Building stone materials are a wide group of building materials and products of a stone-like structure. There are natural stone materials, obtained by mechanical processing (sometimes without special processing) of rocks, and artificial, produced by technological processing of initial mineral raw materials. Thanks to high construction qualities(durability, strength, frost resistance, etc.), prevalence and unlimited reserves of natural raw materials, stone materials are widely used in modern construction. They are the main building materials for the construction of residential, public, industrial buildings and various engineering structures. According to their shape, stone materials are divided into materials consisting of pieces of irregular shape (rubble stone, crushed stone), and piece products having the correct shape (blocks, slabs, shaped products). Depending on the density (volumetric mass), stone materials are divided into heavy (more than 1800 kg/m3), light (from 1800 to 1200 kg/m3) and extra light (less than 1200 kg/m3). Artificial stone materials used as thermal insulation materials can have a density within 500 kg/m3.

The main indicator of stone materials is the compressive strength, characterized by the grade. According to this criterion, stone materials are divided into strong - from 10 to 300 Mn/m2 (1 Mn/m2 "10 kgf/cm2), medium strength - 2.5-10 Mn/m2 and low-strength - 0.4-5 Mn/m2 The tensile strength of stone materials is 7-15 times lower than the compressive strength, so artificial stone materials are often reinforced with fibrous materials (asbestos, glass or organic fiber) or metal (steel reinforcement used in external structures must have a certain strength). degree of frost resistance and water resistance. Depending on the area of ​​application, stone materials are also assessed by water absorption, acid resistance, degree of abrasion, etc.

Natural stone materials, according to the methods of their mechanical processing, are divided into the following main varieties: sand and gravel, obtained by sifting and washing the corresponding loose rocks; rubble stone, mined mainly by mining (by blasting) limestones, sandstones and other sedimentary rocks; crushed stone obtained by crushing rocks; sawn stones and blocks cut from light rocks (tuffs, shell rocks, etc.) directly in a quarry using stone-cutting machines; facing stones, slabs and shaped products (see Finishing materials), manufactured at specialized stone processing enterprises from decorative rocks (marble, granite, limestone, etc.).

Natural stone materials, depending on their purpose (hydraulic structures, road construction, exterior or interior decoration of buildings), are subject to various requirements established by the relevant SNiP and GOST standards. The most common natural stone materials - sand, gravel and crushed stone - are widely used as aggregates in the manufacture of concrete and mortars. Rubble stone is used mainly for laying foundations of buildings, retaining walls, etc. Sawn stones and blocks are used mainly as local wall materials. Facing stones, slabs and shaped products with different surface characteristics (textures) - chipped, hewn, ground and polished - are used in large quantities for exterior and interior decoration of buildings, flooring, making steps, parapets, fences, etc. This is facilitated by their high decorative qualities and durability, as well as a reduction in their cost as a result of the introduction of the latest processing methods (diamond tools, heat treatment, mechanized splitting methods, etc.).

Rocks are widely used as raw materials for the manufacture of various artificial stone materials (for example, ceramics, glass, heat-insulating materials), as well as inorganic binders(gypsum, lime and cement). In the production of these materials and products, technological processes are used that change the composition, structure and properties of natural stone materials. Artificial stone materials can be obtained by the following basic molding methods: from clay and other ceramic masses followed by firing (clay bricks, ceramic stones); from silicate melts (stone casting, slag casting, glass products); from mixtures containing a binder - concrete products and mortars(for example, concrete, reinforced concrete and silicate concrete panels and blocks, sand-lime brick, etc.).

LIMESTONE , sedimentary rock composed predominantly of calcium carbonate - calcite. Due to its wide distribution, ease of processing and chemical properties limestone is mined and used to a greater extent than other rocks, second only to sand and gravel deposits. Limestones come in a variety of colors, including black, but the most common types are white, gray, or have a brownish tint. Bulk density 2.2-2.7. This is a soft breed that can be easily scratched by a knife blade. Limestones boil violently when interacting with dilute acid. In accordance with their sedimentary origin, they have a layered structure. Pure limestone consists only of calcite (rarely with a small amount of another form of calcium carbonate, aragonite). There are also impurities. The double carbonate of calcium and magnesium - dolomite - is usually found in variable quantities, and all transitions between limestone, dolomitic limestone and the rock dolomite are possible. During the process of limestone deposition, water also introduces clay particles, the rock becomes clayey, and the clear boundaries between limestone, clayey limestone and clayey shale are erased. Flint is also a common impurity; it is often present in the form of nodules (flint nodules) or in the form of more or less clearly defined layers. During metamorphism, as the recrystallization of calcite covers the entire rock and a mosaic structure appears (an aggregate of clearly defined, tightly adjacent isometric grains of approximately the same size), limestone gradually turns into marble.

