Prediction models for semi-circular-bend test parameters from binder’s LAS parameters and mixture volumetric properties

ABSTRACT

The current test methods for measuring the fatigue cracking resistance of asphalt mixtures involve many steps which are time-consuming and costly. On the other hand, asphalt binder testing is less time-consuming and more accessible than mixtures testing. Therefore, if the routinely measured properties of the asphalt binder and volumetric properties of the mixtures can be used to predict cracking resistance performance of mixtures, much effort to perform the mixtures testing of asphalt mixtures can be minimised. In this study, prediction models of mixture parameters calculated from the Semi-Circular Bending-Illinois Flexibility Index Test (SCB-IFIT) are developed using an experimental database including 42 mixtures that are short-term aged and 30 mixtures that are long-term aged mixtures. Based on the correlation results and the validation using a separate set of the mixture, the developed models of SCB parameters are found to provide reliable estimates of the flexibility index (FI), post-peak slope and fracture energy (G_f) of asphalt mixtures. The developed models are recommended for initial screening of mixture components (binder and mix variables) or estimating the cracking resistance of asphalt mixtures when testing is not feasible. They are not meant to totally replace the testing of the final selected mixtures.

KEYWORDS:

• SCB-IFIT
• linear amplitude sweep test (LAS)
• fatigue cracking
• flexibility index
• fracture energy
• slope

Disclosure statement

No potential conflict of interest was reported by the author(s).