Resilient response characterisation of hot-mix asphalt mixes for a new South African pavement design method

Abstract

The South Africa National Road Agency Ltd (SANRAL) is in the process of revising the South African Pavement Design Method (SAPDM). A necessary part of this programme is to develop resilient response models. Dynamic (complex) modulus has been used as the resilient response property to characterise five selected South African hot-mix asphalt (HMA) mixes. The objective of this paper is to present dynamic modulus models which were investigated for implementation in the SAPDM. These models include sigmoidal master curves developed for the five mixes based on dynamic modulus laboratory data and two dynamic modulus predictive equations, namely Witczak and Hirsch models. The two predictive equations were evaluated against the dynamic modulus values obtained from the laboratory testing. Based on the results obtained from this study, the Hirsch predictive model was found to be more promising in terms of predictive performance than the Witczak model.