Mechanical p ope ies and du abili y o comp essed ea h blocks
inco po a ing na u al ma e ials
Chia a Tu co
a,*
, Ma a O. Teixei a
b
, Elisabe e Teixei a
a
, Rica do Ma eus
a
a
ISISE, ARISE, Depa men o Ci il Enginee ing, Uni e si y o Minho, Guima ˜
aes, Po ugal
b
2C2T, Depa men o Tex ile Enginee ing, Uni e si y o Minho, Guima ˜
aes, Po ugal
ARTICLE INFO
Keywo ds:
Ea hen cons uc ions
Comp essed ea h blocks
Ag o-indus ial by-p oduc s
Mechanical p ope ies
Du abili y
Non-des uc i e es ing
ABSTRACT
The cons uc ion indus y u gen ly needs enginee ing solu ions ha educe embodied ca bon and
p omo e ci cula ma e ial lows. Comp essed ea h blocks (CEBs) ep esen a p omising low-
ca bon al e na i e, bu hei la ge-scale use is challenged by issues o mechanical s eng h and
du abili y, pa icula ly when na u al ma e ials a e inco po a ed o imp o e he mal pe o mance.
Due o he inhe en a iabili y o na u al p oduc s, hei in e ac ions wi hin mix u es a e s ill
poo ly unde s ood, and quali y con ol o he esul ing ma e ials is lacking. This s udy p o ides a
comp ehensi e in es iga ion o CEBs inco po a ing wo ag o-indus ial by-p oduc s, whea s aw
(WS) and co k g anules (CGs), sou ced locally om Po uguese p oduc ion chains. The expe i-
men al p og am e alua es mechanical p ope ies (comp essi e s eng h, angen s i ness, lexu al
s eng h, ac u e ene gy) and wa e abso p ion beha iou (capilla y abso p ion, o al imme -
sion), and in eg a es non-des uc i e es ing (NDT) echniques, including ul asonic pulse eloci y
(UPV) and elec ical esis i i y, o ou line p ac ical guidelines o op imising addi i e con en
while ensu ing mechanical pe o mance and du abili y. Resul s indica e ha he lowes 5%
olume ic addi ion o WS yields he bes balance be ween enhanced mechanical pe o mance
and accep able wa e esis ance. In con as , CG addi ions mus be limi ed o 3–5% by olume o
a oid signi ican losses in s eng h and wa e esis ance. The s udy demons a es he diagnos ic
and p edic i e capaci y o NDTs o he ma e ials es ed, wi h UPV co ela ing well wi h s eng h
and s i ness, and elec ical esis i i y e ec i ely e lec ing capilla i y. NDTs o e scalable, ield-
applicable ools o quali y con ol, suppo ing a b oade and mo e con iden use o bio-based
ma e ials in mode n cons uc ion.
1. In oduc ion
The cons uc ion sec o plays a c ucial ole in socie y bu has a signi ican en i onmen al impac due o high le els o emissions,
ene gy consump ion, aw ma e ial deple ion, and was e gene a ion [1,2]. Wi hin he Eu opean Union (EU), he buil en i onmen is
he la ges consume o ene gy, accoun ing o 40% o o al ene gy use, and a majo con ibu o o g eenhouse gases emissions,
esponsible o 36% o he o al [3]. Addi ionally, i d i es he ex ac ion o 50% o all aw ma e ials and gene a es 35% o he EU’s
o al was e p oduc ion [4]. Despi e his awa eness, an h opogenic ac i i ies con inue o d i e clima e change, posing se ious and
po en ially i e e sible en i onmen al, social, and economic consequences. In esponse, u gen mi iga ion s a egies a e equi ed, one
* Co esponding au ho .
E-mail add ess: [email p o ec ed] (C. Tu co).
Con en s lis s a ailable a ScienceDi ec
Jou nal o Building Enginee ing
jou nal homepage: www.else ie .com/loca e/jobe
h ps://doi.o g/10.1016/j.jobe.2025.113386
Recei ed 13 Ma ch 2025; Recei ed in e ised o m 24 June 2025; Accep ed 3 July 2025
Jou nal o Building Enginee ing 111 (2025) 113386
A ailable online 3 July 2025
2352-7102/© 2025 The Au ho s. Published by Else ie L d. This is an open access a icle unde he CC BY-NC-ND license
( h p://c ea i ecommons.o g/licenses/by-nc-nd/4.0/ ).
he mos impac ul being he esponsible selec ion and use o building ma e ials.
En i onmen ally conscious building ma e ials p io i ise locally sou ced aw ma e ials, low p ocessing equi emen s, non- oxici y
and ecyclabili y. As a esul , such ma e ials end o ha e low embodied ca bon and ene gy con en . Fea u ing hese cha ac e is ics,
ea h as a building ma e ial is expe iencing a e i al, u he suppo ed by i s na u al hyg oscopic quali ies and abili y o sel - egula e
indoo empe a u e and humidi y [5]. Es ima es sugges ha 8–10% o global households li e in ea hen dwellings [7], and scien i ic
in e es in ea hen ma e ials and me hods has inc eased exponen ially in ecen decades [8], bo h in de eloped and de eloping
coun ies. T adi ionally associa ed wi h e nacula and low-cos housing, ea h is now gaining ac ion in mode n cons uc ion as a
sus ainable al e na i e o high-impac cemen -based ma e ials [6].
Among he a ious ea hen cons uc ion echniques, comp essed ea h blocks (CEBs) ep esen a echnological ad ancemen o e
adi ional adobe. Unlike manual amming ( ammed ea h), CEBs a e compac ed using a mechanical o hyd aulic p ess, esul ing in
dense , s onge uni s ha enhance p oduc ion e iciency and cons uc ion quali y. No ably, CEBs do no equi e i ing, signi ican ly
educing hei embodied ene gy and global wa ming po en ial [9,10]. Howe e , hey exhibi ela i ely high he mal conduc i i y
(0.6–1.2 W/mK) [11], which o en necessi a es he hicke wall assemblies o mee mode n ene gy e iciency s anda ds. This
equi emen , along wi h o he socio-economic ba ie s [12], is conside ed a key ac o limi ing hei widesp ead adop ion in
con empo a y a chi ec u e [13,14]. To add ess his challenge, nume ous s udies p opose inco po a ing ligh weigh and po ous na u al
ma e ials in o CEB mix u es [15]. Gi en economic incen i es, en i onmen al conce ns, and esou ce sca ci y, ag icul u al c op es-
idues a e among he mos used addi i es [16].
