[Animats]

> And dangerous, and won't last more than a few decades. Just watch some of the tofu dreg videos https://www.youtube.com/shorts/1eyUAZCb3sA

Concrete quality requires vigilant testing, testers, and enforcers backing up the testers when they find bad concrete. It's a constant battle. A job as a concrete inspector is no fun.[1] Concrete testing machines are big, heavy, labor-intensive, and often require a forklift to move. This is why much third-world concrete is so bad. You need hard-ass honest inspectors with real authority. And backup inspectors to inspect again.

There's a market here. Design an automatic hand-held testing device you can hold against a concrete surface to get a good evaluation. Ship it with a set of small test blocks, known good and bad, as a check. Market it to home buyers, real estate agents, etc. in countries with poor inspection. It's a hard problem, but a combination of ultrasonics, cameras, ground-penetrating radar, and mechanical probes might do it.[2]

[1] https://www.youtube.com/watch?v=GlDm_BHyNAU

[2] https://geomodel.com/applications/concrete-and-rebar-inspect...