Dry concrete mix: composition, types and features of the

What can be used dry concrete mix in bags? What components does it consist of? What types of dry mixes can be found on sale? How is the concrete prepared on their basis processed to a full set of grade strength? Let's figure it out.

Just add water

It is believed that making concrete during construction is easy with your own hands. The components are well known - Portland cement as a binder, sand and crushed stone as a filler.

Уточним: при необходимости получения материала с улучшенными тепло- и шумоизоляционными свойствами используются пористые заполнители (керамзит, перлит и т.д.). Попадаются они и среди готовых смесей: так, сухая смесь Полистиролбетон в качестве заполнителя использует… пенопластовые шарики.

Depending on the ratio of components, you can get concrete with different properties. The strongest proportions affect brand strength.

When self-cooking, however, the resulting product will inevitably have a large range of properties from batch to batch.

The reasons?

• When mixing by hand, it is difficult to maintain an accurate dosage and, accordingly, proportions.
• Cement from different batches has markedly different astringent properties.
• The strength of concrete is strongly influenced by the amount of dust and other contaminants that inevitably fall into it during mixing.

Fortunately, there is an extremely simple way to simplify your task. Dry mixes for concrete contain precisely dosed components without any impurities. Their composition lacks only mixing water.

Cooking

Instructions for the preparation of concrete from a dry mix does not differ complexity.

В качестве образца давайте выясним, как готовится к применению сухая смесь Пескобетон M300.

• Water is poured into a clean container at room temperature in the amount of 1.5 - 1.6 liters per 10 kilograms of the mixture.
• Then the mixture itself is poured..

Pay attention: if you do the opposite - add water to the dry product - dense lumps are formed at the bottom of the container, which will be quite difficult to break.

• The solution is mixed to a uniform consistency with a construction mixer or drill with the appropriate nozzle.. After 5 minutes of aging and re-mixing, it is ready for use. The pot life is 120 minutes.

Types of mixtures

Dry concrete mixes for concrete are classified primarily by application.

Plastering

Главные отличительные особенности - использование мелкофракционного заполнителя и относительно невысокая марка прочности (как правило, не более M150).

A number of characteristics may vary:

• Increased frost resistance means an increase in the number of freeze and thaw cycles, which the plaster will survive without more than 5% drop in strength. It is achieved by additives that help reduce the number of open pores when setting.
• Plasticity and crack resistance will allow the plaster to transfer the change in linear dimensions of the plastered structure during heating or cooling without signs of destruction.
• Solutions with an accelerated setting are useful when plastering complex surfaces - ceilings, bearing beams, curtain rods, etc..

Masonry

Как правило, это простые составы из песка и цемента. В некоторых случаях присутствуют противоморозные добавки; марочная прочность и в этом случае редко превышает M150. Для газобетона и пеноблоков в качестве заполнителя используется особо мелкий песок: эти материалы требуют минимальной толщины шва.

Screeds, sand concrete

The key feature is the use of aggregate of relatively large fractions (coarse sand and / or small gravel, screening, etc.). This achieves minimal shrinkage during setting; in addition, the freshly molded screed does not crack.

Durability - M200 - M350 - and increased mobility allow using sand concrete for foundations and monolithic works (floors, foundations, beams).

Universal

Universal mixes with a standard set of characteristics are most in demand, allowing them to be used both for the monolith, for the screed, and for plastering. They are used primarily in the repair, when a small consumption of dry mix Peskobeton M300, plaster mix and cement putty makes it inappropriate to purchase lots of each material.

Useful: all compositions, if necessary, can be modified with special additives. Thus, liquid glass will give concrete impermeability to water, and the addition of surfactants (for example, liquid soap) will increase mobility.

Costs

We give several current prices for products for various purposes. The source of information is the website of the Moscow company Besto.

Treatment

A number of operations in the construction process are often performed before concrete is branded in strength. Typical examples are cutting through deformation and shrink seams, drilling holes for communication.

Since when is processing possible?

What is she doing?

• All operations are recommended no earlier than one week after laying the screed, pouring the monolith or plastering. By this time, the concrete is gaining at least 40-50% brand strength.
• The methods and tools used should have a minimal destructive effect; First of all, it is necessary to avoid shock loads. Let's say diamond drilling of holes in concrete is much more preferable than using a crown; Cutting reinforced concrete with diamond circles will cause it to crack with much less probability than working with a jackhammer.

Conclusion

Within this material, we mentioned only the most popular types of mixtures.

As usual, the reader can find additional information in the video in this article. Successes!