Ceramic brick: properties and varieties

Ceramic brick is one of the most common building materials and is widely used for the construction of foundations, cladding of buildings, masonry of capital walls, interior partitions and stoves. Due to its universal shape and high operational characteristics, the structures erected from it are particularly durable and long service life.

Ceramic brick is a building material that is made from red clay by molding and firing. Brick was invented a long time ago, but its production technology and composition have not undergone any significant changes. Previously, the process of making ceramic bricks was complex and time consuming. The clay was thoroughly kneaded, then the blanks of the desired shape were manually formed, they were exposed to dry in the sun, and only after the brick had hardened was it sent for firing in a temporary oven. The production of bricks was carried out especially in the summer period, since it was almost impossible to dry the workpieces in the conditions of low temperatures and high humidity, characteristic of the winter and autumn periods. This continued until the second half of the 19th century, until the first kilns and dryers were invented in Europe.

Today, the ceramic brick production process is fully automated. and is carried out year-round at numerous enterprises. There are two ways to make the material. The first is called semi-dry pressing and consists in the formation of raw clay from low moisture content. The process takes place under a sufficiently high pressure, which makes it possible to ensure a quick setting of the raw material and to obtain a material of high density and hardness at the output. The advantages of this technology are considered to be fast production and simplicity of mechanisms for production. The main disadvantage of the method is the impossibility of using the material for the construction of structures that will be exposed to high humidity. It is precisely because of its low performance that such a brick is used little and the volume of its production is rather low.

The second method is called plastic molding. and consists in extruding clay from a belt press, followed by drying and firing the blanks at a temperature of 1000 degrees. At the same time, the moisture content of the clay reaches 35%, while with semi-dry pressing this figure barely reaches 10%. This method is used to manufacture the bulk of ceramic bricks used in all areas of construction. The advantages of the method include the possibility of producing bricks of various shapes and sizes, which allows the formation of hollow sections in the blanks, changing the operational characteristics of the material. The disadvantages are the high cost of equipment and, in comparison with the first method, a slightly increased time for the production of bricks.

After production, each batch of ceramic bricks is tested. To do this, take several copies and check them for water absorption, compression and impact resistance. The check is carried out on specialized equipment using a multi-ton press.According to the test results, the products are certified in accordance with the strict requirements of GOST with the assignment of the appropriate frost resistance (F) and strength (M) classes. However, in addition to the letter symbol, the marking of the brick also includes numbers. So, the figure located behind the F symbol indicates how many freeze-thaw cycles a brick can withstand without losing its basic operational characteristics.

The numeric indicator following the "M" indicates what the maximum load on 1 cm2 of the brick area can be. Due to the fact that all tests are carried out according to a single standard, certified bricks from different batches may differ only very slightly from each other. This makes it possible to classify items according to the form of execution and size, considering the products belonging to one category or another, conditionally the same. The scope of application of ceramic bricks is quite wide. In addition to construction, the material is successfully used in the construction of fireplaces, fences, columns and stairs, as well as in the restoration of facades and interiors.

The production of ceramic bricks is carried out in accordance with the current GOST 530 2012, which guarantees high operational characteristics of the material and allows its use as the main building material for the construction of multi-storey buildings and industrial structures. In accordance with the specified standard, ordinary ceramic bricks have a standard red-brown color, while the color range of facing models includes all shades and depends on the quality of the clay, the presence of various additives, additives, special dyes and glaze.

Water absorption is the ability of a material to absorb and retain moisture. To determine this indicator, the dry brick is weighed, and then placed in a container with water and left for 38 hours, after which it is removed and re-weighed. "Extra" grams will denote the moisture absorbed by the material. Then the resulting value is converted into a percentage of the total mass of dry bricks and the moisture absorption index is obtained. According to the requirements of GOST, the fractional ratio of moisture to dry weight should not exceed 8% for solid bricks and 6% for hollow bricks.

The thermal conductivity of ceramic bricks is the ability of a material to conduct a certain amount of heat through a square meter per unit of time. The lower this indicator, the better the heat is retained in the room in winter and the less hot air penetrates into it in the summer months.

