Correlating the Dynamic Modulus and the Indirect Tensile Strength of Asphalt Concrete

Abstract

This study has developed a relationship between the Dynamic Modulus (E*) and the Indirect Tensile Strength (ITS) of Hot-Mix Asphalt (HMA) using standard laboratory tests programs. Two types of SuperPave (SP) mixtures were considered namely, SP-III with 15% Reclaimed Asphalt Pavement (RAP) materials and SP-III with 35% RAP materials. Cylindrical samples of 100 mm diameter and 150 mm height were prepared. The samples were then tested for |E*| value at 210C at several loading frequencies following the AASHTO TP 62-07 test protocol. Next, the samples were cut into circular pieces of 38 to 50 mm thickness using laboratory saw. The samples are then tested for ITS value by applying a deformation rate of 50 mm per minute (AASHTO T 283 protocol). The ITS was calculated following the AASHTO T 283-07 test standard. The |E*| values (MPa) of SP-III with 15% RAP at 25, 10, 5.0, 1.0, 0.5, 0.1 Hz are measured to be 65, 59, 52, 34, 31, and 18 times of ITS (psi) respectively. The |E*| values (MPa) of SP-III with 35% RAP at 25, 10, 5.0, 1.0, 0.5, 0.1 Hz are measured to be 41, 38, 33, 24, 20, and 14 times of the ITS (psi) respectively. This study also draws a conclusion that increase in RAP has resulted in increased stiffness and strength.