Modelling of irregular-shaped cement particles and microstructural development of Portland cement

The shape of cement powder particles plays a crucial role in particle packing and hydration process of cement. However, cement powder is generally regarded as sphere for simplification in most cement hydration models. This paper aims to investigate the influence of cement particle shapes on hydration of Portland cement and microstructure of cement paste. A novel central growth model along with a particle packing algorithm is developed to generate cement particles with irregular shapes and reconstruct initial 3D microstructures of Portland cement. Afterwards, the hydration process of cement with different shapes are simulated using CEMHYD3D model. The results indicate that the generated irregular-shaped particles precisely reproduce the real cement particles in terms of surface area, particle size distribution and geometry. The effect of particle shapes on hydration is significant due to the difference in surface area and geometric discrepancy, whereas this effect becomes less obvious with decreasing water-to-cement ratio.