This study presents a comprehensive analysis of self-healing concrete technologies, focusing on autogenous and autonomous self-healing methods, through a systematic literature review of peer-reviewed articles. The autogenous self-healing method relies on the natural hydration and carbonation processes of unhydrated cement particles, enhanced by additives such as fly ash, slag, and superabsorbent polymers. It is effective for small cracks (<200 μm), environmentally favorable, and cost-efficient, although it is limited by relatively slow healing rates and reduced performance over time. The autonomous self-healing method incorporates external agents, primarily bacteria like Bacillus cohnii and Bacillus sphaericus, encapsulated in protective carriers. These bacteria precipitate calcium carbonate (CaCO3) upon activation, sealing cracks up to approximately 1240 μm. While generally more effective in terms of healing efficiency and durability, the autonomous self-healing method involves higher production costs. Life cycle assessment results indicate that the autonomous self-healing concrete can exhibit up to 85% higher environmental impact during the production phase than conventional concrete. However, during the production phase, the autogenous self-healing method shows about 32% higher CO2 emissions than the autonomous method. Results from investigating the mechanisms, performance, repairability, environmental impacts, and economic aspects in this study demonstrate that bacterial concentration and nutrient type critically influence mechanical properties, with optimal strength gains at 105 cells/mL. Both techniques reduce corrosion risk and extend service life, with the autonomous self-healing method displaying superior performance in harsh environments. However, the autogenous self-healing method is more feasible for large-scale applications due to lower costs and simpler implementation. The study concludes that method selection should align with project-specific durability, sustainability, and economic goals.
Bahrami et al. (Tue,) studied this question.