Verification of Time–Temperature Superposition Principle for Shear Bond Failure of Interlayers in Asphalt Pavements

Abstract

Asphalt pavement structures are composed of different asphalt concrete layers with surface layers that are bonded together with a tack coat. Thus, interlayer bonding between pavement layers is a key factor that affects the performance of any pavement structure. However, relatively little attention has been given to the characterization and modeling of interlayer bonding or to associated test methods that can be used in the laboratory to evaluate the bond strength between asphalt concrete layers. This paper presents a test method for evaluating interface bonding between asphalt concrete layers in shear mode. Moreover, the time–temperature superposition (t-TS) principle with growing damage in shear failure mode is examined to characterize the shear bond strength of asphalt concrete pavements for a wide range of temperatures. The subsequent validation of the t-TS principle allows the shear bond strength between asphalt layers at various temperatures and loading rates to be determined with only three or four shear tests. Comparison of the shear stress values calculated from a mechanistic pavement analysis program for a critical condition with the shear strength values at the condition determined from the prediction model developed in this study can provide the foundation for a mechanistic design to prevent shear bond failure between asphalt layers.