In the past, winter construction often meant a halt to concrete projects - low temperatures would impede cement hydration, leading to insufficient concrete strength, cracking or extreme vulnerability to damage. But things have changed now. With the help of advanced additives such as redispersible latex powder (RDP) and cellulose ethers, pouring concrete in winter is not only feasible but can also produce structures as durable as those poured in summer.
Why was pouring concrete in winter once considered a risky endeavor?
The strength of concrete stems from the hydration process: cement reacts chemically with water to form a crystalline structure. This process is highly sensitive to temperature. According to the ACI PRC-306-16 specification of the American Concrete Association, when the temperature is below 4°C, the hydration reaction will significantly slow down; and when it is below 0°C, the free water in the mixture will completely freeze. After water freezes, its volume expands by 9%, generating internal stress. This not only causes the concrete matrix to crack but also damages the bonding structure.
Additives making winter concrete construction feasible: RDP and cellulose ethers
The two additives worked together to solve the three key problems encountered during winter concrete pouring: slow hydration, frost damage, and poor operability.
Cellulose Ester: Water Retention "Expert"
Without water, the hydration process cannot occur - and in winter, water loss is extremely rapid. Hydroxyethyl methylcellulose (HEMC) and other cellulose esters are like "water locks", able to form a thin gel film on the concrete surface, slowing down water evaporation and ensuring that the cement always has sufficient water for the reaction.
Eg:Longou's ModCell® T5035 HEMC---The product is specially designed for high-end tile adhesives and mortars, and it boasts excellent water retention properties - which are crucial in environments where the humidity drops sharply and the wind intensity increases in winter.
2. RDP: The "Flexibility" against Freeze-Thaw
Even when the hydration process proceeds normally, concrete subjected to low-temperature curing often has a hard and brittle texture，prone to cracking under the action of thermal stress. However，RDP forms a flexible polymer film as it dries，absorbing the expansion and contraction stresses generated during freeze-thaw cycles.
The core indicator for choosing RDP in winter is the Minimum Film Formation Temperature (MFFT). If RDP with an MFFT higher than the ambient temperature is used, it will result in incomplete bonding layer and insufficient strength.
Eg:Longuo's ADHES® VE3213, with an MFFT of 0°C, is highly suitable for mild to moderate low-temperature environments ( 0–4°C).
Winter concrete construction: Beyond additives - Key process control
1.Mixing and pouring process
（1）Preheating of raw materials: Heat the water to 60–80℃, and heat the aggregates to 60℃.
（2）Optimize the batching sequence: First, mix the aggregates with hot water for 30 seconds, then add cement, RDP and cellulose ether, and finally add the remaining water. The mixing time should be extended by 50% to ensure uniform mixing of all components.
（3）Temperature control: The temperature of the mixture leaving the mixer should be controlled within 10–15℃, and the temperature of the mixture entering the mold should not be lower than 5℃.
2.Maintenance and protection measures
（1）Insulation covering: Use flame-retardant rock wool insulation blankets (thermal conductivity ≤ 0.04 W/(m・K)), with a lap width of no less than 10cm.
（2）Heating shed construction: For outdoor operations, a heating shed should be built to maintain an internal temperature above 10℃.
（3）Temperature monitoring: Conduct temperature checks once every hour - the temperature difference between the core and the surface of the concrete should be ≤ 25℃, and the cooling rate should be ≤ 3℃/hour to avoid cracks caused by excessive temperature difference.
Common Problems in Winter Concrete Construction
Question: How to prevent fire risks during winter maintenance?
Choose B1-level or higher flame-retardant insulation materials. Keep the heater at least 1 meter away from the concrete surface. Avoid using propane heaters in enclosed spaces - their released moisture can interfere with the formation of RDP polymer films.
Question: Can RDP/cellulose ethers be mixed with antifreeze agents?
Answer: Generally, it is possible, but avoid chlorinated early-strength agents - these substances may react with RDP and reduce the bonding strength.
Question: Can RDP be used at zero-degree temperatures?
Answer: It depends on the MFFT. If the MFFT of RDP is higher than the ambient temperature, it is not recommended to use it - for example, using RDP with an MFFT of 8℃ in an environment of 0℃ will result in a powder-like, non-bonding film.
Question: Can additives replace traditional methods such as insulation blankets for curing?
Answer:No. Additives and insulation measures need to work together. The function of HEMC is to lock in moisture, while insulation measures are to retain the heat generated during the hydration reaction.
Question: Does the viscosity of HPMC affect the construction performance in winter?
Answer: Yes. For horizontal construction, a low-viscosity HPMC is needed to ensure good fluidity and no segregation during mixing; for vertical construction, a high-viscosity HPMC is required to prevent sagging.
The current issue is no longer "Can concrete be poured in winter?", but "How to pour it correctly?".Longou can offer you customized products and construction plans, helping you transform the winter construction challenges into opportunities to ensure the project progress.
Post time: Nov-08-2025