In the process of building high-rise buildings andsmall buildings can not do without the use of concrete solutions. With their help, the foundation, floor screed and monolithic structures are built. However, the cement, which is part of this mixture, is characterized by significant shrinkage, which creates some difficulties in carrying out the finishing. To eliminate this problem, modern manufacturers have created tension cement. Let's look at the features of this product, what properties it has.
Determination of composition
Straining cement is an astringent compound,characterized by the highest strength and rapidity of setting. It is made on the basis of dry clinker powder Portland cement, building gypsum and alumina slag.
The diluted mixture quickly solidifies, gains the necessary strength and begins to expand. Just one day after pouring, the solution takes strength of more than 300 kg / cm³.
Depending on the proportions of the main components,entering into the dry powder, the time of hardening and the characteristics of the final solution can vary considerably. For this reason, a normative document was created, according to which tensile cement is produced, GOST 31108-2003. He strictly determines the number of all components, which eliminates the occurrence of misunderstandings in the construction process. According to its recipe, expanding cement can be 3 varieties:
- NC 10 - non-shrinkable compounds.
- NC 20 - products with average expansion rates.
- НЦ 60 - materials with the maximum linear expansion.
The choice of the type of cement is based on the specifics of its application, but most often the varieties of the NC-20 group are used.
Scope of the mixture
Straining cement (NC) is used in the following works:
- when building swimming pools and reservoirs of treatment plants;
- for the erection of basement premises (susceptible to flooding);
- when constructing facilities designed to store aggressive chemical compounds;
- during the arrangement of roadblocks, runways and floors in industrial enterprises;
- for the creation of hollow and thin-walled structures of increased strength;
- in the production of pressure pipelines;
- in the construction of stadiums, hockey fields, tribunes and racetracks.
In addition, astringent compounds are actively used in the repair of reinforced concrete structures. A solution of this type evenly fills the smallest cracks, making the surface uniform and strong.
Применение напрягающего цемента актуально и в private construction. It is used for erection of underground garages, baths and other premises with a high level of humidity. Often, monolithic furnaces and fireplaces are poured from such a solution.
Specifications
Compared with ordinary portland cement,Straining composition has increased performance. It gives a concrete solution a number of positive properties, which are not always possible to achieve even with the use of modern modifying additives.
Specifications manufacturer of the material indicates on the packaging of a dry mix. They are:
- The initial setting of the solution is after 30 minutes.
- Bending strength after 48 hours is 3.8 MPa.
- Bending strength after 4 weeks - 5.9 MPa.
- Self-stress - 2 MPa.
- Frost resistance indicator - F-30.
- Linear voltage of the solution - 0.3% (up to 1.5%).
- The recommended temperature for work is from +5 to + 35 ° С.
- Compressive strength after 48 hours - 14 MPa.
- Compressive strength after 4 weeks - 49 MPa.
Cement can be purchased in paper bags of 25 and 45 kg. Bulk shipments can be shipped by machine (unpacked).
Material advantages
If we consider the advantages and disadvantagesstraining cement, it becomes clear that the positive properties of the solutions made on its basis, much more. Primarily, this material is valued for the lack of a shrinkage process, which increases the strength of the structures made from it. In addition, the advantages of tensing cement include:
- highest strength;
- setting speed;
- the ability to increase the life of buildings more than 6 times;
- resistance to aggressive media;
- absolute fire safety;
- excellent waterproofing qualities;
- high rates of frost resistance;
- high adhesive ability;
- no cracking processes.
Ability to withstand high pressure andWater resistance are also significant advantages of such solutions. These qualities allow the use of concrete from the straining cement for the arrangement of waterproofing, with no additional materials used.
disadvantages
Not one modern material is not without negativecharacteristics, and expanding concrete is no exception. The disadvantages of tensing cement are not so significant, but they should certainly be studied.
Первым отрицательным качеством застройщики call the high cost of this material. Of course, if you compare it with a conventional cement mortar, in this case, the cost of manufacturing concrete will increase by about a third. However, one should not forget about the improved characteristics of the finished structure, which more than compensates for additional expenses.
The second disadvantage can be attributed to partialloss of the initial qualities of the composition (in terms of the use of structures at temperatures above 35 degrees). This feature of the material is indicated in its technical characteristics, which allows to foresee possible problems and determine the expediency of its use.
Features of the use of tensing cement
Прежде чем приступать к работе с данным solution, you should explore some of the features of this process. To a greater extent they are associated with high-quality preparation of bases and repaired surfaces.
If straining cement is used aswaterproofing, the base on which the solution will be applied, must be sufficiently strong, not have peels, oily stains and residues of paint and varnish coatings. Equally important is the cleanliness of the surface. Small particles of concrete, dust and debris are removed from it.
If using the solution will be createdscreed, the formwork must first be moistened with water. And if we are talking about the repair of finished structures, then all sorts of cracks on them should be thoroughly cleaned of debris, washed and degreased.
Cost of material
On modern building sites strainingCement is presented in a wide variety. However, it is sometimes very difficult to purchase. This is due to the fact that large trading companies prefer to work only with wholesale buyers, and small enterprises very often supply low-quality products.
The amount of material ordered affects itstotal cost. Manufacturers offer good discounts to wholesale buyers, and independently deliver the goods to the specified location. The cost of a large batch of cement should be checked with the supplier. Retail 25 kg bag will cost the buyer about 230-290 rubles.
Finally
Straining cement is an innovative materialhaving a number of positive properties. However, non-observance of the basic rules and technology of pouring a solution can negate all its unique qualities. It should be remembered that the listed advantages of the straining cement are activated only when the mixture hardens in a moist environment. At observance of all requirements cement sets quickly and evenly, forming equal and durable surfaces.
