Evaluation of performance and healing effect of two-component biological self-healing mortar

Abstract

Microbial-induced carbonate precipitation (MICP) technology can heal cracks in concrete materials. The development of this technology is conducive to improving the sustainability of concrete materials and alleviating the environmental burden of concrete production. In this paper, a two-component self-healing agent was prepared using porous volcanic rocks to adsorb microorganisms and mineralized substances under negative pressure conditions, and the cracks were healed under standard curing conditions. The effect of crack healing under different proportions was studied by keeping the same total dosage and modifying the proportion of the two-component self-healing agent. The results showed that the honeycomb-like pore structure of volcanic rock can adsorb a large number of microorganisms and effectively protect their activity. The maximum crack healing width was 335.4 μm after curing for 28 days. The ultimate effect of crack healing was positively correlated with the proportion of mineralized material components. The initial crack healing rate accelerated when the proportion of microbial components was increased. Nevertheless, the mineralization was constrained by the content of mineralized materials, and the maximum value of crack healing could not be achieved. The calcium carbonate precipitates produced by microbial mineralization were conducive to improving the recovery of compressive strength under pre-damage conditions and reducing the chloride penetration to a certain extent under the condition of applied current.

Keywords:

• two-component self-healing agent
• compressive strength recovery
• chloride permeability
• crack healing

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [42077444, 52274217, 51874193, 52274216, 52304242 and 42307585]; youth expert of Taishan Scholars (T S202103073), distinguished professor of Taishan Scholars (T S20190935); the Shandong Natural Science Outstanding Youth Fund [ZR202102220886]; the Shandong Province Natural Science Foundation [ZR2020ME101, ZR2021QE159, ZR2021QE296, ZR2023QE042 and ZR2023QE013]; Qingchuang Science and Technology Program of Shandong Province University [2019KJG008]; the Key Program of the National Natural Science Foundation of China [51934004]; the Qingdao Natural Science Foundation[23-2-1-101-zyyd-jch].