Abstract:
Cement-made materials face durability and sustainability challenges. (is is majorly caused by the presence of cracks. Cracking
affects the mechanical strength of cement-based materials. Microbiologically induced calcite precipitation (MICP) has been found
to enhance compressive strength, thus enhancing on the mechanical and durability properties of these materials. (is paper
presents the findings of a study conducted to investigate the effect of Bacillus cohnii on compressive strength development of OPC
mortar prisms and the effect of Bacillus cohnii on cement setting time and soundness. Microbial concentration of 1.0 ×107
cells·ml−1 was used. Compressive strength tests analyses were carried out for each category of mortar prisms. Compressive
strength tests were carried out on the 2nd, 7th, 14th, 28th, 56th, and 90th day of curing in distilled water and microbial solutions. All
microbial mortars exhibited a greater compressive strength compared to the control with the highest observed at 90 days. Highest
percentage gain in compressive strength was observed at 90 days which is 28.3%. Microstructural analysis was carried out using a
scanning electron microscope (SEM) after 28 days of curing. (e results indicated the presence of calcium carbonate and more
calcium silicate hydrate (CSH) deposits on the bacterial mortars. (e bacteria did not have an effect on cement soundness. Setting
time was significantly accelerated.
