Correlation of Semi-circular Bending and Beam Fatigue Fracture Properties of Asphalt Concrete Using Non-Contact Camera and Crosshead Movement

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 compare the fracture properties of AC under Beam Fatigue Test (BFT) and the Semi-circular Bending (SCB) test using non-contact camera and crosshead movement. A comprehensive comparison of fracture properties of six AC mixtures from the SCB non-contact camera method, SCB Cross Head Movement (CHM) method and Beam Fatigue test (BFT) was conducted. The critical strain energy (Jc) and K1c values for AC mixtures are determined. BFT was performed on the same mixtures and initial stiffness, Nf and PV are determined. Comparison between the tests parameters was performed, and the Jc and K1c of SCB non-contact camera and CHM methods indicated lower fracture properties for PG64-10RAP (LIME), AN-HMA and WMA-ADVERA and higher fracture properties for 710P4-AR, AN-WMA and PG64-28PM mixtures. Similar results were achieved by BFT Nf and PV parameters. Data analysis showed that there is a linear correlation between Jc and K1c from the both SCB test methods, a good correlation between Nf and PV with Jc, and poor correlation between initial stiffness with Jc, Nf and PV. This has indicated that the initial stiffness is not a good representative for fracture properties of AC while Jc, Nf 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.