Crack Self-healing Behavior of Cementitious Composites Incorporating Various Mineral Admixtures

TLDR

The concept offers a maintenance‑free method that reduces both direct and indirect costs, a benefit widely welcomed by contractors. The study aims to develop and apply self‑healing concrete for crack control and enhanced service life, investigating autogenous healing using geo‑materials for practical industrial application. Self‑healing concrete was fabricated in a ready‑mixed factory and employed to construct artificial water‑retaining and tunnel structures. Cracks were largely self‑healed within 28 days of re‑curing, with a 0.15 mm crack fully healed after 3 days, a 0.22 mm crack reduced to 0.16 mm after 7 days, near‑complete healing at 33 days, driven mainly by swelling, expansion, and re‑crystallization, showing that geo‑material dosages hold high potential for repairing cracked concrete in underground infrastructure.

Abstract

This study aims to develop and apply self-healing concrete as a new method for crack control and enhanced service life in concrete structure. This concept is one of the maintenance-free methods which, apart from saving direct costs for maintenance and repair, reduces the indirect costs - a saving generally welcomed by contractors. In this research, the self-healing phenomenon of autogenous healing concrete using geo-materials for practical industrial application was investigated. Moreover, a self-healing concrete was fabricated by ready-mixed car in a ready-mixed concrete factory, then used for the construction of artificial water-retaining structures and actual tunnel structures. The results show that the crack of concrete was significantly self-healed up to 28 days re-curing. Crack-width of 0.15mm was self-healed after re-curing for 3 days and the crack width decreased from 0.22 mm to 0.16 mm after re-curing for 7 days. Furthermore, it was almost completely self-healed at 33 days. It was founded that this phenomenon occurred mainly due to the swelling effect, expansion effect and re-crystallization. From these results, it is considered that the utilization of appropriate dosages of geo-materials has a high potential for one of new repairing methods of cracked concrete under the water leakage of underground civil infrastructure such as tunnels.