Influence of Mechanically Induced Cracking on Chloride Ingress in Concrete

AbstractWhile significant research has been performed to assess the transport properties of concrete, a vast majority of previous research has focused on behavior in undamaged concrete. This paper describes an investigation to assess the influence of a mechanically induced crack on chloride ingress. Tapered cracks were generated in specimens using a wedge splitting test. The specimens were then used to assess: (1) the chloride ingress, and (2) the physical size of the crack using fluorescent epoxy impregnation. This paper describes the results of concretes that were made with three water-to-cement ratios (w/cs) (0.30, 0.42, and 0.50) and three different maximum aggregate sizes (4, 8, and 16 mm). The results indicate that chloride transport in relatively small cracks can be influenced by the mixture composition (w/c and aggregate size) because this influences the tortuosity of the crack. However, as the width of the crack increases the crack begins to behave as a free surface and the influence of w/c is much less important.