This paper describes development of a Portland Cement Concrete Pavement (PCCP) moisture model and associated program for enhancing the Federal Highway Administration (FHWA) HIPERPAV software predictions. This model predicts PCCP moisture transport and moisture loss to the environment due to drying and self-desiccation. The former part is simulated in terms of Fick's law, and the second part is based on Oh and Cha's model. The one-dimensional Crank-Nicolson finite difference method is used to build the mathematical algorithm for solution, and Fortran coding is developed to program this computational procedure and incorporate this moisture model into the HIPERPAV software. The moisture model has been partially validated with other researcher?s experimental data, and results have shown reasonable agreement between predictions and measurements. A sensitivity analysis shows that parameters such as the diffusivity coefficient, surface emissivity and curing method affect moisture variations especially at the positions close to the surface and bottom of the slab. Future research will focus on simulations of PCCP critical stresses and distresses with this enhanced moisture model.
Abstract