Real-time evolution of water permeability in cracking concrete
Résumé
The aim of this paper is to present a study on the relationship between crack geometrical properties (width and area) and water permeability evolution in a cracking saturated concrete sample. The tensile splitting (Brazilian) test is enhanced and adapted so that the monitoring of a single crack opening of the specimen and the water-flux through the crack is possible. The complete description of the crack geometry is firstly obtained. The crack opening displacement (CODm) at mid-height of the sample is derived from LVDTs measurements while the crack path on the whole height is obtained by means of the digital imaging correlation (DIC) technique. For both sides of the sample the complete description of the displacement field is obtained. The COD all along the path of the crack is then computed and a statistical relationship between the computed mean crack area and measured CODm is developed. This relationship is used, during the second series of tests, to relate at each time step of the test the mass flux of water through the cracked samples (under loading) and the mean crack area through the measured CODm. Finally, some considerations about the feasibility of a test for the real-time monitoring of permeability in cracking concrete are presented.