Self-healing Concrete Using Microbial and Chemical Agents: Advances and Limitations

Self-healing concrete is a revolutionary invention in sustainable building that aims to prolong infrastructure’s lifespan while lowering maintenance costs and environmental effect. Without the need for outside assistance, this novel material’s microbiological and chemical agents can self-heal fissures and restore structural integrity. When exposed to moisture and oxygen, bacteria like Bacillus subtilis or Bacillus pasteurii precipitate calcium carbonate, which successfully seals microcracks in microbial self-healing concrete. In contrast, chemical methods use encapsulated healing agents, such as epoxy resins or sodium silicate, which are released when a fracture forms. Both approaches have shown encouraging outcomes in laboratory and field tests, with chemical agents responding quickly to injury and microbiological agents potentially repairing over the long term. Despite these advances, several limitations hinder widespread adoption. Microbial systems face challenges related to bacterial survivability in harsh concrete environments, scalability, and cost-effectiveness. Chemical agents, while efficient, may suffer from limited healing cycles and environmental concerns associated with synthetic compounds. Additionally, the integration of self-healing mechanisms can affect the mechanical properties and workability of concrete, necessitating careful formulation and testing. Current research is focused on optimizing agent delivery systems, enhancing healing efficiency, and developing hybrid approaches that combine microbial and chemical strategies. This chapter examines the most recent developments in self-healing concrete technology, contrasting the workings, efficacy, and pragmatic issues of chemical and microbiological approaches. It also covers new developments that try to get beyond current obstacles, like genetically modified microorganisms and innovative encapsulation methods. In order to move self-healing concrete from experimental to commercial building applications, it is essential to comprehend these developments and constraints.