If it's below 40°F, then use cold weather curing techniques. Options for cold weather concrete curing include blankets, additives and heaters.
For thawing, curing and surface heating the Powerblanket® flat blanket, with patented green heat® technology, saves money by not subjecting projects to costly cold weather delays. Sold in a variety of sizes and easy to install.
Powerblanket Concrete Curing Blanket - 10ft.L x 5ft.W, Model MD0510
Repairing Damaged Concrete During the Winter Season
Powerblanket heated concrete curing blankets are the ideal choice for any cold weather construction project requiring thaw and cure (medium heat)
Heated Concrete Curing Blankets
Heated Concrete Blankets
Concrete Heat Blanket vs. Maturity Method: How to Reduce Curing Costs?
Pouring Concrete in Cold Weather - Can Your Pour in Winter? - Concrete Network
Powerblanket MD0320 electric concrete curing blanket: Powerblanket has changed the conventional method of transferring heat to concrete. The revolutionary new design provides uniform heat across entire blanket, eliminating any hot and cold spots. Powerblanket products provide a maintenance-free heating solution, which eliminates the hassle of dealing with cold weather. If an effective heating solution is applied during the curing process, concrete will cure faster and stronger.
3' x 20' Concrete Curing Blanket - Powerblanket MD0320
Concrete Curing and Power-blanket
Cold Weather Concreting Practices
Pouring Concrete in Cold Weather - Can Your Pour in Winter? - Concrete Network