Where and how antifreeze additives are used in concrete

The effect of low temperatures has a negative effect on the rate of hardening of concrete due to the freezing of water, as a result of which the hydration process stops. Products turn out less strong, and also their frost resistance decreases. This is easily explained by physics - freezing, water expands, which severs the bonds of aggregate and cement.

General information

To ensure consistently high strength of the concrete material, it is necessary to ensure that water is kept in it in a liquid state. Since it is not customary to heat concrete under construction conditions, special antifreeze additives are used. As a result of their introduction, the freezing temperature of the liquid decreases, due to which the process of solidification of the mixture is normalized.

Frost-resistant additives for concrete are liquids that contain calcium nitrate (from 42 to 45%). At the same time, their density is about 1.4 kg / l, and the activity of ions is 5-8 (pH). The use of various substances may slightly change the above indicators.

Additives for concrete in cold weather have the following advantages:

• moisture in concrete mixes freezes at lower temperatures;
• concrete becomes more mobile, making the elements of building structures easier to form;
• the presence of a corrosion inhibitor in their composition slows down the oxidation of reinforcement;
• material becomes waterproof.

Effect when used

1. After the substance is added to the mixture, the carbonated calcium hydroxide in it compacts the concrete.. In addition, the likelihood of "efflorescence" on its surface is reduced.

   

1. The strength indicators at the same time increase almost 2 times, and the material itself is gaining them much faster.. Due to this, the formwork can already be dismantled after 18 hours, defects and chips are completely excluded.

Tip: if you apply additives for concrete in frost, even the lowest grade cement becomes suitable for use, which significantly reduces the total cost of work.

1. The possibility of reducing the thickness of the concrete layerthat will not affect strength performance.
2. Applying additives to concrete in frost, you save on a waterproofing layer, the need for which simply disappears.

The order of application of additives

1. The introduction of all components necessary for the production of concrete, including frost resistant additives for concrete, water, cement, plasticizer, should be carried out simultaneously.

Tip: in order for the additive to be able to slightly replace the mixing water, it is recommended to bring it along with the water.

1. After that, all the components are thoroughly mixed for about an hour until a homogeneous mixture is formed, for which a concrete mixer can be used. At the same time, the degree of homogeneity is directly affected by the mixing time and the characteristics of the equipment itself. Therefore, the more homogeneous the mixture you want to achieve, the longer it will be necessary to mix all the ingredients.
2. The instructions on the packaging allows strict adherence to proportions. Most often, antifreeze additives for concrete are not more than 0.2% of the total mass of cement.
3. Be sure to comply with the temperature recommended by the manufacturer. When lowering this value for every degree, add 0.05% of the additive. This means that when using an additive at a temperature that is lower than the recommended one by 5 degrees, its percentage should be increased to 0.45%.

Most often, manufacturers use grams to indicate the dosage, to obtain milliliters, the weight should be divided by 1.45. After all the calculations have been made, the required amount of the additive is mixed by hand with the solution.

Their use is recommended to limit only minus temperature indicators, and use in other temperature conditions is prohibited. At the same time, in order to avoid drying out of concrete structures, they should be moistened for two days.

Tip: if you have difficulty with dismantling concrete structures, you will be able to cut reinforced concrete with diamond circles with a professional tool.

Application area

Usually a frost resistant concrete additive is used during the construction of monolithic reinforced concrete products. In addition, it is possible to use them for lightweight concrete, as well as when laying pavements. The recommended temperature regime for the use of additives largely depends on the specific substance used, and is in the range between -15 and -25. ⁰WITH.

In addition, winter additives for concrete can be used for other structures:

• bridges;
• oil and gas production platforms;
• dams;
• the dams.

Thanks to him, work on the above objects can be conducted year-round, without stopping for a time of serious frosts and not dependent on atmospheric phenomena. The labor force and equipment are used more rationally, which leads to a significant reduction in terms, and, accordingly, the cost of the project decreases. Most often, additives are packaged in 5-liter cans or in containers with a total volume of 1 cubic meter.

Advice: it is necessary to lay communications through the base of the house - diamond drilling of holes in concrete with special equipment will help.

Conclusion

Do not want to interrupt the construction of concrete work during the cold period - use special antifreeze additives. With their help, the mixture will be able to gain its strength in accordance with all parameters, since they will not allow water to freeze and stop hydration. The video in this article will help you find additional information on this topic.