Not sure what to make of this still but it certainly is a case of microbes in the built environment: Living Concrete Fixes Its Own Cracks With Built-in Bacteria. Not sure why the Malaysian Digest is covering this but it still intrigues me and thought it might be of interest.
See a previous post about it here:
https://www.microbe.net/2011/05/25/bacteria-to-stabilize-buildings/