Experimental Investigation of Strength and Stiffness Characteristics of Hot Mix Asphalt (HMA)

Rutting is a common phenomenon on pavements in Pakistan. Resilient modulus is one the important properties used in the mechanistic analysis of pavement response under dynamic traffic loads as well as used to study the rutting behavior of pavement. This research study investigates the effect of specimen diameter, bitumen grade and compactive effort on the resilient modulus (stiffness) and Indirect tensile strength (Strength) of asphalt concrete. The analysis of experimental results revealed that both the strength and stiffness values for Polymer Modified Bitumen grade were greater than that of unmodified penetration grade bitumen. Similarly, the resilient modulus and indirect tensile strength values of specimens prepared with 100 mm diameter and compacted with Marshall Hammer were more than that of specimens prepared with 150 mm diameter and compacted with gyratory compactor. This research will help the highway agencies in modifying their design methods for asphalt concrete pavements.