Sensitivity Analysis of 2002 Design Guide Distress Prediction Models for Jointed Plain Concrete Pavement

Abstract

The AASHTO 2002 design guide was calibrated with Long-Term Pavement Performance sections scattered throughout the United States but with very few sections from the state of California. To understand the reasonableness of the model predictions for California conditions, a detailed sensitivity study was undertaken. The reasonableness of the model predictions was checked with a full factorial considering traffic volume, axle load distribution, climate zones, thickness, design features, portland cement concrete (PCC) strength, and unbound layers. Satellite sensitivity studies were performed to study the effects of surface absorptivity and coefficient of thermal expansion, which were not included in the primary sensitivity analysis. The findings are summarized from about 10,000 cases run with the software as part of this study. The cracking model was found to be sensitive to the coefficient of thermal expansion, surface absorptivity, joint spacing, shoulder type, PCC thickness, climate zone, and traffic volume. The faulting values are sensitive to dowels, shoulder type, climate zone, PCC thickness, and traffic volume. Although on average both the cracking and faulting models show trends that agree with prevailing knowledge in pavement engineering and California experience, in some cases results were counterintuitive. These cases include thinner sections performing better than thicker sections and asphalt shoulders performing better than tied and widened lanes. It was also found that the models fail to capture the effect of soil type and erodibility index and that the cracking model is sensitive to surface absorption.