Abstract:
The goal of the research presented here was to study the relationship between cracking and water permeability. A feedback-controlled test was used to generate width-controlled cracks. Water permeability was evaluated by a low-pressure water permeability test. The factors chosen for the experimental design were material type (paste, mortar, normal and high strength concrete), thickness of the sample and average width of the induced cracks (ranging from 50 to 350 microns). The water permeability test results indicated that the relationships between permeability and material type differ for uncracked and cracked material, and that there was little thickness effect. Permeability of uncracked material decreased from paste, mortar, normal strength concrete (NSC) to high strength concrete (RSC). Water permeability of cracked material significantly increased with increasing crack width. For cracks above 100 microns, NSC showed the highest permeability coefficient, where as mortar showed the lowest one. The permeability of cracked specimens decreased significantly with time. One-sided attenuation measurement indicated the possibility of autogenous healing of cracks.
Keywords:
attenuation of the signal, autogenous healing, crack width, crack opening displacement (COD), cumulative flow, damage, feedback-controlled test, flow rate, microcracks, nondestructive evaluation, permeability coefficient, permeation curve, recovery, selfsealing, splitting tensile test, water permeability.
tr76.pdf