Cement with high-volume limestone powder: effect of powder fineness on packing density, strength and hydration behaviour

Abstract

The effects of limestone powder (LP) of different fineness on the packing density, strength and hydration behaviour of cement blended with a high volume of LP were studied using Vicat setting time tests, strength tests, isothermal calorimetry and scanning electron microscopy. Three different LP fineness values were examined and it was found that cement replacement by LP with the smallest median particle size produced the highest density. The compressive strength of the blended cement mortar increased with increasing LP fineness. The packing densities of the blended cement were used to infer the evolution of mechanical strength of the blended cement mortar. The addition of LP with a median particle size smaller than that of cement accelerated the hydration of cement in the acceleration period. Compared with LP with a median particle size smaller than that of cement, the production rate of nuclei of cement blended LP with a median particle size larger than that of cement decreased with increasing amounts of LP replacement, while the growth rate of nuclei increased with increasing amounts of LP replacement.