scieee Open visual document viewer

Development of the internal structure of an alkali-activated paste related to the length of curing

Kocáb, Dalibor; Bílek, Vlastimil; Nápravník, Petr; Kucharczyková, Barbara

Abstract

This paper deals with the influence of the length of the moist curing period on the development of the internal structure of a paste based on alkali-activated slag. Waterglass was used as the activator. For the purpose of experiment, the test specimens subjected to the experiment were divided into five sets with different curing regimes combining moist and air curing. The reference set was kept in an environment with relative air humidity 95% during the entire maturing period. The development of the internal structure of the alkali-activated paste was mainly monitored using the resonance method. The obtained results show that the curing regime applied to the test specimens significantly influences the development of the internal structure of the material. The development of the observed dynamic properties (dynamic moduli and Poisson’s ratio) shows the formation of damage to the internal structure of the paste after its exposure to the air. Interestingly, a massive decrease in dynamic modulus of elasticity immediately after exposure to air drying was not prevented, even by intensive moist curing of the paste for 28 days.

Full text

Con en om his wo k may be used unde he e ms o heC ea i eCommonsA ibu ion 3.0 licence. Any u he dis ibu ion o his wo k mus main ain a ibu ion o he au ho (s) and he i le o he wo k, jou nal ci a ion and DOI. Published unde licence by IOP Publishing L d ICBMPT-2023 Jou nal o Physics: Con e ence Se ies 2568 (2023) 012007 IOP Publishing doi:10.1088/1742-6596/2568/1/012007 1 De elopmen o he in e nal s uc u e o an alkali-ac i a ed pas e ela ed o he leng h o cu ing D Kocáb1, V Bílek2, N Náp a ník1 and B Kucha czyko á1 1B no Uni e si y o Technology, Facul y o Ci il Enginee ing, Ve eří 331/95, B no, Czech Republic 2B no Uni e si y o Technology, Facul y o Chemis y, Pu kyňo a 464/118, B no, Czech Republic E-mail: dalibo .kocab@ u b .cz Abs ac . This pape deals wi h he in luence o he leng h o he mois cu ing pe iod on he de elopmen o he in e nal s uc u e o a pas e based on alkali-ac i a ed slag. Wa e glass was used as he ac i a o . Fo he pu pose o expe imen , he es specimens subjec ed o he expe imen we e di ided in o i e se s wi h di e en cu ing egimes combining mois and ai cu ing. The e e ence se was kep in an en i onmen wi h ela i e ai humidi y ≥ 95% du ing he en i e ma u ing pe iod. The de elopmen o he in e nal s uc u e o he alkali-ac i a ed pas e was mainly moni o ed using he esonance me hod. The ob ained esul s show ha he cu ing egime applied o he es specimens signi ican ly in luences he de elopmen o he in e nal s uc u e o he ma e ial. The de elopmen o he obse ed dynamic p ope ies (dynamic moduli and Poisson’s a io) shows he o ma ion o damage o he in e nal s uc u e o he pas e a e i s exposu e o he ai . In e es ingly, a massi e dec ease in dynamic modulus o elas ici y immedia ely a e exposu e o ai d ying was no p e en ed, e en by in ensi e mois cu ing o he pas e o 28 days. 1. In oduc ion Many yea s ago, high CO2 emissions ha accompany he p oduc ion o Po land cemen igge ed a su ge o in e es in al e na i e ino ganic binde s. Today, his end is gaining momen um. One o he mos common binde s ha a e an al e na i e o cemen is alkali-ac i a ed slag (AAS). The p esence o a high alkaline ac i a o in his binde induces he eac ion o he g ound g anula ed blas u nace slag. Apa om he ob ious en i onmen al aspec , he main ad an ages o AAS ma e ials include esis ance o agg essi e en i onmen s [1,2] and high empe a u es [3] o a apid inc ease in s eng h [4]. On he o he hand, one o he bigges disad an ages o AAS is undoub edly