A continuous hydration model for cement paste with realistic CT image-based particles and simulation of microstructural evolution

Accurate simulation of the hydration process and microstructural evolution of cement paste is essential to predict the diffusion and mechanical properties of cementitious materials. This study developed a continuous hydration model integrated with X-ray computed tomography (XCT) image-based cement particles, for the first time, to simulate the hydration process and the resultant microstructural evolution of cement paste. In this model, real cement particles are characterized analytically by spherical harmonic (SH) functions, followed by their SH coefficients to derive the hydration kinetics and rate controlling equation of hydration product. Then the hydration process is realized by merging and embedding of hydration products between multi-sized particles. After validation, the hydration model is applied to investigate the microstructural development of cement pastes with various water-cement ratios at different curing temperatures, showing the strong simulation capabilities of the developed hydration model.