An advanced low temperature rheological and fracture test method for bitumen purchase specifications and pavement performance prediction: 4-mm DSR/ABCD

Abstract

This paper proposes an advanced low temperature rheological test method which could be used to supplement and improve current purchase specifications for grading bitumens, and at the same time provide pavement low temperature thermal crack prediction for the Mechanistic Empirical Pavement Design Guide (MEPDG). The method is referred to as 4-mm DSR/ABCD i.e. 4-mm diameter parallel plate dynamic shear rheometry combined with the Asphalt Binder Cracking Device (ABCD) test. In addition to traditional low temperature binder purchase specifications such as m-value, creep stiffness and binder cracking temperature, the 4-mm DSR/ABCD method allows calculation of the thermal cracking temperature in the asphalt mix from a cooling event. The application of 4-mm DSR is an alternative to the mix indirect tensile (IDT) creep test. The fracture stress of the binder from the ABCD is an alternative to the mix IDT strength test. Mix IDT creep compliance and strength are the two primary inputs to the low-temperature, thermal cracking module in the MEPDG.