Resea ch indica es ha in eg a ing ag icul u al and indus ial by-p oduc s in o ea hen ma e ials can educe he demand o i gin
soil, di e was e om land ills, and enhance ma e ial pe o mance [15,17–20]. Howe e , depending on hei shape, composi ion, and
mic os uc u e, hese na u al addi i es se e di e en unc ions [15]. Fo example, plan ib es and s aw ein o ce ea h-based
ma e ials by mimicking oo -like s abilising mechanisms [21], imp o ing duc ili y bu some imes educing comp essi e o ensile
s eng h. None heless, signi ican enhancemen s in he mal and mois u e egula ion can be achie ed [19]. Simila ly, powde s de i ed
om ui shells o s ones ac as ligh weigh ille s, educing densi y and imp o ing he mal pe o mance due o hei po ous,
lignocellulosic s uc u e [22]. Despi e hese bene i s, he inhe en a iabili y o such ma e ials makes hei esponse unp edic able. As
a consequence, hei in e ac ion wi hin he ea hen ma ix emains poo ly unde s ood, and he expe imen al assessmen becomes
essen ial o assess he p ope ies o ma e ials.
This pape p esen s an expe imen al s udy conduc ed in Po ugal, whe e wo eadily a ailable by-p oduc s we e inco po a ed in o
CEBs o mi iga e he ma e ial’s limi a ions. These a e: (i) whea s aw (WS), a esidue om whea ha es ing, and (ii) co k g anules
(CGs), ecycled om wine bo le co ks. The blocks we e p oduced by a company in he sou h o he coun y, wi h all aw ma e ials
sou ced locally. While he he mophysical p ope ies o hese blocks ha e al eady been examined [22], his s udy ocuses on hei
mechanical and du abili y aspec s, add essing he challenges associa ed wi h he he e ogenei y o na u al was e ma e ials and
ag o-indus ial by-p oduc s.
Compa a i e analyses we e conduc ed be ween modi ied and con en ional CEBs h ough mechanical es s (comp ession and
bending), du abili y assessmen s (wa e abso p ion by capilla i y and o al imme sion), and non-des uc i e es ing (NDT) echniques,
including ul asonic pulse eloci y (UPV) and elec ical esis i i y, explo ed o hei diagnos ic and p edic i e po en ial. Mic o-
s uc u al analyses p o ided insigh s in o ma e ial in e ac ions wi hin he ma ix. In line wi h he p inciples o sus ainabili y and he
ci cula economy, and gi en he global challenges ela ed o was e disposal, his s udy suppo s cu en esea ch ends using ag o-
indus ial by-p oduc s as sus ainable addi i es [15].
2. Ma e ials and me hods
2.1. Raw ma e ials
2.1.1. Soil
The soil used in his s udy was sou ced om he Beja dis ic in he Alen ejo egion o sou he n Po ugal. Key cha ac e is ics a e
p esen ed in Table 1, alongside he co esponding adhe ed s anda ds ollowed o hei assessmen .
Acco ding o hese cha ac e is ics, he soil is classi ied as sandy and sil y. The liquid limi (w
L
=29.5%), and plas ici y index (IP =
11%) indica e mode a e plas ici y. The pa icle densi y o 2.71 g/cm
3
aligns wi h ypical alues o mine al soils [29] wi h limi ed
o ganic con en (3.5%). The P oc o es esul s indica e a ela i ely high d y densi y (2.01 g/cm
3
), su icien o load-bea ing capaci y,
wi h a mode a e wa e con en (12%). The mode a e ac i i y o clay mine als (0.67 mg/g), and sand con en (18.8%) ensu es adequa e
Table 1
Physical and geo echnical cha ac e is ics o he soil used.
Cha ac e is ics Tes me hods S anda ds
Consis ency limi s w
L
=29.5%, IP =11% A e be g limi s NP-143 [23]
Pa icle densi y 2.71 g/cm
3
Pycnome e es NP-83 [24]
Maximum d y densi y 2.01 g/cm
3
P oc o es E 197 [25]
Op imum wa e con en 12%
Sand con en 18.8% Sand equi alen es NP EN933-8 [26]
Ac i i y o clay mine als 0.67 mg/g Blue me hylene es NP EN933-9 [27]
O ganic con en 3.5% Loss on igni ion ASTM D2974 [28]
C. Tu co e al.
Jou nal o Building Enginee ing 111 (2025) 113386
2
binding p ope ies wi hou he occu ence o ad e se e ec s such as swelling and sh inkage. Fu he mo e, in a p e ious s udy [22], he
mine alogical ac ion o he soil used was cha ac e ised by XRD, iden i ying he p esence o qua z and non-swelling kaolini ic clay
mine als such as musco i e and clinochlo e.
Fig. 1 illus a es he pa icle size dis ibu ion, showing a well-g aded soil, wi h a clay con en nea 10%, deemed sui able o p oduce
CEBs [30].
2.1.2. Whea s aw
Whea s aw (WS), an ag icul u al by-p oduc o whea cul i a ion, was used as a na u al ib e o ein o cing he ea hen ma ix.
WS consis s o he whea esidual s alks, including s ems and lea es, and is alued o i s ib ous s uc u e and ligh weigh p ope ies.
Fo his s udy, he WS was supplied by a local a me and chopped in o pieces measu ing 30–50 mm in leng h, wi h a diame e o
app oxima ely 0.85 mm [31], esul ing in a low aspec a io anging be ween 35 and 60. No su ace ea men s o modi ica ions we e
applied.
