Extent of Healing of Cracked Normal Strength Concrete

The goal of the research presented here is to investigate the extent of healing of cracked concrete. A feedback-controlled test was used to generate a crack with a controlled width in concrete specimens. Then, water permeability was evaluated by a low-pressure water permeability test (WPT). Elastic wave signal transmission measurements were performed immediately after cracking and repeated after 100 days of WPT. Immediately after cracking, water permeability increased and the signal transmission decreased with increasing initial crack width. The water permeability of cracked specimens decreased significantly, whereas the signal transmission increased with time. Both permeability and transmission measurements suggest autogenous healing of the cracks. However, the recovery in signal transmission with crack healing is not as spectacular as changes in permeability, inferring only partial mechanical healing of the cracks.