The strength of a ceramic material indicates its ability to withstand mechanical and shock loads and is determined by the internal stress limit during compression, bending and tensile tests of the material. The most durable brands of ceramic bricks are modifications M200, M250 and M300.

The density of a brick is the mass of material in one cubic meter. This value is inversely proportional to the values ​​of porosity and is considered one of the most important characteristics of the thermal conductivity of a brick. Density is not a constant indicator for all types of ceramic stone and varies from 1000 kg / m3 for hollow models to 2100 kg / m3 for clinker ones.

Porosity shows the degree of filling the brick structure with pores as a percentage and has a direct effect on the strength, thermal conductivity and frost resistance of the material. To increase pore formation, the clay composition is mixed with sawdust, peat, coal and crushed straw - that is, materials that completely burn out during firing and leave numerous small voids in their place.Porosity, like density, is not a constant value for different types of bricks, and in clinker products it can reach its minimum value of 5%, while in facing specimens it is 14%.

Frost resistance is denoted by the symbol F and shows how many freeze-thaw cycles a material can transfer before it begins to break. So, the index of clinker models ranges from F50 to F100, which means the ability of this type of ceramic brick to last 50 or 100 years. For facing models, this indicator ranges from 25 to 75, and for masonry full-bodied and hollow specimens, it is limited to values ​​of 15-50 years.

The mass of a brick is an important indicator and is taken into account when calculating the load on the foundation, when determining the carrying capacity of vehicles intended for its transportation, as well as when choosing a crane brand and storage conditions. The mass of ceramic bricks depends entirely on their porosity, density, size and presence of cavities. So, a single ceramic brick will weigh from 3.3 to 3.6 kg / piece in a solid version, and from 2.3 to 2.5 kg in a hollow one. One-and-a-half models weigh a little more: the mass of a hollow one is 3-3.3 kg, and a full-bodied one - from 4 to 4.3 kg.

To simplify the calculations of the difference in the weight of solid and hollow types, you can use the average weight indicators and conditionally assume that the weight of a solid brick with a voidness of up to 13% is 4 kg, while the conditional weight of a hollow brick with a voidness exceeding 15% is 2.5 kg. However, these calculations are valid for one of the most common and common stone sizes - 250x120x65 mm.

Knowing the mass of one brick allows you to calculate the weight of a pallet or cubic meter of masonry with an accuracy of kg. So, 1 cubic meter. m of masonry, consisting of 500 solid bricks, will weigh from 1690 to 1847 kg. In addition, when calculating the number of stones in a cubic meter, you need to know that it accommodates seven rows of double bricks (200-240 pieces), ten rows of thickened one and a half (380 pieces) and 13 rows of a single one.

In accordance with the current GOST standards, brick factories produce three standard sizes of ceramic bricks: single, one-and-a-half and double. Each instance has a regular geometric shape, straight edges and a flat surface of faces. The most common is a single stone (NF) with dimensions of 250x120x65 mm. The dimensions of a one-and-a-half product (1.4NF) are 250x120x88 mm, and a double product (2.1NF) reaches 250x120x140 mm. In addition to the running ones, there are also rare sizes, such as those of eurobricks (0.7NF) and modular copies (1.3NF). The dimensions of the former are only 250x85x65 mm, while the latter are represented by long models measuring 288x138x65 mm.

Russian GOST allows the production of incomplete models with a length of 180, 120 and even 60 mm, as well as the production of shaped products, differing in non-standard shapes. However, these norms are used only in Russian brick factories and are regulated by domestic standards. Foreign counterparts are manufactured according to slightly different requirements and have dimensions of 240x115x71 and 200x100x65 mm. Therefore, when buying material, you must take this point into account and pay attention to the country of origin of this product.

High consumer demand and large the popularity of ceramic bricks is due to a number of important advantages of this material.

• High indicators of strength and frost resistance make it possible to use bricks as the main building material in the construction of buildings in any climatic zone.
• Excellent sound insulation properties make brick an irreplaceable material for the construction of dividing walls in the construction of apartment buildings.
• Low water absorption, not exceeding 14%, prevents the structure from absorbing excess moisture and allows it to dry quickly after rain.