2.1.3. Co k g anules
Co k g anules (CGs), a by-p oduc om co k wine bo le s oppe s p oduc ion, we e inco po a ed as a ille ma e ial. Co k was
selec ed o i s unique p ope ies o low densi y, elas ici y, he mal insula ion, and esis ance o chemical and biological deg ada ion
[22]. Unlike WS, which we e added o ein o cemen , he CGs eplaced a po ion o he aw soil in he mix u es o in es iga e hei
in luence on mechanical and du abili y p ope ies, alongside hei es ablished he mal bene i s. Fo his s udy, g anules we e supplied
by he Po uguese company Amo im. Pa icle size is 2 mm.
2.1.4. O he ma e ials
The in es iga ion also in ol ed he use o lime and wa e . Na u al hyd aulic lime (NHL) ype NHL5, eminen ly hyd aulic lime, was
used o soil s abilisa ion. Tap wa e was used o mixing.
2.2. Mix design and sample p epa a ion
The CEBs we e p oduced a he company’s si e acco ding o hei es ablished p ocedu es. To allow compa isons, his s udy included
a con ol sample ( e e ed o as ‘REF’) consis ing o plain, comme cial CEBs made om soil, wa e , and 5% hyd aulic lime (by olume,
.%). All mix u es we e p epa ed on a olume ic basis, and he mix designs o bo h he con ol and modi ied samples a e de ailed in
Table 2.
Ini ially, he aw ma e ials we e mixed in hei d y s a e o ensu e uni o m dis ibu ion. Wa e was hen added g adually un il he
mix u e me he c i e ia o he d opping ball es [32–34]. This ield es consis s o obse ing he beha iou o a ball o mois mix
Fig. 1. Pa icle size dis ibu ion o he na u al and sie ed soil used.
C. Tu co e al.
Jou nal o Building Enginee ing 111 (2025) 113386
3
d opped om a heigh o 1 m and is conside ed adequa e o non-plas ic ea h echniques [11]. I should be no ed ha on a ull
p oduc ion scale, o en-d ying o he aw soil p io mixing is o en imp ac ical. The e o e, based on he manu ac u e ’s expe ience, he
mixing wa e shown in Table 2 di e s om he op imal le el sugges ed by he P oc o es .
The blocks we e comp essed using a hyd aulic p ess (Eco M´
aquinas, S˜
ao Domingos, B azil – Eco Mas e 7000 Tu bo II) a a p essu e
o 10 MPa. The s eps o he p oduc ion a e shown in Fig. 2 wi h (a) showing he sie ing p ocess, (b) he soil p epa a ion, (c) he mixing
and we ing p ocess, (d) he compac ion p ocess, inally (e) and ( ) de ails o WS-blocks and CG-blocks.
The blocks ha e s anda d dimensions o 300 mm ×150 mm ×80 mm (leng h ×wid h ×a e age heigh ), wi h sligh a ia ions in
heigh depending on he mix u e composi ion. A e comp ession, he blocks we e cu ed in a shel e ed en i onmen . Du ing he i s
week, hey we e wa e -sp ayed wice daily and co e ed wi h a plas ic shee o p e en apid d ying and ensu e adequa e cu ing.
2.3. Expe imen al me hods
2.3.1. Mechanical cha ac e isa ion
2.3.1.1. Comp ession es s. Comp ession es s on he blocks ollowed adap ed p o ocols om EN 772-1 [35]. Blocks we e laid la , and
he load was applied in displacemen con ol mode a a a e o 0.5 mm/min. To educe con inemen e ec s due o he blocks’ aspec
a io and educe he ic ion wi h he load pla e, a ubbe shee was placed be ween he blocks’ op ace and he load pla e [36,37].
Axial de o ma ion (
ε
) [%] was calcula ed as he a io o heigh change (ΔL) [mm] o he ini ial heigh (L) [mm], assuming he
displacemen eco ded by he ansduce ep esen ed he heigh change. S ess (
σ
) [MPa] was de e mined by di iding he load (F) [N]
by he con ac a ea (A) [mm
2
]. The peak comp essi e s eng h (
σ
c) in MPa was calcula ed as:
σ
c=Fmax
A(1)
whe e Fmax is he maximum load [N], and A he con ac a ea [mm
2
]. The appa en elas ic modulus (E0) was de i ed om he angen
slope o he s ess–s ain (
σ
−
ε
) cu e wi hin he elas ic ange 0.5–1.0 MPa o exclude ini ial e ec s such as s esses o plas ic de-
o ma ions [38]. This ange di e ed om p e ious s udies (e.g., 0.2–0.3 MPa by Kouakou and Mo el [39]), which did no align wi h
ou da a. Gi en app oxima ions in he me hod, esul s a e bes in e p e ed ela i ely, ocusing on how na u al ma e ials in luence
pe o mance compa ed o con ols. Six blocks pe mix u e we e es ed, and a e age alues o comp essi e s eng h and s i ness a e
epo ed.
2.3.1.2. Th ee-poin bending es s. Fo he h ee-poin bending es , blocks we e placed on a wo-poin suppo wi h a 200 mm span. A
cen al load was applied in displacemen con ol mode a 0.005 mm/s. To a oid damaging he blocks, no no ching was pe o med.
Howe e , as o he compa a i e amewo k adop ed, he es was use ul o s udy a ia ions in bending s eng h and ac u e ene gy
(wo k). The maximum bending s ess (
σ
) in MPa was calcula ed as:
Table 2
Designed mix u es.
Mix u e ype Id Soil [ .%] Hyd aulic Lime [ .%] Na u al Ma e ial [ .%] Mixing Wa e [ .%]
Re e ence mix u e—REF REF 100% 5% –10%
Mix u es wi h addi ion o 5, 10 and 15 .% WS WS5 100% 5% 5% 13%
WS10 100% 5% 10% 12%
WS15 100% 5% 15% 11%
Mix u es wi h subs i u ion o 1, 3 and 5 .% CGs CG1 99% 5% 1% 16%
CG3 97% 5% 3% 15%
CG5 95% 5% 5% 14%
Fig. 2. Main s eps o he p oduc ion p ocess o he CEBs in ol ed in his s udy.
C. Tu co e al.
Jou nal o Building Enginee ing 111 (2025) 113386
4
σ
=3FmaxL
2bd2(2)
whe e Fmax is he peak load [N], L is he suppo span [mm], and b and d a e he blocks’ wid h and heigh [mm], espec i ely.
