Can your concrete stand up to the weather? Paul Petitti has been doing concrete inspections since the early ‘80s. In the last 27 years as a private engineer and, since 2007, DNR’s senior AFO engineer, Petitti has seen almost everything. Follow his tips for cold weather concreting to be successful.
- Plan ahead, looking at long term forecasts and suspending concrete pouring for the season once cold weather hits.
- When construction can’t be halted, follow these practices once temperature drops below freezing:
- Use insulating blankets to keep ground from freezing before you pour a floor slab and to cover the floor slab after pouring. Leave blankets on for five days.
- Use insulating blankets to keep freshly poured walls from freezing. Leave blankets and forms on for three days.
- If cold weather arrives after properly pouring slabs and walls and the pit’s been backfilled, put a few feet of water into the deep pit to prevent frost heave.
- Be aware:
- Hot water in the concrete mix can help, but it is not a substitute for blankets.
- An accelerator admixture in the concrete (calcium chloride) may also help, but, again, it is not a substitute for blankets.
- Plastic drain tile becomes very brittle in cold weather, so it is subject to breaking during construction activities such as backfilling.
DNR rules refer to the American Concrete Institute’s Standard 306 "Recommended practices for Cold Weather Concreting.” Refer to the 306 Standard for a thorough understanding of cold weather concreting.