i s suscep ibili y o ela i ely subs an ial olume changes. Sh inkage is accompanied by c ack o ma ion, which limi s he wide use o AAS-based ma e ials in p ac ical applica ions. I should also be no ed ha he esul ing p ope ies o hese ma e ials s ongly depend on he ype o he employed ac i a o , i s concen a ion, he ela i e a io o he p ecu so o he ac i a o solu ion, o he ma u ing condi ions. Commonly used alkaline ac i a o s include hyd oxides, silica es and o he sal s o alkali me als (mos o en sodium). The ype o he gi en ac i a o signi ican ly in luences he hyd a ion p ocess o AAS ma e ials, which in u n a ec s hei esul ing physical and mechanical p ope ies. Wa e glass ac i a ion, o example, can esul in high comp essi e s eng hs and e y good wo kabili y [5], bu is a isk o massi e au ogenous sh inkage [6] and d ying sh inkage, which is usually accompanied by c ack o ma ion. The use ICBMPT-2023 Jou nal o Physics: Con e ence Se ies 2568 (2023) 012007 IOP Publishing doi:10.1088/1742-6596/2568/1/012007 2 o sodium hyd oxide, on he o he hand, usually p o ides high ini ial comp essi e s eng hs due o he high a e o hyd a ion bu does no lead o signi ican s eng h inc ease in he subsequen ma u ing p ocess when compa ed o o he ac i a o s. A slow dec ease in capilla y po osi y has been iden i ied as one o he main easons o ha [5,7]. Ma e ials based on ino ganic binde s can unde go di e en s ages o deg ada ion du ing hei li e ime, which is e lec ed in he quali y o hei mic os uc u e. The s a e o a mic os uc u e in e ms o size and dis ibu ion o po es o he deg ee o c acking damage can be desc ibed, o example, by mic oscopic me hods, compu e omog aphy o me cu y po osime y [8,9]. Howe e , all he cases a e, in a way, des uc i e es me hods ha equi e ela i ely demanding sample p epa a ion. I a mic opo e analysis is equi ed, he samples mus o en be ex ac ed om la ge es specimens o di ec ly om building elemen s. In mos cases, he size o he ex ac ed sample is incompa ably smalle han he size o he o iginal es ed elemen , and he e o e makes i almos impossible o comp ehensi ely desc ibe he dis ibu ion o po es o he deg ee o damage o he gi en ma e ial in i s en i e olume. The use o non-des uc i e es ing me hods (NDT) he e o e seems only app op ia e since hey a e sensi i e o he p esence o local damage and c acks. These me hods include, o example, he ul asonic pulse eloci y me hod and he esonance me hod. In his case, he de elopmen o deg ee o damage o he in e nal s uc u e can easily be moni o ed using he change in he dynamic modulus o elas ici y, he so-called ela i e moduli o elas ici y (RDM). In p inciple, he assessmen can be iden ical o eeze- haw esis ance es ing o conc e e ma e ials acco ding o ASTM C666/C666M-15 [10] o CEN/TR 15177 [11]. The ela i e dynamic modulus can be de e mined using bo h o he abo e-men ioned NDT me hods, howe e , he esonance me hod p o ed o be much mo e sui able o his pu pose. This is because i is mo e sensi i e o damage o he in e nal s uc u e and shows a highe dec ease in RDM han he ul asonic pulse eloci y me hod [12]. The ad an age o he esonance me hod is no only i s non-des uc i e cha ac e , which allows epea ed measu emen s on he same specimen o e any equi ed ime ange, he eby educing he demands on he numbe o es specimens, bu i also allows calcula ions o se e al dynamic p ope ies o he examined ma e ial simul aneously. In addi ion o he dynamic Young’s modulus, which can be calcula ed om he na u al equency o longi udinal and ans e se ib a ions, he dynamic shea modulus and he dynamic alue o Poisson’s a io can also be de e mined [13]. This o e s a be e desc ip ion o he de elopmen o he in e nal s uc u e o he ma e ial, bo h om he poin o iew o i s ma u ing and om he poin o iew o damage due o deg ada ion mechanisms. The main objec i e o he pe o med expe imen is