Annotated Bibliography Self Healing Concrete

Self-Healing Concrete: Annotated Bibliography

Abavisani, I., Rezaifar, O., & Kheyroddin, A. (2023). Efficient approaches to autogenous and autonomous self-healing concrete: a review. Magazine of Concrete Research, 75(20), 1051–1079.

Providing technical details, the authors note that while concrete and cement-based composites have reigned as the predominant construction materials worldwide due to their exceptional structural performance, low cost, and abundant availability, they inevitably face degradation from internal cracking or external forces over time. This structural deterioration has heightened the need for innovative solutions to maintain safety and enhance durability. In response, researchers have pioneered a diverse array of so-called “smart” self-healing techniques for cementitious materials.

This study provides a comprehensive review categorizing the latest state-of-the-art self-healing technologies into two main approaches: autogenous self-healing driven by the intrinsic properties of the concrete itself, and autonomous self-healing facilitated by embedding engineered self-mending agents within the concrete matrix. Each category encompasses multiple specific methods utilizing different operating principles and influencing factors. The fundamental mechanisms, advantages, and challenges associated with these various autogenous and autonomous concrete self-healing techniques are critically analyzed. Based on this extensive review, overarching conclusions are presented along with recommendations for future research directions to further advance self-repairing capabilities in next-generation high-performance, resilient concrete infrastructure materials.

Bin Amjad, U., Siddique, M. S., Shahid, T., Ahmed, I., Alogla, S. M., & Ahmad, J. (2023). A study on microbial self-healing concrete using expanded perlite. Bulletin of the Polish Academy of Sciences: Technical Sciences, 71(5), 1–8.

A specific environmentally related virtue of self-healing concrete was highlighted by the authors. For instance, they note that growing concerns over structural safety and sustainability have spurred research into developing “smart” self-healing materials and preventative repair strategies. This study investigates the self-healing capabilities of normal-strength concrete by employing the bacteria Sporosarcina aquimarina - NCCP-2716 immobilized within expanded perlite (EP) as a carrier medium. The efficacy of this bacterial self-healing approach was comparatively evaluated against two alternative techniques: EP-modified concrete and direct introduction of bacteria into the concrete matrix. The bacterial solution embedded in EP was supplemented with calcium lactate as a nutrient source. Experimental findings revealed concrete specimens containing the EP-immobilized bacteria exhibited the most effective crack-healing performance. After a 28-day healing period, crack widths up to 0.78mm were completely mended, outperforming the 0.5mm limit observed with direct bacteria addition. Significant autonomous crack repair was achieved through substantial calcite precipitation induced by the bacterial activity, without compromising the strength of the concrete.

This novel self-healing mechanism leveraging expanded perlite as a microbe carrier and Sporosarcina aquimarina as a healing agent could provide a scientific foundation for developing bacteria-based self-repairing concrete, advancing sustainable and resilient infrastructure materials.

Radhakumar, L., Murugan, S., & Sankaralingam, J. (2023). Comparative Study on the Strength Behavior of Self-Healing Concrete Using Silica Gel and Bacteria as Healing Agents. Journal of Materials in Civil Engineering, 35(12), 1–17.

The authors provide useful technical details concerning concrete cracking which poses an ongoing challenge for the construction industry, necessitating costly and environmentally unsustainable inspection, repair and maintenance of infrastructure. Recent research has explored innovative self-healing concrete (SHC) formulations as a potential solution by incorporating specialized self-mending agents directly into the concrete mixture. The key advantage of SHC lies in its ability to autonomously sense crack formation and initiate self-repair mechanisms without human intervention. This study comparatively evaluated two distinct self-healing approaches through rigorous experimental analysis, with one utilizing silica gel and the other employing polymer-based gel and Bacillus subtilis bacteria as healing agents substituted by cement weight.

The self-healing performance was experimentally verified by assessing the recovery of mechanical properties in cracked concrete specimens treated with these additives. Based on the findings, optimal dosage levels were determined for silica gel and Bacillus subtilis bacteria to function as effective self-healing agents capable of mending cracks within the concrete matrix. In addition, these formulations also show promise in developing self-repairing concrete that can reduce long-term maintenance burdens while promoting environmental sustainability of vital infrastructure.

Shetiya, R. K., Elhadad, S., Salem, A., Fülöp, A., & Orban, Z. (2024). Investigation into the Effects of Crystalline Admixtures and Coatings on the Properties of Self-Healing Concrete. Materials, 17(3), 767.

The authors describe the technical aspects of self-healing concrete in this study and note that they represents an innovative approach to enhancing the durability and service life of concrete structures. This study investigates the effects of incorporating crystalline admixtures and coatings into concrete mixtures to enable autonomous crack repair capabilities. It comparatively evaluates the crack-bridging performance, flexural and compressive strengths, as well as water absorption characteristics of four different self-healing concrete formulations against traditional concrete mixtures. A comprehensive suite of destructive, semi-destructive, and non-destructive testing methods were employed. The self-healing efficacy was assessed through crack-healing tests and microstructural analyses on damaged test specimens. Fresh concrete properties like workability and air content were also examined.

The findings revealed that combining crystalline coatings and admixtures imparted significant self-mending functionalities in concrete. As the dosage increased, the self-healing mixtures exhibited moderately higher compressive and flexural strengths compared to regular concrete. Moreover, they demonstrated substantially lower water absorption, a denser microstructure, and evidence of crack-filling - all indicators of improved durability. This novel approach leveraging crystalline additives shows notable potential for developing robust, self-repairing concrete to extend the service life of infrastructure.

Yao, C., Shen, A., Wang, W., Guo, Y., Dai, X., & Ren, G. (2024). Review on autogenous self-healing technologies and multi-dimension mechanisms for cement concrete. Archives of Civil & Mechanical Engineering (Elsevier Science), 24(1), 1–30.