Lower temperatures contribute to the not so quick hardening of concrete. Water under these conditions freezes, and the hydration of the binder is suspended.
Need to use
For concrete, such processes are undesirable, as they adversely affect strength. As a result, the design becomes loose, and its frost resistance leaves much to be desired. In order to ensure a normal set of strength at low temperatures, it is necessary to take appropriate measures that contribute to the preservation of water in the liquid phase.
General Description of Antifreeze Additives
Antifreeze additives in cement mortar are added at low temperatures. They are a liquid that may have a yellowish or light gray tint, and may also be completely colorless. The mixture has a density in the range of 1.4 kilograms per liter. As for the mass fraction of calcium nitrate, it is in the range from 42 to 45%. The characteristics mentioned may vary, depending on the type of substance used.
Anti-frost additives in cement mortar are added if necessary to increase the mobility of the composition, which greatly facilitates the process of formation of structural elements. These mixtures contain a corrosion inhibitor that protects the reinforcing bars from oxidation. After adding the described composition, the building mixture gains strength in a short time, and the water resistance of the material increases.
The method of application of additives in the preparation of the solution
When antifreeze additives are added to the cement mortar, plasticizer, sand, and cement are used in parallel. It is advisable to add the above composition along with water, because the antifreeze liquid is able to partially replace the mixing water.
All ingredients mix well, during which a concrete mixer should be used. This stage should last for an hour. The result is a homogeneous mixture. The degree of homogeneity will depend on the mixing period and the quality of the concrete mixer. The amount of additive should be equal to the volume that is written on the package. Most often it is 0.2% of the volume of cement by weight. It is important to note that this volume corresponds to the temperature value specified in the instructions.
When antifreeze additives are added to the cement mortar at home, it is important to consider that with decreasing temperature the volume of the product should be increased. It is important to take into account that 0.05% of the composition corresponds to one degree. Dosage is usually indicated in grams. If this value is indicated in millimeters, to determine the amount of composition, it is necessary to divide its mass by 1.45. In the end, it will be possible to obtain the required volume, expressed in millimeters. It remains only to measure the required amount of the mixture, and then introduce it into the solution.
Antifreeze additives in cement mortar, reviews of which are mostly positive, are added exclusively at negative ambient temperatures. Use these mixtures under other conditions is unacceptable. Structural elements and concrete products should be moistened for two days, this will prevent drying out.
Potash consumption
Potash is used in construction as an anti-frost additive. It is also known as technical potassium carbonate. It can be purchased in the form of a crystalline powder, which is characterized by excellent solubility in water. A saturated solution freezes at a temperature that is equivalent to -36.5 degrees. Potash can significantly accelerate the hardening and setting of concrete.
The characteristics of the composition will be maintained if during the pouring process until the strength is reached, the concrete temperature does not drop below -25 degrees. If there is a need to increase the frost resistance of concrete, then additionally add liquid sodium glass.
Similar antifrosty additives are introduced into the cement mortar , as a rule, to ensure a short thickening time. Moreover, the process is practically independent of the ambient temperature. Potash acts as a neutral supplement that does not affect rebar. With a decrease in the temperature mark, the consumption of the substance increases. Thus, if the mark of the thermometer is in the range from 0 to -5 degrees, then for one hundred kilograms of cement you will need from 5 to 6 kilograms of potash.
In the temperature range from -6 to -10 degrees, the antifreeze additive should be used in a volume of 6 to 8 kilograms per hundred kilograms of cement. Whereas at -11 to -15 degrees the potash consumption increases in the range from 8 to 10 kilograms per similar volume of the cement component.
Reviews
According to consumers, antifreeze additives in cement mortar, the consumption of which was mentioned above, are introduced not only for the preparation of concrete mixtures. Among other things, they can be used in lightweight concrete, in the manufacture of road elements, in the mixing of plaster mortars, as well as in the formation of pavement.
In industry, antifreeze additives are used in the construction of bridges, buildings for various purposes, oil and gas platforms, dams and other things. Using these compositions, it is possible to reduce the construction time, as well as reduce the cost of the facility due to the rational use of labor and equipment. This is very popular with private consumers and a professional builder.
Conclusion
If you use antifrosty additives in cement mortar, salt will form together with concrete hydration products. Before using substances with the described purpose, it is necessary to familiarize yourself with the features and characteristics of the ingredient discussed above.