Addition of limestone in the low heat Portland cement part 1.

The substitution of about 50 wt.\% of gypsum by limestone in Portland cement affects the particle size distribution, decreases the total porosity and accelerates the rate of hydration of cement paste. The effect of partially trp to fully substitution of gypsum in the laboratory prepared low heat Portland cement on the characteristics of the hardened cement pastes up to 90 days of hydration was studied. The results show that the substitution of 60 wt. \% of gypsum by fine limestone improves the rate of hydration at early ages up to 28 days, rn addition, the elevated amount of limestone increases the heat of hydration and enhances the compressive strength at early ages.