o employ he esonance me hod as a non-des uc i e es ing me hod o moni o ing he ma u a ion p ocess om he specimens’ manu ac u ing up o long- e m ageing, as he me hod is sensi i e o local damage and mic o-c acks. The a e o in e nal de e io a ion is exp essed h ough he changes in he na u al equencies measu ed in egula in e als on he same se o specimens du ing he whole ime o ageing. This app oach p omises an e ec i e ool o p omp mic o-c acking and in e nal de e io a ion e i ica ion wi hou demanding mic oscopic analysis. Especially, he ob ained dynamic Poisson’s a io could gi e a good idea abou he end o inne de e io a ion. 2. Expe imen Fi e se s o alkali-ac i a ed slag es specimens we e p oduced o his expe imen . The slag was ac i a ed wi h wa e glass. The main moni o ed pa ame e s we e he de elopmen o he esonan equencies o he es specimens and subsequen ly calcula ed RDM and Poisson’s a io. These pa ame e s we e moni o ed as a unc ion o age and he me hod o es specimens cu ing du ing hei ma u ing. 2.1. Ma e ial G ound g anula ed blas u nace slag (LB Cemix, s. .o.) wi h he majo i y o he amo phous phase was used. I s Blaine speci ic su ace a ea was 400 m2/kg. The slag was ac i a ed by he wa e glass solu ion wi h a silica e modulus o 1.5 and a Na+ concen a ion o 4M. The olume ac ion o he slag in he ICBMPT-2023 Jou nal o Physics: Con e ence Se ies 2568 (2023) 012007 IOP Publishing doi:10.1088/1742-6596/2568/1/012007 3 pas e was 0.52. The inal ac i a ing solu ion was p epa ed a ew days in ad ance by mixing o he aw wa e glass wi h a silica e modulus o 1.9 and d y ma e o 47.9% (Vodní sklo, a.s.) wi h 50% sodium hyd oxide solu ion (Ca l Ro h GmbH + Co. KG) and wi h demine alized wa e . The pas e was mixed using a Hoba mixe o 3 minu es, wi h he slag being added e enly in o he p e-weighed ac i a o du ing he i s 50 seconds. A e mixing, he consis ency o he pas e was de e mined using he low able es acco ding o s anda d [14] and he densi y acco ding o s anda d [15]. The diame e o he pou ed pas e a e li ing he cone was 178 mm and 217 mm a e i een jol s. The densi y o he esh pas e was 2080 kg/m3. Th ee gang s eel molds we e used in he p oduc ion o he es specimens o nominal dimensions 40×40×160 mm. The molds we e illed in wo laye s and each laye was compac ed using a high equency ib a ing able o 3 seconds. The desc ibed expe imen in ol ed i een es specimens, which we e di ided in o 5 se s. Ma u ing du ing he i s 24 hou s occu ed in he molds co e ed wi h PE oil unde labo a o y condi ions a a empe a u e o (22±2)°C. The cu ing me hod o he es specimens o he indi idual se s a e hei emo al om he molds was as ollows: • REF – always s o ed in an en i onmen wi h ela i e humidi y (RH) ≥ 95% (excep o he es ing pe iod), • 24H – d ying in he ai immedia ely a e demolding, • 48H – addi ional 24 hou s unde RH ≥ 95%, hen d ying in he ai , • 7D – addi ional 6 days unde RH ≥ 95%, hen d ying in he ai , • 28D – addi ional 27 days unde RH ≥ 95%, hen d ying in he ai . 2.2. Tes me hods The na u al equencies o ib a ion we e measu ed a egula in e als on all es specimens – in he case o he e e ence se con inually, in he case o he o he se s only a e exposu e o he specimens o d ying in he ai . The i s measu emen on he e e ence se was conduc ed immedia ely a e demolding, and he es specimens we e hen placed in a chambe wi h a ela i e humidi y ≥ 95%. Sho ly be o e each subsequen measu emen , he es specimens we e emo ed and su ace-d ied, hei mass and na u al equency o ib a ion we e de e mined, and he specimens we e hen immedia ely e u ned o he chambe . The second se o 24H was measu ed in an analogous way, wi h he only di e ence being he ac ha he specimens we e le o d y in he ai a e he i s measu emen . The es specimens o he o he se s 48H, 7D and 28D we e demolded and placed in he chambe wi h a