Concrete that freezes before the initial set will lose significant strength and will not be as resistant to future weathering. This is likely to happen when the air temperature is below 5 degrees C during the pour or within 24 hours after the pour. Damage to concrete placed in very cold weather can be prevented by using Winter Mixes and winter techniques.
In the winter months concrete is produced with hot water in order to speed up set times and kick-start the cement hydration. We also use chemicals to accelerate the setting of the concrete thereby reducing the time spent waiting before finishing the concrete. This increase in early strength generates heat which fuels the cement hydration during the cooler evening hours.
Concrete should never be placed on any frozen surface. Depending on the ambient temperature covering the forms or ground could be sufficient to keep the frost away. In colder weather heaters will be required to prevent frost and ice from developing.
Covering and effectively insulating concrete is an extremely effective way to ensure your new concrete does not freeze, sets at an acceptable rate and does not suffer any loss of strength.
Our office staff is very knowledgeable in both hot and cold concrete procedures. If you have any questions please call them before your concrete arrives.