Alkali-silica reaction in waterglass-activated slag mortars incorporating fly ash and metakaolin

Shi, Zhenguo; Shi, Caijun; Zhang, Jian; Wan, Shu; Zhang, Zuhua; Ou, Zhihua

doi:10.1016/j.cemconres.2018.03.002

Cited by 117 publications

(33 citation statements)

References 32 publications

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“…However, the growing demand of OPC poses great challenges to concrete industry because of its large carbon emissions [2]. This motivates researchers for seeking suitable alternatives to OPC, and alkali-activated concrete is considered as a potential alternative by utilising industry by-products such as fly ash (FA) and ground granulated blast-furnace slag (GGBS) [3][4][5]. Although alkali-activated concrete shows comparable engineering properties as OPC concrete, critical concerns have been raised that the alkali-activated fly ash (AAF) concrete requires elevated temperature curing to improve early-age strength [1].…”

Section: Introductionmentioning

confidence: 99%

Internal curing of alkali-activated fly ash-slag pastes using superabsorbent polymer

Zhu

Fang

et al. 2019

Cement and Concrete Research

113

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Section: Introductionmentioning

confidence: 99%

Internal curing of alkali-activated fly ash-slag pastes using superabsorbent polymer

Zhu

Fang

et al. 2019

Cement and Concrete Research

113

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“…A state of the interfacial transition zones, as was earlier mentioned, is determined, first of all, by the composition and properties of the hydration products as well as by the interface bond strength due to a mutual penetration of the substances of various constituents of the concrete mixture [31,35]. However, because of small dimensions of the subjects to be studied, the examination of the hydration products in the interfacial transition zones is difficult.…”

Section: Test Methodsmentioning

confidence: 99%

“…These conclusions were further supported by numerous researchers [23][24][25][26][27][28][29][30], which provided practical solutions on struggle with the ASR through addition in the cement composition of Al 2 O 3containing additives. However, this oxide is contained in aggregates as well [31][32][33][34][35]. For this reason, the structure formation processes in the ITZ flow with participation of not only substances of cement components, but of substances of aggregate constituents as well, which always contain finely dispersed clay particles.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Interfacial Transition Zone on Strength of Alkali-Activated Concrete

Schroeyers¹,

Petropavlovskyi²,

Kovalchuk³

et al. 2020

Compressive Strength of Concrete

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A process of structure formation taking place in the interfacial transition zone (ITZ) "cement stone-aggregate" was studied on a variety of concretes made with artificial and real aggregates. The study of these processes in the case of artificial aggregate prepared from a mixture of clay loam and alkali-activated slag cement showed that not only active SiO 2 and Na 2 O but also other substances of both cement and aggregate are involved in the formation of the ITZ. This results in the formation of alkaline and alkaline-alkali-earth aluminosilicate hydrates which strengthen the ITZ and improve strength and durability of the concrete. Thus, the alkali-silica reaction (ASR) transforms from a destructive one (negative effect) into a constructive one (positive effect). The study on the ITZ in the alkali-activated cement concretes made with real alkali-susceptible aggregates selected from crushed basalt rock, glassy waste product from basalt fiber production, crushed perlite rock, and expanded perlite suggested to make a conclusion on the possibility to prevent the destructive processes in the ITZ through the addition of the metakaolin additive into the cement composition in quantities of 5-10% by mass. These conclusions were supported by the long-term testing of strength of these concretes, by measuring the deformations "shrinkage-expansion" as well as the results of study on hardness of the ITZ.

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“…The impact of the amount of used and chemical compositions of pozzolan on expansion reduction are also of interest [21,22]. A few works indicated the influence of oxide of alumina in calcined clay such as meta kaolin (MK) on the change of ASR mechanism and expansion behaviors [23,24,25,26].…”

Section: Introductionmentioning

confidence: 99%

Untitled

2020

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The effect of different local pozzolans, as a supplementary cementitious material (SCM), on the expansion of mortar bar due to Alkali Silica Reaction (ASR) were reported in this paper. Accelerated test on specimens using local volcanic aggregates, rhyolite, was used to investigate and to compare the effects of fly ash (FA) and metakaolin (MK) on the suppression of the length change. In this study, three different percentages of FA, namely, 20, 35 and 50 and three of MK, namely, 10, 15 and 20 were used as cement replacement. The results at 14 days showed slight decrease expansions for 20% FA replacement of 0.073% but the lowest expansions were 0.025% and-0.001%, respectively for 35% FA and 10% MK, compared to 0.176 % of the control mix. Increase the SCMs to 50% FA and 15-20% MK yielded reduction of expansion to the innocuous level. Results from 28 days acceleration registered a slight increase in expansion for FA mixes of 35 and 50% and all MK mixes, but still less than 0.10%, the threshold for innocuous level. Chemical composition analysis revealed decrease in CaO/SiO2 and CaO/Al2O3 ratio of the cementitious systems. This correlated with the expansion reduction. But alumina in Al2O3/SiO2 ratio showed the dominant effect on ASR suppression. Microstructures of all materials and casted specimens were also studied in detail. Considering all aspects, these SCMs, used in suitable amount were considered good candidates for ASR prevention in new concrete structures for both short and long term

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Alkali-silica reaction in waterglass-activated slag mortars incorporating fly ash and metakaolin

Cited by 117 publications

References 32 publications

Internal curing of alkali-activated fly ash-slag pastes using superabsorbent polymer

Internal curing of alkali-activated fly ash-slag pastes using superabsorbent polymer

The Influence of Interfacial Transition Zone on Strength of Alkali-Activated Concrete

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