Self-Healing of Wastewater Concrete Using Bacteria

Abstract

Water is the most essential thing for any living organisms to survive in the earth. For construction
industry water is one of the essential components and its demand is increasing day by day. Due to
continuous contamination of natural water resources, utilization of underground water resources
increases in worst manner. To meet out the water demand for construction works many countries are
using wastewater from treatment plants. In our paper Waste water from treatment plant has been tested
to know the content of contaminants and minerals which are harmful and have utilized for the
preparation of M25 grade concrete and the same grade with tap water as conventional concrete.
Bacillus subtillus is the bacteria used for achieving self-healing of micro crack in the concrete which
increase the strength to a smaller extent. Bacteria have been added in different proportions such as
0.5%, 1% and 2% in waste water for the preparation of concrete and its compressive strength and
tensile strength have been found out. Experimental results of bacterial concrete have confirmed the
presence of calcite crystals which had been filled in micro cracks that leads to increase in Compressive
strength and tensile strength of concrete. SEM analysis shows the evidence for the presence of Calcite
Crystal in concrete, which has been confirmed by the EDAX report. Wastewater from treatment plant
could be effectively used for concrete which found a valuable replace for fresh water in concrete.