2.10 Technology of dry construction mixtures

As is well known, dry mixes are carefully prepared in the factory blend, which consists of mineral and polymer binder, filler, filler and polymer modifiers (hardening accelerators, blowing agents, antifreeze, coloring, water-repellent, etc..), The recognized world leaders in production and use of which today are Germany, Spain and France.

In the Russian market of dry building mixes in the last decade their consumption is growing, the bulk of which priho¬ditsya on the adhesive mixture (35%), plastering and putty mixture.

In Kazakhstan, in particular in the Kostanay region plans to release unique dry mixes of the new generation of domestic natural raw resources, capacity up to 5.5 tons, which have no analogues in the country, which will provide a unique use as a component of mineral powder from gangue, produced by JSC "Kostanay minerals". Mineral powder, having a fiber structure, adding to the mix will give it greater traction, which eventually clear positive impact on the quality of construction.

For simple dry mixes containing basically only cement, sand, and a minimal amount of additives, characterized by thick-layer technology application and minimum parameters of resistance tensile strength and flexural strength, and for the modified dry building mixes are characterized by thin-layer technology applied to high-tech equipment with the latest addition, which ensures high productivity, reduction of material consumption, increase shelf life due to the originality of the products and recipes, the stability of the quality of construction work, to be transported and stored at low temperatures.

Dry construction mixtures and compositions, depending on the type of binder divided into simple, using one type of binder and complex (combined) in the mixed cementitious (cement-lime, lime-ash, lime, plaster, etc.) (Figure 28).

Figure 28 - Areas of application of dry mixes in construction

Functional additives are an essential component of dry building mixtures, without which it is impossible the achievement of a specified level of properties of the mixture, which often improve the quality of the mixture is due to the introduction of increased quantities of cement or of a complex set of costly chemical additives, but at the same time, the most important factor in the optimization of formulations is to reduce the consumption of cement and reduce the cost of production.

Each Supplement with different functional assignments (plasticizers, woodenjewelry, hardeners, accelerators, retarders, etc.) has its own mechanism of action and interactions with cement showing both positive and negative effects.

To improve the performance properties of dry building mixes it is necessary to introduce mineral and organic additives directed action and optimization of their compositions.

Thanks to technology, the high quality of work, reduction of labor intensity and a number of other positive advantages of dry building mixes in recent years, widely used in construction. However, given the conditions of the hot South Kazakhstan climate requires improving the performance of masonry mortars for various reasons, for example, increase adhesion, reduce shrinkage and thermal conductivity, higher resistance to temperature extremes and humidity.

Recently, in order to ensure a high level of stability and quality, improve productivity, optimize transportation costs and efficient use of construction materials there has been wide adoption of dry construction mixtures, the use of which helps to reduce the time and cost of works, allows to implement new technological processes and materials, improving production standards, effectively using small-scale mechanization. Improving the quality of dry mixes is in the direction of their modification through the introduction of various additives and components that gives certain quality indicators.