Influence of Silicon-Aluminium Modified Materials on Durability of Fly Ash-Based Geopolymers

Abstract

The addition of silicon-aluminium materials can improve the strength of geopolymers, but its effect on the durability of geopolymers has not been confirmed. In this paper, chemical corrosion resistance and freeze-thaw cycle tests were carried out on fly ash geopolymer and metakaolin/mineral slag-fly ash geopolymer, and the reaction mechanism was determined by microscopic analysis. In the chemical corrosion resistance tests, three groups of specimens were immersed in different corrosive solutions, and the corrosion resistance of the specimens was measured by testing the compressive strength and quality change of the specimens immersed in the solution for different times. The results show that the addition of silicon-alumina materials can improve the chemical corrosion resistance of geopolymers in a certain extent, and the mineral slag shows better improvement effect. In the freeze-thaw cycle tests, three groups of materials were put into the freeze-thaw test machine, and their freezing-thawing resisting performance was measured by testing their mass loss rate and compressive strength after different cycles. The results showed that the strength loss of the specimens was improved with the addition of the silicon-aluminium materials, but the mass loss rate of the specimens became higher with the addition of metakaolin.