Comparison of Fracture Properties of Asphalt Concrete in Semicircular Bend Test Using Noncontact Camera and Crosshead Movement

Abstract

The semicircular bend (SCB) test has received much attention in recent years. The test is quick, indicative, and has reasonable variability compared with other fracture property tests for asphalt concrete (AC) mixtures. The crack propagation in the test is calculated indirectly using the crosshead movement (CHM) or crack mouth opening (CMO). Although these methods might correlate well to the crack propagation, little research has been done to ascertain this relationship. The main objective of this study is to compare the SCB test using a noncontact camera (NCC) and CHM. A comprehensive comparison of fracture properties of six AC mixtures captured by these two methods is conducted. The critical strain energy (Jc) and (K1c) values for AC mixtures are determined. There is a strong correlation between Jc from SCB NCC and Jc from SCB CHM, and between K1c from SCB NCC and K1c from SCB CHM. The results of this study indicate that the SCB CHM test has great potential as a quality assurance/quality control (QA/QC) test of fracture properties of asphalt mixtures.