Fig. 1From: The effect of isolated Bacillus ureolytic bacteria in improving the bio-healing of concrete cracksa C is the control without bacterial inoculum. B1 and B2 are the bacterial isolates that gave dark pink color after 24Â h. Indicating positive urease results using Phenol red as indicator. b Shows that B1 and B2 bacterial isolates are bacilli cells and their endospores appeared as dark black colored spherical dotsBack to article page