Investigating the thermo-mechanical behaviour of cementitious materials using image processing techniques

Infrared thermography and Digital Image Correlation were used to analyse the mechanical behaviour of mortar, concrete, and high-performance concrete specimens under quasi-static loads. For specimens under compressive loads, Infrared thermography clearly showed the thermo-elastic coupling as well as thermal dissipations due to the microcracking state of freeze/thaw damaged concrete specimens. During an up to failure compressive test, localized thermal effects were observed at the macro-crack location before it appeared. Strain fields at the surface of steel-fibre high-performance concrete specimens under tensile and flexural loadings were determined using the Digital Image Correlation (DIC) technique. These experiments showed that the strain fields early became inhomogeneous. Strains concentrated in multiple localization zones which highlighted the role of the steel fibres in transmitting the internal forces.