Characterization of fatigue performance of asphalt mixture using a new fatigue analysis approach

• The critical location of the specimen in the indirect tensile test is analyzed.
• The yield surfaces of specimen in three fatigue tests are determined by the unified model.
• The parameter RΔ is introduced as an indicator of the safety against failure.
• A new fatigue relation is found to reduce the influence of specimen size and geometry.

Laboratory fatigue testing is widely used to evaluate fatigue characteristics of asphalt mixtures in the pavement design. The fatigue results based on the classical fatigue analysis is influenced by the test types and specimen size. The goal of the research in this paper is to develop a new fatigue analysis method, which enables comparison of the fatigue relations obtained from different types of fatigue test and using different specimen sizes. The yield surface at the critical location of the specimen was determined in the I1 − √J2 space based on monotonic tension and compression test results. Then a new parameter RΔ was introduced as an indicator of the “safety against failure” at a certain stress state. A straight line was found by plotting RΔ at the critical location and the fatigue life on log–log scale. The results show that this new fatigue analysis method provides a possibility to compare the fatigue results obtained from different test types and specimen sizes.