Simulation of long-term water transport in cement paste considering the hydration process

The influence of hydration on water transport within cement paste is usually neglected, especially for the simulation. However, in low water-to-cement ratio cement paste cured underwater, hydration with the affected microstructure occurs along with the water transport and should be taken into account. In this study, the water absorption and hydration degree were monitored in cement pastes with ultra-low w/c cured under water for 360 days. The modified Krstulovic-Dabic model was established to simulate the hydration process of cement paste having low w/c cured in lime-saturated water considering the effect of water absorption and incomplete cement hydration. By calculating the saturation degree, porosity, and diffusion coefficient, the water transport process considering hydration was simulated. The simulation results were verified by the average saturation degree and 1H nuclear magnetic resonance relaxometry with water gradient quantification. The results show that the water content discrepancy between the surface and center of the specimen increased with decreasing w/c. Reasonable agreements between the experimental results and the simulated results can be observed in cement pastes having different w/c.