Impact of Moisture Damage on Rutting Resistance, Shear and Tensile Properties of Asphalt Pavement

In Iraq, under the effect of heavy traffic loading, high temperature and water damages, specific requirements are needed to control the quality of highway pavement materials in order to increase durability. The primary objectives of this study are evaluating the durability of superpave asphalt concrete mixtures which has been assessed through moisture damage resistance. The properties of superpave mix have been verified using indirect tensile strength test, double punch shear strength, compressive strength test, and rutting resistance under repeated loading. The impacts of moisture damage on such superpave asphalt concrete properties were evaluated. To meet the objective of this research, available local materials were used including asphalt cement (40-50), aggregate with nominal maximum size of 12.5 mm, and mineral filler. Three asphalt percentages were implemented, optimum asphalt content and an asphalt content of 0.5 percent above and 0.5 percent below optimum as per superpave procedure. The Superpave Gyratory Compaction was used to prepare the asphalt concrete specimens. The moisture damage impacts on conditioned specimens exhibits low resistance to indirect tensile strength, punching shear, and compressive strength by (-19%, -33%, -6%) at optimum asphalt content as compared with un-condition mix. The moisture-conditioned mix has lower resistance to permanent deformation (at 1000 cycles) by 93% as compared with the unconditioned mixture. Superpave asphalt concrete was shown to be durable against moisture damage by 81% at optimum asphalt content when compared to the requirement of (SCRB, 2007).