
[101,114,217,237]. In addi ion, he use o 10% FRCA wi h 50% CRCA in RAC-C50-F10 esul ed in
a sligh 5% inc ease in Kacc, excep o he one p oduced wi h CEM II/AL, which achie ed a 17%
inc ease, compa ed wi h he NAC-0.51 conc e e.
In con as , he RAC-C60-10 conc e es p oduced wi h he CEM II/AL, CEM II/AS, and CEM
III/B cemen s achie ed 21%, 24%, and 5% highe Kacc alues han ha o he co esponding NAC-
0.51. Mo eo e , he use o 20% FRCA in he subs i u ion o na u al sand led o subs an ial inc eases
in Kacc in compa ison wi h he alues ob ained o NAC, especially in conc e es p oduced wi h IIAL
and IIAS cemen , which achie ed up o 25% highe Kacc alues han hose o NAC-0.51 conc e es.
The lowe pe o mance o RAC han ha o NAC can be a ibu ed o he highe po osi y o ecycled
agg ega es, a ac o ha was especially p onounced in he case o FRCA [51].
The Kacc alue can be employed o es ima e he heo e ical na u al ca bona ion coe icien
(kna THEO) (Table 8) [218,219] o each ype o conc e e p oduced using Eq.6 (3).
Kacc
Kna THEO=(∅acc)0.5
(∅na THEO)0.5,
Eq.6 (3)
He e, Kacc and kna THEO a e he CO2 concen a ions in he accele a ed ca bona ion (3%) and
na u al ca bona ion p ocesses (430 ppm, in Ba celona), espec i ely. The ob ained alues o
Kna THEO we e compa ed wi h he na u al ca bona ion a e ha was de e mined expe imen ally.
6.3.7. Na u al Ca bona ion Resis ance
A e ou days o cu ing, he p oduced conc e e specimens we e exposed o one yea unde na u al
en i onmen al condi ions in Ba celona wi h an a e age o 431 ppm CO2, 56.8% RH, and 20.1 °C, as
illus a ed in Figu e 6. 8. The a e age ca bona ion dep h da a a e one yea o exposu e and he
calcula ed na u al ca bona ion a e (kna ) o he NAC and RAC conc e es a e desc ibed in Table 6. 6.

Chap e 6
89
0
100
200
300
400
500
600
0
10
20
30
40
50
60
70
80
RH (%)& T (ºC)
RH (%) Temp (ºC) CO2 (ppm)
CO2 Concen a ion (ppm)
Figu e 6. 8 En i onmen al condi ions o na u al ca bona ion.
The NAC-0.51 conc e es achie ed a simila o sligh ly highe ca bona ion dep h han ha o NAC-
0.47 and RAC in each co esponding cemen ype. The in luence o he cemen ype was appa en ;
conc e es made wi h he CEM III/B cemen showed signi ican ly highe ca bona ion dep h, ollowed
by hose wi h CEM II/AL. Mo eo e , conc e es wi h CEM II/AS achie ed he lowes ca bona ion
dep h, which was simila o he accele a ed ca bona ion p ocess. In conc e e p oduced using he IIIB
cemen , wi h a la ge amoun o SCMs, due o he educ ion o po landi e (a ailable CaO) and he
lowe pH bu e ing capaci y, he suscep ibili y o ca bona ion was inc eased [109]. While CEM II/AS
and CEM II/AL ha e simila clinke amoun s (app oxima ely 88%), IIAS has mo e hyd aulic CaO
a ailable, which gi es i a highe ca bona ion esis ance han IIAL. The IIAL con ains 10% limes one
ille [109,238–240].
Chap e 6
90
Table 6. 6 Ca bona ion dep h and na u al ca bona ion coe icien o all conc e e
Mix u es
Ca bona ion dep h(mm) a 1 yea
Ca bona ion coe icien
kna (mm/yea 0.5)
II AL
II AS
III B
II AL
II AS
III B
NAC-0.47
4.2(0)
3.5(0.04)
5.1(0.09)
3.82
3.16
5.08
NAC-0.51
4.2(0.02)
3.7(0.04)
5.7(0.11)
4.24
3.50
5.55
RAC-C50
4.2(0.02)
3.5(0.42)
5.2(0.15)
3.89
3.32
5.19
RAC-C50-F10
4.2(0.15)
3.7(0.04)
5.3(0.1)
3.97
3.50
5.33
RAC-C50-F20
4.2(0.09)
3.6(0.09)
5.4(0.31)
3.93
3.49
5.45
RAC-C60
4(0.11)
3.5(0.04)
5.1(0.04)
3.68
3.18
5.12
RAC-C60-F10
4.1(0.02)
3.5(0.02)
5.1(0.04)
3.63
3.21
5.15
RAC-C60-F20
4.2(0.15)
3.7(0.15)
5.2(0.04)
3.90
3.40
5.05
Figu e 6. 9 desc ibes he a io be ween he Kna coe icien o RAC wi h espec o ha o NAC-
0.51 (conc e es wi h simila comp essi e s eng h) o each co esponding cemen ype. I shows ha
he RAC achie ed a lowe Kna alue han ha o NAC-0.51. This beha iou di e ed om he
accele a ed ca bona ion p ocess in which he Kacc alue o RAC was highe han ha o NAC-0.51.
The conc e e specimens we e exposed o na u al ca bona ion a e 4 days o cu ing, which was
p obably due o wa e inside he RCA, which helped wi h in e nal cu ing and educed he ca bona ion
a e [241–243]. In addi ion, he highe calcium a ailabili y in RAC could in luence he imp o emen
o he ca bona ion esis ance o RAC wi h espec o NAC-0.51.
Figu e 6. 9 Ra io o he RAC Kna o he NAC-0.51 Kna .
Chap e 6
91
6.3.8. Kna s Kna THEO
Table 6. 7shows he a io be ween Kna THEO (see Table 6. 5) and Kna (see Table 6. 6) o he
conc e es ob ained h ough accele a ed and na u al ca bona ion p ocesses, espec i ely. The esul s
indica e ha he Kna coe icien was be ween 2.0 and 2.8 imes highe in NAC and be ween 1.6 and
2.4 imes highe in RAC compa ed wi h he Kna THEO coe icien alue. These indings align wi h
hose o o he s udies [115], which epo ha he expe imen ally de e mined na u al ca bona ion
coe icien (Kna ) is 1.6 o 1.8 imes highe han he ca bona ion a e es ima ed using an accele a ed
es . The conc e es we e exposed o na u al ca bona ion be ween May and June (a 20–26 °C and 55%
RH) a e only 4 days o cu ing, which inc eased he ca bona ion a e o he conc e es and, mo e
impo an ly, o NAC (RAC may achie e in e nal cu ing). Mo eo e , Kna was de e mined using only
da a om 1 yea o exposu e, and i may be educed a e a longe pe iod o exposu e [244].
Table 6. 7 Rela ionship be ween Na u al Ca bona ion and Accele a ed Ca bona ion in Conc e es wi h NA and RCA
kna and kna THEO Rela ionship
MIX
CEM II/AL
CEM II/AS
CEM III/B
NAC-0.47
2.5
2.8
2.5
NAC-0.51
2.4
2.5
2.0
RAC-C50
2.2
2.3
2.0
RAC-C50-F10
1.9
2.4
2.0
RAC-C50-F20
1.8
2.1
1.9
RAC-C60
2.1
1.9
1.9
RAC-C60-F10
1.7
1.9
1.7
RAC-C60-F20
1.7
1.9
1.6
Tes s ha e demons a ed ha he ca bona ion dep hs in bo h RAC and NAC inc ease when
samples a e cu ed sho ly in a humid oom and unde go a long cu ing p ocess in d ie en i onmen s,
highligh ing he impo ance o cu ing condi ions [79,245]. The na u al ca bona ion, in luenced by bo h
he du a ion o exposu e and in e ac ion wi h ealis ic en i onmen al cycles, esul s in deepe
pene a ion o CO2 in o conc e e compa ed wi h ha in he con olled en i onmen s o accele a ed
es s [79,246].
Figu e 6. 10 isually compa es he ca bona ion dep h ob ained in he NAC-0.47, NAC-0.51, RAC-
C60 and RAC-C60-F20 (wi h RAC ha ing he highes pe cen ages) conc e es p oduced using di e en
ypes o cemen unde na u al condi ions o e one yea e sus unde accele a ed condi ions o e 91
days.
Chap e 6
92
Figu e 6. 10 Visual compa ison o he ca bona ion dep h in na u al (1 yea ) and accele a ed condi ions (91 days) o
conc e es wi h di e en cemen ypes.
6.3.9. Ca bona ion Analysis a 50 and 100 yea s
Table 6. 8 de ails he p edic ed ca bona ion dep h o each ype o conc e e calcula ed using he
Kna alue o e 50 and 100 yea s o expec ed se ice li es. The Spanish S uc u al Conc e e Code
(SC-BOE) [20] speci ies he minimum co e dep h o conc e e s uc u es exposed o XC3 and XC4
en i onmen s, co esponding o a design li e o 50 and 100 yea s. Fo XC3 exposu e condi ions, a
Chap e 6
93
minimum co e o 20 mm and 30 mm is equi ed o a 50 and 100 yea li espan, espec i ely. Fo XC4
exposu e condi ions, he equi ed minimum co e inc eases o 25 mm and 35 mm, espec i ely. In
addi ion, EC-02, as shown in Table 11 [50], desc ibes ha he minimum co e −gi en he da a om SC-
BOE [20]− should be inc eased by +5 mm when ecycled agg ega es a e used.
Table 6. 8 Ca bona ion dep h a e li espan o 50 and 100 yea s.
Conc e e ypes
kna (50 yea s)
kna (100 yea s)
II AL
II AS
III B
II AL
II AS
III B
NAC-0.47
27.0
22.3
35.9
38.2
31.6
50.8
NAC-0.51
30.0
24.8
39.2
42.4
35.0
55.5
RAC-C50
27.5
23.5
36.7
38.9
33.2
51.9
RAC-C50-F10
28.1
24.8
37.7
39.7
35.0
53.3
RAC-C50-F20
27.8
24.6
38.5
39.3
34.9
54.5
RAC-C60
26.0
22.5
36.2
36.8
31.8
51.2
RAC-C60-F10
25.6
22.7
36.4
36.3
32.1
51.5
RAC-C60-F20
27.6
24.0
35.7
39.0
34.0
50.5
Min. Co e
(mm)
XC3
20+5*
25+5*
XC4
30+5*
35+5*
* EC-0.2 ecommends inc easing he minimum co e by 5 mm when ecycled agg ega es a e used
Acco ding o he esul s (Table 6. 8 and Figu e 6. 11), all o he conc e es p oduced using CEM
II/AL and CEM II/AS achie ed 50 yea s o se ice li e wi h a minimum co e o 30 mm de ined o
an XC4 en i onmen (SC-BOE [20] egula ions). Al hough a minimum co e o 20 mm was gene ally
insu icien o XC3 condi ions, CEM II/AS adequa ely me he 50-yea se ice li e equi emen s
acco ding o he EC-02 ecommenda ion. In addi ion, in he conc e es p oduced wi h CEM II/AS and
CEM II/AL, he minimum co e o 35 + 5 mm was adequa e o 100 yea s o se ice li e in an XC4
en i onmen (SC-BOE [20] and EC-02 [50] egula ions). In all o he conc e es men ioned, he RAC
achie ed simila o e en highe ca bona ion esis ance han he NAC.
