Many concrete contractors must cope with cold weather effects on freshly placed concrete. Insulated curing blankets, used along with other cold weather procedures, can permit concrete work at temperatures as low as -25 degrees Fahrenheit.
INSULATION SUPPLEMENTS OTHER METHODS
Several strategies, combined or used separately, can speed up strength gain in cold weather:
- Make mix design changes
- Heat water and/or aggregates
- Keep the freshly placed concrete warm with a heat source
- Cover concrete with an insulating material
CHOOSING THE INSULATING MATERIAL
Most contractors today use curing blankets. Fiberglass or closed-cell foam insulating material forms the blanket core. It's covered with woven polyethylene fabric and buttoned to the fabric to keep it from bunching or sliding. Blankets made of closed-cell foam are more effective than fiberglass blankets. The foam doesn't absorb water or compress after repeated use. Polypropylene foam provides excellent thermal protection because of its closed-cell structure, small cell size, and very low density.