Characterisation of concrete and mortar cracking by digital image correlation and acoustic emission

Cracks and defects in construction materials can cause an increase in their moisture permeability, and accentuate their degradation. In order to accurately assess the durability and the overall performance of building facades, one must dispose of a reliable method for the identification of the damage state of such materials. The present work aims at developing a methodology for the detection and monitoring of damage and fractures in building materials. Digital image correlation and acoustic emission monitoring were simultaneously performed during tensile loading tests of fibre-reinforced mortar samples. The optical technique was found able to reveal all ranges of cracks, from microscopic to macroscopic, and an image-processing procedure was conducted as to quantify their evolution in the course of the degradation of the samples. It was also found that the acoustic activity could be related to the optical measurements in terms of damage quantification and localisation.