Experimental Study on Influence of Sporosarcina ureae Bacteria on Mechanical and Fresh Properties of Self-Healing Concrete With Focus on Elemental/Microstructural Analysis

Abstract

Concrete is the most widely used construction material globally, but it is inherently prone to various factors such as environmental conditions, mechanical stress, and chemical reactions. Stresses such as cracks can significantly reduce the lifespan of concrete structures, leading to increased maintenance costs and environmental impact. Traditional repair methods often involve using sealants or patching materials, which may not be effective for micro-cracks and can lead to further deterioration over time. This experimental study investigates the use of Sporosarcina ureae bacteria to create self-healing concrete that can autonomously repair. S. ureae is an ureolytic bacterium that hydrolyzes urea to produce ammonia and carbon dioxide, which subsequently reacts with calcium ions present in the concrete matrix to form calcium carbonate (CaCO3). This precipitation of calcite effectively fills the cracks, restoring the integrity of the concrete structure. The study prepared concrete specimens with varying concentrations of S. ureae and subjected them to controlled cracking. Fresh concrete that incorporated S. ureae were tested for slump, while both conventional concrete and the concrete with S. ureae bacteria underwent compressive strength tests using a universal testing machine (UTM). SEM analysis test were conducted.The study monitored the effects of S. ureae on self-healing concrete, specifically focusing on changes in, workability, compressive strength, elemental mapping, of the concrete. The findings highlighted the potential of using S. ureae bacteria to create more durable and sustainable self-healing concrete. By extending the lifespan of concrete structures and reducing the need for frequent repairs, this approach contributes to more cost-effective and environmentally friendly construction practices.