There are many varieties of limestone. Shell rock is a collection of shell fragments cemented into a cellular aggregate. If the shells are microscopic in size, a weakly bound, soft, finely crumbling, smearing rock is formed - chalk. Oolitic limestone consists of small, fish egg-sized balls cemented together. The core of each such oolite ball can be represented by a grain of sand, a fragment of a shell, or a particle of some other foreign material. If the balls are larger, the size of a pea, they are called pisolites, and the rock is called pisolite limestone. Travertine is limestone formed on the surface as a result of the precipitation of calcium carbonate (calcite or aragonite) from the water of carbon dioxide sources. If such deposits are highly porous (spongy), they are called calcareous tuff. Marl is an uncemented mixture of calcium carbonate and clay. The names of some varieties of limestone are determined by the possible direction of its practical use. For example, lithographic limestone is an exceptionally dense, compact and uniform stone used in lithography.

Although limestones can form in any freshwater or marine basin, the vast majority of these rocks are of marine origin. Sometimes they are deposited, like salt and gypsum, from the water of evaporating lakes and sea lagoons, but, apparently, most of the limestones were deposited in seas that did not experience intense drying. In all likelihood, the formation of most limestones began with the extraction of calcium carbonate by living organisms from sea ​​water(for building shells and skeletons). These remains of dead organisms accumulate in abundance on the seabed. The most striking example of calcium carbonate accumulation is coral reefs. In some cases, individual shells are visible and recognizable in the limestone. As a result of wave activity and under the influence of sea currents, reefs are destroyed. Added to the limestone debris on the seabed is calcium carbonate, which precipitates from the calcium-saturated water. Calcite, coming from destroyed older limestones, also participates in the formation of younger limestones.

Limestones are found on almost all continents, with the exception of Australia. They were formed in different geological eras. The thickness of the layers varies from several centimeters to hundreds of meters. Limestones are common in the United States and occupy 75% of the country's area. In Russia, limestones are common in the central regions of the European part, and are also common in the Caucasus, the Urals and Siberia.

Limestones (in the broad sense) have extremely diverse applications. They are used in the form of lump limestone, crushed stone, piece (saw, wall) and rubble stone, facing slabs, mineral chips, crushed sand, mineral powder, mineral wool, limestone flour. The main consumers are the cement industry (limestone, chalk and marl), construction (production of building lime, concrete, plaster, mortars; masonry of walls and foundations; decorative facing work, etc.), road and railway construction, rock placement for protection of shores and hydraulic structures, metallurgy (limestone and dolomite - fluxes and refractories, processing of nepheline ores into alumina, cement and soda), agriculture (limestone flour in agricultural technology and livestock farming), oil and coke chemicals, food (especially sugar), pulp -paper, glass (limestone, chalk, dolomite), leather (limestone), rubber, cable, paint and varnish industries (chalk as a filler). Other areas of application are polishing products made of non-ferrous metals and mother-of-pearl (limestone), electric welding (chalk for covering electrodes), writing chalk (chalk), thermal insulation of building structures and technological equipment ( mineral wool), etc.

In Russia, limestone is mined in quarries in the Moscow region, Leningrad (cladding), Arkhangelsk, Vologda, Tula, Belgorod, Voronezh regions, in the Urals (Perm region) and the Volga region, Krasnodar Territory, in the North Caucasus, in the Urals, in a number of regions of Eastern Siberia. Temples and other buildings of white-stone Moscow were erected from Myachkovo limestones near Moscow. The raw material resources of carbonate raw materials (limestone, chalk, marl, dolomite) in the country are practically inexhaustible, although they are distributed very unevenly. In the Donetsk region of Ukraine there is the largest deposit of limestone and dolomite in Europe, Elenovskoe.

