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Found out today that adding water to concrete after it's mixed can drop PSI by 40%
Was reading through ACI 302 last night and saw that stat about adding extra water on site. Blew my mind because I see guys doing it all the time on residential slabs around Portland. Anyone else run into this where the boss just tells you to wet it down anyway even when you know it's messing with the strength?
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the_max4d ago
Man, @brianreed hit the nail on the head about that pencil crack. I've seen the same thing on a buddy's driveway out in Beaverton - it's like a spiderweb now and it's barely three years old. What gets me is the logic on site: they think a little extra water just saves trouble, but nobody ever stops to ask if the extra water is worth a slab that might not hold up past the warranty. Do any of you guys ever pull out the ACI stat on the spot and risk pissing off the foreman, or is it just easier to let them hose it down and move on?
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brianreed7d ago
The other day I watched a guy dump a whole bucket of water into a mixer on a hot day and the pump operator just shrugged. Meanwhile the engineer was standing right there on site and didn't say a word. Makes you wonder how many driveways and patios out there are just ticking time bombs from all that extra water. My neighbor's slab has a crack you could fit a pencil in and I bet that's exactly what happened. Do you ever call it out or just let it slide to keep the peace?
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jamie_adams7d ago
Yeah that stat checks out. Seen plenty of foremen just hose it down to make it easier to work with, no care about what it does to the slab long term.
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