Crushed stone is an indispensable building bulk material. It is based mainly on non-metallic rocks and some types of ore. Due to the wide variety of types, its scope covers all areas of construction. When choosing the most suitable type of crushed stone, a certain classification system for this material is used, which greatly facilitates the whole process and allows you to create the most durable structures or ensure the duration of the use of other building forms.
In order to more clearly imagine the possibilities of species diversity, one should first understand the principle of production of this building material. It is mainly obtained during the performance of work on the extraction of stone, as well as in the process of processing. From whole pieces various stones with the help of special crushing equipment, grinding is carried out to fractions of the desired size.
Important! This whole process is waste-free. Even the secondary raw materials obtained in the processing of the base material in the form of the smallest crumb find their application.
Principles of crushed stone classification
This material has a wide variety of shapes.
Therefore, there are several classification criteria:
- nature of origin;
- density;
- strength;
- geometric shape;
- granule sizes;
- level of radioactivity;
- frost resistance;
- color.
Nature of origin
When classified according to this principle, a very long list of possible options is formed due to the variety of mined and processed materials.
For convenience, the following main types of crushed stone are distinguished by origin:
Density
This indicator is inextricably linked with the type of feedstock. The higher the density, the wider the range of application. In turn, it is this property that determines the strength of the material.
Strength
The strength parameter determines the degree of resistance of the material to deformation under tensile load and destruction under any mechanical influence. To mark the distinguishing features in terms of strength, a system of brands is used, each of the indicators of which corresponds to certain indicators.
Grading looks like this:
- Weak - the lower limit corresponds to the M200 brand, the upper does not exceed M600.
- Medium - the range of indicators M600-M800.
- Durable - crushed stone, the parameters of which correspond to grades from M800 to M1200.
- High-strength - the upper limit corresponds to the M1600 brand.
Important! All parameters are regulated by GOST standards.
shape geometry
One of the most important criteria that affects the quality of the rammer. The defining indicators are the presence of needle and lamellar granules and their percentage. The determining factor of such particles is their width, the dimensions of which are 3 or more times less than the length of the grains.
There are three main categories of flakiness:
- ordinary, in which the volume of such grains does not exceed 35% of the total mass of the stone;
- improved, the percentage of which varies from 25 to 35;
- cuboid, in which the content of both needle-like and lamellar granules does not exceed 15%.
Granule sizes
According to this principle, the following types of crushed stone fractions are distinguished:
Important! In addition to the above usual categories, there is also rubble custom sizes, fractions of which can reach from 120 to 300 mm.
When choosing a material, taking into account this indicator, both the consumption of crushed stone and the strength of the formed coating are determined - the more voids, the lower the quality.
Level of radioactivity
The natural radioactive background of the material determines the permissible scope. The classification is by class:
Frost resistance
The main indicator is the number of drying and saturation cycles in a solution of sodium sulfate. Depending on the result obtained, the number of cycles of permissible freezing and thawing is determined without breaking the shape and reducing the strength characteristics.
The principle of difference is the marks of the following type:
Hue
Very important criterion, which also directly affects the scope and method of designing structures of various types. It is noteworthy that due to the breadth of the color palette, which is provided by a fairly diverse composition of components, the use of crushed stone is permissible at all stages of construction - both during rough work on the construction of the foundation of structures, and during decorative finishing. 
The main types of crushed stone rocks
This group is represented by a very wide product line, so we will separately note only those types that are in high demand:
Areas of application of crushed stone
It is rather difficult to limit the scope of crushed stone, since its use is advisable at all stages of construction in various directions.
Among the most popular solutions, we note the following:
- Preparation of concrete of different grades when erecting walls of monolithic structures of any scale and laying the foundation.
- Production of block building material.
- Formation of road surfaces of various types - bulk garden paths, asphalt highways, paving with tiles of the pedestrian zone.
- Arrangement of railways, airport runways.
- Landscape design - decoration of decorative embankments, flower beds, artificial reservoirs.
