Asphalt concrete master curve using dynamic backcalculation

Abstract

ABSTRACT The dynamic backcalculation of pavement layer properties, and more specifically the ability to determine the asphalt concrete master curve, using Falling Weight Deflectometer (FWD) data has caught the attention of many researchers for years. The damaged or aged master curve of existing pavement structures allows the accurate prediction of the pavement structural capacity and remaining life – a goal that cannot be achieved through laboratory testing. To address this need, the authors developed a dynamic backcalculation application that employs the ABAQUS software for forward calculation using implicit dynamic analyses, and the Newton-Raphson’s root-solving algorithm for optimisation. The capabilities of the application were demonstrated for three simulated flexible pavement structures and two asphalt concrete mixes using 40 combinations. The asphalt concrete moduli at the FWD most dominant frequencies around 17 Hz, and the variables of unbound layers converged to the exact values in few iterations for all combinations. The master curves, and mainly the maximum moduli, were reliably determined to less than 1% and 4% error for about 60% and 85% of the combinations, respectively. The potential for determining the master curve and maximum modulus was shown to be dependent on the asphalt concrete mix, asphalt concrete temperature and pavement structure.