NUMERICAL MODELING OF CEMENT CONCRETE PAVEMENTS’ INTERNAL MOISTURE FIELDS AT EARLY AGES

Relevant numerical simulation and characteristic analysis were conducted based on Fick’s second law of moisture transport, using the finite difference method, and considering the effects of slab temperature, water absorption base capacity and supply, and concrete self-desiccation on slab moisture. Then the numerical simulation program was verified by comparison with laboratory tests and field tests in different seasons and with similar foreign research. The research shows that the models and parameters in the paper can accurately simulate moisture pavement moisture characteristics. However, the coupled effect of concrete temperature and moisture and the moisture convection boundary conditions at the base should been considered in numerical simulation. Using a Neumann boundary with null moisture flux at the bottom of the slab can cause predicted values to be higher than actual values. Environmental parameters, paving time, and curing methods greatly affect early-age moisture of pavements. By contrast, the effect of material parameters is not obvious. It is recommended to study the top and bottom boundary conditions and parameters of the program in more detail, and pavement construction under hot seasons, high temperatures, or on an overly wet base should be avoided as possible.