Rational Determination of Pavement Layer Structural Coefficients

Seven flexible pavements ranging from interstate to state route are selected. Three different approaches are employed. The first two use the resilient modulus of the material to estimate its structural coefficient. In the first approach, cored specimens are obtained from each of the pavement sections and the resilient moduli of in-service 301 and 446/448 materials are determined in the laboratory. The second approach backcalculates layer elastic modulus from measured pavement deflection. The third approach determines the structural coefficient from the AASHTO flexible pavement performance equation based on traffic and serviceability history data.