The cold weather is upon us, which means we need to take extra care in our concrete. A.H. Harris is your choice for tips & solutions for handling the cold this season. Concrete placed during cold weather will develop sufficient strength and durability to satisfy intended service requirements only if it is properly produced, placed and protected.
ACI 306 “Cold Weather Concreting” defines cold weather concreting as a period when for more than three (3) consecutive days, the following conditions exist:
- The average daily air temperature is less than 5°C (40°F) and,
- The air temperature is not greater than 10°C (50°F) for more than one-half of any 24 hour period.
To handle the cold, have everything you might need on hand and review these tips:
- Frozen ground—NEVER place concrete on frozen ground or onto ice or snow. There are a couple of problems with this. First, frozen ground will settle when it thaws, cracking the concrete. Second, when the ground is cold, the concrete in contact with it will be cold and will set more slowly. You can even get crusting, with the top part of the concrete set and the bottom still soft.
- If the ground is frozen, you can thaw it using hydronic heat pipes and blankets, or electric blankets.
- Remove all snow and ice in areas where concrete is to be placed. Also remove any standing water that could get mixed into the concrete.
- Warm up anything that will come in contact with the concrete, including forms and any embedments, to at least 32°F. If it’s not too cold and you cover everything with tarps the day before the pour, it will stay dry and warm enough. Keep tools in your truck or trailer.
- Be ready with blankets, even if you don’t think it will get that cold. Also consider whether you will need lights if the concrete sets more slowly than expected and the winter sun sets just as you’re finally ready to start finishing.
See the 2015 Fall / Winter flyer for concrete blankets, electric blankets, tarps, drum heaters, calcium chloride, lights, cold weather extension cords and more products for winter protection. Visit your local Harris to get advice and all the gear needed to get you ready for winter or keep you going despite the cooler weather. A.H. Harris, since 1916.