ADDITION OF BACTERIOLOGICAL ADDITIVES IN THE PRODUCTION OF SELFHEALING CONCRETE

Abstract

Self-repairing concrete is a product in which microorganisms will be used to produce limestone to fill cracks appearing on the surface of concrete structures. It is presented by the author that specially selected types of bacteria of the genus Bacillus, a calcium-based nutrient known as calcium lactate, and nitrogen and phosphorus are added to the ingredients of concrete when it is mixed. These self-healing agents can remain dormant within concrete for up to 200 years. Self-repairing materials are a special type of materials that regenerate their strength properties after minor damage caused to the material during its service life. Self-repair technology is particularly useful in the case of composite materials because composites have low damage detection capability and are susceptible to sudden and brittle failure. Modern man-made materials have excellent mechanical properties. However, they lack the ability to self-repair. Therefore, in the event of damage, there is the possibility of loss of mechanical strength and, over time, a gradual loss of functional strength in the absence of human intervention.Different bacterial species along with abiotic factors such as salinity, ambient pH value, temperature, nutrient availability and habitat composition play a significant role in the calcium carbonate precipitation process in a wide range of different environments. There are four key factors that determine the MICP process: (I) calcium concentration, (II) dissolved inorganic carbon concentration, (III) pH value and (IV) presence of nucleation centres.