 鲜花( 776)  鸡蛋( 24)
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Commonsense tips for concreting in cold weather:
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4 i- L: ^* M& O1 ]8 P- c' w- T; t 1。 Discuss with your ready-mix producer the possibilities of using hot water, heating the aggregates, increasing the cement content, or adding an accelerating admixture.
* n' l$ q: k: G x: G5 O 2。Order air entrainment if the concrete is exposed to freeze-thaw conditions during or after construction.
% ^: ?& u- |+ ?8 D# w2 | 3。Plan ahead. Have insulation and heaters ready, and inform your ready-mix producer of what concrete temperature you'll need for your project.
9 k# D0 x$ v: s) m 4。Don't place concrete on a frozen subgrade; thaw the subgrade with steam or protect it with insulation.
/ k5 I+ Z6 \+ I 5。Add a gallon of water per cubic yard of concrete to increase set time up to one-half hour; adding two gallons can increase set time up to an hour.
+ C2 P I" w! `! i 6。Provide triple insulation thickness at the corners and edges of walls and slabs.
) t) B! r* g. Z6 l% d. d 7。Protect fresh concrete against the disruptive effects of freezing until the concrete attains a compressive strength of about 500 psi. Concrete gains very little strength at low temperatures.' j. y( K4 u2 ]( n9 J
8。Don't expose concrete surfaces to a sudden temperature drop; gradually reduce the insulation or enclosure temperature to control concrete cooling (no more than a 50 degree F drop in 24 hours).
+ ]* e0 `. ~6 e3 G7 X5 z 9。 Avoid using unvented heaters; carbon dioxide from the heaters can cause soft, dusting floors.. H F% P$ Z2 N! L" g5 M
10。Keep heaters attended at all times; they are a fire hazard when burning and are of no value when out of fuel., W0 K. F6 w6 f1 M4 x. p' o
11。It is good practice in cold weather to leave forms in place as long as possible. Even within heated enclosures, forms serve to distribute heat more evenly and help prevent drying and local overheating.- A' ~! I( ]8 ^) B: t# O1 r
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楼主: bigzzh
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发表于 2013-11-20 22:37
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