Setting behavior of blended cement with limestone: influence of particle size and content

The combined effects of particle size, surface area, and limestone content on the properties of blended cement with limestone were studied. Limestone powders with six different particle diameters and surface areas relative to the cement particles were tested: two sizes smaller with greater surface area, two sizes larger with less surface area, and two sizes similar to the original cement particle. Two systems were studied: blended cement with limestone consisting of one particle size distribution and limestone consisting of a combination of three particle sizes. The setting history and hydration degree were examined using a Vicat needle apparatus and performing Rietveld quantitative phase analysis of X-ray diffraction. The packing density of the different pastes was calculated based on the amount of water required for normal consistency. It was shown that the properties of blended cements with different particle sizes were affected significantly by two mechanisms: nucleation and packing density. These two mechanisms affected the chemical and physical properties of the blended cement by altering its setting rates.