• The complete environmental safety of the material, due to the natural origin of clay, allows the use of bricks in the construction of fireplaces and interior finishing work.
• The high thermal stability of the products allows them to be used in the construction of furnaces and the arrangement of chimneys.
• Excellent decorative qualities provide ample opportunities for using ceramic bricks in the implementation of bold design projects.

The classification of ceramic bricks occurs according to several criteria, the most fundamental of which is the functional purpose of the material. On this basis, four large groups are distinguished, each of which has only its inherent qualities and operational characteristics.

This type of material is the most widespread and is used when performing a simple type of masonry in the construction of buildings and structures. Ordinary brick, in turn, is subdivided into two more types, and it can be hollow and full-bodied.

Full-body models are used in cases where the structure to be erected will be subjected to constant mechanical, shock or weight loads. The material is widely used in the construction of load-bearing columns, walls and pillars. For such structures, it is better to choose grades M250 and M300, which have maximum strength and durability. However, when using solid material, it should be borne in mind that the thermal insulation characteristics of the structure being built will be significantly reduced. This point must always be taken into account and additional measures must be taken to preserve heat inside the room. The average density of solid bricks varies from 1600 to 1900 kg / m3, the porosity is 8%, and the thermal conductivity values ​​range from 0.6 to 0.7 conventional units. Solid brick is capable of withstanding up to 75 freeze-thaw cycles, therefore it can be used for the construction of fences, external stairs and walls.

Hollow porous bricks are intended for the construction of low-rise residential buildings, the walls of which will not experience serious weight loads. In addition, the hollow material is often used as a filling element in frame-monolithic apartment buildings and in the construction of interior partitions. In the latter case, it is allowed to use a less durable material with indices M100 and M150. The voids inside the brick can be located both vertically and horizontally, however, it should be borne in mind that horizontally directed cavities significantly reduce the overall strength of the structure. The number of voids in a hollow brick can reach 13% of the total volume, which makes the production of the material economically viable and significantly reduces the cost of the objects being built. In addition, due to the high thermal insulation properties due to the presence of internal cavities, houses built from hollow bricks are very warm.

The density of such a material ranges from 1000 to 1450 kg / m3, the porosity is on average 7%, and the thermal conductivity values ​​vary from 0.3 to 0.5 conventional units. The configuration and depth of cavities in a brick is different. The holes can be both through and one-sided execution, and the shape of their cross-section can be round, square and rectangular. When using hollow bricks, an important condition for successful construction is the ability of the bricklayer to carry out the masonry in such a way that the cement mortar does not get into the cavities and does not squeeze out all the air from there. Otherwise, the hollow brick will lose its main purpose of preserving the air gap inside the masonry and will not be able to provide the necessary thermal insulation of the room.

This type of brick is called front or front. The main purpose of the material is exterior cladding and restoration of buildings.The brick has a high density, reaching 1450 kg / m3, porosity of 14% and thermal conductivity up to 0.5 units. The material is produced in a wide range of colors and is distinguished by uniformity of staining, absence of defects, beautiful surface and precise shapes of bricks. For the most part, facing stone is produced in a hollow version, which allows, simultaneously with finishing, to carry out additional thermal insulation of the premises and reduces the cost of facing.

Facing bricks are produced in five versions: regular, textured, figured, glazed and engobed.

• Ordinary brick has a smooth outer surface and is available in a wide variety of colors and shades. The advantages of this type are the durability of the cladding and the absence of the need for frequent repairs. The disadvantages include the high cost of the material, which, when facing large areas, significantly affects the budget.
• Textured brick It is used for interior and exterior decoration of premises and is distinguished by the presence of a relief texture with an imitation of a pattern of wood fibers or natural stone, as well as with the image of geometric patterns, symbols and drawings. In the manufacture of textured bricks, gunning is widely used, the essence of which is to apply a decorative layer with an image already on it under high pressure.