F ac u e ene gy (W ) [J] was de e mined om he o ce-displacemen cu e a ea up o he peak load using he apezoidal in e-
g a ion me hod in MATLAB©. Blocks we e inspec ed pos - es o examine ac u e planes, pa icula ly o WS ib e p esence. Th ee
blocks pe mix u e we e es ed, and a e age alues o maximum lexu al s eng h and ac u e ene gy we e epo ed.
2.3.2. Mic os uc u al in es iga ions
Mic os uc u al in es iga ions we e conduc ed o gain insigh s in o he in e nal s uc u e and o cha ac e ise he in e ac ions o aw
ma e ials wi hin he soil ma ix. Bo h analyses we e pe o med on aw ma e ials and block samples (a e mechanical es ing) o
compa e pa e ns.
2.3.2.1. In a ed spec oscopy. A enua ed To al Re lec ance-Fou ie T ans o m In a ed (ATR-FTIR) spec oscopy measu ed he ab-
so p ion o in a ed adia ion, e ealing unc ional g oups and chemical s uc u es. An IRA ini y-1S SHIMADZU spec opho ome e
(Kyo o, Japan) wi h an ATR diamond c ys al accesso y was used, pe o ming 45 scans pe sample wi h a spec al esolu ion o 16 cm
−1
o e a wa e numbe ange o 4000–400 cm
−1
. Each analysis was epea ed h ee imes, and o cla i y, only one ep esen a i e pa e n
is shown.
2.3.2.2. The mog a ime ic analysis. The mog a ime ic Analysis (TGA) measu ed weigh changes as a unc ion o empe a u e o
e alua e decomposi ion, oxida ion, and he mal s abili y. An SDT Q600 V20.9 Build 20 ins umen was used wi h a hea ing a e o
10.0 ◦C/min up o 1100.0 ◦C. Samples weighing 20–30 mg was analysed in iplica e o each block ype and a ep esen a i e pa e n is
shown.
2.3.3. Du abili y cha ac e isa ion
2.3.3.1. Wa e abso p ion by capilla i y. Capilla i y coe icien s we e de e mined adap ing es p o ocol om LNEC E 393 [40].
O en-d ied blocks we e placed sideways in con ac wi h a 5 ±1 mm wa e laye . A in e als (0, 5, 10, 15, 30, 45 min, and 1, 1.5, 2, 3,
4, 5, 6, and 24 h), weigh changes and wa e ise heigh s we e eco ded. The capilla i y coe icien (cb), in g/cm
2
min
0.5
, was calcula ed
using:
cb=m1−m0
A
√(3)
whe e m0 is he d y block mass [g], m1 is he mass a e imme sion [g], A is he con ac a ea [cm
2
], and is he imme sion ime [min].
The angula coe icien o he s aigh line be ween 10-min and 5-h alues, deno ed as Cb, ep esen s capilla y abso p ion o e ime
[41,42]. Th ee blocks pe sample we e es ed.
2.3.3.2. Wa e abso p ion by o al imme sion. Fo o al imme sion es ing, adap ed om LNEC E 394 [43], o en-d ied blocks we e
subme ged in wa e a 20 ±3 ◦C. Mass changes we e used o calcula e wa e abso p ion (W) as:
W=m1−m0
m1−m2×100 (4)
whe e m0 is he d y mass, m1 is he we mass in ai , and m2 is he hyd os a ic mass o he we specimen.
2.3.4. Non-des uc i e es ing
2.3.4.1. Ul asound pulse eloci y. Adap ing om NP EN 12504–4 [48], UPV measu emen s we e aken using a P oceq PUNDIT Lab
es e wi h a 54 kHz equency [49,50]. Coupling gel was applied o elimina e ai gaps a he in e ace wi h he ansduce s. To educe
in e e ence om he en i onmen , an XPS boa d was used o place he blocks while eco ding measu emen s. The UPV, in m/s, was
calcula ed as:
UPV =L
(5)
whe e L is he dis ance be ween he ansduce s [mm], and is he wa e a el ime [s]. Measu emen s we e aken on he majo leng h
o he block, spanning 300 mm. Fi e eadings we e aken pe sample.
2.3.4.2. Elec ical esis i i y. The elec ical esis i i y (
ρ
), in kΩcm, was measu ed a ambien empe a u e (20 ±1 ◦C), on wa e -
sa u a ed blocks using a ResipodP oceq de ice wi h 38 mm dis ance among he elec odes. Fi e eadings we e aken pe sample.
C. Tu co e al.
Jou nal o Building Enginee ing 111 (2025) 113386
5
3. Resul s and discussion
3.1. Mechanical p ope ies
3.1.1. Comp essi e s eng h and s i ness
The s ess-s ain cu es in Fig. 3 illus a e he esul s o comp ession es s o (a) con ol sample blocks (REF), (b) blocks wi h 1 .%
CGs (CG1), (c) blocks wi h 3 .% CGs (CG3), (d) blocks wi h 5 .% CGs (CG5), (e) blocks wi h 5 .% WS (WS5), ( ) blocks wi h 10 .% WS
(WS10), (g) blocks wi h 15 .% WS (WS15).
The s ess-s ain cu es o he e e ence blocks (REF) exhibi nea -linea elas ic beha iou , wi h minimal ini ial de o ma ions
a ibu ed o se lemen s (Fig. 3(a)). In WS-blocks, he ini ial de o ma ions a e mo e p onounced, and he s esses achie ed gene ally
su pass hose o he REF blocks (Fig. 3(b–d)). Con e sely, CG-blocks display signi ican ly highe de o ma ions, cha ac e ised by a mo e
nonlinea , plas ic beha iou wi h dis inc pa e ns a low and high s ain le els (Fig. 3(e–g)). Despi e hese di e ences, he s ess le els
in CG-blocks emain compa able o ha o he con ol sample REF. O e all, inc easing na u al by-p oduc s con en leads o a p o-
g essi e educ ion in s i ness and peak s eng h.
