Ultrasound pulse velocity to measure repair efficiency of concrete containing a self-healing vascular network

Self-healing of concrete is not science-fiction anymore. In recent years, research studies were focusing on concrete that includes encapsulated repair agent and has the ability to autonomously detect cracks and trigger the reparation processes. The design of self-healing concrete is today optimized and considers 1D or 2D tubular vascular networks that are embedded into concrete during casting. The tubes are empty and sound and the agent is stored and embedded in concrete reservoirs till the moment that cracking occurs. Due to internal stresses, the tubes break at the crack plane and the repair agent is released into the tubes reaching and filling the crack. The performance of self-healing concrete is previously assessed using several monitoring techniques (acoustic emission, ultrasound transmission, digital image correlation, etc.) but repair efficiency was not quantified. In this study, ultrasound pulse velocity measurements are performed on small-scale concrete beams and on real-size slabs in order to measure regain in mechanical properties after healing. Up to eight piezoelectric PZT transducers are attached on concrete and receive the transmitted acoustic signals providing an integrated monitoring system. Significant wave velocity recovery is measured and associated to stiffness and (partial) strength recovery after healing.

ISBN:9781138626331

Publication year:2018