The self-healing of marine concrete cracks based on the synergistic effect of microorganisms and inorganic minerals

Abstract

To achieve the goal of self-healing of marine concrete cracks and fixation of harmful ions invading the cracks, researches on the synergy of microbial mineralization and inorganic mineral hydration were carried out. The fixation effects of Cl−, SO42− and OH− in simulated solution with different inorganic mineral dosages were tested by experiments. Further, the growth performances of microorganisms in the modified simulated solution were also tested. Finally, the self-healing effect of cracks in cement-based materials was experimentally verified. The results showed that the Cl− and SO42− in the simulated solution can be effectively fixed by the double metal hydroxide, and combined with a part of H2O to form hydration products that accumulated in the deep region of the crack. A large amount of OH− were also consumed for the formation of double metal hydroxides, which greatly lowered the pH of the simulated solution. Thus, the chemical environment of the simulated solution became suitable for the growth of microorganisms, and the number of microorganisms in the solution increased significantly. Eventually, the hydration product and the mineralization product area were connected to form a superimposed repair zone, thereby expanding the repair scope. The test results could provide reference for concrete crack self-healing and anti-corrosion of buildings applied on marine environment.