Fig. 4 p esen s he a e age (a) peak comp essi e s eng h, and (b) angen s i ness (appa en elas ic modulus) o each ba ch o
CEBs es ed.
The addi ion o WS enhances he comp essi e s eng h o he blocks a all concen a ions compa ed o he REF sample (2 MPa) and
he s i ness up o WS10. Howe e , he mos no able imp o emen occu s o WS5 (5 .% WS addi ion), wi h he s eng h inc easing o
2.4 MPa (16.7%) and he s i ness o 49.6 MPa (7.4%). Fu he inc eases in WS con en educe he ein o cemen e ec . In con as , CG-
blocks demons a e ei he simila o educed comp essi e s eng h and s i ness compa ed o he con ol. A 1 .% CGs (CG1), he
s eng h emains nea ly unchanged (2.1 MPa, ~1 % inc ease). Highe concen a ions o CG lead o a p og essi e deg ada ion o
mechanical p ope ies: in he case o he CG5 mix u e, 5% less s eng h and 21% less s i ness. These esul s indica e ha while WS
e ec i ely imp o es comp essi e s eng h and s i ness, CG nega i ely impac s hese p ope ies and is be e sui ed as a ille ma e ial,
Fig. 3. S ess-s ain cu es de i ed om comp ession es s.
C. Tu co e al.
Jou nal o Building Enginee ing 111 (2025) 113386
6
and in limi ed quan i ies.
In ela ion o damage and ailu e modes, mos blocks showed e ical ac u es along he load axis, o en p eceded by hin c acks on
he uppe and lowe su aces (Fig. 5(a–c), REF, WS5, and CG3 blocks’ specimen espec i ely). In some cases, diagonal shea planes
o med, indica ing an in e nal imbalance in s ess dis ibu ion. These mechanisms a e usually ollowed by edge c ushing and disin-
eg a ion (Fig. 5(d) and (e), WS-blocks de ails) o agmen a ion (Fig. 5( ) and (g), CG-blocks de ails). Blocks con aining he highes WS
con en showed a mo e g adual ailu e, sugges ing ha ib es helped o ill he c acks and delay o al disin eg a ion (Fig. 5(h), WS15
blocks a he end o he es ). In con as , blocks wi h no o low na u al ma e ial con en showed a mo e sudden ailu e.
3.1.2. Flexu al s eng h and ac u e ene gy
The o ce-displacemen cu es in Fig. 6 illus a e he esul s o he h ee-poin bending es s o (a) REF, (b) CG1, (c) CG3, (d) CG5,
(e) WS5, ( ) WS10, and (g) WS15.
The cu es highligh he peak load (black do ), and he segmen (iden i ied by he hickes po ion o he lines) used o calcula e he
ac u e ene gy up o ailu e. The la ini ial po ion obse ed in some cu es, whe e displacemen inc eases a low loads, a ises om
adjus men s o he specimen on he load suppo s. This beha iou is a ibu ed o impe ec ions in he blocks, such as gaps and
misalignmen s.
The cu es exhibi quasi-b i le beha iou wi h no plas ic de o ma ion. The eco ded o ce-displacemen esponses a e p edomi-
nan ly associa ed wi h c ack p opaga ion and ac u e. Compa ed o he con ol sample REF (Fig. 6(a)), he inclusion o WS inc eases
he load-bea ing capaci y and oughness, pa icula ly in he WS5 and WS10 cases (Fig. 6(b) and (c)). Fo WS15 (Fig. 6(d)), highe
Fig. 4. Comp ession es esul s: (a) comp essi e s eng h a he peak, and (b) angen s i ness.
Fig. 5. Damage pa e ns and ailu e modes o CEBs subjec ed o comp ession es s.
C. Tu co e al.
Jou nal o Building Enginee ing 111 (2025) 113386
7
de o ma ions occu a lowe loads. The double-hump ea u e in one o hese cu es is asc ibed o he ib es’ ole in esis ing ac u e.
While he CGs do no enhance oughness, he cu es show highe esidual s eng h compa ed o he con ol REF-blocks. In e ms o
oughness, he cu es o CG1 (Fig. 6(e)) esemble he con ol sample; CG3 and CG5 (Fig. 6( ) and (g)) show mo e elas ic beha iou .
O e all, he esul s sugges ha he p esence o bo h na u al ma e ials in luence pos - ac u e beha iou by imp o ing duc ili y and
ene gy dissipa ion, consis en wi h p io s udies [21,52].
Fig. 6. S ess-s ain cu es de i ed om h ee-poin bending es s.
Fig. 7. Th ee-poin bending es esul s: (a) lexu al s eng h a he peak, and (b) ac u e ene gy a ailu e.
C. Tu co e al.
Jou nal o Building Enginee ing 111 (2025) 113386
8
Fig. 7 p esen s he a e age lexu al s eng h and ac u e ene gy a ailu e o each ba ch o CEB es ed.
The con ol sample REF blocks exhibi ed a peak lexu al s eng h o 0.174 MPa (Fig. 7(a)). Adding 5 and 10 .% WS inc eases his
s eng h by 39% (0.242 MPa) and 23.7% (0.215 MPa), espec i ely. Howe e , a 15 .% WS, he s eng h dec eases by 4.5%, indica ing
a h eshold whe e excess ib e con en nega i ely a ec s he ma e ial. Fo CGs, he inclusion o 1 .% g anules esul in an 11% inc ease
in lexu al s eng h (0.193 MPa), bu highe concen a ions lead o educ ions o 19.5% and 23.4%, wi h s eng h d opping o 0.133
MPa.
Fig. 7(b) shows ha all blocks wi h na u al ma e ials exhibi highe ac u e ene gy han he con ol sample. The bending beha iou
o he analysed CEBs changes wi h he addi ion o WS and CG, as discussed ea lie . Fo WS, up o a 10 .% con en , he blocks
demons a e inc eased s eng h and oughness. Beyond his h eshold, highe ib e pe cen ages inc ease duc ili y, allowing o g ea e
displacemen . Though he absence o no ching may ha e sligh ly o e es ima ed he ac u e ene gy, he p esence o WS s ill in luences
he wo k equi ed o p opaga e c acks and cause ailu e. Despi e his, he low ib e con en p e en s ue plas ic de o ma ion o
duc ili y. Sho ib es like s aw, wi h a low aspec a io (35–60), p ima ily enhance s i ness and oughness a low concen a ions [53].
