MICROBIAL GEOTECHNOLOGY: EVALUATION OF STRENGTH AND STRUCTURAL PROPERTIES OF MICROBIAL STABILIZED MUD BLOCK (MSMB)
Microbial Geo technology is a new branch of geotechnical engineering that pact with the applications of microbiological methods to geological materials used in engineering. In this research, microbes were isolated and analyzed for various pozzolanic reactions as well as microbial fibrous reinforcement properties. The precipitation of CaCO3 in their micro environment by conversion of urea into ammonium and carbonate were confirmed further. The bacterial spore which is immobilized in soil matrix becomes metabolically active when revived by water entering freshly into the soil. The mycelial network of isolated fungi will provide fibrous reinforcement to the mud block. The micro organism is identified as Sporosarcina pasturii with 98% query sequence similarity. After the detailed review done by NCBI members allotted unique Accession number KP938 774 for S. pasturii. Hence now onwards this bacterium known as S.pasturii GRI Auro. The objective of the present investigation is to study the potential influence bacteria Sporosarcina pasteurii GRI Auro, and fungus Aspergillus sp. on the strength, durability and mechanical characteristics of compressed earth block. The studies are carried out in red soil. Different concentrations of microbial consortium (105,107,109 cells/ml) were introduced in mud block. Microbial Stabilized Mud Block (MSMB) were prepared by using Tara Balram soil press and cured by spraying an optimized nutrient media for 28 days. Microbial Calcite Precipitation (MCP) was identified and quantified by X ray diffraction (XRD) Fourier Transform Infrared (FT IR) analysis and visualized by Scanning Electron Microscope (SEM) Results showed that the rate of water absorption was significantly reduced and compressive strength was enhanced in microbial treated bricks. The results suggested that the microbial activities can significantly improve mechanical properties of microbial stabilized mud block. Hence microbial isolates can be used as additive to stabilize soil.