GRAVEL(from the French gravier), loose rock consisting of more or less rolled rock fragments and (less commonly) various minerals ranging in size from 1 to 10 in diameter mm(according to other sources, from 2 to 20 mm). By size, gravel can be divided into fine (1-2.5 mm), medium (2.5-5 mm) and large (5-10 mm). Based on their origin, gravel is divided into river, lake, sea and glacial. gravel is used as a building material, as a coarse aggregate for concrete, and in road construction. Cemented gravel is called gravelite.

GRANITE , the most common rock in the continental crust. It is an apparently crystalline coarse-, medium-, or fine-grained massive igneous rock formed by the slow cooling and solidification at great depth of magmatic melt. Granite can also form during metamorphism, as a result of granitization processes various breeds. Individual granite massifs are often attributed to either igneous, metamorphic, or even mixed origin.

The color of granite is predominantly light gray, but pink, red, yellow and even green (amazonite) granites are also common. The structure is usually uniform-grained, most grains have an irregular shape due to constrained growth during mass crystallization. There are porphyritic granites in which large crystals of feldspars, quartz and mica stand out against the background of a fine- or medium-grained groundmass. The main rock-forming minerals of granite are feldspar and quartz. Feldspar is represented mainly by one or two types of potassium feldspar (orthoclase and/or microcline); in addition, sodium plagioclase - albite or oligoclase - may be present. The color of granite, as a rule, is determined by the predominant mineral in its composition - potassium feldspar. Quartz is present in the form of glassy fractured grains; It is usually colorless, in rare cases it has a bluish tint, which the entire breed can acquire. In smaller quantities, granite contains one or both of the most common minerals of the mica group - biotite and/or muscovite, and in addition, scattered dissemination of accessory minerals - microscopic crystals of magnetite, apatite, zircon, allanite and titanite, sometimes ilmenite and monazite. Prismatic crystals of hornblende are observed sporadically; Garnet, tourmaline, topaz, fluorite, etc. may appear among the accessories.

With increasing plagioclase content, granite gradually turns into granodiorite. With a decrease in the content of quartz and potassium feldspar, granodiorite undergoes a gradual transition to quartz monzonite, and then to quartz diorite. Granites with a low content of dark-colored minerals are called leucogranites.

In the marginal zones of granite massifs, where the rapid cooling of magma retards the growth of crystals of rock-forming minerals, granite gradually turns into fine-grained varieties. Granite porphyries include a variety of granite consisting of individual large grains (phenocrysts) immersed in a finer-grained groundmass, which consists of small, but still visible crystals. Depending on the presence of minor, predominantly dark-colored minerals, several varieties of granite are distinguished, for example, hornblende, muscovite or biotite.

The main form of occurrence of granite is batholiths, which are huge massifs with an area of ​​hundreds to thousands of square kilometers and a thickness of 3-4 km. Granites can occur in the form of stocks, dikes and intrusive bodies of other shapes. Sometimes granitic magma forms layer-by-layer injections, and then the granites form a series of sheet-like bodies alternating with layers of sedimentary or metamorphic rocks. Granites are widespread on all continents. Most often, they come to the surface in areas composed of ancient rocks, where, as a result of erosion-denudation processes, the overlying sediments were destroyed. In the USA, granites are common along the coast Atlantic Ocean(from Maine in the north to Georgia in the south), make up large massifs in the north of the country, in the central part of the Ozark Plateau, in the Black Hills and the Front Range of the Rocky Mountains. In Russia, granites are widespread in the Karelo-Kola region, the Urals, Eastern Siberia, the Far East, the Caucasus, etc.

Granite has long been used by man as a building stone due to its uniform structure, pleasant color, great strength and fairly simple ways extraction and processing. The main disadvantages of granite are its rough surface, which accumulates dirt and grime, as well as rapid cracking or spalling during a fire. Approximately half of the mined granite (by cost) is used as piece (saw, or wall, as well as facing) stone, i.e. blocks or slabs, and the other half is crushed and crushed. Monuments are made from piece stone. In the US, granite is mined primarily in Vermont, Georgia, South Dakota and Wisconsin. Crushed and crushed granite (crushed granite and partly rubble) is used mainly in the production of concrete, for road surfaces, as riprap and railway ballast. The main producers of crushed granite and rubble stone in the USA are the states of California, North Carolina, Georgia, South Carolina and Vermont.

