Effect of protogenetic alkali sulfates on the hydration and hardening of cement with different tricalcium aluminate content

Abstract The reaction of protogenetic alkali sulfates including arcanite (K2SO4), thenardite (Na2SO4) and aphthitalite (K3NS4) with calcium aluminate have a great influence on cement hydration and hardening. Considering the increased protogenetic alkali sulfates with the widespread use of rotary kilns and low-quality fuels during cement production, the effect of alkali sulfates under different dosages of C3A on hydration heat evolution, initial setting time, compressive strength, volume stability and hydration product were studied. The results show that protogenetic alkali sulfates combined with C3A have unfavorable effects on setting time, compressive strength, and linear expansion ratios by dry and water curing. The effect is negatively correlated with [Na2Oeq]·[C3A]/[SO3]2 molar ratio of cement. The [Na2Oeq]·[C3A]/[SO3]2 molar ratio