Calculation of Internal Humidity Field of Concrete Based on ANSYS

In order to calculate the humidity field of concrete using the temperature field module in finite element program, a comparison between thermal field and humidity field was made of their differences in the differential equations, initial and boundary conditions, etc. Based on the temperature field module in ANSYS, a finite element method was proposed to calculate the humidity field in concrete. From the aspect of self-desiccation and desiccation, this method was verified against the existing test results of the relative humidity in concrete. The values of parameters for ANSYS analysis such as the coefficients of the internal moisture consumption function, moisture diffusion coefficients, and surface factors which affect the humidity field in concrete were analyzed. The results show that the relative humidity, diffusion coefficients, self-desiccation formula, and the coefficient of moisture transfer in surface used in the humidity field calculation can be replaced by the temperature, thermal diffusivity, adiabatic heating function, and the heat transfer coefficient used in the temperature field calculation. Using the temperature field module to analyze the humidity field in concrete, the maximum error between the calculated results and the existing test results is 7.3%, which meets the engineering requirements. The self-desiccation formula obtained from the experimental results can be applied to the moisture field calculation of the concrete with a water cement ratio ranging from 0.28 to 0.68.