Estimation of water flow through cracked concrete under load

The goal of this research is to study the relationship between cracking and water permeability of normal-strength concrete under load and to compare the experimental results with theoretical models. A feedback-controlled wedge splitting test was used to generate width-controlled cracks. Speckle interferometry was used to record the cracking history. Water permeability of the loaded specimens was evaluated by a low-pressure water permeability test at the designed crack mouth opening displacements (CMODs). Water permeability results are compared with those previously obtained for unloaded specimens for which cracks were induced by a feedback-controlled splitting tension test. The experimental results indicate tliat water permeability of cracked material significantly increases with increasing crack width. The flow for the same cracking level is repeatable regardless of the procedure used for inducing the cracks. No direct relationship between water flow and crack length was observed, whereas clear relationships exist bet\veen CMOD or crack area and flow characteristics. Experimentally measured flow is compared to theoretical models of flow through cracked rocks with parallel walls and a correction factor accounting for the tortuosity of the crack is determined. Calculated flow through cracks induced by wedge-splitting test provides an acceptable approximation of the measured flow.