Self-healing concrete: comparative performance evaluation

This study investigates the self-healing capacity of concrete using two distinct admixtures: sodium silicate and membrane-forming crystalline admixtures (MFCAs) in comparison with concrete’s own intrinsic healing to evaluate their effectiveness, thus allowing users to better select the appropriate methods. Meeting this objective, 12 mix designs were developed, including control mixes with various combinations of cementitious binders without healing agents. The study assessed fresh and hardened properties through a series of mechanical and durability tests, including compressive strength, flexural strength, rapid chloride permeability, water permeability, and ultrasonic pulse velocity, evaluated at 28 and 56 days. Results indicated that while both healing agents introduced moderate reductions in early mechanical strength, they significantly enhanced transport-related properties and showed clear signs of matrix densification and crack sealing. MFCAs, particularly when combined with silica fume, demonstrated superior healing performance in terms of permeability reduction and durability enhancement, serving sustainability. This study supports the use of self-healing materials for infrastructure exposed to aggressive environments and recommends further exploration into layered applications and encapsulated healing systems.