IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) e-ISSN: 2278-1684,p-ISSN: 2320-334X, Volume 21, Issue 4 Ser. 1 (Jul. – Aug. 2024), PP 11-15 www.iosrjournals.org DOI: 10.9790/1684-2104011115 www.iosrjournals.org 11 | Page Self-Healing Concrete (SHCr): The Role of Sodium Alginate Isaac O. Agbamu 1 , Mieczysław Kuczma 2 , Marcin Wysokowski 3 , Oluka N. Ngofa 4 Poznan University of Technology, Poznan, Poland 1,2,3,4 International Hellenic University, Kavala, Greece 5 Faculty of Civil Engineering, Geodesy and Transport, Institute of Building Engineering 1,2 . Department of Chemical Technology, Institute of Chemical Technology and Engineering 3,4 . Department of Chemistry, Institute of Petroleum and Gas Technology 5 . Abstract. The first reason why concrete is a very useful material in construction is because of its density and strength. However, they tend to crack and require constant fixing, and this is usually expensive and tiresome. This research aims to investigate the feasibility of employing sodium alginate, a naturally occurring polysaccharide, as an encapsulated self-healing system for concrete. When sodium alginate is applied on concrete, it interacts with the calcium ions in the concrete to create a calcium alginate gel which helps to close up any cracks and also increases the durability of the concrete. The study embraced the usage of sodium alginate, rapeseed oil, calcium chloride, and water hydrate, which were blended with the IKA T25 harmonisation machine. The outcomes of the experiments indicate that self-healing concrete based on sodium alginate has higher durability, and the need for repairs is minimised; thus, the use of sodium alginate in new construction can be considered a promising direction. Keywords: Climate change, Crack repair, Calcium alginate gel, Self-healing concrete, Sodium alginate, Sustainable construction, --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 10-07-2024 Date of Acceptance: 20-07-2024 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction Concrete is one of the most widely used construction materials today because of its high density and strength. However, it is sensitive to cracking, which compromises the structural integrity of the building and requires constant reinforcement. Traditional methods of repair are costly and sometimes time-consuming; therefore, the search should be for products and systems that enhance the durability of reinforced concrete structures. One of them is self-healing concrete (SHCr), particularly when sodium alginate (SA) is used as the healing component. SA is a natural polysaccharide with the chemical formula  ଺  ଻  ଺ . It is a very active compound, soluble in water, and forms a calcium alginate gel when mixed with calcium ions. This gel has a significant function in the healing process as it fills all the cracks and pores that are characteristic of many concrete structures (Shah & Huseien, 2020; H. Wang et al., 2022; H. Zhang et al., 2021) II. Methods 2.1 Materials The materials used in this study included sodium alginate, rapeseed oil, calcium chloride with water hydrate, and a healing agent. These materials were combined in appropriate percentage ratios to achieve optimal self-healing properties. 2.2 Mixing Procedure The ingredients were mixed using a harmonisation machine, IKA T25. The process involved dissolving sodium alginate in water, followed by the addition of rapeseed oil and calcium chloride. The mixture was then homogenised to ensure an even distribution of the healing agent throughout a concrete matrix.