Crack Monitoring and Strain Measurement in Asphalt Mixture by Digital Image Correlation

A full field method for the description of in-plane strain fields is applied for improving Asphalt Mixture cracking behaviour insights. A Digital Image Correlation (DIC) system based on the Least Square Matching technique is used to compute strains and depict crack path in the process from microcrack initiation to failure. A Brazilian test was performed using hole-notched specimens. The test generates tensile stresses in a known and limited portion of the specimen simplifying test monitoring and image capture for subsequent application of the DIC system. The results show the capability of the DIC system to allow a dense description of the field all over the cracking process involving the peak and the post-peak softening slope. Compared to traditional strain devices, the system provides a wealth of information, as well as an easier and faster setting process.