Improvement the characteristics of recycled concrete by isolation and addition <i>Alkalibacterium iburiense</i> as abioconcrete bacteria

This research aims to isolate and identify calcite-precipitating bacteria and investigate whether they can be used in concrete to enhance its mechanical qualities and self-healing capabilities.Microbial-induced precipitation of calcium carbonate is a new technique for making cement concrete stronger.The present study aims to compare cement concrete's compressive and split-tensile strengths to those of conventional concrete to examine the possible use of alkaliphilic bacteria to improve its qualities and ability to self-repair hairline cracks in concrete.Through conducting experiments on concrete samples at ages 7, 28, and 56 days, to which the isolated bacteria were added and characterized at the molecular level using the AccuPrep Genomic DNA Extraction kit, amplified, and subjected to agar gel electrophoresis, the sequences were obtained and compared with those in the GenBank database using the BLAST tool in the NCBI-GenBank database.Using PCR and scanning electron microscopy, it was confirmed that the isolated alkaline bacteria had a 99.69% identity rate.The bacteria Alkalibacterium iburiense were used at different concentrations of 10and 10.Additionally, 2% of recycled coarse aggregate and 10% & 20% was used.It was found that the concrete properties were improved.It was determined that the optimum improvement in mechanical properties was with the addition of bacteria at a concentration of 10 and a total recycled aggregate ratio of 10% after 56 days.The compressive, tensile, and flexural strengths increased by 25.75%, 17.27%, and 19.4%, respectively.