Anti-Freeze Admixtures for Concrete: Benefits, Performance and Application
Construction during the colder months always involves certain risks. At low temperatures, the cement curing process slows down significantly, while water in the concrete may freeze, forming ice crystals that damage the structure of the material. To prevent these processes, anti-freeze admixtures for concrete are used – special products that ensure normal curing of the concrete mix at sub-zero temperatures.
These admixtures allow concrete work to be carried out in winter while maintaining the strength, crack resistance and durability of structures.
What are anti-freeze admixtures for concrete
Anti-freeze admixtures are special chemical products added to concrete or mortar to ensure curing at temperatures below +5 °C. Their action consists in accelerating the cement hydration process and lowering the freezing point of water.
According to BAYRIS technical data, anti-freeze admixtures make it possible to carry out concreting at temperatures from +5 °C to –15 °C. They increase the strength and crack resistance of concrete, improve the plasticity of the mortar and prevent its segregation.
How anti-freeze admixtures work
Anti-freeze admixtures change the physicochemical properties of water and cement. Active components, including sulphonates, nitrates and modifying additives, influence the crystallisation process, preventing water from freezing, and accelerate the cement hydration reaction. As a result, concrete gains the necessary strength before temperature affects the curing process.
The use of such admixtures ensures accelerated setting of concrete (from 30 to 100 % depending on temperature), which prevents the mix from freezing. In addition, anti-freeze plasticisers reduce water demand by up to 10 %, increasing the density and quality of the finished concrete.
Efficiency of using a plasticiser
The table below shows how the properties of the concrete mix change when Bayris plasticiser is used.
| Components | Without plasticiser | With plasticiser (0.5 l / 50 kg of cement) |
|---|---|---|
| Cement (M400) | 350 kg | 350 kg |
| Crushed stone | 1200 kg | 1200 kg |
| Sand | 650 kg | 650 kg |
| Water | 210 l | 180 l |
| W/C | 210/350 = 0.6 | 180/350 = 0.52 |
| Concrete strength after 28 days | 20 MPa (M200) | 27 MPa (M250) |
When and how to use anti-freeze admixtures
Anti-freeze plasticisers are designed for all types of concrete: reinforced and non-reinforced, as well as for mortar mixes and dry building mixes. They can be used when installing screeds, in monolithic construction, masonry and other works at low temperatures.
Recommended dosage:
- from +5 °C to –5 °C — 0.6 l per 50 kg of cement;
- from –5 °C to –10 °C — 1.2 l per 50 kg of cement;
- from –10 °C to –15 °C — 1.4 l per 50 kg of cement.
Main rules for winter concreting:
- Use rapid-hardening cements (PC I–400, PC I–500, PC II/A-S–400).
- Store all components in a warm room; frozen aggregates are not permitted.
- Heat the mixing water to +70–80 °C; the temperature of the finished mix should be around +30 °C.
- Before placing, remove snow and ice from formwork, moulds and reinforcement.
- After placing, protect the concrete from heat loss – use insulating mats, film or heating.
If these rules are followed, concrete with anti-freeze admixtures cures evenly and gains the required strength without the risk of freezing.
An anti-freeze admixture is not antifreeze
It is important to understand that an anti-freeze plasticiser is not antifreeze.
Antifreeze prevents liquids from freezing, but it does not affect the chemical process of cement curing. BAYRIS anti-freeze admixtures work differently: they interact with cement, accelerating hydration and ensuring rapid setting of concrete.
The chemical composition of such admixtures allows the liquid not to freeze during short-term temperature drops to –10 °C, but the main function of the product is not to maintain a liquid state, but to ensure concrete strength development even in cold conditions.
Typical mistakes during application
- Using detergents or soap as substitutes for plasticisers. Such substances react with cement and disrupt the hydration process.
- Excessive dosage of the admixture. Too large a quantity may cause segregation of the mix.
- Using frozen materials. This reduces the effectiveness of any admixtures.
- Lack of insulation after concreting, which leads to cooling and damage to the concrete structure.
Why choose chloride-free admixtures
Some low-cost anti-freeze admixtures contain chlorides, which may cause reinforcement corrosion and efflorescence. In contrast, Bayris products are completely chloride-free, ensuring safe use in reinforced concrete structures and a long service life for building elements.
Advantages of BAYRIS anti-freeze admixtures
- The ability to carry out concreting at temperatures down to –15 °C.
- Increased strength and crack resistance of concrete structures.
- Improved workability and plasticity of the mix.
- Accelerated setting during the first hours after placement.
- Reduced water demand by up to 10%.
- Chloride-free – safe for reinforcement.
- Versatile application – suitable for concrete, screeds, masonry mortars and rendering mortars.
Conclusions
Anti-freeze admixtures for concrete are an effective solution for winter concreting. They accelerate the setting process, increase structural strength and make it possible to carry out construction work at temperatures down to –15 °C.
The BAYRIS brand offers a range of chloride-free anti-freeze plasticisers based on sulphonates and nitrates. They combine anti-freeze, plasticising and strengthening properties, ensuring reliable concrete performance even in the most challenging weather conditions.
Modern technologies make it possible to build during winter without compromise – concrete with BAYRIS admixtures can be just as strong as concrete placed in summer.