Pouring Concrete in Winter

If the average daily temperature is below +5°С and the minimum daily temperature is below 0°С, concreting should be carried out by the process charts, which contain:

the process of manufacturing and transportation of RMC, which ensures the set temperature of the concrete is maintained during unloading and placing;
the methods and temperature conditions for curing and further care of concrete;
the rules for the use of moisture-proof materials and insulation of formwork and open surfaces of the structure;
the information on the strength of concrete at the time of demoulding;
the terms of and procedure for demoulding.

Use fast-setting portland cement with high heat. CEMARK SHDYDKYI is the best choice for concreting in the cold season.
Use antifreeze additives – they reduce the freezing point of the water in the concrete structure.
Prepare the concrete mix inside the heated premises using heated water and thawed (or heated) aggregate with a temperature above 0°C. The maximum acceptable temperature of the water used to prepare the concrete mix is 80°C.
First, load the coarse aggregate and about half of the heated water into the mixer. Then rotate the mixer a few turns and add sand, cement and the remaining water.
When transporting the RMC to the site, cover and insulate it to prevent the mix from cooling down.
Concrete must be poured continuously. In case of a forced interruption, cover and insulate the concrete surface and, if necessary, heat it.
Immediately after concreting, cover the surfaces of monolithic concrete and precast structures, which are not covered with the formwork, with waterproofing and thermal insulation materials. During concrete curing in a heated enclosure, the ambient temperature in contact with it should not be below +5°C.
In monolithic construction, the “thermos” method can be used to maintain the temperature of the concrete while it is gaining in strength. The technique consists of retaining the internal heat of concrete and the heat released during its hardening. A “thermos” can be made of any material with high heat-retaining ability. Such materials are used to equip the formwork and cover the concrete surface.

The temperature of concrete during pouring, the method and insulation materials should be chosen so that by the time the temperature drops to 0°C, the strength of concrete will have reached 60% of its design strength.

The “thermos” method can be combined with electric heating methods to ensure maximum speed and efficiency of strength gaining and the completion of works in a short time.