COLD WEATHER CONCRETE
The following information will help you successfully place concrete in cold weather. As always, Cemstone is committed to our mutual success and following these guidelines will result in satisfied customers.
Special precautions are needed for placing concrete in cold weather conditions. Cemstone uses heated mixing water and if needed, heated aggregates to keep concrete temperatures at the time of batching above 60°F in cold weather.
The slider below explores ten items that will help prevent cold weather concrete issues.
Hot weather is any combination of the following conditions that tends to impair the quality of freshly mixed concrete by accelerating the rate of moisture loss and rate of cement hydration, or otherwise causing detrimental results:
- High ambient temperature
- High concrete temperature
- Low relative humidity
- Solar radiation
The following list of practices and measures to reduce or avoid the potential problems of hot weather concreting are:
- Select concrete materials and proportions with satisfactory records in hot weather conditions;
- Cool the concrete;
- Use a concrete consistency that permits rapid placement and effective consolidation;
- Minimize the time to transport, place, consolidate, and finish the concrete;
- Plan the job to avoid adverse exposure of the concrete to the environment; schedule placing operations during times of the day or night when weather conditions are favorable;
- Protect the concrete from moisture loss during placing and curing periods; and
- Schedule a preplacement conference to discuss the requirements of hot weather concreting.
Potential problems for concrete in the freshly mixed state are:
- Increased water demand
- Increased rate of slump loss and corresponding tendency to add water at the job site
- Increased rate of setting, resulting in a greater difficulty with handling, compacting and finishing and a greater risk of cold joints
- Increased tendency for plastic shrinkage cracking
- Increased difficulty in controlling entrained air content
Potential deficiencies to concrete in the hardened state may include:
- Use of cements with increased rate of hydration;
- Use of high-compressive-strength concrete, which requires higher cement contents;
- Design of thin concrete sections with correspondingly greater percentages of steel, which complicate placing and consolidation of concrete;
- Economic necessity to continue work in extremely hot weather; and
- Use of shrinkage-compensating cement.