A model investigation of the influence of particle shape on portland cement hydration

The NIST Virtual Cement and Concrete Testing Laboratory (VCCTL) is used to simulate the influence of particle shape on the hydration kinetics and setting of portland cement. Building on previous work in reconstructing particle shapes from real cements, real-shape particles are used to produce three-dimensional digitized cement paste microstructures, and the hydration of these microstructures is tracked using VCCTL. The degree of hydration and percolation of solids is monitored and compared to experimental data at several water–cement ratios. The simulations predict that shapes of particles influence cement hydration in two ways: the additional surface / volume ratio relative to spherical particles results in greater rates of hydration, and the anisometry in shape influences the degree of hydration at which the particles and hydration products percolate to form a stiff three-dimensional network.