What purpose do warmers and blankets serve in cold weather concreting?

• A. They speed up hydration
• B. They protect to avoid freezing and cracking
• C. They color the concrete
• D. They improve surface texture

Answer: (B)

The key idea is preventing damage from freezing during the curing period. Warmers and blankets keep the concrete warm enough so the water inside the pores doesn’t freeze as it cures. When freezing occurs, internal pressure from ice formation can crack the concrete and slow down or stop hydration, leading to weaker strength. By supplying heat and insulation, these devices maintain a suitable temperature and slow heat loss, letting hydration proceed and reducing the risk of cracking.

They also help retain moisture, which supports proper curing. They aren’t used to color the mix or to change the surface texture; their primary purpose is protection against freezing and preventing related cracking while promoting proper strength development.