How to Pour Concrete in Cold Weather
Posted On: 12/03/2018 | Posted by: DY Concrete Pumps
Many construction operations must keep working throughout the year to keep up with project demands and avoid costly shutdowns. In regions where the thermometer takes a nosedive during the colder months, such as the northern United States and Canada, this continuation requires knowing how to pour concrete in winter. The American Concrete Institute defines cold weather as a period of three days or more where the average daily air temperature is less than 40 degrees Fahrenheit and does not exceed 50 degrees Fahrenheit for more than 12 hours during any 24-hour period.
While pouring concrete is challenging, you can attain a successful outcome by adhering to the following recommendations:
- Avoid pouring concrete onto frozen ground, ice or snow. If necessary, use space heaters or other portable heating equipment to generate sufficient thawing before pouring. Provide adequate ventilation when using combustion heaters inside enclosures.
- When choosing cold weather concrete, select a material that includes the proper amount of air-entrained voids that will minimize the impact of frequent freezing and thawing. The concrete should also feature minimal slump and a low water-to-cement ratio, which will help to prevent bleeding and significantly reduce setting time.
- Hydration describes the chemical reaction that occurs when the compounds in the cement used to make the concrete form bonds with the hydrogen and oxygen molecules in water and become hydrated. During this time, the concrete is in a plastic state to facilitate transporting and placing. Even if you keep the dry product in a warm area, it may be necessary to elevate the temperature during the hydration period. You can accomplish this by adding more cement or water to the mixture, heating the aggregates in the mix or using a chemical accelerator.
- Determine the appropriate protection requirements for the concrete, including steps to prevent freezing immediately after pouring. You will also need to ascertain if there are any special considerations or strength requirements to meet so that you can provide adequate protection for the poured concrete at specific temperatures.
- Pour and place the concrete as soon as possible after its arrival at the job site. Remember — fresh concrete that freezes within the first 24 hours can lose up to one half of its strength.
- When pouring concrete in winter, always use a chart to track changes in the internal temperature of the concrete, as well as the air temperature.
- If you’re planning to use heated enclosures during your cold-weather concrete pouring project, make sure they’re both weatherproof and windproof. Maintain the temperature of the concrete at above 40 degrees Fahrenheit for at least four days after removing the enclosure (or insulated blankets if you use those instead).
Contact DY Concrete Pumps for Advice Regarding Concrete Pumping in Cold Weather
DY Concrete Pumps, Inc. has been a trusted supplier of concrete pumping equipment to the construction industry for more than 30 years. Headquartered in Calgary, AB, Canada, we understand what it takes to deliver superior results when pumping and pouring concrete in freezing weather. Contact us to learn more today.