Pros and cons of the construction of the concrete blocks

By Admin | Construction Materials
23 April 2016

manufacturers of aerated concrete, on numerous sites for the sale of, say, that the best building material does not exist.On no less massive, forums on the construction claim otherwise, in the homes of aerated concrete is impossible to live comfortably.The purpose of this article - revealing the truth.Which are the pros and cons of aerated concrete blocks, in which specific processes for the construction of their optimal use, and in which there is an alternative.How not to overpay for materials and labor, and did not regret his actions later.

Aerated concrete blocks, the pros and cons of their use

Contents:

  1. What they are and how they are made concrete blocks
  2. Stamps and types of concrete blocks
  3. Pros concrete blocks
  4. Cons concrete blocks
  5. Video: Aerated itthe pros and cons

What are and how they are made concrete blocks

before we look at just the pros and cons of aerated concrete, let us define and see what material we deal with.

There are several ways the manufacture of aera

ted concrete.The factory used autoclave and hydration methods.However, the initial stage of the process are identical for all types.

1. Cleaning and preparation of forms to fill

There are two types of forms:

  • collapsible - design consists of a pallet, boards and several jumpers that can be removed to fill the elements of a larger volume;
  • Kolpachny - represent a monolithic structure.Mainly used in large-scale production.

2. Preparation composition

apply a lot of recipes, depending on their use of different end-product specifications.

usual mixture consists of:

  • cement grade of at least M400 - 500 (50-70%);
  • filler - sifted sand fines (20-40%);
  • aluminum powder or paste (0.04-0.09%);
  • lime (5%);
  • water (0.8%).

3. Fill

prepared mixture is poured into molds preheated to 400C, and carefully leveled.

4. Drying.

There are significant differences begin affecting the quality of the blocks.

  • When placed in the autoclave curing takes place at elevated pressure up to 12 bar, humidity and temperature to 2000C.These products are the most durable and high quality.Can be used for masonry bearing walls.
  • When hydration solidification form is placed in a special box with heating and high humidity.Such aerated concrete is used for insulation.
  • artisanal production form just wrapped up several hours before removing for further drying in unsuitable premises.Such units generally better nowhere to use.

The structure of the aerated concrete

Stamps and types of concrete blocks

First of all aerated concrete blocks are separated by grades.Brand - is actually the density of the product.

Mark strength MPa Thermal conductivity W / (M2h0S) Application (characteristics)
D350 0,7-1,0 0,08-0,09 Itbrittle material, is used as a heater.
D400 1-1,5 0,1-0,11 is used as insulation, for filling openings and the construction of piers.
D500 2-3 0,12-0,13 Load-bearing walls in low-rise construction.
D600 2,5-4,5 0,14-0,15 Bearing walls with ventilated facades

There are special items created by the special recipe with the addition of reactive modifiers having improvedheat resistance and acoustic insulation.These blocks are used for lining or the construction of specialized facilities.

Just divide the product by type of binder: lime-plaster and cement.And the type of filler: slag, ash, sand, using waste of ferroalloy production and secondary products.The use of these materials is regulated by GOST.On the main strength and insulating properties of the final product, these materials affect slightly.

sizes of concrete blocks

small proportion of the material makes it possible to produce products of enlarged size.Most popular tech form - is a box with grooves and ridges on the ends.

Sizes silicate blocks

The height and length of the element, are standard 250h625mm, and the width varies between 100-400mm.There are elements of other shapes and sizes, for insulation or reinforced device jumpers.

Pros concrete blocks

+ 1. The level of insulation

plus1

main indicator, which emphasize sales managers, this is an incredible level of thermal insulation material.Aerated concrete wall will have a lower cost than the construction of bricks with comparable thermal insulation properties.

+ 2. High precision and large size

plus2

High precision and large block sizes allow to build a wall with minimal deviations and speed.Accordingly, costs are reduced external finish.Using the slotted prevents the formation of cracks in the brickwork.

