Self-healing properties and improvement methods of mortar cracks in marine corrosive environments

The crack healing of marine concrete is of great significance to ensure its durability. The crack self-healing performances of ordinary concrete and self-healing concrete under the curing of tap water or seawater has been tested. The results show that seawater has a certain promoting effect on the self-healing of cracks, especially on the surface healing effect. The healing products under the autogenous healing or seawater curing are mainly hydrated products and their carbonized products, and the quantity is small, making it difficult to meet the requirements of water plugging. By introducing aluminum ions into the cracks, layered double hydroxides can be formed in situ with divalent metal ions in the alkaline environment of the cracks, greatly improving the healing speed and efficiency of the cracks. The formed layered double hydroxides can not only combine many water molecules to produce good volume expansion, but also adsorb and fix corrosive ions. In addition, the formation of layered double hydroxides will consume a large amount of hydroxide ions, which will also improve the chemical conditions of the crack solution to a certain extent, and provide the possibility to enhance the application of microbial technology in cement-based materials. The research results provide a reference for the development of marine self-healing concrete.