Figu e 6. 11 shows he a io o ca bona ion dep hs a e a li espan o 50 and 100 yea s ( alues
desc ibed in Table 6. 8) wi h espec o he minimum co e de ined by SC-BOE o XC3 (20 mm and
25 mm). In addi ion, he a ios o he minimum co e equi emen s o XC3 (EC-02), XC4 (SC-BOE)
and X4 (EC-02) wi h espec o ha o XC3 (SC-BOE) a e desc ibed.

Chap e 6
94
0.0
0.5
1.0
1.5
2.0
2.5
Ra io Ca bona ion dep h
(50 yea s)/ 20mm(XC3)
CEM II-AL CEM II-AS CEM III-B
XC3 (SC-BOE) XC3 (EC-02) XC4(SC-BOE)
XC4( EC-02)
0.0
0.5
1.0
1.5
2.0
2.5
Ra io Ca bona ion dep h
(100 yea s)/ 25mm(XC3)
CEM II-AL CEM II-AS CEM III-B
XC3 (SC-BOE) XC3 (EC-02) XC4(SC-BOE)
XC4( EC-02)
(a)
(b)
Figu e 6. 11 Compa ison o he ca bona ion dep h ela i e o exposu e class XC3 o all conc e es (a) 50 yea s, (b) 100
yea s.
6.4. Conclusions
The ollowing conclusions can be d awn om he esul s o his s udy:
• This s udy demons a es ha inco po a ing up o 60% CRCA and 20% FRCA can esul in
comp essi e s eng h le els compa able o hose o NAC by lowe ing he RAC’s wa e –cemen
a io by app oxima ely 0.04. This unde sco es he po en ial o RCA as a sus ainable al e na i e
while main aining s uc u al in eg i y.
Rega ding he d ying sh inkage:
• All RAC p oduced, wi h a maximum o 60% CRCA and 20% FRCA and independen ly o he
cemen ype employed (IIAL, IIAS and IIIB), achie ed admissible alues a 91 days (maximum
o -580 μm/m);
• The conc e e p oduced using up o 60% CRCA achie ed a simila sh inkage alue o ha o
NAC-0.51 conc e e p oduced wi h he same cemen . Howe e , he conc e e using 20% FRCA
(wi h 60% o CRCA) made wi h CEM II/AL, CEM II/AS, and CEM IIIB achie ed 16.1%,
57.2%, and 22.1%, espec i ely, highe sh inkage han ha o he NAC. Howe e , all achie ed
lowe d ying sh inkage alues han he accep able alues de ined by he ACI (up o −800
μm/m);
• EC-02 is mo e accu a e han SC-BOE in p edic ing he d ying sh inkage o RAC ega dless o
he cemen ype used. Bo h s anda ds ail o accu a ely es ima e NAC-0.51 p oduced wi h CEM
III/B, as hey p io i ize 28-day comp essi e s eng h o e he ini ial sh inkage alues. This
Chap e 6
95
unde sco es he need o mo e comp ehensi e models inco po a ing en i onmen al ac o s and
di e en cemen and agg ega e ypes.
Rega ding he du abili y p ope ies:
• RACs wi h 50% and 60% CRCA (p oduced wi h an e ec i e w/c a io o 0.47) exhibi simila
o highe esis ance o chlo ide ion pene a ion and ca bona ion in compa ison wi h NAC-0.51
(e ec i e w/c a io o 0.51) when hey ha e simila comp essi e s eng hs;
• The conc e es (including he RACs) p oduced wi h CEM III/B ob ained a low chlo ide
concen a ion a he conc e e su ace (Cs) and low non-s eady s a e di usion coe icien (Dnss)
alues. Howe e , he use o 20% FRCA inc eased chlo ide ion pene a ion;
• RAC-C60-F20 achie es high du abili y in chlo ide-agg essi e en i onmen s when i is
p oduced using cemen s wi h high BFS con en , such as CEM III/B. In addi ion, i achie es
highe chlo ide esis ance han ha o NAC p oduced using CEM II/AL and CEM II/AS;
• RAC-C60-F10 p oduced wi h CEM II/AS achie es mode a e chlo ide ion pene abili y
esis ance, while any conc e e, including NAC, p oduced wi h IIAL p esen s no esis ance o
chlo ide ions;
• The conc e es made wi h CEM II/AS, ollowed by CEM II/AL and CEM III/B, achie ed he
highes ca bona ion esis ance, independen o he ype o agg ega es used;
• The use o 20% FRCA inc eased he ca bona ion a e (up o 25%) compa ed wi h NAC-0.51
when an accele a ed ca bona ion es was ca ied ou . Howe e , unde na u al condi ions, hese
RAC conc e es exhibi ed a lowe ca bona ion a e han ha o NAC-0.51;
• The ob ained na u al ca bona ion a e (Kna ) alues we e be ween 2.0 and 2.8 imes highe o
NAC and be ween 1.6 and 2.4 imes highe o RAC han he heo e ical na u al ca bona ion
a e (kna THEO) ob ained om he accele a ed ca bona ion es .
Recycled conc e e wi h up o 60% CRCA and 20% FRCA achie ed an adequa e d ying sh inkage
alue and showed sa is ac o y du abili y pe o mance in XC1 o XC4 and XS1 en i onmen s,
depending on he ype o cemen used:
• RAC-C60-F20 p oduced wi h CEM II/AS cemen achie ed adequa e ca bona ion esis ance in
XC3 and XC4 en i onmen s, ensu ing a se ice li e o 50 yea s. Howe e , o chlo ide
esis ance, only conc e e wi h up o 60% CRCA and 10% FRCA exhibi ed mode a e chlo ide
ion pene a ion alues and lowe chlo ide di usion coe icien s (Dnss) han hose o CEM II/A-
L cemen ;
• RAC-C60-F20 p oduced wi h CEM II/AL cemen , while p o iding adequa e ca bona ion
esis ance in XC4 en i onmen s, p esen ed high chlo ide ion pene a ion and a high Dnss alue,
wi h alues sligh ly highe han hose o NAC-0.51;
Chap e 6
96
• RAC-C60-F20 p oduced wi h CEM III/B exhibi ed low ca bona ion esis ance and e y high
chlo ide pene a ion esis ance, as indica ed by lowe su ace chlo ide concen a ions (Cs) and
educed Dnss alues, simila ly o NAC-0.51.
Fo u u e esea ch, i is ecommended ha he long- e m du abili y and esis ance o
en i onmen al ac o s such as co osion and ca bona ion in s uc u al conc e es made using RCA a e
explo ed. This in es iga ion should ocus on RAC wi h a simila comp essi e s eng h o ha o NAC,
which can be achie ed by adjus ing he e ec i e wa e −cemen a io in RAC mixes. Fu he mo e, i is
c ucial o del e deepe in o he analysis o conc e e p oduced using 60% CRCA and 20% FRCA,
e alua ing i s beha iou unde a ious en i onmen al and exposu e condi ions, including eal-scale
es s.
Chap e 7
97
1.
7. Chap e 7. Fine and coa se ecycled
agg ega es-Type B in conc e e p oduc ion
Limi ing he maximum ine and coa se ecycled
agg ega es-Type B used in s uc u al conc e e
Au ho s:
Ca la Vin imilla, Mi en E xebe ia
Jou nal:
Cons uc ion and Building Ma e ials
Publica ion Da e:
Volume 459, 17 Janua y 2025, 139791
DOI:
h ps://doi.o g/10.1016/j.conbuildma .2024.139791
ABSTRACT
The use o mixed ecycled agg ega e (MRA) is inc easingly being adop ed as a sus ainable solu ion
o he en i onmen al impac o conc e e p oduc ion. This s udy in es iga es he sui abili y o using
a ying p opo ions o ine MRA (FMRA) and coa se MRA (CMRA) classi ied as ype B MRA
(MRA wi h a maximum o 30% mason y was e) o p oduce s uc u al conc e e sui able o exposu e
o XC1 o XC4 en i onmen s. Two expe imen al phases we e conduc ed. In Phase 1, an e ec i e
wa e - o-cemen a io o 0.48 was employed, along wi h up o 100% CMRA and up o 25% FMRA,
o p oduce conc e e. In Phase 2, he e ec i e wa e - o-cemen a io was 0.52, wi h up o 50% CMRA
and up o 15% FMRA used in conc e e p oduc ion. In he wo phases, 300 kg o CEM IIAL 42.5 R
cemen was used, and he physical p ope ies (densi y, abso p ion and accessible po osi y),
mechanical p ope ies (comp essi e s eng h, spli ing ensile s eng h and modulus o elas ici y),
sh inkage p ope ies and du abili y p ope ies (so p i i y and wa e pene a ion) we e assessed. In
addi ion, he c i e ia s ipula ed in Eu ocode 2 and in he Spanish s uc u al conc e e code (SC-BOE)
we e used o alida e he s uc u al MRA conc e e p oduced. The esul s indica e ha he
simul aneous combina ion o up o 40% CMRA and 15% FMRA in Phase 1 achie es comp essi e
s eng h and du abili y p ope ies simila o hose o con en ional conc e e p oduced wi h an
Chap e 7
104
comp essi e s eng h simila o ha o NAC. In addi ion, he s eng h inc eased p og essi ely o e he
cu ing pe iod (Table 7. 4, da a in pa en heses). The comp essi e s eng h in MRACs exhibi ed an
e olu ion simila o ha obse ed in NAC1.
Employing FMRA in combina ion wi h CMRA yielded low comp essi e s eng h. The MRAC-
C20-F51 and MRAC-C30-F101 conc e es achie ed a 15% lowe comp essi e s eng h han ha o
NAC1 a day 28 (Table 7. 4& Figu e 7. 2-a). Howe e , employing 5% FMRA in p oducing conc e e
did no yield a nega i e impac , as MRAC-C20-F51 achie ed an only 5% lowe s eng h han MRAC-
C201, while MRAC-C30-F101 achie ed an 8.2% lowe s eng h han MRAC-C301. In addi ion, he
MRAC-C40-F151 and MRAC-C50-F251 conc e es achie ed a 20% lowe s eng h han he NAC1
conc e e. The MRAC-C50-F251 conc e e achie ed a 7.8% lowe s eng h han MRAC-C501.