In Russia, more than 50 deposits of granite are known, suitable for use as piece stone, as well as rubble and crushed stone - on the Karelian Isthmus, in the Onega and Ladoga regions, the Arkhangelsk and Voronezh regions, in the Urals (in the Sverdlovsk and Chelyabinsk regions), in Primorye and Khabarovsk Territory, Eastern Transbaikalia, etc. Rapakivi granites of the North-West of Russia and amazonite granites of Transbaikalia and the Ilmen Mountains in the Urals are especially decorative. Some deposits are developed periodically, mainly for rubble and crushed stone, but as needed, granite blocks are mined there, which are cut into facing slabs, hewn into piece stone or used in monumental sculpture. Large deposits of high-grade facing granite are located in Ukraine (in Zhitomir and other regions); some of them are operated primarily for rubble and crushed stone

Road construction works, complex construction work, including the construction of subgrade and road pavement, as well as artificial structures and road maintenance buildings. In a narrower aspect, road construction work is limited to the construction of the road itself, i.e., the construction of the roadbed and road pavements, and in populated areas construction of expressways isolated from pedestrians, creation of interchanges in different levels, sidewalks and squares, construction of underground tunnels and ground overpasses. Soils are used as road-building materials, for example clays, loams, sandy loams, sands (for the roadbed); crushed stone, sand, gravel, bitumen, Portland cement, asphalt concrete, cement concrete (for pavements), asphalt chips; various surfactant additives that improve the properties of coating materials, as well as finished goods in the form of blocks, pipes, side stones, etc. Construction of the road begins with preparatory work: clearing the area of ​​forest, bushes, stones, etc. During excavation work on the construction of embankments up to 1 m high, the main road machines are motor graders or bulldozers that move and level the soil, and rollers that compact the subgrade. For the construction of embankments up to 2 m high or more, the main machines are a scraper, a motor grader and a roller. Excavators, cars, and transport carts are used to move soil.

When constructing roads, the number of consecutive sections (so-called captures) and the required road cars depends on the nature of the base and type of coating. For example, the technological process during construction asphalt concrete pavement may include the construction of a lower base layer of sand, a top layer of crushed stone treated with cement, two layers of bitumen-mineral mixtures and a coating of asphalt concrete. The sequence of work is as follows: transportation of sand, its leveling and compaction; delivery of crushed stone, cement and water; mixing; transportation of finished bitumen-mineral and asphalt concrete mixtures; leveling and compaction. For different road pavements, the technological process changes, but the main operations - transportation of materials, laying, leveling, compaction - remain the same.

The most progressive method of road construction work is in-line, in which all work on separate sections of the same length is carried out by specialized units moving along the road one after another in a certain technological sequence. The length of the sections is usually 200-600 m

Artificial building materials

Artificial building materials include: brick (silicate, ceramic), concrete blocks, cinder blocks. Most often, preference is given to artificial building materials, including burnt stone, since it has certain dimensions, which greatly facilitates the work. Ceramic red stones and bricks are used for masonry, both external and interior walls premises.

Bricks Available in several types and grades: hollow and solid, frost-resistant (grades 15, 25, 35, 50), durable (grades 300, 250, 200, 175, 150, 125, 100, 75), regular (with dimensions 250x120x65 mm), thickened (with dimensions 250 X 120 X 80 mm).

Stones are made by molding and are only hollow. Different types stones also have different sizes, for example: regular - 250x120x138 mm, enlarged - 250 X 138 X 138 mm, modular - 288 X 138 X 138 mm.

Silicate white brick refers to the most common and economical materials. It is non-firing and is made from a mixture of quartz sand and lime by pressing with further processing in an autoclave. Modular and single bricks are produced, as well as silicate stones. Single sand-lime brick can be full or hollow (dimensions 250 X 120 X 65 mm). Modular - 250 X 120 X 88 mm, silicate stones - 250x120x138 mm. Both stones and modular bricks are produced only hollow.

