Keywords: asphalt, Superpave, Indirect Tensile Test, antistripping, stripping, fatigue life, rutting, fatigue.

Keywords: Rutting, Tensile Strength, Superpave, Fatigue.

Many factors contribute to the degradation of asphalt pavements. When high quality materials are used, distresses are typically due to traffic loading, resulting in rutting or fatigue cracking. The presence of water (or moisture) often results in premature failure of asphalt pavements in the form of isolated distress caused by debonding of the asphalt film from the aggregate surface or early rutting/fatigue cracking due to reduced mix strength. Moisture sensitivity has long been recognized as an important mix design consideration. The tensile strength is primarily a function of the binder properties. The amount of asphalt binder in a mixture and its stiffness influence the tensile strength. Tensile strength also depends on the absorption capacity of the aggregates used. At given asphalt content, the film thickness of asphalt on the surface of aggregates and particle-to-particle contact influences the adhesion or tensile strength of a mixture. Various studies have repeatedly proved that the tensile strength increases with decreasing air voids. The tensile strength of a mixture is also strongly influenced by the consistency of the asphalt cement, which can influence rutting. Thus, tensile strength plays an important role as a design and evaluation tool for Superpave mixtures Moisture damage of asphalt pavements is a serious problem. The presence of moisture tends to reduce the stiffness of the asphalt mix as well as create the opportunity for stripping of the asphalt from the aggregate. This, in combination with repeated wheel loadings, can accelerate pavement deterioration. Strength loss is now evaluated by comparing indirect tensile strengths of an unconditioned control group to those of the conditioned samples. If the average retained strength of the conditioned group is less than eighty-five percent of the control group strength, the mix is determined to be moisture susceptible. This research study shows that reliance on the Tensile Strength Ratio (TSR) values onl.

Introduction and Research Approach -- Findings -- Interpretation, Appraisal, and Applications -- Conclusions and Recommendations -- References -- Appendixes.

This laboratory manual presents Superpave mix design system in a complete, step-by-step format. It is intended for engineers and technicians in public and private organizations to use when designing paving mixes for all classes of highways, from farm-to-market roads to urban freeways. An essential companion to this manual is "The Superpave Mix Design System Manual of Specifications, Test Methods and Practices." The Superpave software program--"The Superpave Specification, Mix Design and Support Program"--And its users manual are also necessary to take full advantage of the mix design system.