Dynamic Modulus of Asphalt Concrete with a Hollow Cylinder Tensile Tester

Abstract

A hollow cylinder tensile tester (HCT) has recently been shown to be a suitable surrogate test device for the Superpave® indirect tension test. The feasibility of using the HCT to obtain the dynamic modulus of asphalt concrete was explored. Previous studies have shown the dynamic modulus of asphalt concrete in tension and compression to be similar at low temperatures and high loading frequencies and that minor differences can be expected at higher temperatures and lower loading frequencies. Here, the HCT device compared favorably with dynamic modulus measurements obtained with uniaxial compression testing apparatus at 0°C and 20°C. In addition, test results were found to be in reasonable agreement with the Witczak dynamic modulus predictive equation. The ability to simply and rapidly measure the creep compliance, tensile strength, and dynamic modulus of bituminous paving mixtures over a range of temperatures and loading conditions makes the HCT device a useful general-purpose mixture analysis tool. It appears that this portable device may serve as a practical method to satisfy testing requirements for high reliability (Level 1) pavement designs in the forthcoming AASHTO 2002 design guide being developed under NCHRP 1-37A for the mitigation of both fatigue cracking and thermal cracking. However, a broader experimental program, including tests at higher temperatures and a broader range of test frequencies, is needed to fully validate the compatibility of HCT measurements with NCHRP 1-37A models.