Influence of Temperature on the Mechanical Response of Asphalt Mixtures Using Microstructural Analysis and Finite-Element Simulations

Abstract

Asphalt pavements are commonly used for highways and airport runways. In pavement design and analysis, environmental factors such as temperature need to be taken into account to accurately predict the service life of asphalt pavements. The effect of temperature variations on the mechanical performance of asphalt mixtures was investigated at the microscale in this study. X-ray computed tomography (X-ray CT) scanning and digital image processing (DIP) techniques were applied to detect, analyze, and reconstruct the microstructure of asphalt specimens. Based on DIP, indicators related to air voids before and after fatigue testing were obtained and are discussed in this study. The results show that higher test temperatures resulted in larger air voids and promote crack initiation. Asphalt specimens measured at higher temperatures exhibited more prominent cracking characteristics because of decreased bonding capability between asphalt mastic and aggregates and because of decreased strength of the asphalt mastic. Finite-element simulations were conducted to simulate uniaxial compression tests. With increasing temperature, the proportion of larger compressive maximum principal stresses at the interface between the asphalt mortar and the aggregates decreased. Energy dissipation decreased with increasing temperature. The results reveal the significant influence of temperature on the fatigue damage and mechanical responses of asphalt; further investigations should be carried out to facilitate the improvement of the pavement design process.