Comparison of long term performance between alkali activated slag and fly ash geopolymer concretes

By A. Wardhono, Chamila Gunasekara, D. Law, Sujeeva Setunge. 2017

246 citations recorded by the source corpus.

Abstract This paper reports the comparison of engineering properties of alkali activated slag (AAS) and low calcium fly ash geopolymer (FAGP) concretes up to 540 days. The results showed that the AAS concrete had higher compressive and tensile strength, elastic modulus and lower permeation characteristics than FAGP concrete in the initial 90 days. However, a reduction in AAS concrete performance was observed between 90 and 540 days, while an increase was noted in FAGP concrete over the same time period. The microscopy revealed that both reactions progressed beyond 90 days with the slag–alkali producing excess C–S–H gel which was observed to increase the crack propagation and crack width at latter ages, attributed to the combined effect of disjoining pressure and self-desiccation. The fly ash geopolymerization also continued following an initial 24 h heat curing resulting in a crack-free dense microstructure at 540 days. Overall the discrepancy in microstructural development beyond 90 days in the two concretes would explain the contradictory performance over the longer time frame.

Subfields: Civil and Structural Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/6ae4ac1e7742b76ee0d768f350722c56577a989f

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In Civil and Structural Engineering

In Materials Chemistry

Citations in the corpus

Compressive Strength of Fly-Ash-Based Geopolymer Concrete by Gene Expression Programming and Random Forest (2021, background): “[77] showed through scanning electron microscopy (SEM) that after 240 days, the gel fills out the interior voids, which results in the formation of semihomogenous, but compacted, microstructure.”
Mitigating the autogenous shrinkage of alkali-activated slag by metakaolin (2019, unknown): “Since AAS without MK undergoes high autogenous shrinkage, microcracks may have developed within the paste, as also reported intensively in literature [93,95–97], and therefore harm the flexural strength of AAS paste [93,98].”
Clean production and properties of geopolymer concrete; A review (2020, background): “Wardhono et al. (Wardhono et al., 2017) found that increasing the packing density of the Al–Si gel matrix can positively affect the elastic modulus and strength development of FAGP concrete between 90 days and 540 days.”