Table 7. 4 Comp essi e s eng h o all conc e es p oduced (inc ease in comp essi e s eng h in %)
Phase 1 Mix u es
Comp essi e s eng h
Phase 2 Mix u es
Comp essi e s eng h
7 d
28d
56d
7 d
28d
56d
NAC₁
55.7
64.3 (15.4)
64.7 (0.6)
NAC₂
44.7
53.9 (20.5)
57.8 (7.4)
MRAC-C20₁
53.5
61.6 (15.1)
61.7 (0.2)
MRAC-C20₂
43.9
48.8 (10.9)
53.1 (8.9)
MRAC-C30₁
53.7
62.5 (16.4)
63.4 (1.4)
MRAC-C30₂
43.9
48.0 (9.3)
53.3 (11.0)
MRAC-C50₁
47.2
57.4 (21.7)
58.5 (1.9)
MRAC-C40₂
40.3
47.0 (16.6)
51.5 (9.6)
MRAC-C100₁
38.1
45.7 (20.0)
46.3 (1.3)
MRAC-C50₂
39.7
46.8 (17.8)
51.2 (9.3)
MRAC-C20-F5₁
48.5
58.3 (20.2)
58.5 (0.3)
MRAC-C20-F5₂
42.4
48.1 (13.6)
54.4 (13.0)
MRAC-C30-F10₁
46.9
57.2 (21.9)
57.8 (1.0)
MRAC-C30-F10₂
40.3
47.6 (18.1)
50.9 (6.9)
MRAC-C40-F15₁
46.6
55.1 (18.2)
55.4 (0.5)
MRAC-C40-F15₂
39.4
45.7 (16.1)
49.6 (8.4)
MRAC-C50-F25₁
44.6
52.3 (17.3)
53.2 (1.7)
MRAC-C50-F15₂
36.5
43.4 (18.7)
46.2 (6.6)
* Comp essi e s eng h alues o 100-mm cubic specimens.
*(in b acke s) Inc ease in comp essi e s eng h: om day 7 o day 28 and om day 28 o day 56 o cu ing

Chap e 7
105
a)
b)
Figu e 7. 2 Rela i e comp essi e s eng h a day 28: (a) Phase 1 (e ec i e w/c = 0.48) and (b) Phase 2 (e ec i e w/c =
0.52)
In Phase 2, he MRACs achie ed a less han 11% lowe comp essi e s eng h is-à- is ha o
NAC2 a day 7 o cu ing excep o MRAC-C50-F152, which achie ed an 18.3% lowe s eng h han
NAC2.
A 28 and 56 days o cu ing, he comp essi e s eng hs o he MRAC-C202, MRAC-C302, MRAC-
C402 and MRAC-C502 conc e es we e lowe han ha o NAC2 by 9.5%, 10%, 12.8% and 13.1%,
espec i ely (Figu e 7. 2-b). MRAC p oduced wi h a CMRA pe cen age composi ion o up o 50%
achie ed simila p ope ies o hose o NAC [21,89,148,169,247,254].
Based on 28 days alues, MRAC-C20-F52 and MRAC-C30-F102 achie ed a 10% lowe
comp essi e s eng h han NAC2 (Table 7. 4& Figu e 7. 2-b). Al hough MRAC-C40-F152 and MRAC-
C50-F152, espec i ely, achie ed 15% and 19.5% lowe s eng hs han ha o NAC2, MRAC-C40-
F152 achie ed a 2.4% lowe s eng h han ha o MRAC-C402. In addi ion, MRAC-C50-F152 achie ed
a 6.4% lowe s eng h han ha o MRAC-C502. The small di e ences in comp essi e s eng h can be
a ibu ed o an enhanced in e acial zone esul ing om he use o ough ce amic, along wi h he
inhe en s eng h o he ce amic ma e ial [57,196]. Ped o e al. [51] and Díaz e al. [169] obse ed ha
using he 25/25 and 50/50 eplacemen pe cen age p opo ions o MRA ( ine/coa se) yielded 3–10%
and 10–17% lowe s eng hs, espec i ely han he NAC. Mas e al. [253] ound ha he use o 15%
and 30% o MRA (0/8) educed comp essi e s eng h by 20.6% and 24.1%, espec i ely, indica ing
sensi i i y o high le els o MRA eplacemen .
The o al wa e /cemen a io o conc e e inc eased as a highe pe cen age o MRA was used in
conc e e p oduc ion. In addi ion, as shown in Table 7. 1 and Table 7. 2, he conc e es p oduced in
Phase 2 (wi h an e ec i e w/c a io o 0.52) had a highe o al wa e -cemen a io han hose o Phase
1 (wi h an e ec i e w/c a io o 0.48). Mo eo e , Figu e 7. 3 shows ha by analysing each phase
independen ly, he conc e es p oduced wi h a highe pe cen age o MRAC and, consequen ly, wi h a
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Ra io comp essi e s engh all
conc e e/NAC
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Ra io comp essi e s engh all
conc e e/NAC
Chap e 7
106
highe o al wa e -cemen a io, achie ed lowe comp essi e s eng h. Due o he highe wa e
abso p ion o MRA and weake bond o he cemen i ious ma ix, MRA de e io a es he conc e e
mic os uc u e, educing i s abili y o each op imal s eng h [150,168]. Figu e 7. 3 also shows ha he
MRAC conc e e p oduced wi h a simila o al wa e -cemen a io bu a lowe e ec i e wa e -cemen
a io (phase 1) achie ed highe s eng h han he conc e e p oduced in phase 2.
NAC-300₁
MRAC-C20₁MRAC-C30₁
MRACC50₁
MRAC-C100₁
MRAC-C20-F5₁
MRAC-C30-F10₁MRAC-C40-F15₁
MRAC-C50-F25₁
NAC-300₂
MRAC-C20₂MRAC-C30₂
MRAC-G40₂MRAC-C50₂
MRAC-C20-F5₂MRAC-C30-F10₂
MRAC-C40-F15₂
MRAC-C50-F15₂R² = 0.9072
R² = 0.8875
40.0
45.0
50.0
55.0
60.0
65.0
70.0
0.50 0.55 0.60 0.65 0.70 0.75 0.80
Comp essi e s eng h (MPa)
To al wa e / cemen
PHASE 1
PHASE 2
Figu e 7. 3 Comp essi e s eng h a io s To al w/c a io
The analysis p esen ed in Table 7. 4 and Figu e 7. 3 e eals ha all he MRACs p oduced in Phase
1 (e ec i e w/c a io = 0.48) exhibi ed a g ea e o simila comp essi e s eng h o ha o NAC2
(e ec i e w/c a io = 0.52) a 28 and 56 days o cu ing, espec i ely, excep o MRAC-C1001.
Reducing he w/c a io o he MRAC o 0.48 signi ican ly enhanced i s s eng h, allowing some
mix u es o achie e alues compa able o NAC2 (desc ibe ia a g ey squa e in Figu e 7. 3) and pe o m
simila ly in s uc u al applica ions. Op imising he w/c is c i ical o MRAC o achie e comp essi e
s eng hs compa able o hose o NAC; howe e , he e ec i eness o his app oach is c i ically
dependen on he quali y o he RA used.
The conc e es we e designed o a C30/37 s eng h class a ing. Based on he SC-BOE [20], he
minimum ck and he a e age comp essi e s eng h ( cm) should be 30 MPa and 38 MPa Eq.7 (1),
espec i ely, o a conc e e cylinde o Ø150 mm and leng h 300 mm. In addi ion, he s eng h in cubic
specimens measu ing 150 × 150 × 150 mm ( cm,cub150) is calcula ed ela i e o cylind ical specimens
( cm,cyl) using Eq.7 (2) [20]. Fu he mo e, he ela ionship be ween he comp essi e s eng hs o cubic
specimens wi h di e en dimensions is exp essed as Eq.7 (3) [126]. Based on hese calcula ions, a
minimum a e age s eng h o 46 MPa in cubic specimens ( cm,cub100) was equi ed in he MRAC
conc e es p oduced o mee he alida ion equi emen s o he code. Al hough he s eng h o he
Chap e 7
107
MRACs (Table 7. 4) was lowe han ha o he NAC, all he conc e e mix u es in Phase 1 p oduced
wi h an e ec i e w/c a io o 0.48 me he s eng h equi emen , excep MRAC-C100₁. In addi ion, all
he conc e e mix u es in Phase 2 me he s eng h c i e ia, excep MRAC-C40-F152 and MRAC-C50-
F15₂.
cm = ck + 8MPa Eq.7 (1)
cm,cub150 = cm,cyl  0.9 Eq.7 (2)
cm,cub100= 1.09· cm,cub150 Eq.7 (3)
7.3.2.2 Spli ing ensile s eng h
All MRAC conc e es ob ained lowe spli ing ensile s eng h han he NAC conc e e. In addi ion,
he conc e es p oduced wi h a highe pe cen age o MRA su e ed a highe dec ease in spli ing ensile
s eng h (see Table 7. 5).
In Phase 1, MRAC-C201 and MRAC-C301 exhibi ed spli ing ensile s eng hs ha we e sligh ly
lowe han ha o NAC1 by 0.9% and 5.3%, espec i ely. Howe e , MRAC-C501 and MRAC-1001
achie ed 13% o 22.3% lowe spli ing ensile s eng h han NAC1. Se e al esea che s [149,196,253]
ha e also obse ed simila beha iou in MRAC conc e es. B a o e al. [251] and Can e o e al. [252]
epo ha conc e e p oduced wi h 50% CMRA achie ed a 9–26% lowe spli ing ensile s eng h han
NAC. Fu he mo e, acco ding o se e al esea ch s udies [247,255], conc e es p oduced wi h 100%
CMRA can achie e up o 30% lowe s eng h han NAC. Acco ding o E xebe ia&Gonzales e al.
[254], he lowe ensile s eng h is con ingen upon he la ge nominal size o MRA (20 mm), and he
la shape o MRA gains is ins umen al in he achie ing o he lowe spli ing ensile s eng h.
Inco po a ing FMRA in o he conc e e esul ed in a much lowe spli ing ensile s eng h (Table 7. 4).
The MRAC-C20-F51, MRAC-C30-F101 and MRAC-C50-F251 conc e es achie ed 4.5%, 7.7% and
19.8% lowe s eng hs han he co esponding MRAC-C201, MRAC-C301 and MRAC-C501 conc e es.
MRAC p oduced using CMRA and FMRA achie ed be ween 12.7% and 33% lowe s eng h han
NAC1. Simila ly, Ped o e al. [51] de e mined ha conc e e p oduced using ine and coa se RA
(FMRA/CMRA) in eplacemen a ios o 25/25, 50/50, 100/0, 0/100 and 100/100 yielded 13.8% o
38% lowe spli ing ensile s eng h han NAC.
