Self-healing by biocomposite containing metakaolin immobilized bacterial spores in concrete using low-cost corn steep liquor media

The present study aimed to develop a biocomposite constituting metakaolin as a suitable carrier material for immobilizing bacterial spores. The biocomposite was stored at 4 °C and 25 °C and showed a sustainable shelf-life of bacterial spores during the storage period of 180 days. Biocomposite was assessed for urease activity and calcium carbonate precipitation in corn steep liquor (CSL) as the growth medium. Significant improvements in strength and permeation were observed at 7 and 28 days of testing in concrete added with biocomposite. The study was extended to test the self-healing capabilities of biocomposite in prismatic specimens using CSL medium. Crack healing showed significant improvement in ultrasonic pulse velocity, indicating progressive healing of the crack, and the repaired surface was examined by water tightness. The precipitated minerals were assessed by scanning electron microscopy and X-ray diffraction. The CSL can be used as low-cost growth media, eventually decreasing the cost of self-healing concrete.