EFFECTIVENESS OF SELF-HEALING TECHNOLOGIES IN CEMENT BASED MATERIALS: CONCEPT FOR AN INTER-LABORATORY EXPERIMENTAL EVALUATION BY MULTIPLE TEST METHODS. A PROPOSAL BY COST ACTION CA 15202 SARCOS

The use of self-healing cement-based materials has been recognized as a viable pathway to enhance the durability of reinforced concrete structures and contribute to increase their service life. Research activities have provided enlightening contributions to understand the crack-healing mechanisms and have led to the blooming of stimulated and engineered self-healing technologies, whose effectiveness has been proven in the laboratory and, in a few cases, also scaled up to field applications, with ongoing performance monitoring. Nonetheless, the large variety of methodologies employed to assess the effectiveness of the developed self-healing technologies makes it necessary to provide a unified framework for their validation. This is also instrumental to pave the way towards a consistent incorporation of self-healing concepts into structural design and life-cycle analysis codified approaches and promote their diffusion into the construction market. COST Action CA15202 SARCOS (www.sarcos.eng.cam.ac.uk) has revealed that a reliable assessment of a healing technology has to rely upon multiple measurements, encompassing all the issues recalled above and establishing correlation between the measured crack closure and recovery of the engineering properties of interest. In this paper the concept for a multi-laboratory evaluation of self-healing technologies is presented.