Real-time water permeability evolution of a localized crack in concrete under loading

This paper presents a real-time relation between the evolution of fluid permeability and the crack width opening in a saturated concrete sample. The standard Brazilian test has been enhanced so that one single controlled crack (up to 300 μm) is generated in the specimen. The procedure has been then adapted so that the simultaneous monitoring of the cracking process and the evolution of a fluid flow through the specimen are possible. Poiseulle's cubic law is commonly used in numerical analyses for describing the percolation of a fluid in a crack: this law is then corrected accordingly to our experimental observations thus taking into account the actual morphology of the opening crack. The effect of the size of the specimen (diameter and thickness) on the percolation process as well as threshold effect are also investigated and discussed.