Acco ding o Nedeljko ić [57], conc e e p oduced using 10%, 30% and 50% FMRA (in
eplacemen o NA sand) and 100% coa se NA yielded 10.2%, 10.8% and 17.8%, espec i ely, lowe
s eng h han NAC. Howe e , se e al s udies [145,196,256] ha e de e mined ha he use o FMRA
and ce amic ine agg ega es yields a highe spli ing ensile s eng h han ha o NAC conc e e a
simila end as ha obse ed o comp essi e s eng h.
Chap e 7
108
Table 7. 5 Spli ing ensile s eng h and modulus o elas ici y (MRAC/NAC a io)
Phase 1 Mix u es
Spli ing ensile
S eng h (MPa)
Modulus o
elas ici y (GPa)
Phase 2 Mix u es
Spli ing ensile
S eng h (MPa)
Modulus o
elas ici y (GPa)
NAC₁
3,79
40,45
NAC₂
3.77
38.79
MRAC-C20₁
3.76 (-0.91)
35.83 (-11.44)
MRAC-C20₂
3.7 (-1.86)
35.57 (-8.29)
MRAC-C30₁
3.59 (-5.25)
35.26 (-12.84)
MRAC-C30₂
3.62 (-3.85)
35.14 (-9.41)
MRAC-C50₁
3.29 (-13.14)
34.54 (-14.61)
MRAC-C40₂
3.55 (-5.84)
32.79 (-15.47)
MRAC-C100₁
2.95 (-22.3)
25.75 (-36.34)
MRAC-C50₂
3.28 (-13.05)
32.34 (-16.63)
MRAC-C20-F5₁
3.59 (-5.38)
34.97 (-13.55)
MRAC-C20-F5₂
3.54 (-6.1)
34.57 (-10.88)
MRAC-C30-F10₁
3.30 (-12.7)
33.66 (-16.79)
MRAC-C30-F10₂
3.33 (-11.72)
32.38 (-16.52)
MRAC-C40-F15₁
3.28 (-13.5)
31.94 (-21.04)
MRAC-C40-F15₂
3.30 (-12.38)
31.8 (-18.02)
MRAC-C50-F25₁
2.54 (-33.0)
29.53 (-27.01)
MRAC-C50-F15₂
3.11 (-17.50)
29.34 (-24.36)
In Phase 2, much like in Phase 1, i was obse ed ha he MRAC-C302 and MRAC-C402 conc e es
achie ed 3.9% and 5.8% lowe s eng h han NAC2. Howe e , he s eng h di e ence was as high as
13.1% when 50% CMRA (MRAC-C502) was employed. Se e al esea che s [257,258] ha e
de e mined ha conc e e p oduced wi h 25% and 50% CMRA achie es up o 4% and 9%, espec i ely,
lowe lexu al ensile s eng h han NAC.
In con as o Phase 1, conc e e p oduced wi h up o 15% FMRA and CMRA in Phase 2 (Table 7.
4) achie ed simila s eng h o he co esponding conc e e p oduced using only CMRA and NA sand.
MRAC-C20-52, MRAC-C30-F102, MRAC-C40-F152 and MRAC-C50-F152 achie ed 4.2%, 7.8%,
6.54% and 4.5% lowe s eng h han hei co esponding conc e e p oduced using only CMRA and
NA sand. Se e al esea che s indica e ha conc e e made using a high pe cen age o MRA in
eplacemen o NA achie es sligh ly lowe o simila , bu compa able spli ing ensile s eng h o NAC
[148,205,259].
Acco ding o se e al esea che s [103,185,260], he spli ing ensile s eng h educ ion in ecycled
conc e e can be assumed o be up o 15-20% is−à− is ha o NAC, wi hou comp omising sa e y and
wi hou a c i ical isk o c acking. Acco ding o SC-BOE [20], equi ed 2.9 MPa o C30/37 conc e e,
all he MRAC achie ed adequa e pa ame e alues, excep MRAC-C100₁ and MRAC-C50-F25₁.
The s eng h alues achie ed by he specimens in Phase 1 and Phase 2 indica e ha NACs and
conc e es p oduced wi h he same pe cen age composi ions o CMRA and FMRA achie e compa able
p ope ies no wi hs anding he highe w/c a io employed in Phase 2. This beha iou is a ibu able o
he bene icial e ec s o wa e in he agg ega es, which enhance he p ope ies o he conc e e h ough
he hyd a ion o he cemen pas e [196].
Based on he SC-BOE [20], he spli ing ensile s eng h ( c m) o NAC can be de e mined as a
unc ion o i s ck (Eq.7 [4]). Fo each ype o conc e e p oduced, he ck was e alua ed by aking in o
accoun he ck o each sample ( cm,cub), as ou lined in Table 7. 3, using Eqs.7 (3), 7 (2) and 7 (1),
Chap e 7
109
hen he c m was de e mined. The ela ionship be ween he expe imen al and heo e ical alues o
he di e en ypes o conc e e a e p esen ed in Figu e 7. 4.
c m= 0.3 ck/2/3 Eq.7 (4)
a)
b)
Figu e 7. 4 Ra io o he expe imen al alue o he heo e ical alue o he spli ing ensile s eng h: (a) Phase 1 (e ec i e
w/c = 0.48) and (b) Phase 2 (e ec i e w/c = 0.52)
Du ing Phase 1 (Figu e 7. 4-a), he heo e ical me hod (based on Eq.7 [4]) exhibi ed p ecision,
wi h di e ences o below 5% o NAC1 and MRAC specimens, excep o MRAC-C50-F251 conc e e
in which he heo e ical me hod o e es ima es i s spli ing ensile by 21%. In Phase 2 (Figu e 7. 4-b),
i was obse ed ha he heo e ical me hod unde es ima ed he expe imen al alues. This sugges s ha
al hough he speci ic o mula in he SC-BOE [20], which is based on comp essi e s eng h, pe o ms
well o low w/c conc e es, i may no ully cap u e he spli ing ensile s eng h alue when conc e e
was p oduced wi h an e ec i e w/c a io o 0.52.
7.3.2.3 Elas ic modulus
Based on he modulus o elas ici y a 28 days Table 7. 5), he MRAC conc e es achie ed a lowe
modulus o elas ici y han he NAC conc e es due o he highe po osi y o MRA, [64,171,261]. The
alue o he modulus o elas ici y dec eased e en u he when highe pe cen ages o MRA we e
u ilized [126,185,247].
The modulus o elas ici y o conc e e p oduced in phase 1 and phase 2 was simila , as he modulus
o elas ici y is in luenced by he coa se agg ega e used in he conc e e p oduc ion [262]. In addi ion,
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Ra io Spli ing ensile S engh
(Expe imen al/ heo icalSC-BOE)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Ra io Spli ing ensile S engh
(Expe imen al/ heo icalSC-BOE)

Chap e 7
110
due o he low s i ness o he adhe ed mo a , employing mo e han 5% o FMRA inc eases he
educ ion o modulus o he MRAC wi h espec o ha o NAC conc e e [263,264].
Based on he esul s o he es s (Phase 1 and Phase 2), he conc e es p oduced wi h 20%, 30%,
40%, 50% and 100% CMRA and NA sand achie ed app oxima ely 9%, 11%, 13%, 15% and 36%
lowe modulus o elas ici y han NAC. Acco ding o se e al esea che s [171,214,252], MRAC
p oduced wi h up o 25%, 50% and 100% CMRA achie ed 5–10%, 15–25% and 25–30%,
espec i ely, lowe modulus o elas ici y han NAC. In addi ion, se e al esea che s [265] ha e
de e mined ha conc e e p oduced wi h 100% coa se b ick agg ega es has up o 68% lowe modulus
o elas ici y han NAC.
When FMRA was employed in addi ion o CMRA, he modulus o elas ici y o MRAC was lowe
han ha o conc e e p oduced only using CMRA. The use o 10% and 15% o FMRA wi h up o 40%
o CMRA yielded a less han 10% lowe modulus o elas ici y han he co esponding conc e e
p oduced using only CMRA. Howe e , he MRAC-C40-F15 conc e e achie ed a 20% lowe modulus
o elas ici y han NAC. In addi ion, mixes inco po a ing a 25% FMRA (MRAC-C50-251) exhibi ed a
signi ican ly low modulus o elas ici y, achie ing a 12.14% lowe modulus o elas ici y han he
MRAC-C501 conc e e and a 27.01% lowe modulus han NAC1. Ped o e al. [51] ound ha conc e e
p oduced wi h coa se and ine eplacemen s (CMRA/FMRA) o 25/25 and 50/50 achie ed 15% and
20% lowe modulus, espec i ely, han NAC. The modulus dec ease ob ained by MRAC wi h espec
o NAC in phases 1 and 2, excep MRAC-C100₁ and MRAC-C50-F25₁, we e lowe han he alues
published by he Building Con ac o s Socie y o Japan [266], which es ablishes ha RAC (p oduced
using ine and coa se RA) achie e 25–40% lowe alue han NAC. The MRAC-C100₁ and MRAC-
C50-F25₁ achie ed a dec ease o 36.34% and 27.01%, espec i ely, alues es ablished by he Building
Con ac o s Socie y o Japan.
To alida e he alues achie ed by MRACs, he expe imen ally achie ed alues we e compa ed
o he heo e ically de e mined alues, aking in o accoun bo h he SC-BOE [20] and Eu ocode 2: EN
1992–1-1 (EC-02)[50]. The modulus o elas ici y o NAC conc e e can be es ima ed using Eq.7 (5)
as pe SC-BOE [20]. The e o e, a NAC (30/37) conc e e wi h a minimum cm o 38 MPa (cylind ical
specimen) should ha e a minimum modulus o elas ici y o 33 GPa. In ligh o his alue, he MRAC-
C1001, MRAC-C50-F251, and MRAC-C50-F152 conc e e mix u es exhibi ed lowe alues, indica ing
highe de o mabili y (Table 7. 5).
Ecm = 22.( cm
10)0.3 Eq.7 (5)
The a io be ween he expe imen al alue is-à- is he heo e ical alue achie ed by each conc e e,
pe he SC-BOE, a e p esen ed in Figu e 7. 5-a. When MRAC was p oduced wi h an e ec i e w/c
a io o 0.48 (Phase 1), he modulus o elas ici y o MRAC p oduced wi h up o 50% CMRA and
na u al sand was highe o simila han he heo e ically es ima ed alue. Howe e , he expe imen al
alue o CMRA-C1001 was 21% lowe han he heo e ically es ima ed alue. Fu he mo e, when
Chap e 7
111
FMRA was employed in p oducing conc e e, he heo e ical me hod o e es ima ed he expe imen al
alues (expe imen al alues we e lowe han he heo e ically es ima ed alues), wi h expe imen al
alues being up o 14% lowe han he heo e ically es ima ed alues, excep o MRAC-C20-F5, o
which he alues we e simila . In con as , when MRAC was p oduced wi h an e ec i e w/c o 0.52,
Eq.7 (5) adequa ely es ima ed he modulus o elas ici y alue o all he MRACs, excep o MRAC-
C50-F152, o which he expe imen al alue was lowe han he heo e ically es ima ed alue.