Bouhicha e al. [54] highligh ed ha , in ea hen blocks, s aw educes sh inkage, sho ens cu ing ime, and imp o es comp essi e
s eng h when used a op imal ein o cemen a ios. Howe e , s udies sugges ha an ideal ib es amoun h eshold exis , beyond
which he bene i s associa ed wi h hei p esence diminish due o accumula ion and o e lap [21]. While ib es imp o e duc ili y, i
o e load occu s, hey may lead o excessi e de o ma ions deemed unaccep able o p ac ical applica ions.
Fig. 8 shows an example o a h ee-poin bending es on a block om he WS10 ba ch. The images include (a) he es se up, (b) he
b oken sample a e es ing, and (c) a de ail o he pe pendicula o ien a ion o ib es o he ac u e plane [54].
In con as o WS, CG inco po a ion a concen a ions >1 .% educes he blocks’ s eng h and s i ness. The addi ion o CGs in-
c eases de o mabili y a lowe loads, jus i ying he high ac u e ene gy obse ed in he CG5 ba ch. Howe e , he g anules do no
p o ide any s eng hening e ec .
3.1.3. Mic os uc u al insigh s
3.1.3.1. In a ed spec oscopy. Mic os uc u al in es iga ions pe o med on samples aken om he es ed blocks p o ide in o ma ion
on he cha ac e is ics o he ma e ials p esen and he na u e o he bonds. Fig. 9 shows he esul s o he in a ed spec oscopy.
Fig. 9(a) shows he ATR-FTIR spec a o he aw ma e ials p o iding insigh s in o he s uc u es p esen . The soil spec um shows
peaks in he 3700–3400 cm
−1
ange, a ibu ed o O−H s e ching in clay hyd oxyl g oups, and in he 1100–1000 cm
−1
ange, co -
esponding o Si−O and Al−O s e ching in aluminosilica es (e.g., kaolini e and o he clay mine als) [55]. Peaks in he 2500–2000
cm
−1
egion sugges he p esence o ni ile impu i ies (C ≡N) [56]. The NHL spec um is domina ed by a peak nea 1410 cm
−1
,
indica i e o ca bona e ions (CO
3
2−
), wi h addi ional peaks a 871.82 and 709.80 cm
−1
associa ed wi h calci e (CaCO
3
) [57]. O−H
s e ching peaks in he 3700–3400 cm
−1
ange a e also obse ed, likely due o clays and impu i ies na u ally p esen in hyd aulic lime.
The WS spec um ea u es a b oad peak a ound 3340 cm
−1
, a ibu ed o O−H s e ching in cellulose and hemicellulose, and ano he
peak a 1035 cm
−1
co esponding o C−O s e ching in cellulose [58,59]. The CGs spec um exhibi s a b oad peak be ween 3410 and
3460 cm
−1
, a ibu ed o O−H s e ching in lignin, alongside bands a 2919 and 2852 cm
−1
, indica i e o C−H s e ching in CH
2
g oups
[60,61]. Addi ional bands con i m he p esence o sube in, lignin, and polysaccha ides [61].
The block spec a (Fig. 9(b)) a e cha ac e ised by p ominen peaks in he 1100-900 cm
−1
ange, co esponding o he hyd a ion
p oduc s o calcium silica e (C–S–H) and alumina e (C–A–H) phases de i ed om he NHL used o s abilise he soil [55,62]. Addi-
ionally, peaks nea 1420 cm
−1
indica e he p esence o ca bona es [62,63], o med as a seconda y p oduc om he ca bona ion o
esidual ee lime.
3.1.3.2. The mog a ime ic analysis. Fig. 10 shows he esul s o he TGA.
Fig. 10(a) shows he TGA o he aw ma e ials. The soil he mog am shows mass losses nea 300◦C, a ibu ed o he decomposi ion
o o ganic ma e , a 470◦C and abo e 800◦C a ibu ed o he decomposi ion o clay mine als compa ible wi h hose de ec ed by XRD
(musco i e and clinochlo e) [64]. The NHL he mog am displays wo cha ac e is ic peaks: one nea 410◦C, co esponding o he
dehyd oxyla ion o calcium hyd oxide, and ano he a ound 760◦C, a ibu ed o he decomposi ion o calci e [65]. The he mog ams o
WS and CGs show mass losses nea 300◦C a ibu able o he decomposi ion o hemicellulose and cellulose. Beyond 400◦C, mo e
e iden in he he mog am o co k, he loss is a ibu ed o he decomposi ion o mo e s able a oma ic s uc u es such as lignin and
Fig. 8. Th ee-poin bending es on a WS10 block.
C. Tu co e al.
Jou nal o Building Enginee ing 111 (2025) 113386
9
[38] A.W. B uno, L.M. Lalica a, R. Abdallah, A. Lagazzo, S. A is-Roucan, F. McG ego , C. Pe lo , D. Gallipoli, Syne gic e ec o hyd a ed lime and gua gum
s abilisa ion on he mechanical, he mal and hyg oscopic beha iou o a Ligu ian ea h ma e ial, Cons . Build. Ma e . 439 (2024) 137258, h ps://doi.o g/
10.1016/J.CONBUILDMAT.2024.137258.
[39] C.H. Kouakou, J.C. Mo el, S eng h and elas o-plas ic p ope ies o non-indus ial building ma e ials manu ac u ed wi h clay as a na u al binde , Appl. Clay Sci.
44 (2009) 27–34, h ps://doi.o g/10.1016/J.CLAY.2008.12.019.
[40] E. Lnec, Be ˜
oes. De e minaç˜
ao da abso ç˜
ao de ´
agua po capila idade - conc e e, 393. De e mina ion o he Abso p ion o Wa e Th ough Capilla i y, 1993.
[41] C. Tu co, A. Paula Junio , C. Jacin o, J. Fe nandes, E. Teixei a, R. Ma eus, In luence o pa icle size on comp essed Ea h blocks p ope ies and s a egies o
enhanced pe o mance, Appl. Sci. 14 (2024), h ps://doi.o g/10.3390/app14051779.
