Practicality of Driven Parameters of Semicircular Bending Test at Intermediate Temperature

Abstract

The semicircular bending (SCB) test characterizes crack resistance by determining the fracture toughness of asphalt mixtures. This test has been favored by many researchers due to the easy sample preparation and the simplified analysis. This study investigates asphalt mixtures in Utah by evaluating repeatability and reproducibility of the SCB test. A multilaboratory study consisting of both laboratory and field samples was conducted. Based on statistical results from the laboratory study, around 20% difference is conservatively enough to consider the FI average of one material different from the FI average of another material. Based on the field study results obtained from actual field projects, the range of FI results has been evaluated by the impact of driven parameters. The SCB test is capable of distinguishing between different mixtures showing that a threshold FI value between 6 and 8 could discern improper mixtures due to low binder content or any other material design deficiency. This concept can also be implemented as a quality control tool to supervise contractors. All in all, the SCB test procedure appears to be a potential crack propagation assessment candidate for fatigue resistance index. Implementation of this test is a promising tool for agencies and departments of transportation as a performance base design criterion.