Replies

1. 
   Mark_T | Nov 20, 2005 04:02pm | #1

   Is a frostwall the same thing as a stem wall?

2. 
   Norse | Nov 20, 2005 04:21pm | #2

   Precautions? You bet ya! The water in the concrete cannot freeze until the hydration process is complete. If its cold, order the mix with hot water and then find a way to insulate or heat the wall for several days. Usually, insulation blankets suffice (they're made for concrete and you may be able to rent them). I've seen hay used but I'm not sure how effective it is. There's lots of resources on the web regarding cold weather concrete. It would indeed be a shame to go to all that work and have it ruined!
   Norse

1. 
   brownbagg | Nov 20, 2005 05:23pm | #3

   also think about 2% calicum2+3=7

1. 
   WayneL5 | Nov 20, 2005 05:58pm | #4

   Brownbagg, I've had an engineer tell me that calcium chloride will cause corrosion of embedded steel, and he recommended never using it.  You have lots of experience with concrete, what have you found?

1. 
   brownbagg | Nov 20, 2005 08:19pm | #7

   A concrete plant will not use any chemicals that are harmfull to the finish product or not reccommended by the american concrete institute. In cold weather, concrete must be accelerated to advance hydration. This is controled by 1) type 111 high early cement 2) lowering water cement ratio by adding cement, about 200 lbs per yard 3) curing at a higher temperature, blankets, heaters, steam, hay 4) a chemical admixturescalicum chloride (CACL2) will cause corrosion in steel. But at a high dose. remember, concrete company will not sell a liability prooduct.by maintaining the dose to 2% it is quite safe for reinforcementCACL2 is not recoommended in 1) prestress concrete 2) concrete containing embedded aluiminum (conduit) 3) concrete subject to alkali aggregate reaction 4)slab with metallic shake finishes 5) hot weather concrete 6) massive concrete placements. There are also some non corrosive accelerator but they are also more expensive. I like the super plasticizer, which is not an accelerator but a water reducer, which have the same effect.Calicum is not an antifreeze product, it only allows the concrete to set quicker. Cold retared concrete setting. The product much still be protected first seven days against freezing. Around here on cold weather we will calicum the mix. Once setting as taken place, cover with hay and soil for first seven days. The local concrete plants will now excatlly what to do with cold weather concrete.2+3=7

1. 
   Catskinner | Nov 20, 2005 08:22pm | #9

   Hey Johnnie we must have been typing at the same time. I should have waited, you could have saved me a lot of writing. <G>

2. 
   WayneL5 | Nov 20, 2005 09:35pm | #11

   Thank you.  I appreciate the detail.

3. 
   blue_eyed_devil | Nov 20, 2005 06:55pm | #5

   Straw is used around here all the time. Straw the area right now. That will keep the ground from freezing. After the dig, straw the open trench. After the pour, straw over the top of the footing.

   Straw does work.

   blue

    

1. 
   Pitt | Nov 20, 2005 07:25pm | #6

   Straw does work but it needs to be sandwiched between two layers of plastic in order to protect the concrete from freezing before the heat of hydration process is complete. Keep the concrete covered for 7 days. ( Heat of hydration is the chemical reaction between cement and water which causes the concrete to harden. If the concrete temperature drops below 50 degrees F, this process stops. Your also protecting it from wind which will dry out the surface and cause the top of the slab to set up faster than the bottom 0. 

   Insulated blankets are great but the plastic and straw are probably much cheaper than renting blankets for 7 days.

   Heated water is also advisable.

   Do not use calcium chloride, this will cause corrosion of any steel reinforcing.

   Hope this helps,

   Pitt

4. 
   Catskinner | Nov 20, 2005 08:20pm | #8

   Depends on how worried you are about the cold and how much you want to spend.

   At one end of the scale is calcium chloride and straw. Whether the calcium will ever cause a problem depends upon your local conditions, it is used successfully in some parts of the country, in other parts it's trouble.

   At the other end of the scale you can cover the site with concrete blankets daily until the concrete shows up, heat the ground before you pour, batch your air-entrained concrete with high-early strength additives, go a little strong on the cement, use an accellerant,have it batched with hot stone and hot water, then cover it for three days.

   I've done all of the above, it just depends upon what you want and how worried you are about the weather.

   "There are 10 kinds of people in the world, those who understand binary and those who don't"

5. 
   Piffin | Nov 20, 2005 08:49pm | #10

   Using calacium and hot water and insulation, it is easy enough to keep the crete from freezoing while it kicks.

   The hard part is to keep the ground under it from freezing from dig untill backfill. Frozen ground heaves up. build on top of that and it will settle later. The headaches start the following year.

    

    

   Welcome to the
   Taunton University of Knowledge FHB Campus at Breaktime.
    where ...
   Excellence is its own reward!