In industrial and private construction, many building materials are used. One of them is slag concrete blocks. They were first used more than 100 years ago, but to this day they are quite popular.
What distinguishes this material from modern analogs and what properties it is endowed with, we told in our article.
Composition and manufacturing technology
Initially, cinder blocks were made of concrete and slag, from where the name of the material came from. Modern products include new additives, giving them additional strength and a number of positive qualities.
Today, a block may include:
- river sand;
- granite crushed stone;
- crushed brick;
- fragments of hardened cement;
- concrete;
- coal slag;
- ash;
- shards of glass;
- expanded clay crumb;
- sawdust;
- volcanic ash.
Slag concrete blocks are manufactured using vibrocompression technology. Any of these components is mixed with cement mortar in a certain proportion and poured in special forms. The filled blanks are sent to a vibrating stand, where the final solidification of the solution takes place.
Specifications
Depending on the filler used, the technical characteristics of cinder blocks can vary. For example, a filler in the form of crushed stone, pebbles and sand gives the product high strength and thermal conductivity. Hollow varieties are often made from these materials.
Additives from slag, expanded clay and perlite are used to produce light blocks. They are characterized by lower thermal conductivity. But products from sawdust are characterized by a high degree of environmental friendliness, heat resistance and fire safety. But they do not tolerate direct contact with water.
If we single out the average indicators of physical and mechanical properties, then they are as follows:
- noise insulation abilities - from 42 dB;
- resistance to low temperatures - from F 15 to F 25;
- thermal conductivity indicators - from 0.35 to 0.46 W / m 2 ;
- ability to absorb moisture - from 25 to 75%.
The cost of cinder block products varies in the range from 12 to 125 rubles per stone. The final price tag is influenced by the type of product and the filler used in the manufacture.
Types of slag concrete products
Slag stones come in two varieties: hollow and solid. Each species has distinctive properties and its own scope.
So, solid cinder blocks are considered the most durable and heavy building material. They are used for arrangement of foundations, construction of load-bearing structures, columns, basement floors.
Hollow products are used in the construction of external walls and piers indoors. It has a light weight, so it is quite easy to use. The technical characteristics of this variety depend on the number of empty cells in the block.
Void options of 40% are characterized by the lowest thermal conductivity and fragility. And products in which air cells do not exceed 30% of the block volume combine the qualities of hollow and solid blocks. Therefore, they are most often used in construction.
Dimensions and weight of building blocks
All cinder blocks are divided into two types: standard and facing. Each option has its own dimensions and weight. The dimensions of slag concrete blocks are set by standards.
So, ordinary products have parameters of 390 x 190 x 188 cm. Cladding products are characterized by dimensions of 390 x 120 x 188 or 390 x 90 x 188. In the construction markets, you can find products of other sizes, but this suggests that the products were made using the artisanal method .
There is a document that controls the quality of building materials, including slag concrete blocks, - GOST 6133-99. It clearly spells out the technology of manufacturing products and their final size. The error in the parameters should not exceed 3-4 mm. Products with large deviations from the standard may be of poor quality.
As for weight, full-bodied stones show maximum performance. Their mass is about 25-29 kg (depending on the type of filler). Hollow wall products can weigh from 12 to 23 kg.
Positive properties of slag concrete materials
Long-term use of slag concrete blocks is explained by a number of their advantages. First of all, it is low cost. Compared to ordinary brick, cinder block is considered more accessible to the average buyer.
In addition, their advantages include:
- high strength (especially full-bodied options);
- durability (service life about 100 years);
- resistance to moisture (except for products with additives in the form of sawdust);
- lack of rot and mold processes;
- invulnerability to rodents;
- low thermal conductivity;
- resistance to fire;
- low weight of some varieties;
- large dimensions to speed up the construction process.
Also, the advantages include a simple manufacturing technology. In order to save money, anyone can independently make such a building material. This will require a special form and the main components: cement, water and any fillers.
You can use fragments of bricks and glass break. It will be possible to use such products only in their own construction, but such an approach will help to significantly reduce the cost of acquiring materials.
A bit about the flaws
Visual inspection of the cinder block helps to identify their main drawback - an unpresentable appearance. It is quite difficult to make a beautiful masonry from this material. In most cases, it is subjected to decorative decoration.
Also the negative properties of slag concrete blocks include:
- low rates of noise absorption;
- high hygroscopicity;
- high thermal conductivity of full-bodied options;
- the difficulty of communicating through the block.
Some experts question the safety of the cinder block. A large number of chemical elements in the slag does not allow us to talk about its complete harmlessness. Moreover, there is an opinion about the radioactivity of slag stones.
There is no scientific evidence of the negative impact of the material on the environment and humans. Therefore, today it is actively used in the process of building construction.
Scope of application
Building from slag concrete blocks is popular due to the cheapness of the basic material. However, for the construction of multi-storey buildings, these products are not used. This is due to the fragility of the wall varieties and the weak presentability of the stone itself.
In most cases, the material is used in the construction of warehouses, industrial workshops, house buildings, premises for livestock, for the arrangement of borders and flower beds.
Full-bodied varieties are used in the process of creating the foundation, during the construction of underground premises and for the construction of load-bearing walls. It is quite difficult to work with massive material, so construction equipment is most often used.
How is cinder block laying?
Hollow products have a fairly light weight, which allows you to do the laying of structures with your own hands. The work is performed as follows:
- The foundation surface is cleaned, blocks are installed at the edges (or corners) of the future structure. A cord is stretched between them, which will regulate the evenness of further masonry.
- Cement mortar is laid out on the foundation, blocks are installed on it. In the process of work, the product should be taken very carefully, to avoid bumps and falls of stones.
- Laying the second row also begins with the installation of corner elements. Evenness and correctness of work is controlled by a plumb or level.
- The adjacent rows of the cinder block are laid with dressing of the seams: so that the joints of the elements of the lower row fall in the middle of the block of the upper row. The thickness of the seam between the stones should not exceed 15 mm. Otherwise, the building will be exposed to large heat losses.
Thus, the entire masonry is performed. The process is simple, so you can easily build a small building or fence from cinder blocks.
To improve the characteristics of the cement composition, experts recommend adding a little ash or red clay to it (in the proportion of 4 parts of the mixture to 1/3 of the ash).
During the construction process, contact with moisture should not be allowed. Open pallets are recommended to be covered with foil.
Summarizing the above
Slag concrete blocks - a modern building material, which allows in a record time to build various buildings with a minimum of cost. However, before chasing low cost, it is necessary to consider some of the disadvantages of products from slag. If you take them into account at the stage of purchasing the material, in the future you will not have unforeseen problems.