Master curve of dynamic modulus for modified asphalt mixtures

The master curve of hot mix asphalt is one of the widely used models to describe the variation of dynamic modulus of asphalt mixtures with different temperatures and loading frequencies. The main objective of this paper is to evaluate the effect of modifier types on the dynamic modulus performance for different asphalt mixtures. Six types of binder modifiers that are widely used in Riyadh city were investigated using Asphalt Mixture Performance Tester (AMPT). The modifiers were five types of polymers, namely, Lucolast7010, Anglomak 2144, Pavflex140, SBS KTR 401 and EE-2, and Crumb Rubber. The unconfined asphalt mix samples were tested at four temperatures; 14°F (-10 °C), 40°F (4.4 °C), 70°F (21.1 °C) and 130°F (54.4°C) and six loading frequencies; 25, 10, 5, 1, 0.5 and 0.1Hz. The modulus values at these temperatures and frequencies are used to construct the master curves. Results showed that all the modified asphalt mixtures showed higher mixture stiffness as compared to the unmodified mixture. The influences of mix temperatures and loading frequencies on the dynamic modulus of the mixtures depend on the type of modifier used to upgrade the asphalt binder. A master curve model with excellent goodness-of-fit was obtained which can be utilized to predict the dynamic modulus of the modified asphalt mixtures at any temperatures and loading frequencies.