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Pouring a big floor last Thursday and realized my vibrator was doing more harm than good
We were running a 30 yard slab at a shop in Eugene and I kept getting these honeycomb pockets near the edges. Old foreman walks over and tells me I'm over-vibrating the mix, basically pushing all the fines away from the forms. He had me back off and just let the concrete settle on its own. Night and day difference. Anyone else had to unlearn bad habits with a vibrator?
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tessap9718h ago
Over-vibrating is real but I'm not sold on just letting concrete settle on its own either. Had a job last year where we backed off too much on the vibrator and ended up with rock pockets near the rebar because the mix didn't flow into the tight spots. There's a sweet spot between working it enough to get consolidation and overdoing it where you push the cream away. Seems like the old foreman might have been right for that specific mix or maybe the slump was a little high to begin with. Sometimes the issue isn't the vibrator, it's how wet the concrete is when it comes off the truck.
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zarat3717h ago
Ha! So the sweet spot is just "don't screw it up either way.
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hernandez.gavin13h agoMost Upvoted
Seems like the old foreman might have been right" is always a gamble. But nobody's talking about the timing of the vibrator. I've seen guys hit it the second the chute opens and then again right before finishing. That's two different problems happening at different stages. Early vibration helps fill, late vibration just pushes water up.
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