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

Abstract

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, N f 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 N f 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.