“Concreting” in the Winter

Throughout the United States and Canada contractors experience the dilemma of how to place concrete repair materials in cold weather conditions.  When freshly placed Portland cement concrete falls below 40°F (4.4° C), hydration of the cement particles virtually stops.  This can result in numerous failures occurring within the new placement.  However, proper planning and knowledge of precautions that can be taken will aid in ensuring a lasting repair.

The American Concrete Institute has published ACI 306R-10, Guide to Cold Weather Concreting, which has valuable recommendations that can be utilized on new concrete placements.  MAPEI has outlined general recommendations in its Technical Bulletin “The Impact of Cold Weather on Concrete Repair Materials, 010810-TB”, for concrete repair materials and self-leveling underlayments.  These recommendations include:

-Use an infrared thermometer to accurately determine the substrate and ambient temperatures.

-Never apply repair products over frozen or frosted surfaces.

-Use recognized methods supported by industry standards to bring substrate and ambient temperatures to well above the recommended installation threshold of 45°F (7°C).

-Provide sufficient heat so that the substrate temperature remains above the minimum temperature until the repair material has reached at least 25% of its 28-day compressive strength. Maintain sufficient heat while placing the repair product as well as during finishing and throughout the curing period.

As always, your individual job may require more or less planning to successfully install concrete in less than optimal conditions.   Consult with your local MAPEI CRS sales representative or with MAPEI CRS Technical Services for help in choosing the correct product and placement requirements for your needs.