SELF-HEALING MATERIAL BACTERIAL CONCRETE

Abstract

The requirement of high durability for structures exposed to harsh environment such as seafloor, offshore, tunnels, highways, bridges, sewage pipes and structures for solid, liquid wastes containing toxic chemicals and radioactive elements may not be achieved using today's ordinary portland cement (OPC). This research gives information about the aims at increasing the strength and the total durability of the concrete used in the present day by introducing bacteria (Bacillus pasteurii). This micro organism is a soil bacterium. Bacillus pasteurii exhibits a phenomenon known as bio-calcification as a part of its metabolic activity. Bio-calcification is a process through which the micro-organsim externally secretes calcium precipitate, which in the presence of a carbonate ion forms CaCO 3 which fills up the voids in the concrete texture thus making it more compact. This inturn improves the strength in concrete due to growth of the filler material within the pores of the concrete mixer. A comparison study was made with concrete cubes and beams subjected to compressive and flexural strength tests with and without the bacterium. It was found that there was high increase in strength and healing of cracks subjected to loading on the concrete specimens.