Study on improving the activity of mineralized microorganisms by regulating the chemical environment of marine concrete crack area with inorganic minerals

The activity of mineralized microorganisms in concrete crack area, including growth activity and enzyme level, was an important prerequisite to realize the self-healing of concrete cracks. At the same time, Cl- and SO42- in seawater could accelerate the corrosion of marine concrete through cracks. Therefore, the self-healing of marine concrete cracks faced the dual test of improving the activity of mineralized microorganisms and slowing down the erosion of harmful ions. In this paper, improving the activity of mineralized microorganisms by regulating the chemical environment of marine concrete crack area with inorganic minerals was studied systematically. Firstly, the concentration of ions in simulated solution were analyzed, and pH value of solution was studied; Through the deposition of inorganic minerals, Cl-, SO42- and OH- were adsorbed and fixed, and pH value decreased significantly. Secondly, the composition and morphology of inorganic minerals were analyzed by SEM, EDS and XRD. Inorganic minerals presented a laminate structure, which were confirmed as bimetallic hydroxides of calcium and aluminum. Finally, microorganisms were cultured in simulated solution of marine concrete crack area, and the growth performance of microorganisms was tracked and analyzed; microbial growth was significantly improved, which was basically equivalent to that of the control group. The effect of bimetallic hydroxide on improving the environment and promoting the growth of microorganisms was confirmed, and the research provided a new idea for the self-healing of marine concrete cracks.