Approach to Estimate Time to Friction Loss in Pavement Mechanistic-Empirical for the Florida Concrete Test Road

Abstract

Local calibration of the fatigue cracking model used in the AASHTO Pavement Mechanistic-Empirical (ME) software is critical to accurately prediction of the performance of jointed plain concrete pavement (JPCP). Although calibration involves optimizing coefficients used in the model, other design inputs such as time to friction loss can have a significant impact on pavement performance. The degradation of friction between the concrete and supporting layers is a critical input since it indicates deterioration of the JPCP system before fatigue cracking is observed on the surface. This paper proposes an approach for estimating the time to friction loss for JPCP based on the relationship between effective thickness and pavement age determined with falling weight deflectometer (FWD) data. This study shows that using the estimated time to full friction loss rather than the default time causes a significant impact on pavement performance compared with only optimizing calibration coefficients. Ten sections with a similar climatic zone and JPCP structures to Florida’s concrete test road were considered in the development of a relationship between the time to full friction loss and pavement structure thickness. The relationship was used to estimate the expected time to friction loss for the Florida concrete test road as approximately 55 months for sections with a concrete thickness of 7 in. and 164 months for concrete sections of 10 in.