Application of Energy-Based Crack Initiation Approach to Low-Temperature Damage and Recovery Based on Noncontact Resonance Testing

Abstract

Low temperature has a tendency to cause microdamage in asphalt concrete because of the relative thermal contraction of mastic and subsequent accumulation of thermal stresses. This paper presents the applicability of an energy-based micromechanical approach for assessing low-temperature damage and recovery in asphalt concrete based on a newly developed noncontact resonance testing. The principle of local energy balance and redistribution was applied to estimate average thermal microcrack length by considering local thermal strain energy release zones and surface energy of cracks initiated at preexisting air voids. A damage probing test was carried out by thermal loading and unloading of five different asphalt concrete specimens. The test was carried out by using a recently developed noncontact resonance method. The stiffness modulus was determined from the resonance test and utilized in the energy balance and redistribution formulation. Coefficients of thermal contraction of the specimens were also determined based on the noncontact resonance test and by applying the principle of the impact-echo method and calculating changes in thickness of the test specimens.