ela i e humidi y ≥ 95%, and he i s measu emen was conduc ed only a e hey we e emo ed om he chambe o he i s ime and exposed o d ying in he ai – i.e. a he age o 48 hou s, 7 days, espec i ely 28 days. The measu emen s we e conduc ed un il he pas e eached he age o 120 days. The ai d ying was pe o med in an ai -condi ioned labo a o y a a empe a u e o (22±2)°C and RH (55±5)%. A each measu emen in e al, he mass o he es specimen was de e mined oge he wi h he i s na u al equency o longi udinal L, ans e se and o sional ib a ion . The de e mina ion o he na u al equencies was conduc ed using an impac hamme (exci e ), an accele a ion senso (senso ), an oscilloscope and e alua ion so wa e, which wo ks on he p inciple o as Fou ie ans o ma ion (see igu e 1). The measu emen o he na u al equencies o he es specimens and de e mina ion o dynamic p ope ies (Young’s modulus E L and E , shea modulus G and Poisson’s a io ν ) was conduc ed in acco dance wi h s anda d [13]. Subsequen ly, RDM was calcula ed using he measu ed equencies acco ding o he p ocedu e in [10]. The alues o he na u al equencies o he e e ence se REF, acqui ed du ing he i s measu emen a e demolding a he age o 24 hou s, we e conside ed as e e ence alues o he calcula ion o RDM(L), RDM(F) and RDM(T) o all es se s. The ela i e modulus o elas ici y was de e mined acco ding o he equa ion: 𝑅𝐷𝑀𝑖=𝑓 𝑖2 𝑓 0 2∙100, (1) whe e RDMi is he ela i e dynamic modulus o elas ici y o he i- h measu emen , i is he a e age na u al equency o he specimens in a se a he i- h measu emen and 0 is he a e age equency ICBMPT-2023 Jou nal o Physics: Con e ence Se ies 2568 (2023) 012007 IOP Publishing doi:10.1088/1742-6596/2568/1/012007 4 o he es specimens o he REF se a he i s measu emen a e demolding. RDM is he e o e no calcula ed o indi idual es specimens, bu o en i e se s. This me hod was selec ed o allow compa isons be ween indi idual se s. The measu emen was ini ia ed a di e en ages o each se , he e o e he e is no eason o ela e RDM o he i s measu emen o he indi idual specimens. The measu ed na u al equencies o he es specimens a e demolding (se s REF and 24H) exhibi ed such low a iabili y ha i is possible o conside he a e age na u al equencies o he REF se as he i s 0 measu emen o all o he se s wi hou signi ican s a is ical e o . Mass change, howe e , was de e mined o all specimens sepa a ely acco ding o he equa ion: ∆𝑚𝑖=𝑚𝑖−𝑚0 𝑚0∙100, (2) whe e Δmi is he ela i e change in mass o he i- h measu emen , mi is he specimen mass a he i- h measu emen and m0 is he specimen mass a i s i s measu emen . The esul ing mass change Δm is de e mined o each se a each measu emen as he a e age alue o he indi idual mass changes o h ee es specimens in a se . Figu e 1. Dis ibu ion o senso s (S) and exci e s (E) o he de e mina ion o he i s na u al equencies (le ), illus a i e pho o o he de e mina ion o he i s na u al equency o longi udinal ib a ion ( igh ). 3. Resul s and discussion The de e mined Young’s moduli, shea modulus, Poisson’s a io and mass changes a e p esen ed in he ollowing igu es as a i hme ic means o h ee independen measu emen s conduc ed on he specimens o each es se . Va iabili y o he measu emen esul s, exp essed wi h he sample s anda d de ia ion, is shown in he g aphs using e o ba s. Figu e 2 p esen s he de elopmen o he dynamic moduli o elas ici y E L and E . Figu e 3 shows he de elopmen o he dynamic shea modulus G and he dynamic Poisson’s a io ν . In he case o he REF se , a g adual inc ease o all h ee de e mined dynamic moduli o elas ici y can be obse ed h oughou he en i e measu emen pe iod up o 120 days o age, which co esponds o he no mal de elopmen o mechanical p ope ies o conc e e ma e ials du ing ma u ing a high ela i e humidi y [16,17]. Howe e , his is no he case o he se s whose specimens we e exposed o d ying in ai a a ce ain