Investigation of fracture properties of California asphalt mixtures using semicircular bending and beam fatigue tests

摘要

Fatigue cracking is a primary distress in asphalt concrete (AC) due to repetitive stresses and strains caused by both traffic loading and environmental factors. The fatigue resistance of AC is investigated by a number of fatigue tests. The main objective of this study is to investigate the use of the semi-circular bending (SCB) test as a quality assurance/quality control (QA/QC) measure for field construction. The comparison of fracture properties of seven AC mixtures from the SCB and beam fatigue test (BFT) is conducted. The J_c and K_(1c) values for the seven mixtures were determined. The BFT was performed on the same mixtures and the initial stiffness, Nf and plateau value (PV) were determined. The coefficient of variation (CV) ranged from 0% to 38% for J_c and from 0% to 35% for K_(1c). The CV ranged from 10% to 93% for the initial stiffness, 2% to 83% for Nf and 8% to 167% for PV. The SCB J_c and BFT N_f and PV indicated lower fracture properties for PG64-10RAP (LIME), AN-HMA and WMA-ADVERA mixtures than other mixtures. The BFT N_f and PV achieved similar ranking for all mixtures. There is good correlation between N_f and PV with J_c, and not a good correlation between the initial stiffness with J_c, N_f and PV. This has indicated that the initial stiffness is not a good representative for fracture properties of AC while J_c, N_f and PV are better indicators. The results of this study indicate that the SCB test has a great potential as a QA/QC test of fracture properties of asphalt mixtures.