Also produced facing silicate brick and stones. They can be unpainted or colored (the entire mass is painted or only the front edges are painted). The most common colors are blue, greenish, cream, yellowish, etc. Due to the fact that sand-lime brick has very low water resistance, it cannot be used when laying foundations and plinths below the waterproofing layer. This brick is not yet used for masonry. chimneys and ovens (it cannot withstand high heat).

Chamotte yellow brick It is manufactured in two types: refractory and fireproof. It has dimensions of 250 X 123 X 65 mm and can be used to build any premises. When choosing bricks for construction, it is necessary to carefully inspect them. Cracks and swellings, distortions of the ribs and irregular shape are unacceptable.

Concrete wall blocks can be made of slag concrete and other composite mixtures based on cement or lime. They can be used for laying walls and foundations, for building partitions or for facing masonry.

Artificial building materials are obtained mainly from natural materials. At the same time final product differs from the raw materials used in its production both in physical and chemical properties. During the processing of raw materials, various chemical reactions, which radically change its properties. An example is artificial stone, which can imitate any natural stone, but at the same time it is quite durable and affordable.

Natural building materials undergo only mechanical processing, while all chemical and physical properties materials. These are widely used today in construction. natural materials, such as sand, gravel, crushed stone, wood, stone, clay, lime, etc.

A large variety of materials are used in construction. Based on their intended purpose, building materials are usually divided into the following groups:

Binding building materials (air binders, hydraulic binders). This group includes various types cements, lime, gypsum;

Wall materials - enclosing structures. This group includes natural stone materials, ceramic and silicate bricks, concrete, gypsum and asbestos-cement panels and blocks, enclosing structures made of glass and silicate cellular and dense concrete, reinforced concrete panels and blocks;

Finishing materials and products - ceramic products, as well as products from architectural and building glass, gypsum, cement, polymer-based products, natural finishing stones;

Heat and sound insulating materials and products - materials and products based on mineral fibers, glass, gypsum, silicate binder and polymers;

Waterproofing and roofing materials ~ materials and products based on polymer, bitumen and other binders, asbestos-cement slate and tiles;

Sealing - in the form of mastics, plaits and gaskets for sealing joints in prefabricated structures;

Fillers for concrete ~ natural, from sedimentary and igneous rocks in the form of sand and crushed stone (gravel), and artificial porous;

Piece sanitary products and pipes - made of metals, ceramics, porcelain, glass, asbestos cement, polymers, reinforced concrete.

Classification of building materials by purpose allows us to identify the most effective materials, determine their interchangeability, and then correctly draw up a balance between the production and consumption of materials.

Artificial building materials are divided according to the main feature of their hardening (formation of structural bonds) into:

Non-firing - materials whose hardening occurs at ordinary, relatively low temperatures with crystallization of new formations from solutions, as well as materials whose hardening occurs in autoclaves at elevated temperatures (175...200 ° C) and water vapor pressure (0.9 ... 1.6 MPa);

Firing - materials, the formation of the structure of which occurs during their heat treatment mainly due to solid-phase transformations and interactions.

This division is partly conditional, because it is not always possible to determine a clear boundary between materials.

In non-firing conglomerates, cementing binders are represented by inorganic, organic, polymer, and also mixed (for example, organomineral) products. Inorganic binders include clinker cements, gypsum, magnesium, etc.; organic - bitumen and tar binders and their derivatives; to polymer - thermoplastic and thermosetting polymer products.

In firing-type conglomerates, the role of binder is played by ceramic, slag, glass and stone melts.

Organic binders make it possible to obtain conglomerates that differ in: the temperature of their use in construction - hot, warm and cold asphalt concrete; according to workability - hard, plastic, cast, etc.; according to the size of the filler particles - coarse-, medium- and fine-grained, as well as fine-grained.

Polymer binders- important components in the production of polymer concrete, building plastics, fiberglass and other, often called composite materials.

The classification of artificial building materials (conglomerates), united by a general theory, is expanding with the advent of new binders, the development of new artificial aggregates, new technologies or significant modernization of existing ones, and the creation of new combined structures.