age. The AAS pas e ha was le wi hou cu ing immedia ely a e demolding (24H se ) exhibi s an inc ease in dynamic elas ic moduli up o 21 days o age, wi h he inc ease being lowe han ha o he REF se . A e he 21s day o age, he e is a g adual dec ease in Young’s modulus, which was de e mined using he na u al equency o longi udinal and ans e se ib a ions. The dynamic shea modulus does nei he dec ease no inc ease signi ican ly – a pe sis en s agna ion has been eco ded om he age o 21 days. A i s glance, i may seem ha he pas e wi hou cu ing ma u es in a s anda d manne only a a slowe a e when compa ed o cu ed specimens. In his case, howe e , he imp o emen in he quali y o he in e nal s uc u e o he pas e is only supe icial since i al eady exhibi s c ack ICBMPT-2023 Jou nal o Physics: Con e ence Se ies 2568 (2023) 012007 IOP Publishing doi:10.1088/1742-6596/2568/1/012007 5 o ma ion. This is e y well illus a ed by he de elopmen o he dynamic Poisson’s a io. Fo he e e ence se , he alue o he Poisson’s a io a he age o 3 days is 0.30, hen i g adually dec eases o he alue o 0.25 a he age o 21 days and emains cons an he eina e . In he case o he 24H se , he alue o he Poisson’s a io a he age o 3 days is only 0.15, which is alid un il he age o 21 days, howe e , i hen exhibi s a sha p dec ease o an un ealis ic alue o -0.20. O cou se, his does no mean ha he AAS pas e will become an auxe ic ma e ial wi hou cu ing. This only indica es a s a e when he in e nal s uc u e o he es ed ma e ial is so damaged (in his case by c acks om d ying sh inkage) ha he heo e ical ela ionships o he na u al equencies o he indi idual ib a ion modes cease o apply. Figu e 2. De elopmen o he dynamic Young’s modulus, de e mined using longi udinal ib a ion E L (le ) and ans e se ib a ion E ( igh ). Figu e 3. De elopmen o he dynamic shea modulus G (le ) and Poisson’s a io ν ( igh ). All es specimens ha we e cu ed o a leas 1 day unde he en i onmen wi h RH ≥ 95% beha e essen ially iden ically a e exposu e o he ai d ying. A he same ime, hei beha iou is en i ely he opposi e o REF and 24H. A e emo al om he en i onmen wi h RH ≥ 95%, all dynamic modulus alues immedia ely (wi hin 24 hou s) dec ease sha ply, up o 70% o he o iginal alue de e mined immedia ely a e emo al om he humid chambe . A e his ex eme dec ease in he alues o he dynamic moduli o elas ici y, he e is a slow g adual inc ease, howe e , he in e nal s uc u e o he AAS pas e has al eady been i e e sibly damaged. The damage is e y well illus a ed (especially o he 48H and 7D se s) by he de elopmen o he Poisson’s a io, which immedia ely inc eases o un ealis ic alues exceeding 0.5. In he case o he 28D se , he Poisson’s a io does all wi hin ealis ic limi s, bu ICBMPT-2023 Jou nal o Physics: Con e ence Se ies 2568 (2023) 012007 IOP Publishing doi:10.1088/1742-6596/2568/1/012007 6 he luc ua ions du ing he i s 14 days a e exposu e o he specimens o he ai d ying indica e issues in he in e nal s uc u e o he pas e. The ex eme dec ease in he dynamic modulus o elas ici y o he cu ed se s (48H, 7D and 28D) a e he end o cu ing is pa ly caused by a massi e mass loss o he AAS pas e (see igu e 4), since mass is inco po a ed in he calcula ion o he modulus o elas ici y. The g aph in igu e 4 e eals ha he la e cu ing inishes, he smalle he mass loss, which can be a ibu ed o wa e binding in he hyd a ion p oduc s du ing ongoing hyd a ion. Simul aneously, he mass o all he se s somewha s abilizes a e 28 days o d ying. I is also impo an o no e ha he impac o mass loss on he dec ease in modulus o elas ici y is no signi ican . All he es ed cu ed specimens exhibi ed a signi ican dec ease in RDM (see igu e 5), al hough his is ma hema ically independen o he mass o he es specimens, see equa ion (1). Figu e 4. A e age mass change o he es specimens o indi idual se s a e he s a o he measu