Self-Healing Capacity of Cementitious Composites: Experiments and Modeling

Abstract

This paper aims at a thorough characterization of the self-healing capacity of cementitious composites, i.e. their capacity to completely or partially re-seal cracks and, in case, also exhibit recovery of mechanical properties. This problem will be investigated through both experiments and modeling with reference of a normal strength concrete under different types of exposure: i.e., air exposure and water immersion. The effects of the self-healing phenomena on the recovery of stiffness and loadbearing capacity have been evaluated by means of 3-point bending tests performed up to controlled crack opening and up to failure, respectively before and after conditioning. With reference to the modeling issue, an interface fracture based model, formulated and calibrated by the second and fourth author for the description of fracture processes in concrete, has been herein extended to include the effects of crack healing, through suitably defined functions which affect the time evolution of mechanical properties of concrete. Sensitivity to the effects of different parameters, e.g. tensile strength, fracture energy etc. will also be discussed. The obtained promising results stand as the first step for the development of a comprehensive “durability based” framework through which the effects of crack healing in cementitious composites could be consistently included into predictive modeling and design of concrete structures.
Both the experimental analysis and the theoretical formulation proposed in this work stem out from the European Project “EnCoRe” (FP7-PEOPLE-2011-IRSES n. 295283; www.encore-fp7.unisa.it) funded by the European Union as part of the Seventh Framework Programme.