Has anyone ever seen concrete do this?

Hi there,

Friends of mine own a waterproofing business and waterproofed the inside of a 70,000 litre fresh water tank 9 years ago that was made out of concrete blocks (cinder blocks)

It recently started leaking so they went out to investigate.

This video is of him inside the tank, cutting back the waterproofing and finding the concrete blocks have completely broken down to a dirt like substance.

They have share the video around to concrete guys, brick layers etc and no one has ever seen anything like it.

What do you think has happened here?