Non-destructive testing techniques to evaluate the healing efficiency of self-healing concrete at lab-scale

Abstract

Within the European FP7 project HEALCON, Non-Destructive Testing (NDT) and monitoring techniques are developed and combined to characterize the effects of self-healing mechanisms in small and full-size specimens. In the first stage, healing mechanisms were evaluated at lab-scale. Specimens containing encapsulated polymer precursors were cracked and reloaded after the healing period. During loading, healing and reloading, NDT techniques (acoustic emission analysis, vibration analysis and ultrasonic measurement) were applied to help understanding the cracking behavior, capsule breakage and healing efficiency. Moreover, the effect of the flexibility of the polymeric healing agent on the crack re-opening during reloading was investigated on cracked and healed mortar specimens, using acoustic emission and digital image correlation techniques. The results show the applicability of NDT methods to evaluate the self-healing efficiency for small specimens. Comparing the NDT techniques, some of them (e.g. ultrasound) seem to be good candidates for in situ monitoring of the healing efficiency.