emen o na u al equencies. Figu e 5. Rela i e dynamic modulus de e mined om he na u al equency o longi udinal (le ), ans e se (middle) and o sional ib a ions ( igh ). When using wa e glass as an ac i a o , he p oduced pas es a e damaged by sh inkage c acks always a e cu ing has been e mina ed, ega dless o he leng h o he cu ing pe iod. I cu ing las ed o a leas 48 hou s, he c acks become qui e p onounced a e he end o he cu ing pe iod, see igu e 6. When he ICBMPT-2023 Jou nal o Physics: Con e ence Se ies 2568 (2023) 012007 IOP Publishing doi:10.1088/1742-6596/2568/1/012007 7 AAS ge exposed o d ying in he ai only a e 28 days o cu ing, a dec ease in he dynamic modulus o elas ici y o 50% (G ) o up o 30% (E ) o he o iginal alue was eco ded in jus 24 hou s. The di e en beha iou o he specimens exposed o d ying immedia ely a he age o 24 hou s compa ed o all o he cu ing in e als unde speci ic humidi y is closely ela ed o di e en s ages o hyd a ion, i.e. o di e ences in he mic os uc u e, especially in e ms o he ineness o i s po osi y. I has been obse ed [18] ha a simila AAS pas e, only wi h a sligh ly lowe olume ac ion o slag (0.52 s 0.50) and a a sligh ly highe empe a u e (25°C), exhibi ed he maximum o he main hyd a ion peak on he calo ime ic cu e a e app oxima ely 24 hou s. I we conside he s ong dependence o he a e o alkali-ac i a ion o he slag on empe a u e [19,20], his s udy can assume ha he main calo ime ic peak will appea a li le la e . This peak is ela ed o a massi e o ma ion o hyd a ion p oduc s, which p oduces ine mic os uc u e and a he same ime signi ican ly inc eases mechanical p ope ies [21]. This means ha he mic os uc u e o he specimens om he 24H se was undamen ally di e en om he mic os uc u e o all he o he se s o he es specimens exposed o d ying a e a longe cu ing pe iod. As a esul , signi ican ly coa se po osi y can be expec ed, and he e o e smalle o ces leading o sh inkage [22,23] bu a he same ime a smalle s ess concen a ion in he pas e sample due o i s low s i ness/lowe se ing. The e is also he highes po en ial o pa ial healing o any de ec s ha may ha e o med as a esul o he simul aneously ongoing hyd a ion. These ac o s, he e o e, p obably led o he ac ha he dynamic modulus o elas ici y con inued o inc ease app oxima ely h ee weeks a e he specimens had been exposed o ai , despi e he ac ha he i s c acks appea ed on he su ace o he specimens wi hin 24 hou s o he s a o d ying ( igu e 6, abo e). On he o he hand, specimens ha we e cu ed o longe pe iods exhibi an immedia e and e y sha p dec ease in dynamic moduli, because he ine po es d y ou and c acks o m e y in ensi ely due o he associa ed la ge sh inkage, ( igu e 6, below). A e his sha p dec ease, he dynamic moduli o elas ici y inc ease again, which can be a ibu ed o g adual pa ial closing o he c acks – p obably mainly due o d ying and sh inkage o he inside o he specimen, which may ha e bound he sh inkage in he ea ly s ages o d ying, and hus con ibu ed o he ini ial o ma ion o su ace c acks in pa icula . An impo an ac o can also be he na u e o he o med c acks, which can a y depending on he leng h o cu ing pe iod. The e i ica ion and u he analysis o hese assump ions is he subjec o ano he ongoing ollow-up esea ch. Figu e 6. Tes specimens a e 24 hou s o exposu e o d ying in he ai – he specimen om he 24H se (abo e), he specimen om he 7D se (below). ICBMPT-2023 Jou nal o Physics: Con e ence Se ies 2568 (2023) 012007 IOP Publishing doi:10.1088/1742-6596/2568/1/012007 8 4. Conclusion This s udy ocused on he in luence o he cu ing pe iod (in an en i onmen wi h RH > 95%) o slag pas es ac i a ed by wa e glass wi h a silica e modulus o 1.5 on hei dynamic p ope ies. Based on he conduc ed expe imen , he ollowing can be s a ed: • he examined alkali-ac i a ed pas e is ex emely p one o c ack o ma ion du ing