Strain Response of Hot-Mix Asphalt Overlays for Bottom-Up Reflective Cracking

Abstract

Abstract This paper examines the cyclic strain response of typical hot-mix asphalt (HMA) overlays above jointed PCC slabs prone to bottom-up reflective cracking. The occurrence of reflective cracking under the combined effect of traffic and environmental loading significantly reduces the design life of the HMA overlays and can lead to its premature failure. In this context, viscoelastic material properties combined with cyclic vehicle loadings and seasonal pavement temperature distribution were implemented in a series of FE models in order to study the evolution of horizontal tensile and shear strains at the bottom of the HMA overlay. The effect of several design parameters, such as subbase and subgrade moduli, vehicle speed, overlay thickness, and temperature condition, on the horizontal and shear strain response was investigated. Results showed that the rate of horizontal strain accumulation and the rate of shear strain accumulation at the bottom of the HMA overlay drop with higher vehicle speed, higher subgrade modulus, and higher subbase modulus. Moreover, the rate of horizontal strain accumulation increases with higher overlay thickness. Although initial strain values were higher at positive pavement temperature distributions, the corresponding rates of strain accumulation were higher at negative pavement temperatures. Finally, an extrapolation of the strain history curve for various pavement design parameters was used to estimate the number of load repetition that can lead to bottom-up crack initiation.