Comparison on the properties of ITZs in fly ash-based geopolymer and Portland cement concretes with equivalent flowability

Published on May 1, 2021in Cement and Concrete Research8.328
· DOI :10.1016/J.CEMCONRES.2021.106392
Zhiyu Luo11
Estimated H-index: 11
(UTS: University of Technology, Sydney),
Wengui Li32
Estimated H-index: 32
(UTS: University of Technology, Sydney)
+ 2 AuthorsSurendra P. Shah114
Estimated H-index: 114
(UTA: University of Texas at Arlington)
Sources
Abstract
Abstract This paper aims to compare the properties of interfacial transition zones (ITZs) in Portland cement (PC) concrete and geopolymer concrete. Portland cement and geopolymer pastes were designed with the equivalent flowability to provide similar mix and casting condition of ITZs. Two types of modelled ITZs were prepared to facilitate the nanoindentations across ITZs, microstructural characterization, and comparison on the properties of ITZs with less influential factors. The results showed that the interfacial bonding of ITZs between geopolymer matrix and aggregate is relatively stronger than the counterpart in the PC concrete. There is a high amount of crystalline hydration products in the ITZs of PC concrete, but a layer gel-rich paste with denser microstructures in the ITZs of geopolymer concrete. Additionally, the interface morphology and nanoindentation analysis indicate that the property of ITZs in the modelled geopolymer concrete is not poorer than that of the corresponding geopolymer paste.
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