1) Concrete strength is reduced by 50% if freshly mixed concrete freezes due to exposure to low temperatures below 5°C for three days. Freezing and thawing cycles also increase porosity and reduce strength. 2) Several methods can be used to maintain the temperature of freshly poured concrete in cold weather, including enclosures, insulating materials, and heaters to protect the concrete and allow proper curing. 3) Specifically, polyethylene sheets or insulating blankets made of fiberglass or sponge rubber can be used as insulating materials, while direct-fired or indirect-fired heaters supply heated air to keep the concrete warm.