I finally checked the PSI on a batch of mix that came out weird last week

So I had this job where the concrete looked fine going in but after 3 days it still felt soft. I finally looked at the batch ticket and saw the PSI was rated at 2500 instead of the 3500 I ordered. My supplier swears that's normal for certain pours but I think they just messed up. Has anyone else caught a mix being way off from what you asked for?

3 comments

3 Comments

bethcarr3mo ago

That 2500 PSI on a 3500 job is a huge red flag, especially since they didn't warn you beforehand. Was the softness just in spots or across the whole slab, because that could tell you if it was a bad batch or a placement issue?

gavinhunt1mo ago

Buddy of mine had the same thing happen on his garage slab, ended up being a bad batch from the plant but the crew made it worse by adding water onsite. Took a core sample and it came back 2800 PSI in some spots and 1900 in others. They ended up settling for a discount rather than ripping it out because the soft spots were in the middle where the load was less.

tara_palmer3mo ago

Bet on that being a placement issue. Sounds like someone was in a hurry and didn't vibrate it right. Bad batch usually shows up more uniform weak. But spotty softness? That's on the crew. Lucky they didn't have to tear it all out and repour.