Visualization and quantification of self-healing behaviors of microcracks in cement-based materials incorporating fluorescence-labeled self-healing microcapsules

Abstract

Fluorescence-labeled self-healing microcapsules demonstrate the excellent ability to heal microcracks, and can also visualize the healing process of microcracks. The healing process of internal and external microcracks was visualized and quantified with laser scanning confocal microscope (LSCM) and step profiler. When 3.0 wt% microcapsules were incorporated into cement-based materials, the strength recovery rate was the highest, reaching 35.8%, and the healing effect of external microcracks reached 19.2%. When microcracks appear inside the resin matrix, fluorescence-labeled self-healing microcapsules can not only detect the specific location of the microcracks but also repair them, and quantify the width of microcracks. The change in the pore structure of cement-based self-healing materials is mainly due to the release of core materials into the microcracks and pores, thereby achieving the healing effect. It provides a unique insight into the visualization and quantification of self-healing behaviors of microcracks.