Transport properties of concrete altered by crack-induced damage

This paper investigates the transport properties altered by crack-induced damage of two structural concretes [ordinary portland cement concrete (OPC) and high-volume fly ash concrete (HVFC)]. The crack-induced damage is represented by axial residual strain, ultrasonic speed, open porosity, and crack geometry of specimens, and the transport properties were measured for gas permeability and water sorptivity on dried specimens. The hydraulic diffusivity is derived from water sorptivity and used to characterize the altered transport properties. Geometrical analysis of crack network confirms that the crack pattern is determinant for the altered extent of transport properties. Very limited change was observed for hydraulic diffusivity for cracks with low connectivity. The hydraulic diffusivity shows a strong and linear correlation with sorptivity while its correlation with gas permeability is nonlinear with scatter. The scatter comes from the connectivity of cracks in the gas flow direction. Accordingly, correct representation of crack pattern is crucial to quantify the altered transport properties by crack-induced damage.