Acco ding o EC-02, he modulus o elas ici y is heo e ically es ima ed using Eq.7 (6):
Ecm= KE.(1−0.25.αRA). cm1/3 Eq.7 (6)
Whe e he coe icien kE ep esen s he ype o agg ega e and is 9,500 [21], and αRA is he a io
o he u ilized quan i y o FMRA and CMRA o he o al quan i y o agg ega es employed, aking
ine and coa se agg ega es in o accoun [50]. Figu e 7. 5-b shows ha Eq.7 (6) unde es ima es he
modulus o elas ici y o MRAC p oduced using CMRA o all specimens p oduced in Phase 2
(employing an e ec i e w/c o 0.52) and Phase 1 (employing an e ec i e w/c o 0.48), excep o
MRAC-C1001, which achie ed a 6.0% lowe expe imen ally de e mined alue han he heo e ically
es ima ed alue o i s modulus o elas ici y.
Based on he in o ma ion p esen ed in Figu e 7. 5, i is no ewo hy ha he impac o MRA on
he di e ence be ween he expe imen ally de e mined modulus o elas ici y is-à- is he heo e ical
alue was g ea e in Phase 1 han in Phase 2. This phenomenon is a ibu able o he lowe w/c a io
and highe s eng h in he o me (Phase 1) han in he la e (Phase 2).
0.7
0.8
0.9
1.0
1.1
1.2
Ra io Modulus o elac ici y (Expe imen al
alue/ Theo e ical SC-BOE)
Phase 1 e ec i e w/c=0.48
Phase 2 e ec i e w/c=0.52
0.7
0.8
0.9
1.0
1.1
1.2
Ra io Modulus o elac ici y (Expe imen al
alue/ Theo e ical Ec-02)
Phase 1 e ec i e w/c=0.48
Phase 2 e ec i e w/c=0.52
a) SC-BOE
b) EC-02
Figu e 7. 5 Analysis o modulus o elas ici y es ima ion: (a) Ra io o expe imen al alue/ heo e ical SC-BOE (b) Ra io o
expe imen al/ heo e ical EC-02
Chap e 7
112
The MRAC40-F15 p oduced in he wo phases − wi h a educ ion anging om 11.44% o 21.04%
in Phase 1 and 8.29% o 16.63% in Phase 2− mee he anges accep ed by he SC-BOE [14] wi h a
lowe educ ion han he 20% educ ion p o e ed by se e al au ho s [51,185,222,255] who p opose
ha conc e e mix u es wi h ecycled agg ega es wi hin hese educ ion ma gins can be sui able o
s uc u al applica ions. The modulus o elas ici y is c ucial o con olling de o ma ions unde load,
and despi e he obse ed educ ions, s uc u es buil wi h MRAC s ill main ain hei de o mabili y
wi hin sa e limi s.
7.3.3. D ying sh inkage
The d ying sh inkage (µƐ) and pe cen age mass loss (%) alues achie ed by all he conc e e
mix u es p oduced in Phase 1 a e ou lined in Figu e 7. 6-a. CMRA-C201 and CMRA-C301 achie ed
lowe o simila sh inkage alues han NAC1, and employing FMRA in he p oduc ion o CMRA-
C20-F51 and CMRA-C30-F101 yielded a sligh ly highe sh inkage alue han NAC1. These esul s
a e also p esen ed in Figu e 7. 7-a. in which he a io o he MRAC sh inkage alues is-à- is hose
o NAC1 a e ou lined. Howe e , when MRAC was p oduced wi h a high pe cen age composi ion o
MRA (coa se and ine), i achie ed high sh inkage alues. This beha iou is a ibu able o he high
po osi y o ine MRA and he consequen low densi y esul ing om he p esence o ha dened mo a
wi hin i s s uc u e. This phenomenon esul s in low ma e ial s i ness and he ma e ial’s abili y o
es ain de o ma ion [263]. Based on hese esul s, i can be concluded ha signi ican changes in
conc e e sh inkage occu s when conc e e is p oduced using 50% CMRA (wi h na u al sand) and
when conc e e is p oduced wi h 40% CMRA and 15% FMRA. MRAC-C501 and MRAC-C1001,
espec i ely, achie ed 20% and 72.8% highe d ying sh inkage alues han NAC1 (Figu e 7. 7-a).
MRAC-C1001 achie ed a d ying sh inkage alue o −855.4 μ/m. Vin imilla and E xebe ia [126]
de e mined ha conc e e p oduced using 100% CRCA and NA sand achie es a 60% highe sh inkage
alue han NAC. In addi ion, Ped o e al. [51] obse ed ha conc e e p oduced wi h 100% coa se
MRA and NA sand achie es a 72% highe sh inkage alue han NAC. Fu he mo e, he MRAC-
C40-F151 and MRAC-C50-F251 conc e es in his s udy exhibi ed 16.2% and 25.3% highe d ying
sh inkage alues han NAC1 a 91 days (Figu e 7. 7-a), achie ing alues o −574.9 μ/m and −620.2
μ/m, espec i ely.
Figu e 7. 6-b desc ibes he mass loss o all he conc e es p oduced in Phase 1. Simila o he
sh inkage alues, conc e e made wi h a high MRA achie ed a high mass loss. NAC1 achie ed a mass
loss o 2.2%, MRAC-C201 and MRAC-C20-F51 achie ed a mass loss alue o 3.2%, MRAC-C301,
MRAC-C30-F101 and MRAC-C40-F151 achie ed an app oxima e mass loss alue o 3.6%, MRAC-
C501 and MRAC-C50-F251 achie ed mass loss alues o 3.8% and 4.1%, espec i ely, and MRAC-
C1001 achie ed a mass loss o 5.5% he highes mass loss alue eco ded. These alues a e sligh ly
highe han hose obse ed by Vin imilla and E xebe ia [126], who de e mined ha conc e es
p oduced wi h up o 100% CRCA and na u al sand achie ed up o 3.5% mass loss. Simila ly, conc e e
p oduced wi h coa se and ine RCA (CRCA/FRCA) in a ios om 50/20 o 100/100 su e ed mass
losses anging om 3.4% o 5.4%. In a p e ious s udy [105], conc e e p oduced employing a 50/20
a io o di e en cemen ypes esul ed in a mass loss o 2.5% o 3.5%.
Chap e 7
113
-6.0
-5.0
-4.0
-3.0
-2.0
-1.0
0.0
0 7 14 21 28 35 42 49 56 63 70 77 84 91
Mass Loss (%)
Time (Days)
NAC₁MRAC-C20₁
MRAC-C30₁MRAC-C50₁
MRAC-C100₁MRAC-C20-F5₁
MRAC-C30-F10₁MRAC-C40-F15₁
MRAC-C50-F25₁
a)
b)
Figu e 7. 6 D ying sh inkage alues in Phase 1: (a) D ying sh inkage MRCA1&FMRA1, (b) Mass loss
MRCA1&FMRA1
a)
b)
Figu e 7. 7 Rela i e sh inkage a io a day 91: (a) Phase 1 (e ec i e w/c = 0.48) and (b) Phase 2 (e ec i e w/c = 0.52)
Conc e e p oduced wi h a high wa e –cemen a io su e s high sh inkage [121,267]. Al hough
he conc e e mix u es in Phase 2 had a highe wa e con en han he Phase 1 conc e es, he sh inkage
alues in Phase 2 we e lowe . This can be a ibu ed o sligh a ia ions in he a mosphe ic condi ions
o he clima ic oom du ing he es p ocedu e. Phase 1 was conduc ed du ing sp ing and summe ,
wi h s able a mosphe ic condi ions o he clima ic oom, ea u ing an a e age empe a u e o 22℃
and a ela i e humidi y (RH) o 51%. On he o he hand, in Phase 2, conc e es we e assessed in
au umn and win e while he main enance wo ks we e se in he clima ic oom. Consequen ly,
al hough he a e age a mosphe ic condi ions in he clima ic oom we e 19 ℃ and 53% RH, i caused
-900
-800
-700
-600
-500
-400
-300
-200
-100
0
0 7 14 21 28 35 42 49 56 63 70 77 84 91
D ying sh inkage s ain (µm/m)
D ying ime (days)
NAC₁MRAC-C20₁
MRAC-C30₁MRAC-C50₁
MRAC-C100₁MRAC-C20-F5₁
MRAC-C30-F10₁MRAC-C40-F15₁
MRAC-C50-F25₁
0.0
0.5
1.0
1.5
2.0
Ra io sh inkage all conc e e/NAC₁
0.0
0.5
1.0
1.5
2.0
Ra io sh inkage all conc e e/NAC₂
Chap e 7
120
a)
b)
Figu e 7. 12 Wa e pene a ion unde p essu e: (a) Phase 1 (e ec i e w/c = 0.48) and (b) Phase 2 (e ec i e w/c = 0.52)
7.4. Conclusions
The esul s o he es s pe o med in his s udy suppo he ollowing conclusions:
• The MRACs p oduced −using up o 50% coa se MRA wi h na u al sand and up o 40% coa se
MRA combined wi h 15% ine MRA, wi h an e ec i e w/c a io o 0.48 (Phase11) and an
e ec i e w/c a io o 0.52 (Phase 22) achie ed densi ies 2.2 o 2.33 kg/dm³, app oxima ely 5%
lowe han he densi y o NACs. Fu he mo e, accessible po es emain below 15%, ensu ing
accep able quali y.
• MRAC conc e es mee he comp essi e s eng h equi emen s o s uc u al conc e e in ended
o use in XC1 o XC4 en i onmen s (46 MPa cubic specimens), excep o MRAC-C1001,
MRAC-C40-F152 and MRAC-C50-F152.
• MRAC specimens achie e a lowe s eng h han NAC when p oduced wi h an iden ical e ec i e
w/c a io. Howe e , he use o a 0.04 lowe e ec i e w/c a io in MRAC-C30-F10, MRAC-
C40-F15 ( ine and coa se ac ions), and MRAC-C50 (only coa se ac ion) yields simila
s eng hs o ha o NAC.
• The spli ing ensile s eng h and modulus o elas ici y o MRAC dec ease wi h an inc ease in
he MRA pe cen age p opo ion. The e ec i e w/c a io does no signi ican ly impac hose
p ope ies o MRACs wi h he same MRA eplacemen pe cen age.
