Deformation Mechanism in Asphaltic Concrete

Abstract

A theoretical approach is presented to describe the permanent deformation mechanism in asphaltic concrete subjected to traffic simulated dynamic loading. The approach is based on mechanical energy concepts and leads to a better realization of the rutting mechanism in flexible highway pavements. A power relationship between the rate of permanent strain accumulation and the number of dynamic load repetitions was derived. Two parameters were introduced in this relationship: exponential parameter “m” and intersection parameter “A.” The first parameter, m, is dependent on the material type. Parameter A is a function of stress‐strain pattern and intensity, stress level, and dissipated plastic strain energy during the dynamic loading. The derived relationship was experimentally verified with excellent correlation. Parameter m was showed to be constant for all samples of the same material tested under various conditions. Regression analyses showed that “A” was a function of the applied deviator stress and the resilient modulus. An adjusted parameter $“m_a”$ was introduced to replace “A” and to account for minor variations in the values of parameter m. The developed correlation provides an improved and simple technique to predict permanent deformation history of asphaltic concrete in flexible pavement.