BETON

CONCRETE is one of the most widespread and important construction materials who is received by hardening of a mix of knitting substance, waters, fillers and additives.




Concrete is widely applied in civil and industrial building. In a case erection of a structure from concrete, its kinds and marks are defined at the stage of project creation. Different kinds and marks of concrete are applied to various elements of a building design. It is necessary to define, for what particularly element of a design (the base, bearing alls, internal partitions, floors) gets out concrete mark.

The basic characteristic of concrete is durability at compression which defines concrete mark. By the form knitting substance concrete happen:
- The cement;
- The silicate;
- polimerbetonyi, etc.

On volume weight concrete are divided on:
- Heavy - volume weight above 1800 kg/m3, are applied in industrial building;
- Lungs - the volume weight does not exceed 1800 kg/m3.

The concrete price depends:
- From concrete type (heavy concrete is cheaper cellular);
- From concrete mark (the more the figure indicated in mark of concrete, the above the price).

Does not follow:
- To apply heavy concrete to erection of internal partitions or at a building superstructure;
- To apply cellular concrete at the system of underground designs (cellars, cellars, etc.).

Concrete acquisition directly at the manufacturer that will allow to save significant money resources is optimum.



Preparation of a concrete mix

In individual building for preparation of a concrete mix as knitting it is used portlandtsement marks 400 more often.
It is necessary to mean, that cement very much gigroskopichen, i.e. fast absorbs in itself a moisture from air and hardens. Therefore it is not necessary to purchase cement in advance and if it is purchased it should be stored in tightly closed container (for example, densely turned in polyethylene).
Used sand should be pure (without clay, ilovyih and organic inclusions) and large. For allocation of foreign impurities sand is recommended to be sifted. The more purely sand, the above durability of a received concrete mix. Use not enough the cleared sand will entail increase in the cost of cement at 10-20 percent from the recommended.
Rubble is better for applying small (fraction of 5-20 mm). Optimum results are given by use of rubble from natural rocks, small river or droblennogo gravel. Application of artificial rubble, slags is possible, keramzita, however it is necessary to remember, that the concrete design with use of such fillers will be less durable.

Approximate quantity of components for preparation of a concrete mix of 100 l:
Cement - 30 kg (3 buckets);
Sand - 70 kg (5 buckets);
Rubble - 100 kg (8 buckets);

Water for mix preparation should be pure, without foreign impurities. The quantity of water is difficult for establishing in advance since it depends on initial humidity of sand and rubble and from vlagopotrebnosti cement. Usually necessary quantity of water is defined in the course of mix preparation. At first dry making (cement, sand, rubble) mix up among themselves, and then small portions add water until the mix will not acquire a consistence of "dense cottage cheese". The mix should not spread, therefore it is possible to prepare it manually by means of a sovok or bayonet shovel on a metal or wooden board, concrete for a floor. It is necessary to remember, that works on preparation of a concrete mix should pass at a positive ambient temperature.

Ferro-concrete

Ferro-concrete designs subdivide on modular and monolithic. Modular ferro-concrete designs (for example, houses) collect directly on a building site from separate elements (blocks, panels etc.), produced on factories.
Monolithic ferro-concrete designs concrete at-sight buildings and allow to create the modern house of as much as possible free lay-out with the big areas of many premises and high teploizolyatsionnyimi properties of outside walls. For this type of building use a rigid metal skeleton and monolithic designs of overlappings and walls.

Pay attention

As knitting in ferro-concrete often apply straining cement which has property to increase in volume in process tverdeniya. As a result the armature receives pressure of a stretching, concrete - compression, and the concrete design becomes self-strained. The concrete connected to a metal skeleton gives unlimited possibilities for use in, so-called, wide-span designs, for example, premises to 100 sq. m, at "overflowing" of one functional space in other, the big covered pools etc. without additional intermediate support, saving thus a small thickness of walls and high teploizolyatsionnyie properties of a protecting design. Three-layer designs of outside walls from two layers of monolithic ferro-concrete in the thickness of 5 sm with an effective heater (expanded polystyrene) in the middle. Such design is received easy, with high degree teploizoliruyuschih properties and any manages much more cheaply, than with brick application.
Besides, concrete on the basis of straining cements are practically water-proof, that allows to use them at building without an additional waterproofing.

Dignities

· raised treschinostoykost;

· high durability;

· high water resistance;

· high korroziynaya firmness;

· durability

Defects

The metal armature leads to creation of electric fields in concrete which have adverse effect on health of people.