Development of quality control test procedure for characterizing fracture properties of asphalt mixtures

Abstract

The main objective of this study is to investigate the use of the semi-circular bend (SCB) test as a quality assurance/quality control (QA/QC) measure for field construction. In particular, the objectives include the following: (1) compare the fracture properties of asphalt concrete (AC) mixtures using the SCB test to those of the fatigue beam test (FBT); and (2) evaluate the impact of moisture damage on the fracture and fatigue properties as determined by SCB and FBT. Two binder types, PG64-10 and PG58-22, were used in this study. The job mix formulas for each mix type considered were identical except for the binder type. The asphalt binder met California specifications. Granite was the predominate aggregate used in the AC mixture types considered. There was one day of production for the SCB and FBT mixtures. Viscosity and dynamic shear rheometer, aging, and bending beam rheometer measurements were used to determine the rheological properties of both binder types. The AC mixture fracture properties were determined using the SCB and FBT tests. Both mixtures were compacted to a target air void of (5 ± 1%) in beams and core specimens. Cores for SCB testing and beams for FBT were sawed from the same slab that was fabricated to ensure consistency among specimens. This will reduce the variability of the results due to changes in the specimens. The specimens were tested in both dry and wet conditions to evaluate the impact of moisture-induced damage on the measured properties.