Enhancing the self-healing mechanism of concrete using crystalline admixtures – A review

Sustainability is of ever-increasing importance in the construction industry, and self-healing concrete offers a promising solution to the issue of cracking in concrete. By incorporating crystalline admixtures into a concrete mix, the efficiency of self-healing can be improved in a non-invasive and non-destructive way. In this review, key findings have been compiled from several studies that tested or discussed the effectiveness of self-healing with crystalline admixtures. The review show that it is necessary to first analyse the chemical composition of the raw materials as they have a direct influence on healing efficiency. In addition, at least five analysis methods should be implemented when determining self-healing efficiency, with special emphasis on internal crack-healing efficiency, which can be measured effectively by a technique such as X-Ray tomography. While crack sealing is now considered more critical than mechanical properties, strength retention remains an important property in ensuring the durability of the concrete. Based on this review, this study suggests a general experimental procedure to be followed when conducting self-healing tests with concrete containing crystalline admixture and proposes specific methods for conclusive research work.