Influences of Sodium Silicate Modulus on Mechanical Properties and Microstructure of Fly Ash Geopolymer

In order to explore the water glass modulus that can make the fly ash base polymer the highest strength and the best performance, fly ash is used as the raw material to prepare alkali-activated fly ash-based geopolymer test blocks. Through unconfined compression test, SEM test, XRD test, the influence of different water glass modulus and age on its mechanical properties is studied. The results are as follows. When the sodium silicate modulus is 1.1, the strength of fly ash-based geopolymer is the highest, reaching 6.1MPa after 28 days of curing. With the growth of age, the strength of fly ash-based geopolymers continues to increase. It is observed from the SEM test that when the modulus is 1.1, the structure is dense, the porosity is small, the alkali excitation effect is obvious, and the reaction is relatively complete.