Development of the indirect ring tension fracture test for hot-mix asphalt

Abstract

Almost all of the current hot-mix asphalt (HMA) fracture tests are considered to be research tools. This paper describes the development of the indirect ring tension (IRT) fracture test for HMA, which was designed to be an effective and user-friendly test that could be used at the Department of Transportation level. Numerical modelling was utilised to calibrate the stress intensity factor formula of the IRT fracture test for various specimen dimensions. The results of this extensive analysis were encapsulated in a single equation. An experimental plan was developed to optimise the test parameters for HMA specimens. The experiment results revealed that the test is highly repeatable, and capable of capturing the variations in the fracture properties of HMA. Moreover, the data from laboratory tests were utilised to estimate the maximum allowable crack lengths for the pavements based on a viscoelastic model.

Keywords:

• indirect ring tension
• fracture test
• performance test
• hot-mix asphalt

Acknowledgements

The authors wish to thank Asphalt Institute for providing all the equipment and materials used in this research. The authors also like to thank Mr R. Michael Anderson, the director of research and laboratory services at Asphalt Institute, for his interest in and support of the testing programme. Additionally, the authors wish to thank the University of Kentucky for its support of this work.