Exploration of Temperature and Loading Rate Interdependency for Fracture Properties of Asphalt Mixtures

The importance of studying asphalt mixture and the effect of temperature on fracture properties to improve cracking performance, service life expectancy, and design effectiveness of roads is critical. The increased use of Reclaimed Asphalt Pavement and other additives in mix design requires greater understanding on the effects of loading rate and temperature on fracture behavior. The objective of this study was to assess interdependence of loading rate (time) and temperature on asphalt fracture properties and evaluate the adequacy of standard testing conditions. Evaluation consisted of 5 mixtures from two regional sources, Vermont and Virginia. Fracture tests were conducted through the Disk-shaped Compact Tension and the Semi-Circular Bending geometries using varying loading rates in an effort to study the applicability of the time-temperature superposition principle (TTSP). Comparisons were made between 4 combinations of temperatures and loading rates. The goal of this effort was to evaluate loading rate adjustments to compensate for changing test temperatures. Results indicated that linear viscoelastic TTSP is valid in the pre-peak region of asphalt fracture behavior. SCB test results at low temperature with an adjusted loading rate were able to match the pre-peak behavior