Influence of Desulphogypsum on Cementitious Property and Hydration Mechanism of Fly Ash-Lime System

摘要

By adding different amount of desulphogypsum, lime, Na2SO4, NaOH, calcined desulphogypsum into fly ash, researches show that: the strength of the system was a bit improved when only mixed with desulphogypsum or calcined desulphogypsum. When the alkaline activators, lime and NaOH, were mixed into fly ash, the activity of fly ash was activated, and the cementitious property of the system was obviously improved. When the optimal mass fraction of the admixture is desulphogypsum 7%, lime 8%, NaOH 0.5%, the flexural strength and compressive strength of system reached 4.19MPa and 16.70MPa at 28days age. In the system with fly ash, lime, desulphogypsum, NaOH etc, the effect of hydration reaction of fly ash is strengthened, and its main products ettringite, calcium silicate hydrate, strengthen the microstructure of the system to improve its density.