Modelling the performance of jointed plain concrete pavements to dynamic vehicle loads

A whole life pavement performance model (WLPPM) is being developed for jointed plain concrete pavements (JPCPs). The aim is to predict long-term degradation of JPCPs, including cracking, faulting, pumping and surface roughness, due to applied traffic and environmental loads. A case study of part of the model is presented in which fatigue cracking along the wheel path of a JPCP due to repeated vehicle loading is investigated using linear elastic fracture mechanics (LEFM). A finite element model of several jointed slabs was developed to obtain the stress responses of concrete pavements under the combination of vehicle loads and temperature variations. A temperature field was applied to obtain the deflection and flexural stress due to curling. A quarter vehicle model was used to calculate the dynamic tyre force variation in response to the resulting periodic surface profile. Pavement response influence functions were then used to combine the 'static' response of concrete slab with the dynamic tyre forces, to determine the dynamic variation of surface stress and fatigue damage predictions at various positions along the road. The study showed that dynamic tyre forces have a significant effect on the location and magnitude of fatigue cracking in jointed concrete slabs. Cracking rate and the location of the peaks are influenced by the combination of temperature gradient, vehicle characteristics and speed and slab properties.