Assessment of Self-Healing in Pre-Cracked Concrete with Low-Carbon Binder Blends under Cyclic and Submerged Exposure

Abstract This study presents an investigation into the self-healing potential of concrete incorporating various binder systems under two exposure conditions. Seven binder types were evaluated, including three factory-blended cements and four laboratory-prepared blends containing fly ash or Ground Granulated Blast Furnace Slag (GGBFS). Load-induced cracks were introduced in concrete beams, which were tested using a custom-designed water permeability method before and after one year of exposure to either continuous water submersion or cyclic wet/dry conditions. Results indicate that continuous water submersion promotes self-healing in most cases. All factory blended cements demonstrated healing to a varying degree. In contrast, mixtures where slag partially replaced Portland cement showed no indication of self-healing under either condition. Cyclic wet/dry conditions generally resulted in limited self-healing. The inclusion of polyvinyl alcohol (PVA) fibres contributed positively to healing, although the effect was less pronounced than in mixtures with cement-only or fly ash-based binders. Despite the limited number of specimens, the study provides valuable insights into long-term self-healing behaviour on early-age cracks and different exposure scenarios. The permeability-based test method used proved practical for identifying self-healing trends and may be of use for future studies of self-healing in cementitious systems.