Investigating the Tensile Strength and Permanent Deformation of Asphalt Concrete using Different Gradation Methods

Abstract

The current study emphasizes on the evaluation of the effect of aggregate skeleton and temperature variation on the tensile strength and permanent deformation of asphalt concrete. The aggregate skeleton was designed within the Pakistan's National Highway Authority Class-B (NHA-B) gradation limits by utilizing the gradation concepts of Conventional method and Bailey method. Modified Marshall method was practiced for determining Optimum Binder Content (OBC). Superpave Gyratory Compactor was utilized for preparation of specimens for performance testing. Indirect Tensile Strength (ITS) test and Hamburg Wheel Tracker (HWT) test were conducted on both types of asphalt mixtures at 25°C and 40 °C. Results declared that both aggregate skeleton and temperature affect the tensile strength and permanent deformation of asphalt concrete. Bailey gradation bituminous mixtures disclosed more defiant behavior to tensile and permanent deformation compared to Conventional gradation bituminous mixtures. Moreover, for both gradation bituminous mixtures, better performance of asphalt concrete in terms of tensile strength and permanent deformation was observed at low temperature compared to high temperature.