The effect of nanoparticles on the self-healing capacity of high performance concrete

The development of self-healing high performance concretes (HPC) is mainly based on the necessity to guarantee durable concrete structures under extreme environmental and/or operating conditions. The implementation of self-healing HPC can be an efficient solution to these special situations avoiding or reducing future rehabilitations. These special concretes can significantly reduce the maintenance costs although the initial cost of the concrete infrastructure is expected to increase. Due to their special composition, HPC have certain self-healing capacity but it must be improved by using engineered additions in order to heal wider cracks or to have a faster response. However, although the use of nanoparticles is significantly increasing in the construction industry, only few works can be found in the literature focused on the exploitation of nanoparticles for improving the self-healing performance of HPC. In the present chapter, the main publications related to this issue are described, as well as the modifications that the inclusion of these self-healing systems based on nanoparticles causes in the microstructural, physico-mechanical, and durable performance of the corresponding HPC. Additionally, an overall idea concerning the modifications promoted in certain properties by self-healing systems not based on nanoparticles in HPC is also given.