Artificial stone materials based on mineral binders

Asbestos-cement products

Asbestos cement is an artificial stone material obtained by hardening a mixture consisting of cement, water and asbestos. Depending on the type of products, as well as on the quality of the asbestos used, its content in the raw material mixture varies from 10 to 20%, and Portland cement - from 80 to 90%. Loose asbestos fibers, adhering to the cement stone, reinforce it and give asbestos-cement products high strength. Asbestos cement, with a relatively low density (1600-2000 kg/m3), has high strength properties (tensile strength in bending up to 30 MPa, and in compression up to 90 MPa). Asbestos-cement materials do not pass through electric current, do not burn, are frost-resistant, have low water and air permeability, however, they have increased fragility and can warp if unevenly saturated with water.

Lime based products

Products consisting of a mixture of lime, sand and water, molded and subjected to heat and humidity autoclave treatment, are called silicate. For a long time, the only type of silicate building materials was sand-lime brick, for the manufacture of which quartz sand and air-lime are used. If part of the quartz sand is finely ground, then the strength of the products after autoclave hardening will increase significantly, and in this case silicate concrete is obtained, in which the binder is a finely ground lime-silica mixture.

Gypsum and gypsum concrete products

Gypsum-based products can be obtained either from gypsum dough, that is, from a mixture of gypsum and water, or from a mixture of gypsum, water and aggregates. In the first case, the products are called gypsum, in the second - gypsum concrete. The binders for the manufacture of gypsum and gypsum concrete products, depending on their purpose, are construction and high-strength gypsum, waterproof gypsum-cement-pozzolanic mixtures, as well as anhydrite cements. Natural materials are used as fillers in gypsum concrete - sand, pumice, tuff, fuel and metallurgical slag; light porous aggregates of industrial production - slag pumice, expanded clay gravel, agloporite, as well as organic fillers - sawdust, shavings, waste paper, stems and reed fiber, etc.

Gypsum is an air binder, therefore gypsum and gypsum concrete products (partition panels and slabs, floor slabs, cladding sheets, ventilation ducts, stones for masonry walls, architectural details) are used mainly for the internal parts of buildings that do not bear large loads. Gypsum products can be solid or hollow, reinforced or unreinforced.

Types of artificial stone materials

Depending on the type of binder, products based on cement, lime, and gypsum are distinguished. The type of binder and the adopted production method determine the hardening conditions of non-firing materials. Hardening can occur both under natural conditions and under conditions of thermal and humidity treatment (steaming or processing in autoclaves).

As fillers for the production of artificial stone materials quartz sand, pumice, slag, ash, and sawdust are used. To increase flexural strength, products are reinforced with fibrous materials - asbestos and wood.

Based on the type of mineral binder, artificial stone products can be divided into four groups: gypsum and gypsum concrete; products based on magnesium binders; silicate; asbestos-cement, made on the basis of Portland cement with the addition of asbestos.

The main non-fired stone materials and products include gypsum concrete and gypsum products, sand-lime brick and silicate concrete products, asbestos-cement products. Unlike ceramic materials, the production of such materials is carried out at relatively low temperatures. So, the manufacturing temperature sand-lime brick 170-180°C, and the heat treatment time is 10-14 hours, while ceramic brick fired at 900-1100°C for 24-30 hours. Thus, fuel costs for the production of sand-lime brick are much lower than for the production of ceramic bricks. Other types of unfired stone materials require even less fuel. However, as a rule, ceramic materials are more durable and resistant to water, aggressive solutions and high temperatures.

Conclusion

Artificial building materials and products are produced mainly from natural raw materials, less often from industrial by-products, agriculture or raw materials obtained artificially. The produced building materials differ from the original natural raw materials both in structure and in chemical composition, which is associated with the radical processing of raw materials in a factory using special equipment and energy costs for this purpose. Factory processing involves organic (wood, oil, gas, etc.) and inorganic (minerals, stone, ores, slag, etc.) raw materials, which makes it possible to obtain a diverse range of materials used in construction. Between certain types materials there are large differences in composition, internal structure and quality, but they are also interconnected as elements of a single material system.

Literature

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