Characterizing the effect of compressive damage on transport properties of cracked concretes

Abstract

This paper reports a comprehensive experimental investigation on the impact of mechanical cracking on transport-related properties of concrete, including air permeability, surface sorptivity and electrical resistance. Cylinder specimens of \(\phi150\,\hbox {mm}\times400\,\hbox{mm}\) are subject to cyclic axial compressive loading and different damage levels are generated by changing cyclic loading numbers under displacement control. The characterization parameters of cracking include scalar damage factor, residual strains and open porosity. Prior to and after loading, for each specimen, the ultrasonic pulse velocity is measured perpendicular to the loading direction and both residual axial and lateral strains are recorded by strain gauges. Two discs of 50 mm thick are cut out from the middle height of each unloaded concrete cylinder and dried to constant weight at 60°C. Thereafter, the discs are subject to gas permeability, water sorptivity, open porosity and electrical resistance tests. The correlations are discussed in depth for damage characterization indicators and damage-altered transport properties, in particular, the relation between altered gas permeability and ultrasonic damage is quantified. From the obtained data, it is found that ultrasonic damage factor is correlated strongly with altered gas permeability while open porosity is well correlated to altered sorptivity and electrical resistance.