Evaluation of the Low Temperature Properties of Asphalt Mixtures Using a Digital Image Correlation Approach

Asphalt concrete performance hinges on its cracking resistance. Numerous test methods have been used to consider fracture of asphalt concrete at intermediate and low temperatures. All focus on global mixture measurements of load and displacement at a discrete location on the test specimen. Digital image correlation (DIC) measurements provide a means to evaluate the full-field response of asphalt concrete undergoing fracture. In particular, several studies have employed DIC to quantify the size of strain localization as a potential definition of the fracture process zone (FPZ). The current study evaluated the low temperature fracture properties of asphalt concrete using the disk-shaped compact tension (DC(T)) test (ASTM D7313-13) and in-plane DIC-measured FPZ size. Tests were completed to compare the sizes of the FPZ with respect to the test specimen thickness, aging of neat and polymer-modified asphalt mixtures, maximum aggregate size, and reclaimed asphalt pavement (RAP) content. Results in the current study found that DIC measurements differentiated the size of the FPZ in terms of polymer modification, aging, and RAP content.