A simple fracture model for hot mix asphalt based on fundamental fatigue parameters

Abstract

This work reports the development of a simple mechanistic fracture model based on a modified Paris’ law using the J-integral. An internal damage parameter, namely the fracture index (FIc), was calculated from this model and was used as an index for ranking the fracture performance of different hot mix asphalt materials tested in fatigue. The relaxation test coefficient (m) and the dissipated pseudo strain energy for the fine aggregates matrix (FAM) volume were used as fundamental parameters for deriving this model. The study revealed there is compatibility between the FIc and phenomenological approach using the number of load cycles at failure. In this work, limestone and granite aggregates were used with two binder grades: 40/60 and 160/220 to prepare four mixtures with two different gradations: gap-graded hot rolled asphalt and continuously graded dense bitumen macadam. The study showed that limestone mixes perform better in fracture than their granite counterparts.