Integrative modeling on self-desiccation and moisture diffusion in concrete based on variation of water content

In the present paper, an integrative moisture distribution model that can catch both self-desiccation and moisture diffusion in concrete simultaneously is developed. In the modeling, self-desiccation due to cement hydration and moisture diffusion are simulated with the same relation of water content in cement paste and internal relative humidity of concrete. The above relationship of water content and internal relative humidity of concrete is developed based on Kelvin's law and capillary pore distribution in the cement paste that can be determined by test. The water content in cement paste is used as the critical parameter to predict the reduction of internal relative humidity in concrete, which may be resulted either by cement hydration or by environmental dying. Using the model, the moisture distribution of three concrete, C30, C50 and C80 that represent low, middle and high strength concrete in practice, is simulated respectively. The effect of curing condition on the development of internal relative humidity inside of concrete is analyzed. The model can be used for moisture field calculation of concrete elements under any given curing strategy, such as sealing and drying strategy, as well as drying conditions.