I've been using the wrong concrete mix for interior slabs for years

A guy on a job in Phoenix last month saw me ordering 4000 psi mix for a warehouse floor and asked if I was worried about shrinkage cracks. He said for big interior pours with no freeze-thaw, a lower psi mix with a good water reducer actually performs better and costs less. Has anyone else switched to a 3000 psi mix for similar jobs and seen fewer issues?

2 comments

2 Comments

hugobarnes2mo ago

Worried about shrinkage cracks" is putting it mildly. I spent a decade chasing those hairline cracks before a batch plant guy set me straight on the lower psi mix. It was a real forehead-slapper moment for sure.

king.aaron2mo ago

Forehead-slapper moment" is right. I guess we all pay for that one expensive class on proper concrete.