• The spli ing ensile s eng h o all MRACs, excep o MRAC-C1001 and MRAC-C50-F251,
mee s he equi ed 2.9 MPa o C30/37 conc e e, which is sui able o use in XC1 o XC4
en i onmen s.
0
10
20
30
40
50
60
Wa e Pene a ion (mm)
A e age Pene a ion Da ≤30mm
Maximun Pene a ion Dmax ≤ 50mm
0
10
20
30
40
50
60
Wa e Pene a ion (mm)
A e age Pene a ion Da ≤30mm
Maximun Pene a ion Dmax ≤ 50mm

Chap e 7
121
• Conc e e wi h maximum eplacemen s o 40% CMRA and 15% FMRA achie es modulus o
elas ici y alues compa able o hose o NACs wi h modulus o elas ici y alues enginee ed
using he SC-BOE me hod o C30/37 conc e e. The EC-02 me hod, which akes in o accoun
he impac o MRA componen s, p o ides sa is ac o y es ima es o all MRACs.
• Conc e e inco po a ing up o 50% CMRA (wi hou FMRA) in Phase 1 and 30% in Phase 2
exhibi ed a d ying sh inkage alue simila o ha o NACs. The use o up o 15% FMRA wi h
40% o CMRA in Phase 1 sligh ly inc eased (16%) he sh inkage alue o conc e e whe eas in
Phase 2, he use o 10% FMRA esul ed in a 44% inc ease in sh inkage.
• The heo e ical me hod o he SC-BOE, s uc u al code c i e ia, accu a ely es ima es sh inkage
alues o conc e e wi h up o 30% CMRA and 10% FMRA. Al hough EC-02, which employs
he ηshRA ac o , limi s he use o MRA o up o 40% CRMA o 30% CMRA oge he wi h
10% FMRA, i p o ides accu a e es ima es o all conc e e ypes.
• MRACs exhibi highe so p i i y alues han NACs due o hei highe po osi y. Howe e , he
conc e e p oduced wi h up o 40% CMRA and 15% FMRA achie es so p i i y alues below
0.05 mm/min0.5, which indica es good du abili y.
• All conc e es p oduced in his s udy mee he wa e pene a ion h eshold o XC1 o XC4
en i onmen s s ipula ed by he SC-BOE. In gene al, an inc ease in he FMRA con en esul s in
an inc eased wa e pene a ion h eshold.
Based on he indings o his s udy, conc e e p oduced wi h 40% CMRA and 15% FMRA and an
e ec i e w/c a io o 0.48 achie es comp essi e s eng h and du abili y p ope ies simila o hose o
con en ional conc e e p oduced wi h an e ec i e w/c a io o 0.52. Howe e , o gua an ee mechanical
pe o mance o conc e e p oduced wi h 30% CMRA and 10% FMRA (which ep esen s a 20%
eplacemen o he o al olume o agg ega es) sa is ies all he speci ica ion equi emen s. Fu he
in es iga ion is equi ed o de e mine he long- e m du abili y e ec o MRACs especially conc e e
p oduced wi h 40% CMRA and 15% FMRA (which ep esen s a 28% eplacemen o he o al olume
o agg ega es).
U ilizing MRA (bo h ine and coa se) is a iable op ion o p oducing conc e e, no wi hs anding
no being speci ied in SC-BOE. In addi ion, small quan i ies o FMRA can be inco po a ed
success ully.
Chap e 8
122
1.
8. Chap e 8. Gene al conclusions and
u u e esea ch lines
8.1 Gene al conclusions
This s udy analyzed he easibili y o using ecycled conc e e agg ega es (RCA) and mixed
ecycled agg ega es (MRA) in Op imize use o Recycled Agg ega e in High Du abili y S uc u al
Conc e e: An Expe imen al S udy. Di e en eplacemen a ios, he maximum iable subs i u ion
limi o s uc u al conc e e p oduc ion, o hese ecycled agg ega es we e es ablished o RAC
applica ions in XC1-XC4, XS1 en i onmen s, wi h a comp essi e s eng h o 30/37 MPa. In all
expe imen al phases, a cemen dosage o 300 kg pe cubic me e o conc e e was used. The de eloped
mix u es we e ho oughly e alua ed in e ms o hei physical, mechanical, and du abili y p ope ies,
ensu ing hey mee he equi emen s o s uc u al applica ions in sus ainable and long-las ing
en i onmen s.
The gene al conclusions o he in es iga ions a e lis ed below:
P ope ies o ecycled agg ega es
• RCA-Type A, consis s o o e 90% conc e e and na u al s one (RCU95 classi ica ion). The
esea ch indica es a densi y ange o 2.32-2.36 kg/dm3 and wa e abso p ion be ween 5.16%
and 5.73%. These alues mee he EN 206 s anda d o Type A agg ega es (> 2.1 kg/dm3
densi y and <7% wa e abso p ion, acco ding o SC-BOE).
• RCA-Type A can comply wi h key pe o mance indica o s o s uc u al conc e e. The
agg ega es also mee he equi emen s o sand equi alen , Los Angeles coe icien , lakiness
index, and alkali-agg ega e eac i i y (expansion < 0.1% a e 14 days).
• MRA-Type B, wi h conc e e and na u al s one exceeding 50% and ce amic con en below
30% (mee ing EN 206 Type B classi ica ion: RC50, RCU70, Rb30-, Ra5-, FL2- and XRg2).
Densi y anges om 2.08 o 2.28 kg/dm3, exceeding he UNE EN 206 equi emen o >1.7
kg/dm3.
The wa e abso p ion o coa se MRA (CMRA) ac ions (8.75-9%) exceeds he 7% limi se
by SC-BOE. Howe e , he s udy highligh s ha he a e age wa e abso p ion o he combined
NA and CMRA emains below he h eshold when used in conc e e p oduc ion.
• MRA exhibi s in e io pe o mance compa ed o NA and RCA-Type A (lowe densi y, highe
po osi y), bu i can s ill be sui able o conc e e i mix designs accoun o he highe wa e
abso p ion and po en ial impac on wo kabili y. Using a lowe pe cen age o MRA can also
help mi iga e hese e ec s
Chap e 8
123
The Adjus men s in Mix Design
To achie e p ope ies compa able o na u al agg ega e conc e e (NAC), ce ain adjus men s in he mix
design wi h ecycled agg ega e conc e e (RAC) and mixed ecycled agg ega e conc e e (MRAC) a e
equi ed. In he RAC mix u es, he na u al coa se agg ega e was ini ially eplaced by coa se RCA
(CRCA) a le els anging om 20% o 100%. Subsequen ly, ine ecycled conc e e agg ega e (FRCA)
was inco po a ed in adjus ed p opo ions, eaching up o 100% in he mixes wi h he highes CRCA
con en . Fo he MRAC mix u es, he na u al coa se agg ega e was subs i u ed wi h coa se mixed
ecycled agg ega e (CMRA) in p opo ions anging om 20% o 100%. Addi ionally, ine mixed
ecycled agg ega e (FMRA) was in oduced, eplacing up o 25% o he na u al sand.
• Th oughou he expe imen al campaign, he amoun o chemical admix u es, including
plas icize s and supe plas icize s, mus be adjus ed when conc e e is p oduced using ecycled
agg ega es o achie e adequa e wo kabili y. The equi ed dosage was highe in RACs and
MRCs compa ed o NAC, which consis en ly emained wi hin a ange be ween luid and
liquid.
• Adjus men s in mix design showed ha educing he wa e -cemen a io in RAC and MRAC
had a posi i e impac on i s du abili y. The NAC and RAC we e designed wi h e ec i e wa e -
cemen a ios o 0.47 and 0.51, espec i ely. This adjus men , educing he e ec i e wa e -
cemen a io by app oxima ely 0.04 in RAC and MRACs wi h espec o ha o NAC, allowed
o a mo e equi able du abili y assessmen , compensa ing o he highe po osi y and wa e
abso p ion o RCA. As a esul , he educ ion in he wa e -cemen a io imp o ed he RAC’s
esis ance o ca bona ion and chlo ide ions, b inging i s pe o mance close o ha o NAC.
• The wa e abso p ion o RAs is signi ican ly highe in RCA-Type A and pa icula ly in MRA-
Type B han ha o NA. This cha ac e is ic di ec ly in luences he design and pe o mance
o conc e e, as excessi e e ec i e abso p ion capaci y can a ec wo kabili y and e ec i e
w/c a io, consequen ly, he cemen hyd a ion. The e o e, he use o agg ega es wi h high
mois u e pe cen ages is ecommended, p e e ably in a ange o 70-80% o hei abso p ion
capaci y. This p ac ice allows o op imiza ion o he e ec i e wa e -cemen a io and
imp o emen o mix consis ency, as well as ensu es be e mechanical pe o mance and
du abili y in s uc u es made wi h ecycled conc e e.
Physical and Mechanical P ope ies
• The conc e es, RAC (up o 60 % CRCA wi h 30 % FRCA) and MRAC (up o 50% CMRA
wi h na u al sand and up o 40% CMRA wi h 15% FMRA) exhibi sligh ly lowe densi ies
(app oxima ely 5%) compa ed o na u al agg ega e conc e e (NAC), anging om 2.2 o 2.33
kg/dm³, bu emain wi hin accep able limi s o s uc u al applica ions. The accessible po e
alues a e main ained below 10% o RAC and 15% o MRAC, ensu ing adequa e quali y.
• This esea ch has demons a ed he easibili y o u ilizing high pe cen ages, up o 100%, o
bo h coa se and ine RCA and MRA in conc e e p oduc ion. Al hough bo h ypes o ecycled
conc e e exhibi a dec ease in mechanical p ope ies compa ed o NAC, hey emain sui able
o a wide ange o non-s uc u al applica ions.
Chap e 8
124
• The esea ch has demons a ed ha conc e es inco po a ing up o 60% CRCA and 20%
FRCA, as well as up o 40% CMRA and 15% FMRA, exhibi ed a educ ion in spli ing ensile
s eng h compa ed o NAC. In RAC, he inco po a ion o up o 20% FRCA showed no
signi ican a ia ion compa ed o conc e es made wi h only CRCA. Simila ly, MRAC wi h
up o 15% FMRA achie ed s eng hs simila o hose o conc e es made wi h only CMRA,
and in some cases, e en imp o ed he mechanical p ope ies. No ably, di e en wa e - o-
cemen a ios had no signi ican impac on he spli ing ensile s eng h o NAC, RAC, and
MRAC.