• Shaped or shaped bricks is a material with a non-standard configuration and is used in the design of curvatures on columns, arches and other architectural forms.
• Engobed brick presented in the form of a two-layer colored artificial stone with a smooth surface. The engobing technology involves the application of a layer of white clay to the dried raw material, followed by firing. Moreover, the clay is pre-painted in different colors using special dyes and pigments. This material looks very good in the interior and is often used in the decoration of hallways, corridors and public spaces.
• Glazed brick produced by applying a special glaze consisting of low-melting glass. As a result of the application of a glassy waterproof coating, the frost resistance and moisture resistance of the ceramic cladding significantly increase. Various dyes are added to the glaze at the manufacturing stage, resulting in a deep color and a shiny transparent texture on the brick surface.

Clinker stone is used for cladding basements and building facades, in the construction of floors in industrial workshops, as well as in paving roads, bridges and sidewalks. The brick is characterized by high strength and long service life, which is due to the technology of manufacturing clinker models. The fact is that a special grade of refractory clay is used for their production, which is fired at higher temperatures than in products made using traditional technology. This is both a plus and a minus of clinker bricks. The advantage is considered to be the highest strength, corresponding to the M400-M1000 indices, and excellent frost resistance, which allows the stones to withstand from 50 to 100 freeze-thaw cycles. The disadvantages include the too high cost of the material and high thermal conductivity due to the increased density of raw materials.

The material owes its high refractory properties to fireclay clay, which makes up 70% of the total mass of the brick. This type of clay is able to easily withstand temperatures of 1600 degrees, while maintaining the operational properties and integrity of the forms. Refractory bricks have found wide application in the construction of fireplaces and stoves, and therefore began to be produced in non-traditional forms designed for use in stoves.So, in addition to standard forms, the range includes products of wedge-shaped, arched and trapezoidal configurations, which perfectly fit into stove and fireplace designs.

Many enterprises are engaged in the production of ceramic bricks in Russia, but I would like to highlight some of them separately.

Ceramic factory from Golitsyno is the most powerful brick manufacturing enterprise in our country, it produces about 120 million units per year. The plant's specialists have established a thorough control over the quality of products, carried out at each stage of production. This allows us to track and promptly remove defective items and supply only high-quality materials to the market. The production of products is carried out on the latest foreign equipment using the latest developments and modern technologies. The range of the company is represented by a large number of solid and hollow stone, as well as many varieties of facing bricks.

Enterprise "Slavic brick" possesses a powerful production base and produces up to 140 million units per year. The company has been operating for 20 years, during which it has accumulated vast experience in the production of building materials and reached the European level. The enterprise was built according to the project of the company Hans Lingl from Germany and today is the most modern brick factory in Russia. A large number of various types of ceramic stone, including both ordinary red blocks and decorative facing models, come off the production conveyor of the enterprise.

Products of "Novokubansk plant of ceramic wall materials" is also well known in our country. The enterprise has its own raw material base and controls the quality of its products, starting with the procurement of raw materials. The company's annual production capacity is 70 million pieces per year.

Association "Wall materials" includes several enterprises located in the Moscow and Leningrad regions, the total productivity of which reaches 450,000,000 pieces per year. Today the company offers the widest range of ceramic building materials in Russia and is one of the leaders in the production of ceramic stone in the post-Soviet space.

The main criteria for choosing a brick are its technical characteristics and quality. To determine the properties of the material, it is necessary to familiarize yourself with the product labeling and study the accompanying documentation. It is much more difficult to determine the quality of products, and since the overall strength of the structure being built and its operational properties depend on this factor, one cannot be mistaken here.

So, when buying, it is recommended to take a few bricks from the pallet and knock on them with a trowel handle. If the product is of high quality, then the emitted sound will be long, sonorous and slightly metallic, and vice versa, if there is a defect or low quality brick, the sound will be short and dull. If at least one of the tested bricks made a dull sound, it is better to refuse to buy this batch. You can check the brick in a more radical way. To do this, you need to split it with a hammer, and if the material turns out to be of high quality, then the brick will split into several large parts, and if the quality of the material is low, it will crumble into dust.

Tips for laying brick stoves and fireplaces in the video below.