Revised Faulting Model to Account for Dowel Looseness and Corrosion in Long-Life Pavements

The current AASHTOWare Pavement Mechanistic-Empirical Design faulting model framework has several limitations, which prohibit the consideration of alternative dowels commonly used in long-life pavements. Users cannot account for key design parameters, such as dowel stiffness, which is a critical need given the increased use of alternative dowel bars. Also, the effect of corrosion is not integrated into the model. Lastly, because of a lack of available faulting data from doweled pavements, the calibration alone is unable to account for the effect of loss of dowel performance resulting from corrosion. This study presents a revised faulting model framework which incorporates key design, loading, and environmental parameters. First, a comprehensive dowel damage model was developed based on an accelerated dowel loading test. The damage model incorporates critical parameters such as dowel stiffness which, before this work, could not be directly considered. Second, a novel corrosion model informed by a laboratory analysis is incorporated to account for the reduction of dowel diameter caused by corrosion. Lastly, the concept of “equivalent dowel diameter” was introduced into the faulting model. The faulting model was calibrated using faulting data from a national database of in-service pavements. A series of model adequacy checks was conducted to demonstrate that the model does not exhibit bias and to illustrate the effect of key parameters on predicted faulting. The improved faulting model framework is the first comprehensive model able to account for damage accumulation resulting from both vehicle loads and corrosion for the range of dowel bars currently on the market.