Abstract:This study investigates the dependence of overlay field cracking performance on overlay thickness and fracture energy of asphalt mixture. A total of 15 pavement sections in Minnesota for which Disk-shape Compact Tension (DCT) testing was performed on field cores from overlays were used for the study. Due to the difference in the overlay lives, different cracking performance measures such as average transverse cracking rate (ATCR), maximum transverse cracking rate (MTCR) and transverse cracking performance index (TCTotal) were calculated. These cracking performance measures were compared with asphalt overlay thicknesses and DCT fracture energies. The analysis indicated the dependence of TCTotal on both overlay thickness and fracture energy. The observed relationship was assessed for reliability using a statistical analysis and a new performance parameter that combines overlay thickness with fracture energy is proposed to provide measure of total fracture resistance of the overlay. Preliminary thresholds are also proposed for selection of overlay thicknesses and material types in new overlays.
© 2019 Elsevier Ltd