d ying, • he pas es exposed o ai immedia ely a e demolding (aged 24 hou s) we e ela i ely leas p one o c ack o ma ion and, despi e he appea ance o c acks, exhibi ed an inc ease in dynamic moduli du ing he i s weeks o d ying, • on he o he hand, cu ing unde humidi y up o he age o 2, 7 and 28 days led o he same end beha iou in he o m o a conside able dec ease in he dynamic moduli (up o 30% o he o iginal alue) du ing he i s 24 hou s o d ying, wi h he dec ease being mos p onounced, especially, o specimens cu ed o 28 days, • he esonance me hod has demons a ed i s bene i s o moni o ing o he de elopmen o he in e nal s uc u e o he AAS pas e, no only he ela i e modulus o elas ici y bu also he de elopmen o he dynamic Poisson’s a io, which in he case o de ec s eached un ealis ic alues o he s udied ype o ma e ial. The esul s p esen ed in his pape a e pa o an ongoing complex expe imen , which is planned o end when he samples a e 1 yea old. Cu en ly, he esul s acqui ed om he scanning elec on mic oscope, me cu y po osime y and di e en ial he mal analysis a e being con inually e alua ed, he de elopmen o esonan equencies and s eng h cha ac e is ics a e being measu ed, as well as moni o ing o c acks o e ime. The esul s will be g adually p esen ed in u u e publica ions. Acknowledgemen This esea ch was unded by he Czech Science Founda ion, g an numbe 22-02098S, p ojec i le “Expe imen al analysis o he sh inkage, c eep and c acking mechanism o he ma e ials based on he alkali-ac i a ed slag”. Re e ences [1] Shi C, K i enko P and Roy D 2006 Alkali ac i a ed cemen s and conc e es (London: CRC P ess) [2] H ubý P, Bílek V, Topolář L, Kalina L, Ma ko M, Šoukal F, D ořák R and He čík T 2021 IOP Con . Se .: Ma e . Sci. Eng. 1205 [3] Manjuna h R, Na asimhan M and Umesha K 2019 Cons . Build. Ma e . 229 pp 1–19 [4] Mohamed O A 2019 Ma e . 12 pp 1–21 [5] Fe nández-Jiménez A, Palomo J and Pue as F 1999 Cem. Conc . Res. 29 pp 1313–21 [6] Li Z, Lu T, Liang X, Dong H and Ye G 2020 Cem. Conc . Res. 135 pp 1–15 [7] Haha M, Lo henbach B, Le Saou G and Winne eld F 2012 Cem. Conc . Res. 42 pp 74–83 [8] Zuo Y and Ye G 2018 Ma e . 11 pp 1–23 [9] Komá ko á T, K álíko á M, Ko ács P, Kocáb D and S a ař T 2015 Ma e . echnol. 49 pp 1–9 [10] ASTM C666/C666M – 15 2015 S anda d Tes Me hod o Resis ance o Conc e e o Rapid F eezing and Thawing (Wes Conshohocken: ASTM In e na ional) [11] CEN/TR 15177 2006 Tes ing he eeze- haw esis ance o conc e e – In e nal s uc u al damage (B ussels: Eu opean Commi ee o S anda diza ion) [12] Kocáb D, Vymazal T, Komá ko á T and Lišo ský M 2023 AIP Con e ence P oceedings (in p in ) [13] ASTM C215-19 2019 S anda d Tes Me hod o Fundamen al T ans e se, Longi udal, and To sional Resonan F equencies o Conc e e Specimens (Wes Conshohocken: ASTM In e na ional) [14] EN 1015-3 1999 Me hods o es o mo a o mason y – Pa 3: De e mina ion o consis ence o esh mo a (by low able) (B ussels: CEN) [15] EN 1015-6 1998 Me hods o es o mo a o manso y – Pa 6: De e mina ion o bulk densi y o esh mo a (B ussels: CEN) [16] Kocáb D, K álíko á M, Cik le P and Misák P 2017 Ma e . echnol. 51 pp 657–665 ICBMPT-2023 Jou nal o Physics: Con e ence Se ies 2568 (2023) 012007 IOP Publishing doi:10.1088/1742-6596/2568/1/012007 9 [17] Ne ille A M 2011 P ope ies o Conc e e (Ha low: Pea son) [18] Bílek V, H ubý P, Iliushchenko V, Koplík J, Kříkala J, Ma ko M, Hajzle J and Kalina L 2022 Ma e . 15 pp 1–21 [19] Geb egziabihe B S, Thomas R J and Pee hampa an S 2016 Cons . and Build. Ma e . 113 pp 783–793 [20] Chi hi apu hi an A and Nei hala h N 2013 Cons . and Build. Ma e . 45 pp 233–242 [21] Bílek V, Kalina L, No o ný R, Tkacz J and Pařízek L 2016 Ma e . 9 pp 1–12 [22] Bee sae s G, Ascensão G and Pon ikes Y 2021 Cem. Conc . Res. 141 106330 [23] Collins F and Sanjayan J G 2000 Cem. Conc . Res. 30 pp 1401–1406