Investigations on Strength and Durability aspects of Bacterial Mortars & Concrete

Different species of bacteria have been reported to precipitate Calcite, produce endospores, survive concrete production and multiply in hydrating Mortar and Concrete body, precipitating calcite in voids/pores / microcracks resulting in autogenous repair in-situ or self healing of mortar and concrete  thereby making the concrete structures water tight with  enhanced durability. Literature reports feasibility of using micro encapsulated spores to self-heal cracks in a cementitious matrix. The food & nutrient for the bacterial growth and multiplication were incorporated together the bacterial concentrate during the mixing process of mortar and concrete  

The studies were carried out with bacterium Bacillus pasteurii and their growth was measured by Optical density and microscope was used to check the live bacteria. These bacteria concentrate along with the deposition agents, urea and Ca source (Ca –Lactate) was added during the mixing process of Mortar and concrete. The resultant mortar and concrete were evaluated for compressive strengths and durability properties of concrete in terms of RCPT, Sorptivity, water permeability . The changes in the microstructure of bacterial mortar and concrete were assessed by SEM/Optical microscopy.

The article discusses the data generated on the use of Bacillus pasteurii and its impact on the properties of Mortars and Concretes in terms of increased durability & strength along with some aspects of pore filling, reduction in the crack development (self healing) in concrete. . This was published and presented at 15th NCB Int Seminar on Cement , Concrete and Building Materials

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