[42] M. Boulmaali, A. Belham i, In es iga ion o he mal ine ia and hyd ic p ope ies o an eco-building ma e ial: comp essed s abilized ea h blocks, Hea and Mass
T ans e /Wae me- Und S o uebe agung 59 (2023) 713–727, h ps://doi.o g/10.1007/s00231-022-03292-1.
[43] Lnec, Be ˜
oes. De e minaç˜
ao da abso ç˜
ao de ´
agua po ime s˜
ao - conc e e, E 394, De e mina ion o he abso p ion o wa e by imme sion (1993) (in Po uguese).
[44] E.V.M. Ca asco, S.R. Sil a, J.N.R. Man illa, Assessmen o mechanical p ope ies and he in luence o he addi ion o sawdus in soil–cemen b icks using he
echnique o ul asonic aniso opic inspec ion, J. Ma e . Ci . Eng. 26 (2012) 219–225, h ps://doi.o g/10.1061/(ASCE)MT.1943-5533.0000723.
[45] A. Idde , A. Hamouine, B. Labbaci, R. Abdeldjeba , The po osi y o s abilized ea h blocks wi h he addi ion plan ibe s o he da e palm, Ci il Eng. J. (I an) 6
(2020) 478–494, h ps://doi.o g/10.28991/cej-2020-03091485.
[46] E.R. Teixei a, G. Machado, A. de P. Junio , C. Gua nie , J. Fe nandes, S.M. Sil a, R. Ma eus, Mechanical and he mal pe o mance cha ac e isa ion o
comp essed Ea h blocks, Ene gies 13 (2020) 2978, h ps://doi.o g/10.3390/en13112978.
[47] P. Kasiniko a, D.D. T ipu a, P edic ion o physical-mechanical p ope ies o hollow in e locking comp essed uns abilized and s abilized ea h blocks a di e en
mois u e condi ions using ul asonic pulse eloci y, J. Build. Eng. 48 (2022) 103961, h ps://doi.o g/10.1016/J.JOBE.2021.103961.
[48] NP EN 12504-4:2007, No ma Po uguesa, Ensaios De Be ˜
ao Nas es u u as—Pa e 4: De e minaç˜
ao Da Velocidade De P opagaç˜
ao Dos Ul a-sons. Po uguese
No m—Tes ing Conc e e in S uc u es—Pa 4: De e mina ion o Ul asonic Pulse Veloci y, 2007.
[49] E.V.M. Ca asco, S.R. Sil a, J.N.R. Man illa, Assessmen o mechanical p ope ies and he in luence o he addi ion o sawdus in soil–cemen b icks using he
echnique o ul asonic aniso opic inspec ion, J. Ma e . Ci . Eng. 26 (2014), h ps://doi.o g/10.1061/(asce)m .1943-5533.0000723.
[50] P. Kasiniko a, D.D. T ipu a, P edic ion o physical-mechanical p ope ies o hollow in e locking comp essed uns abilized and s abilized ea h blocks a di e en
mois u e condi ions using ul asonic pulse eloci y, J. Build. Eng. 48 (2022), h ps://doi.o g/10.1016/j.jobe.2021.103961.
[51] H., G.P., A.A.R., S.M. Layssi, Elec ical esis i i y o conc e e, Conc . In . 37 (2015) 41–46.
[52] F. Ayme ich, L. Fenu, L. F ancesconi, P. Meloni, F ac u e beha iou o a ib e ein o ced ea hen ma e ial unde s a ic and impac lexu al loading, Cons . Build.
Ma e . 109 (2016) 109–119, h ps://doi.o g/10.1016/j.conbuildma .2016.01.046.
[53] A. Labo el-P ´
ene on, J.-E. Aube , C. Magnion , P. Mailla d, C. Poi ie , E ec o plan agg ega es on mechanical p ope ies o Ea h b icks, J. Ma e . Ci . Eng. 29
(2017), h ps://doi.o g/10.1061/(ASCE)MT.1943-5533.0002096.
[54] M. Bouhicha, F. Aouissi, S. Kenai, Pe o mance o composi e soil ein o ced wi h ba ley s aw, Cem. Conc . Compos. 27 (2005) 617–621, h ps://doi.o g/
10.1016/J.CEMCONCOMP.2004.09.013.
[55] J.P. Bo ajo, S. Lis e, J. Se a, P. Gonz´
alez, S. Chiussi, B. Le´
on, M. P´
e ez-Amo , H.O. Yl¨
anen, M. Hupa, In luence o he ne wo k modi ie con en on he
bioac i i y o silica e glasses, Key Eng. Ma e . (2004) 254–256, h ps://doi.o g/10.4028/WWW.SCIENTIFIC.NET/KEM.254-256.23, 23–26.
[56] M.P. Be ns ein, S.A. Sand o d, L.J. Allamandola, The in a ed spec a o ni iles and ela ed compounds ozen in A and H 2 O, As ophys. J. 476 (1997)
932–942, h ps://doi.o g/10.1086/303651/FULLTEXT/.
[57] ¨
O. Cize , C. Rod iguez-Na a o, E. Ruiz-Agudo, J. Elsen, D. Van Geme , K. Van Balen, Phase and mo phology e olu ion o calcium ca bona e p ecipi a ed by
ca bona ion o hyd a ed lime, J. Ma e . Sci. 47 (2012) 6151–6165, h ps://doi.o g/10.1007/S10853-012-6535-7/FIGURES/9.
[58] T. Hong, J.Y. Yin, S.P. Nie, M.Y. Xie, Applica ions o in a ed spec oscopy in polysaccha ide s uc u al analysis: p og ess, challenge and pe spec i e, Food
Chem. X 12 (2021), h ps://doi.o g/10.1016/J.FOCHX.2021.100168.
[59] S.H. Gha a , Agg ega ed unde s anding o cha ac e is ics o whea s aw node and in e node wi h hei in e acial bonding mechanisms. h p://bu a.b unel.ac.
uk/handle/2438/13451, 2016. (Accessed 9 Ap il 2024).
