Modeling Damage to Rigid Pavements Caused by Subgrade Pumping

The efficient utilization of construction and maintenance resources requires the ability to effectively predict and model subgrade pumping in rigid concrete pavements. A review of the evolution of a rigid pavement pumping model is presented in this paper. Extensions were made to an existing model to consider the effects of climate and drainage conditions, as well as soil composition on pumping magnitudes. Additional modifications permit the effect of nonconventional vehicle configurations to be considered in the calculation of pumping values. Finally, the process of calculating pumping volumes and distributing void areas was altered to provide a more realistic effect. This improved model allows proposed designs to be analyzed to determine optimum pavement characteristics. The model is implemented in a finite-element–based method for analysis of pavements that also includes the effects of concrete cracking and fatigue. Urgent need for experimental data on the size and growth of voids beneath a pavement slab is pointed out.