Use of Bacteria Externally for Repairing Cracks and Improving Properties of Concrete Exposed to High Temperatures

The current paper presents the results of an experimental study on application calcium carbonate precipitation bacteria as a new approach to repairing damaged concrete when exposed high temperatures. To do so, cylindrical and cubic specimens were initially heat in furnace for 1 h, after reaching two different temperatures 600 800 °C. A rate 5.5 °C per minute was used achieve target Then, types bacteria, namely Sporosarcina pasteurii Bacillus sphaericus, with cell concentration 107 cells/mL, utilized externally, repair thermal cracks, enhancing mechanical properties durability concrete. efficiency bacterial remediation technique then evaluated through compressive strength, ultrasonic pulse velocity (UPV), electrical conductivity tests control (unexposed heat), those temperature or without healing. demonstrate that strength test decreased by about 31–44% compared ones. However, at °C, repaired S. B. sphaericus showed increases 31–93%. This increase is associated deep superficial cracks pores specimens. Furthermore, subjected had significant 1.65–3.47 times In addition, 22–36%