Effect of Bacillus Megaterium Bacteria and Different Calcium Source on Strength and Permeation Properties of Concrete

Document Type : Original Article

Authors

1 Civil Engineering, Faculty of Engineering, Menofia University

2 Department of Civil Engineering, Faculty of Engineering, Menofia University, Egypt

3 Department of Microbial Biotechnology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Egypt

4 Department of Industrial Biotechnology, Genetic Engineering and Biotechnology Research Institute (GEBRI), University of Sadat City, Egypt

Abstract

Different methods were used to repair concrete cracks. Recently, microbially induced calcium carbonate precipitation is presented as self-healing technique for concrete manufacture, which is proposed as an eco-friendly method. It is a biomineralization process. microbial activities induced precipitation that can heal cracks it. Effect of biomineralization in concrete by incorporation of ureolytic sp. (Bacillus Megaterium) is investigated. Fresh and hardened tests were carried out on concrete at various ages. “Bacillus Megaterium” (Bm) with cell density of 2×〖10〗^9 CFU/mL were used where added to mixtures with two ratios 0.5% and 0.25% of cement weight. Calcium lactate, Calcium acetate and Calcium formate were added as nutrition to bacteria by 0.25% and 0.125% of cement weight. Test results indicated that inclusion of Bm in concrete enhanced properties. Bacteria addition and all nutritions used revealed varied decrease in rate of water absorption and capillary permeability coefficient. Bm 0.5% with acetate nutrition concrete mix had maximum increase in compressive strength at all ages. It had compressive strength 152.99% of that of compressive strength of control concrete mixture at 28days. Bm 0.5% with lactate nutrition concrete mix had flexural strength values 162.74% of that of control concrete flexural strength at 28days. Enhancement of properties was due to calcite deposition on the bacteria cell surfaces within the pores. SEM imaging indicated the formation of calcite crystals in different shapes according to added nutrient of bacterial concrete specimens.

Keywords

ERJ. Engineering Research Journal
Volume 45, Issue 3
Vol. 45, No.3 issued on 1/7/2022 in 5 Parts: Part (1) Electrical Engineering, Part (2) Mechanical Engineering, Part (3): Production Engineering, Part (4): Civil Engineering, Part (5) Architectural Engineering.
July 2022
Pages 401-412

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