Authors: Mrs. Vandana Rahul Shah
Abstract: Concrete, though the most widely used construction material, is prone to cracking, which compromises durability, service life, and sustainability of structures. Conventional repair methods are temporary, costly, and labor-intensive. In recent years, self-healing concrete has emerged as a promising alternative, capable of autonomously repairing cracks and enhancing long-term performance. This review focuses on two major self-healing approaches: bacterial concrete, where microorganisms such as Bacillus subtilis precipitate calcium carbonate within cracks, and crystalline admixture-based concrete, where chemical additives react with unhydrated cement particles and moisture to form insoluble crystals. A comparative analysis of past studies indicates that bacterial concrete can effectively heal cracks up to 0.8 mm, providing superior strength and durability improvements, though at higher cost. Crystalline admixtures, on the other hand, are economical, commercially available, and suitable for healing micro-cracks up to 0.5 mm, particularly in water-retaining structures. The paper highlights the mechanisms, advantages, limitations, and applications of both approaches, and identifies future research directions including hybrid systems, large-scale field trials, and cost optimization. Findings suggest that self-healing concrete technologies have significant potential to reduce maintenance needs and promote sustainable infrastructure development.
