Microbial loading and self-healing in cementitious materials: A review of immobilisation techniques and materials

• Published in: Materials & design 2024-09, Vol.245, p.113249, Article 113249
• Main Authors: Mohamed, Abdulahi, Fan, Mizi, Bertolesi, Elisa, Chen, Hanyuan, Fu, Ziyan, Roberts, Terry
• Format: Article
• Language: English
• Subjects: Concrete; Cracks; Microbial immobilization; Organic and inorganic materials; Self-healing
• ISSN: 0264-1275
• DOI: 10.1016/j.matdes.2024.113249

[Display omitted] •Various materials and technologies used for immobilization of bacteria for self-healing concrete are compiled;•Organic and inorganic immobilization of bacteria are both effective though inorganic nanomaterials exhibits superior;•Natural renewable carrier materials especially nanocellulose are considered the priority of further explorations;•Immobilization materials and methods are crucial for creating a successful self-healing system and hence composite properties. Concrete has been a material of choice when it comes to building materials for decades. However, concrete has a number of challenges in which a major challenge being microcracking leading to excess damage and wastes. The development and advancement of self-healing technology throughout the past decade have seen the popular use of immobilization as a way of protecting bacteria from the harsh environments found in cementitious materials. This paper reviews the materials used for immobilization, categorising into organic materials and inorganic materials, and investigates the various immobilization techniques used to immobilize bacteria into polymeric structures and porous materials. The study evaluates the key findings in literature surrounding immobilization materials and methods as well as highlighting possible alternative sustainable materials and methods including waste/by-product resources. It was found that inorganic materials were superior to organic material in terms of self-healing and mechanical properties, with nanomaterials producing the highest crack closure of 1.20 mm. Various immobilization techniques efficiency was tested comparing microencapsulation, vacuum impregnation and adsorption methods. Further studies are needed to understand the relationship between carrier materials and cementitious matrix and explore the possible use of nanomaterials as a way of uniformly distributing bacteria in cementitious matrix.