• This s udy demons a es ha educing he e ec i e wa e -cemen a io by app oxima ely 0.04
in RAC and MRACs (e ec . w/c a io o 0.47) ensu es comp essi e s eng h equi alen o ha
o NAC (e ec . w/c a io 0.51) wi h a minimum comp essi e s eng h o 30/37 MPa. Conc e es
wi h 100% CRCA and hose inco po a ing 60% CRCA and 30% FRCA simul aneously achie e
comp essi e s eng hs compa able o NAC. Simila ly, conc e es wi h 50% CMRA and hose
wi h 50% CMRA combined wi h 25% FMRA also each equi alen comp essi e s eng hs.
Howe e , exceeding hese eplacemen le els leads o signi ican educ ions in comp essi e
s eng h.
• The use o ecycled agg ega es in conc e e (RAC and MRAC) educes he modulus o elas ici y
as he pe cen age o NA eplacemen inc eases; howe e , mixes wi h up o 60% CRCA and
30% FRCA, and 40% CMRA wi h 15% FMCA achie e accep able alues acco ding o
s uc u al egula ions. I was obse ed ha ecycled sand has a mo e signi ican impac on his
educ ion compa ed o he coa se ac ion. Mo eo e , while he modulus o elas ici y in NAC
a ies wi h he wa e /cemen a io, in RAC, i depends di ec ly on he pe cen age o ecycled
agg ega e eplacemen .
Sh inkage and P edic i e Models: Exis ing models o p edic ing conc e e beha iou equi e
adjus men s o RAC:
• The s udy demons a es ha conc e e mix u es inco po a ing up o 100% CRCA, e en in
combina ion wi h 20% FRCA, consis en ly exhibi ed d ying sh inkage alues below he -800
με/m h eshold ecommended by he Ame ican Conc e e Ins i u e (ACI). Simila ly, mix u es
con aining MRA, up o 50% CMRA and 25% FMRA showed sa is ac o y pe o mance,
main aining accep able sh inkage le els. These esul s emained consis en ac oss di e en
wa e - o-cemen a ios (0.47 and 0.51). Howe e , i dec eased o highe pe cen ages o
ecycled agg ega es.
• All RAC mix u es, wi h up o 60% CRCA and 20% FRCA— ega dless o he ype o cemen
used (CEM II/AL, CEM II/AS, and CEM III/B)— and wi h e ec i e wa e -cemen a io o
0.47, achie ed accep able sh inkage alues a 91 days, emain below he -600 με/m.
• Sh inkage p edic ion models o RAC exhibi a ying le els o accu acy. The SC-BOE model
p o ides p ecise p edic ions o conc e es wi h up o 60% CRCA and 20% FRCA, as well as
o mixes wi h up o 30% CMRA and 10% FMRA. Howe e , i s accu acy dec eases o highe
pe cen ages o ecycled agg ega es.
• The EC-02 model, which inco po a es he ηshRA ac o (0.4 o RCA and 0.2 o MRA),
demons a es g ea e p ecision compa ed o he SC-BOE model. This model p o ides
Chap e 8
125
accu a e p edic ions o conc e es wi h up o 60% CRCA and 20% FRCA, as well as o
mixes wi h up o 40% CMRA o 30% CMRA oge he wi h 10% FMRA. The inclusion o
hese speci ic ac o s enhances he model's abili y o accoun o he unique p ope ies o
ecycled agg ega e conc e e.
• Bo h models ha e limi a ions, especially when p edic ing sh inkage in conc e es wi h high
blas u nace slag con en cemen s (such as CEM III/B). These indings highligh he need
o mo e comp ehensi e models ha accoun o en i onmen al ac o s, cemen ypes, and
he speci ic p ope ies o ecycled agg ega es o enhance sh inkage p edic ions, especially in
he ea ly s ages o conc e e cu ing.
Du abili y
• RAC inco po a ing up o 60% CRCA and 20% FRCA, as well as 40% CMRA and 15% FMRA,
demons a ed sa is ac o y pe o mance in e ms o so p i i y, wi h alues below 0.05
mm/min⁰·⁵, indica ing good du abili y. Fu he mo e, all conc e es, including RAC and MRAC,
complied wi h he wa e pene a ion unde p essu e equi emen s es ablished by he S uc u al
Conc e e Code.
• RACs exhibi ed compa able o supe io chlo ide esis ance o NAC when bo h had simila
comp essi e s eng hs, wi h up o 60% CRCA eplacemen , ega dless o he cemen ype.
Howe e , inc easing FRCA con en up o 20% FRCA ends o inc ease chlo ide pene a ion.
The use o CEM III/B cemen signi ican ly imp o ed chlo ide pene a ion in all conc e es,
including RACs wi h up o 60% CRCA and 20% FRCA. The selec ion o cemen ype is
c ucial: CEM III/B cemen p o ed o be he mos e ec i e, ollowed by CEM II/AS, which
showed accep able alues wi h up o 60% CRCA and 10% FRCA. On he o he hand, he
conc e e p oduced using CEM II/AL exhibi ed he poo es pe o mance in e ms o chlo ide
pene a ion, ende ing i unsui able o hese ypes o agg essi e en i onmen s.
• The s udy highligh s he complexi y o ca bona ion esis ance ac oss conc e es p oduced using
di e en ypes o cemen . I con i ms he supe io pe o mance o conc e es made wi h CEM
II/AS cemen , ollowed by CEM II/AL, and inally, CEM III/B in e ms o ca bona ion
esis ance, ega dless o he agg ega es used. No ably, RACs wi h up o 60% CRCA and 20%
FRCA exhibi ed simila ca bona ion esis ance o NAC wi h simila comp essi e s eng h,
indica ing ha RCA can be e ec i ely u ilized wi hou signi ican ly comp omising
pe o mance. This inding unde sco es ha ca bona ion esis ance is p ima ily go e ned by he
ype o cemen a he han he agg ega e eplacemen , suppo ing he iabili y o inco po a ing
high le els o ecycled agg ega es in conc e e p oduc ion.
• The inclusion o up o 60% CRCA was ound o be sui able o ca bona ion esis ance, yielding
pe o mance compa able o ha o NAC wi h simila comp essi e s eng h. Addi ionally, he
inco po a ion o 20% FRCA p oduced no able esul s: while i inc eased he ca bona ion a e
in accele a ed es s, i exhibi ed be e pe o mance han NAC unde na u al exposu e
condi ions. A key obse a ion was ha he na u al ca bona ion a e was signi ican ly highe
han ha p edic ed by accele a ed es s. This disc epancy unde sco es he u gen need o he
de elopmen o mo e accu a e models o assessing he long- e m du abili y o conc e e in
se ice.

Chap e 8
126
• The ob ained na u al ca bona ion a e (Kna ) was 2.0 o 2.8 imes highe o NAC and 1.6 o
2.4 imes highe o RAC compa ed o he heo e ical na u al ca bona ion a e (Kna THEO)
de i ed om he accele a ed ca bona ion es . These esul s highligh he dispa i y be ween
na u al and accele a ed ca bona ion a es, emphasizing he need o ca e ul conside a ion when
ex apola ing long- e m ca bona ion pe o mance om accele a ed es ing.
In luence o Cemen Type in du abili y o RAC.
The ype o cemen plays a c ucial ole in he pe o mance o conc e es wi h ecycled agg ega es:
• CEM II/A-S p o ides a well-balanced pe o mance in e ms o ca bona ion esis ance and
chlo ide pene a ion.
CEM II/AS cemen demons a es excellen pe o mance in conc e e mixes, pa icula ly o
ca bona ion esis ance. In RAC-C60-F20 conc e e, i ensu es adequa e du abili y in XC3 and
XC4 en i onmen s, achie ing a 50-yea se ice li e. This cemen ype also exhibi s esis ance
o chlo ide pene a ion. Conc e e inco po a ing up o 60% CRCA and 10% FRCA exhibi s
mode a e chlo ide ion pene a ion alues and lowe chlo ide di usion coe icien s.
• CEM III/B o e s supe io chlo ide esis ance bu lowe ca bona ion esis ance.
RAC-C60-F20 p oduced wi h CEM III/B, is sui able o en i onmen s exposed o chlo ides
due o i s high chlo ide pene a ion esis ance, as indica ed by he low su ace chlo ide
concen a ions (Cs) and educed Dnss alues. Howe e , i exhibi s he lowes ca bona ion
esis ance compa ed o he o he mixes analyzed.
• CEM II/A-L is less e ec i e in enhancing he du abili y o RACs.
RAC-C60-F20, p oduced wi h CEM II/AL cemen , demons a ed adequa e ca bona ion
esis ance in XC4 en i onmen s. Howe e , i s pe o mance in e ms o chlo ide ion esis ance
was signi ican ly lowe , making i less sui able o agg essi e exposu e condi ions.
Feasibili y and Po en ial o RCA and MRA in Conc e e o S uc u al Applica ions
• This esea ch has demons a ed he easibili y o inco po a ing bo h CRCA and FRCA in
conc e e mix u es. Speci ically, he simul aneous inco po a ion o FRCA is easible, allowing
o a mix u e con aining 60% CRCA and up o 20% FRCA while main aining he equi ed
physical, mechanical, and du abili y p ope ies, p o ided ha he app op ia e cemen ype is
selec ed acco ding o he exposu e condi ions.
• Conc e e con aining MRA is sui able o s uc u al applica ions, allowing up o 40% CMRA
wi h 15% FMRA.
• These indings signi ican ly exceed he 20% limi o coa se ecycled conc e e agg ega es
s ipula ed in he Spanish S uc u al Conc e e Code (SC-BOE), demons a ing he easibili y
o highe subs i u ion a es. The success ul applica ion o ine ecycled agg ega es u he
expands he po en ial o ecycled ma e ials in conc e e p oduc ion.
• This esea ch lays he ounda ion o an inc eased u iliza ion o ecycled agg ega es in he
cons uc ion indus y, p omo ing sus ainabili y and os e ing a mo e e icien ci cula
economy wi hin he sec o .
Chap e 8
127
8.2 Fu u e Resea ch Lines
• An imp o ed u u e esea ch line would in es iga e he beha iou o conc e es wi h 60%
CRCA and 20% FRCA unde di e se en i onmen al condi ions, including ma ine, indus ial,
u ban, and ex eme empe a u e se ings. The s udy should encompass long- e m du abili y
ials in eal s uc u es, pe o mance op imiza ion using a ious cemen ypes and admix u es,
mic os uc u al analysis o he in e acial ansi ion zone, and assessmen o speci ic du abili y
aspec s such as chlo ide pene a ion, ca bona ion, and sulpha e esis ance.
