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Had a slab blowout on me yesterday with a bad batch of mix | Concrete Finishers - Vivisector

Had a slab blowout on me yesterday with a bad batch of mix

Pouring a 12x16 patio in Austin and the truck showed up looking watery. I should have sent it back but figured it would be fine after some mixing. Halfway through the pour the edges started cracking and crumbling like sand. Lost the whole load and had to tear out about 10 yards of fresh concrete. Has anyone else had a bad batch ruin a pour and did you get the supplier to cover the cost?

3 comments

3 Comments

ray_sullivan3mo ago

Hold up, I gotta push back a little. I've been pouring for like 15 years and I've never run a slump test on a residential patio or sidewalk. Honestly, you can usually tell if it's too wet just by lookin at it and checking the mix with a shovel. I'm not sayin a bad batch can't happen, but half the time guys blame the mix when really they just poured too fast or didn't get it worked in right. The edges crackin off coulda been from you waitin too long to finish it if the heat was cookin the surface. I'd push back on the supplier but I bet they fight you on it unless you got real proof.

jenny_lane123mo ago

Did you run a slump test on it before you started pouring? Tbh that's really the only way to know for sure if the mix is too wet, not just eyeballing it. If the edges were crumbling like sand it sounds like the mix was way too high on water and the aggregate started separating from the cement paste. I had a similar thing happen with a sidewalk once and the supplier tried to blame it on me not ordering the right mix, but I had photos and the test results to show it was their load.

walker.julia3mo ago

Is that really something most people do though? I feel like half the guys I see on job sites just eyeball it and hope for the best. @jenny_lane12 you're totally right about the slump test being the only real way to prove the mix was bad, because suppliers will always try to point the finger back at you. That crumbling edge thing is a dead giveaway that the water to cement ratio was off, like the aggregate just fell right out of the paste. I had a driveway pour where the top layer started flaking off a year later, and I'm pretty sure it was the same issue from day one. A five minute test saves a whole lot of headache down the road if you ask me.