Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4912976 | Construction and Building Materials | 2017 | 10 Pages |
Abstract
This study investigates the pore structure and shrinkage behavior of metakaolin-based geopolymer pastes and mortars containing 0-30% fly ash. Fly ash substitution decreases average reactivity of the solid precursors, resulting in a lower reaction rate and accompanying longer reaction time. Composition of the sodium aluminosilicate (N-A-S-H) gel formed in the geopolymers has been changed, and the continued reaction after hardening of the pastes generates a more compact binding gel phase with lower Al/Si ratio. Refinement of the pore structure entails a higher capillary tension developed in the binders to increase the autogenous shrinkage, but also restricts the water evaporation from the pore networks, resulting in a decreased drying shrinkage. The geopolymer mortars provide higher compressive strength and lower total shrinkage when compared with the pastes.
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Authors
Tao Yang, Huajun Zhu, Zuhua Zhang,