Synopsis:
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 and then water permeability was evaluated by a low-pressure water permeability test. The factors chosen for the experimental design were: material type, thickness of the sample and average width of the induced cracks. The water permeability test results indicated that the relationships between permeability and material type differ for uncracked and cracked material. Permeability of uncracked material decreased from paste, mortar, normal strength concrete (NSC) to high strength concrete (HSC), as expected. However, for cracks above 100 microns, NSC showed the highest permeability coefficient. Water permeability of cracked material increased with increasing crack width, material type had effect on permeability and there was little thickness effect. HSC behavior in terms of crack recovery and permeability for cracks above 100 microns ranged between mortar and normal strength concrete.
Keywords:
cracks, crack width', crack opening displacement (COD), cumulative flow, damage, feedback-controlled test, permeability coefficient, recovery, splitting tensile test, water permeability.
tr77.pdf