+ 3. The ability to non-use of the composition of the cement masonry

plus3

Using a special adhesive, instead of the usual cement mixture to minimize the effect of thermal bridges.This reduces the heat loss from 25% to 8-10%.The amount of adhesive used is substantially less, to 5 times, compared with the cement mortar.

+ 4. A good level of vapor and air permeability

plus4

steam and air permeability coefficient similar structures made of wood.It is alleged that the circulation of air and humidity level in such a house will be governed by a natural way, creating an optimum microclimate.

+ 5. Resistance to fire

plus5

high level of resistance to fire and other aggressive environmental influences.

+ 6. Lightweight

plus6

Lightweight elements allows you to create light walls, which do not need a heavy-duty base, which also reduces the cost of construction.

+ 7. Easy workability

plus7

of aerated concrete blocks are easily sawn, drilled and amenable to any manual handling.

+ 8. Environmental cleanliness

plus8

Aerated concrete blocks is an environmentally friendly building material.In this regard, it is better than a brick but worse than the tree.

+ 9. Has biological stability

plus9

Aerated concrete blocks are resistant to damage by various microorganisms, rodents and insects.Although small green patina on it may still be produced, but only in case of permanent humidification.

+ 10. Frost

plus10

Aerated concrete blocks have a good level of frost which makes F-50, r. E. 50 freeze-thaw cycles.

Cons concrete blocks

Let us point by point, it really is true, the information provided by the seller.

- 1. The necessary wall thickness

minus1

Many manufacturers regulate sufficient wall thickness to 380mm.But sellers forget to mention that this thickness is sufficient under ideal conditions and is absolutely dry building materials.According to the SNIP 23-01-99 "Building Climatology" thermal resistance of the outer wall of the middle band Russia is the coefficient of 3.15.From another source of SNIP II-3-79 * "Building Heat Engineering" we find out that the level of humidity of concrete blocks varies from a minimum of 5% to 12% of the maximum allowed.For brand products D500 it will be 0.17 W / (M2h0S).The result is that the minimum wall thickness for the Moscow region should be 535 mm.

Take into account thermal bridges that give an additional 10% loss of shielding - 588 mm.The presence of technologically necessary, jumpers and reinforced zones to reinforce the window openings that allow another 10 to 30% and get the wall 65 cm thick.

- 2. highly hygroscopic

minus2

One of the most significant disadvantages of concrete blocks their high absorbability.The amount of moisture in total weight can reach 35%.It is practically negates the quality of insulating material.Moreover, swelling occurs elements, leading to linear deformation, cracking or peeling.It is recommended to produce regular, once every 2 years, the processing of special water-repellent surfaces, which leads to a significant increase in operating costs.

- 3. The appearance of cracks due to incorrect installation of the foundation

minus3

according to a posting on numerous forums of construction, there is the problem of cracking walls, both lines masonry and directly blocks themselves.Practice shows that microcracks appear to have 2-4 year of operation, they may be affected up to 20% of the blocks.This is due to the fact that large construction elements are very sensitive to shrinkage foundation thus plus aerated turned negative.Used for bonding adhesive blocks can not provide monolithic structures, such as occurs with a heavy masonry.It follows from this conclusion - to save on the foundation does not succeed.

- 4. Problems with interior decoration

minus4

Another shortcoming of aerated concrete is shown at interior decoration.Manufacturers recommend using plaster gypsum-based, and it really has a high level of adhesion to the surface of the gas concrete.But sharp thermal gradients at a wall cracks immediately, follow the contours of the masonry.These areas need to be strengthened mounting grid, which further increases the cost of finishing.

Results

Aerated concrete blocks is a high-tech material.Its production and installation requires a high level of knowledge and strict observance of the process technology.

1. feasibility of using concrete blocks as the main structural material for construction of the building is a big question, however, in strict compliance with all the technology possible.

2. The use of aerated concrete elements for the construction of high-speed internal jumpers, in principle, welcome.

3. as insulation material aerated concrete slabs have a decisive advantage over traditional polystyrene foam or mineral wool, for no price or technological installation, and on thermally insulating properties even somewhat inferior.

Video: Aerated its pros and cons

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