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Description: TITLE: UTILIZING FAILURE ENVELOPE APPROACH TO CHARACTERIZE FATIGUE/FRACTURE RESISTANCE OF ASPHALT MIXTURES USING THE SEMI-CIRCULAR BENDING TEST
Abstract:Characterizing fatigue/fracture resistance of asphalt mixtures has been a big challenge for decades. Many laboratory tests were developed utilizing different theories to characterize fatigue/fracture performance of asphalt binder/mixtures. In many cases, the currently used laboratory tests do not provide universal agreement different tests will rank the fatigue/fracture characteristics of tested mixtures differently. Furthermore, the current test do not provide good correlation to field data.

The Semi-Circular Bending (SCB) test is currently one of the simple tests that can be used to characterize fatigue/fracture performance of asphalt mixtures. However, an empirical method is used to analyze the data obtained from this test. A proposed mathematical approach was used to analyze the data. The results from this approach were compared to the current empirical method. A wide range of asphalt mixtures was tested at different temperatures and failure envelopes were developed to better understand the fatigue/fracture behavior of asphalt mixtures. Results showed good correlation between the currently used and the new mathematical analyses. Recommendations were carried out for the current SCB testing protocol.

Proposed failure envelope approach was found to be sensitive to different factors affecting fatigue/fracture performance of asphalt mixtures. Further work is ongoing to generalize the proposed failure envelope so that it includes most of the parameters that affect fatigue/fracture performance of asphalt mixtures. Another major goal is to correlate the proposed failure envelope to the rheological parameters of asphalt binders.