[60] C.G. Boe iu, D. B a o, R.J.A. Gosselink, J.E.G. Van Dam, Cha ac e isa ion o s uc u e-dependen unc ional p ope ies o lignin wi h in a ed spec oscopy, Ind.
C ops P od. 20 (2004) 205–218, h ps://doi.o g/10.1016/J.INDCROP.2004.04.022.
[61] D.G. B anco, C.A. San iago, F.J. Oli ei a, L. Cab i a, D.V. E uguin, Su ace p ope ies o co k in ela ion o eac i e washing, Colloids Su . A Physicochem. Eng.
Asp. 624 (2021) 126762, h ps://doi.o g/10.1016/J.COLSURFA.2021.126762.
[62] A. Madadi, J. Wei, A. Madadi, J. Wei, Cha ac e iza ion o calcium silica e hyd a e gels wi h di e en calcium o Silica a ios and polyme modi ica ions, Gels 8
(2022) 75, h ps://doi.o g/10.3390/GELS8020075, 8 (2022) 75.
[63] V.H.J.M. dos San os, D. Pon in, G.G.D. Ponzi, A.S. de G.e. S epanha, R.B. Ma el, M.K. Schü z, S.M.O. Einlo , F. Dalla Vecchia, Applica ion o ou ie ans o m
in a ed spec oscopy (FTIR) coupled wi h mul i a ia e eg ession o calcium ca bona e (CaCO3) quan i ica ion in cemen , Cons . Build. Ma e . 313 (2021)
125413, h ps://doi.o g/10.1016/J.CONBUILDMAT.2021.125413.
[64] M. F¨
old ´
a i, Handbook o The mog a ime ic Sys em o Mine als and i s Use in Geological P ac ice, Geological Ins i u e o Hunga y, 2011.
[65] D. Shanmuga el, R. Dubey, R. Ramadoss, Use o na u al polyme om plan as admix u e in hyd aulic lime mo a mason y, J. Build. Eng. 30 (2020) 101252,
h ps://doi.o g/10.1016/J.JOBE.2020.101252.
[66] D. Csan´
ady, O. Feny esi, B. Nagy, An empi ical model o hea - ea ed s aw bulks’ he mal conduc i i y based on changes in mass and chemical composi ion,
J. The m. Anal. Calo im. 148 (2023) 3731–3749, h ps://doi.o g/10.1007/s10973-023-11945-4.
[67] L.J. Gibson, E. Eas e ling, M.F. Ashby, The s uc u e and mechanics o Co k, P oc R Soc Lond A Ma h Phys Sci 377 (1981) 99–117. h ps://www.js o .o g/
s able/2397034. (Accessed 6 No embe 2023).
[68] R. Chauhan, R. Kuma , P.K. Diwan, V. Sha ma, The mog a ime ic analysis and chemome ic based me hods o soil examina ion: applica ion o soil o ensics,
Fo en. Chem. 17 (2020), h ps://doi.o g/10.1016/J.FORC.2019.100191.
[69] C. Rod iguez-Na a o, T. Ili´
c, E. Ruiz-Agudo, K. Ele , Ca bona ion mechanisms and kine ics o lime-based binde s: an o e iew, Cemen Conc . Res. 173 (2023)
107301, h ps://doi.o g/10.1016/J.CEMCONRES.2023.107301.
[70] M. Boulmaali, A. Belham i, In es iga ion o he mal ine ia and hyd ic p ope ies o an eco-building ma e ial: comp essed s abilized ea h blocks, Hea and Mass
T ans e /Wae me- Und S o uebe agung 59 (2023), h ps://doi.o g/10.1007/s00231-022-03292-1.
[71] M. Saman h, K. Sub ahmanya Bha , Con en ional and uncon en ional chemical ea men me hods o na u al ib es o sus ainable biocomposi es, Sus ain.
Chem. Clim. Ac ion 3 (2023) 100034, h ps://doi.o g/10.1016/J.SCCA.2023.100034.
[72] J. Chanu , Y. Wang, I. Dal Cin, E. Fe e , R.D. Gougeon, J.P. Bella , T. Ka bowiak, Su ace p ope ies o co k: is co k a hyd ophobic ma e ial? J. Colloid In e ace
Sci. 608 (2022) 416–423, h ps://doi.o g/10.1016/J.JCIS.2021.09.140.
[73] R. Panagio ou, M.A.A. Ky iakides, R. Illampas, I. Ioannou, An expe imen al app oach o he in es iga ion o he pe o mance o non-s abilized comp essed
Ea h blocks (CEBs) agains wa e -media ed wea he ing, J. Cul . He i . 57 (2022) 184–193, h ps://doi.o g/10.1016/j.culhe .2022.08.009.
[74] C.T.S.S. Becke , P.A. Jaquin, J.-C.C. Mo el, Wea he ing he s o m: a amewo k o assess he esis ance o ea hen s uc u es o wa e damage, Cons . Build.
Ma e . 242 (2020) 118098, h ps://doi.o g/10.1016/j.conbuildma .2020.118098.
[75] P. Walke , T. S ace, P ope ies o Some Cemen S abilised Comp essed Ea h Blocks and Mo a s, 1997.
[76] ASTM In e na ional, C597: S anda d es me hod o ul asonic pulse eloci y h ough conc e e, (n.d.). h ps://www.as m.o g/c0597-22.h ml (accessed July 1,
2024).
[77] N. Sa hipa an, W.G.B.S. Jayasunda a, K.S.D. Sama akoon, B. Banujan, P edic ion o cha ac e is ics o cemen s abilized ea h blocks using non-des uc i e
es ing: ul asonic pulse eloci y and elec ical esis i i y, Ma e ialia 29 (2023) 101794, h ps://doi.o g/10.1016/J.MTLA.2023.101794.
[78] G.E. A chie, The elec ical esis i i y log as an aid in de e mining some ese oi cha ac e is ics, T ans. AIME 146 (1942) 54–62, h ps://doi.o g/10.2118/
942054-G.
C. Tu co e al.
Jou nal o Building Enginee ing 111 (2025) 113386
16
