Methods to evaluate intermediate temperature properties of asphalt mixtures by the semi-circular bending (SCB) test

The fatigue fracture behaviour of hot asphalt mixtures (HMA) has been studied using a newly proposed semi-circular bending (SCB) test. Fracture properties of asphalt mixtures are currently being evaluated using the SCB test with the application of fracture mechanic concepts to characterise fatigue behaviour. This article reviews studies regarding the intermediate temperature fracture resistance of various asphalt mixtures to evaluate and correlate these fracture properties to cracking performance such as fundamental assessment of fracture through the SCB tests. Results of the experimental research work in Utah show that the expected variability of these tests exceeds the range of values observed. Therefore, the within-laboratories repeatability and reproducibility between different laboratories of the SCB tests in Utah were not desirable. Thresholds established for the slope of toughness (J(c)) and flexibility index value need modification to be applied as a tool to reject or accept the results for different asphalt mixtures.

Automated summary

This article reviews the fatigue fracture behaviour of hot asphalt mixtures using a semi-circular bending test, evaluating the fracture properties of different asphalt mixtures at intermediate temperatures. The study found that the variability in test results exceeded expectations, highlighting the need to modify thresholds for toughness slope (J(c)) and flexibility index values for different asphalt mixtures.