Is there a real advantage to using 5 sack concrete when pouring an new residential slab or is 4.5 sack sufficient? The engineered plans spec 3000 psi min. Contractors state 4.5 sack is the standard. Is 5 sack overkill or a reasonable quality spec worth the extra cost?
Thanks in advance for your opinions.
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Personally, I only do slabs (monolithic, usually here in GA) at "6-sack" equivalent. Like 3500#, with the fiber also. Just feel better about it, since everything else I build might be sitting on it. Foundations have more section modulus, so I can go with 2500-3000 on them.
Forrest
Of 3 bids, all spec in 4.5 sac as standard but sometimes up it to 5 sac. Seems to be the difference of 3,000psi and 3,500 psi. Ground here is stable (weathered limestone) so I am wondering if I should stay with the standard or up it to 5 sac to be sure.
We always pour 6-sack slabs. Easier to work with and a nicer finish.
OMIGOD!
Section Modulus!
More sacks or less sacks!
Did I wander into a chat room about E.D.?
Gene, former B.S.C.E., after two Glenlivets and more cabernet than he can recall . . .
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Whoops!
Forrest - more sacks makes you stronger
For me it would all depend on the upcharge. If it isn't much I would go for the 5 sack. But 4.5 works so all you are paying for is your own peace of mind.
we use 6 sack so we can pour a little wetter and still get good break. a 4.5 sack is really a weak 3000, so anything over 4 inch slump I be scared. withs a 6 sack, a 6 inch slump still breaks good.
Edited 1/13/2007 9:28 am by brownbagg