Mechanistic-empirical study of effects of truck tire pressure on asphalt pavement performance

Truck tire inflation pressures have steadily increased in the recent decades. A most apparent effect of the increased tire pressure would be reduction in the tire-pavement contact area, which may in turn result in an increase in the tire-pavement contact stress and then more damaging effects to the pavement. This dissertation uses a Monte Carlo simulation based mechanistic-empirical method to identify and quantify the tire pressure effects on flexible pavement performance. In this study, measured non-uniform tire-pavement contact stress data for different tire load and inflation pressure conditions and for three popular tire/axle configurations were input to the finite element program ANSYS to compute immediate pavement responses for various asphalt pavement structures. Typical computation results from the finite element program were compared with the results of the linear elastic multilayer program CIRCLY using the traditional tire model in which tire-pavement contact stress is assumed uniformly distributed over a circular contact area and equal to tire inflation pressure. The effects of tire inflation pressure on pavement performance were initially analyzed by inputting the typical computation results into pavement distress transfer functions and variability in loading, pavement or environment conditions was not considered. Critical pavement responses responsible for pavement distresses in bottom-up cracking and rutting were determined. A quick solution method for the prediction of critical pavement responses was developed using regression models that relate critical pavement responses with tire loading and pavement structural conditions. And finally a Monte Carlo simulation based C++ program was developed to predict the effects of increased truck tire pressure on selected pavement structures with variability in loading, pavement, and environment conditions included. The dissertation study found the traditional tire model and the associated linear elastic multi-layer program tended to overestimate horizontal tensile strains at the bottom of the asphalt concrete layer and underestimate vertical compressive strains at the top of the subgrade layer. The quick solution models developed in this study could predict pavement responses in a good accuracy and be used to replace the time-consuming finite element models. The Monte Carlo simulation program found increased pavement fatigue cracking and rutting would be expected when average tire pressure was increased.Civil, Architectural, and Environmental Engineerin