• I is ecommended o expand esea ch on he du abili y o conc e e wi h MRA h ough a
comp ehensi e app oach encompassing: exposu e o a ious en i onmen al condi ions
(including ma ine, indus ial, and u ban a eas), eeze- haw cycles, and high empe a u es;
op imiza ion o mix u es using di e en ypes o cemen , addi i es, and mine al admix u es;
s udy o MRA p e- ea men and imp o emen me hods; and conduc ing long- e m es s on
ac ual s uc u es. This esea ch should include analysis o ca bona ion, chlo ide pene a ion,
and esis ance o a ious agg essi e agen s, as well as he de elopmen o p edic i e models o
es ima e he se ice li e o MRA conc e e in di e en scena ios.
• Pe o m s uc u al es s such as comp ession, lexu al, and shea es s on bo h con en ional and
ecycled agg ega e conc e e elemen s o compa e hei load-bea ing capaci y, s i ness, and
de o ma ion beha iou .
• De elop p edic i e models and simula ion ools o e alua e he pe o mance o s uc u al
elemen s made wi h ecycled agg ega es, conside ing he e ec s o a ious cemen ypes and
en i onmen al exposu e condi ions.
• Based on he indings, p opose new guidelines and ecommenda ions o inco po a ing
ecycled agg ega es in o s uc u al conc e e, wi h a ocus on op imizing bo h pe o mance and
sus ainabili y.
• Fu u e s udies should aim o conduc a comp ehensi e Li e Cycle Assessmen (LCA) o
conc e e inco po a ing Type A and Type B ecycled agg ega es. This assessmen would
quan i y he en i onmen al impac s h oughou he en i e conc e e li ecycle, compa e i wi h
con en ional conc e e, and iden i y key sus ainabili y ho spo s. The indings would suppo he
de elopmen o op imized mix designs and s a egies o maximize he en i onmen al bene i s
o using ecycled agg ega es in s uc u al applica ions.
128
6. Re e ences
[1] C. qiang Wang, L. xiao Cheng, Y. Ying, F. hua Yang, U iliza ion o all componen s o was e conc e e:
Recycled agg ega e s eng hening, ecycled ine powde ac i i y, composi e ecycled conc e e and li e
cycle assessmen , J. Build. Eng. 82 (2024) 108255. h ps://doi.o g/10.1016/j.jobe.2023.108255.
[2] L. Xu, J. Wang, X. Hu, B. Ran, T. Wu, X. Zhou, Y. Xiong, Physical pe o mance, du abili y, and
ca bon emissions o ecycled cemen conc e e and ully ecycled conc e e, Cons . Build. Ma e . 447
(2024) 138128. h ps://doi.o g/10.1016/j.conbuildma .2024.138128.
[3] Z. Li, L. yuan Li, S. Cheng, E alua ion o modulus o elas ici y o conc e e con aining bo h na u al
and ecycled conc e e agg ega es, J. Clean. P od. 447 (2024) 141591.
h ps://doi.o g/10.1016/j.jclep o.2024.141591.
[4] K. Ouyang, J. Liu, S. Liu, B. Song, H. Guo, G. Li, C. Shi, In luence o p e- ea men me hods o
ecycled conc e e agg ega e on he pe o mance o ecycled conc e e: A e iew, Resou . Conse .
Recycl. 188 (2023) 106717. h ps://doi.o g/10.1016/j. escon ec.2022.106717.
[5] M.J.; Al-Khee an, Y.S.; Jweihan, M.; Rabi, S.H. Gha a , M.J. Al-Khee an, Y.S. Jweihan, M. Rabi,
S.H. Gha a , Ci a ion: Du abili y Enhancemen o Conc e e wi h Recycled Conc e e Agg ega e: The
Role o Nano-ZnO, (2024). h ps://doi.o g/10.3390/buildings14020353.
[6] G. Habe , S.A. Mille , V.M. John, J.L. P o is, A. Fa ie , A. Ho a h, K.L. Sc i ene , En i onmen al
impac s and deca boniza ion s a egies in he cemen and conc e e indus ies, Na . Re . Ea h En i on.
2020 111. 1 (2020) 559–573. h ps://doi.o g/10.1038/s43017-020-0093-3.
[7] J.R. Co eia, J. de B i o, A.S. Pe ei a, E ec s on conc e e du abili y o using ecycled ce amic
agg ega es, Ma e . S uc . 39 (2006) 169–177. h ps://doi.o g/10.1617/s11527-005-9014-7.
[8] R. Zaha ie a, F. Buyle-Bodin, F. Skoczylas, E. Wi quin, Assessmen o he su ace pe mea ion
p ope ies o ecycled agg ega e conc e e, Cem. Conc . Compos. 25 (2003) 223–232.
h ps://doi.o g/10.1016/S0958-9465(02)00010-0.
[9] L. E angelis a, J. de B i o, Du abili y pe o mance o conc e e made wi h ine ecycled conc e e
agg ega es, Cem. Conc . Compos. 32 (2010) 9–14.
h ps://doi.o g/10.1016/j.cemconcomp.2009.09.005.
[10] EUROPEAN AGGREGATES ASSOCIATION A Sus ainable Indus y o a Sus ainable Eu ope,
(2017). www.uepg.eu (accessed June 15, 2022).
[11] A.N. de E.F. de Á. ANEFA, Es adís icas - ANEFA, (n.d.). h ps://www.a idos.o g/es adis icas/
(accessed June 26, 2022).
[12] P. Vela do, I.F. Sáez del Bosque, M.I. Sánchez de Rojas, N. De Belie, C. Medina, Du abili y o
conc e e bea ing polyme - ea ed mixed ecycled agg ega e, Cons . Build. Ma e . 315 (2022) 125781.
h ps://doi.o g/10.1016/j.conbuildma .2021.125781.
[13] Akmal Abdel a ah, Sami Tabsh, She i Yehia, U iliza ion o Recycled Coa se Agg ega e in Conc e e
Mixes, J. Ci . Eng. A chi . 5 (2012). h ps://doi.o g/10.17265/1934-7359/2011.06.010.
[14] A. Ba budo, J. Ayuso, A. Lozano, M. Cab e a, A. López-Uceda, Recommenda ions o he
managemen o cons uc ion and demoli ion was e in ea men plan s, En i on. Sci. Pollu . Res. 27
(2020) 125–132. h ps://doi.o g/10.1007/s11356-019-05578-0.
129
[15] F. de And ade Salgado, F. de And ade Sil a, Recycled agg ega es om cons uc ion and demoli ion
was e owa ds an applica ion on s uc u al conc e e: A e iew, J. Build. Eng. 52 (2022) 104452.
h ps://doi.o g/10.1016/j.jobe.2022.104452.
[16] C. Lla as, R. Quiñones, N. Bizcocho, En i onmen al Impac Assessmen o Cons uc ion Was e
Recycling e sus Disposal Scena ios Using an LCA-BIM Tool du ing he Design S age, Recycling. 7
(2022). h ps://doi.o g/10.3390/ ecycling7060082.
[17] Eu opean Union and i s Membe S a es, Eu ope 2020: A S a egy o Sma , Sus ainable and Inclusi e
G ow h .:. Sus ainable De elopmen Knowledge Pla o m, (n.d.).
h ps://sus ainablede elopmen .un.o g/index.php?page= iew& ype=99&n =16&menu=1449
(accessed Decembe 6, 2022).
[18] P og am - RECYBETON, (n.d.). h ps://www.pn ecybe on. /p og am/ (accessed Decembe 6, 2022).
[19] Eu opean Economic and Social Commi ee, The Pa is P o ocol – A bluep in o ackling global
clima e change beyond 2020 - Posi ion pape – July 2015 |, (n.d.). h ps://www.eesc.eu opa.eu/en/ou -
wo k/publica ions-o he -wo k/publica ions/pa is-p o ocol-bluep in - ackling-global-clima e-change-
beyond-2020-posi ion-pape -july-2015 (accessed Decembe 6, 2022).
[20] Bole ín O icial del Es ado (BOE), S uc u al Conc e e Code, in: 2021.
h ps://www.boe.es/eli/es/ d/2021/06/29/470.
[21] N. Tošić, J.M. To en i, T. Sed an, I. Ignja o ić, Towa d a codi ied design o ecycled agg ega e
conc e e s uc u es: Backg ound o he new ib Model Code 2020 and Eu ocode 2, S uc . Conc . 22
(2021) 2916–2938. h ps://doi.o g/10.1002/suco.202000512.
[22] Global Cemen and Conc e e Associa ion, FUTURO DEL HORMIGÓN, (n.d.).
h ps://gccassocia ion.o g/conc e e u u e/wp-con en /uploads/2021/10/GCCA-Conc e e-Fu u e-
Roadmap-O e iew-Spanish.pd (accessed Decembe 6, 2022).
[23] A. de ab ican es de cemen o en E. (OFICEMEN), El consumo de cemen o c ece un 11% en 2021,
(n.d.). h ps://www.o icemen.com/el-consumo-de-cemen o-c ece-un-11-en-2021/ (accessed Decembe
5, 2022).
[24] A.N.E. de F. de H. p epa ado ANEFHOP, La p oducción de ho migón c ece un 13,1% en 2021 según
ANEFHOP, (n.d.). h ps://www.ane hop.com/p oduccion-ho migon-c ece-131-2021-segun-ane hop/
(accessed Decembe 6, 2022).
[25] A.N. de F. de Á. (ANEFA), Es adís icas -La dimensión del sec o de los á idos en 2021, (n.d.).
h ps://www.a idos.o g/es adis icas/ (accessed Decembe 6, 2022).
[26] V.W.Y. Tam, M. Soom o, A.C.J. E angelis a, A e iew o ecycled agg ega e in conc e e applica ions
(2000–2017), Cons . Build. Ma e . 172 (2018) 272–292.
h ps://doi.o g/10.1016/j.conbuildma .2018.03.240.
[27] Eu opean S a is ics-Eu os a , Ene gy, anspo and en i onmen s a is ics 2020 edi ion, 2020.
h ps://ec.eu opa.eu/eu os a /abou /policies/copy igh .
[28] Inno a ion Union, Communica ion F om he Commission o he Eu opean Pa liamen , he COuncil,
he Eu opean Economic and Social Commi ee and he Commi ee o he Regions, (2010) 1–43.
h ps://eu -lex.eu opa.eu/legal-con en /EN/ALL/?u i=celex%3A52011DC0885 (accessed Decembe 6,
2022).
[29] S. Yehia, K. Helal, A. Abusha kh, A. Zahe , H. Is ai iyeh, S eng h and Du abili y E alua ion o
Recycled Agg ega e Conc e e, In . J. Conc . S uc . Ma e . 9 (2015) 219–239.
h ps://doi.o g/10.1007/s40069-015-0100-0.
[30] J. Xiao, Y. Tang, H. Chen, H. Zhang, B. Xia, E ec s o ecycled agg ega e combina ions and ecycled
powde con en s on ac u e beha io o ully ecycled agg ega e conc e e, J. Clean. P od. 366 (2022)