- Improvement of the soil - installation of fencing systems and drainage complexes.
- Animal husbandry - crushed limestone is added to animal feed as natural calcium.
- Creation of a protective layer on roads with ice.
Video
Watch the video, which clearly shows the whole process of extracting crushed stone.
Conclusion
Given the diversity of the species range of crushed stone, when choosing, be sure to consider the full range of criteria. Only in this case the result will correspond to the specified parameters, and the period of operation will be long.
It will probably not be an exaggeration to say that crushed stone is the most demanded of solid dense stony materials during construction. various types buildings and structures.
Crushed stone is used as a filler for concrete and as drainage in a variety of places, used in the construction of roads and laying railway tracks, in the arrangement of various objects landscape design etc. It is even painted, then creating multi-colored bright panels from colored pebbles.
However, despite this prevalence, quite a lot of people do not know which one construction material hides behind the name crushed stone and how it differs from gravel, with which it is quite often confused.
HOW TO DIFFERENTIATE GROUND FROM GRAVEL
Let's start with a basic definition: rubble is called bulk material, which is obtained by crushing natural or artificial stone materials. This means that the main feature of crushed stone is the geometric shape of individual pebbles. That is, if you see a bunch of hard pebbles with sharp edges, then it will be crushed stone, regardless of color and origin.
A similar difference in the shape of individual pebbles (grains) also determines the difference in their adhesion to a mixture of cement and sand in the production of concrete. With crushed stone, due to uneven sharp edges and a rough surface, the adhesion is higher and the resulting concrete will be stronger than if gravel is used as an aggregate.
It has already been mentioned above that crushed stone is, in fact, the form of individual pebbles. As for the "content", that is, the properties of the material itself, they can vary within fairly wide limits.
So, if crushed stone was obtained from natural stone, then it can be both igneous (granite, gabbro, basalt, etc.), and metamorphic (gneisses, eclogites, marble, etc.) and sedimentary (limestones, dolomites) rocks.
In addition, crushed stone can be obtained in the process of crushing various solid wastes that appear after construction work or in the production of ceramics, and even slags and slag alloys from various metallurgical enterprises (blast furnace, steel plants, etc.).
MAIN TYPES OF CRUSHED STONE FOR CONSTRUCTION
At construction work In the vast majority of cases, three types of natural crushed stone are used: granite, gravel and limestone. The most common crushed stone from artificial stone materials is secondary.
It is mainly used to obtain particularly hard concrete, when pouring building foundations, building bridges, highways, etc.
is the result of crushing gravel from a sand-gravel mixture mined in a quarry or from the bottom of a reservoir. In terms of its properties, it is inferior to granite, but its cost is also lower.
In individual suburban construction, the use of crushed gravel is the most optimal, unless, of course, an underground bunker is built in case nuclear weapons are used.
Obtained by crushing limestone. Being sedimentary rocks, limestones have the lowest strength, which leads to a lower cost of such crushed stone.
It is intended for the so-called irresponsible construction: low-rise buildings, roads with a small load, the production of reinforced concrete structures: trays and rings, etc.
It is due to this that the most beautiful compositions of stalactites and stalagmites are formed in the caves, and karst funnels appear in limestone rocks.
If carbon dioxide is present in the water, then the dissolution process is much faster. This gas is released as a result of the reaction of calcium carbonate with acids. Therefore, in proximity ground water with high acidity (if their pH is below 6.0), it is better to give preference to more resistant rubble, since in the future this can significantly affect the stability of the foundation of the building.
It is the result of crushing of recyclable concrete, bricks, aerated concrete, etc. Most often, sellers offer secondary crushed stone from concrete. It has a lower cost than natural, but by buying such material you are, in fact, buying a pig in a poke.
If you are already planning to use such secondary crushed stone in critical places of structures or buildings under construction (for example, for pouring a foundation), then to guarantee the quality, you can make trial cubes of new concrete with it and send it to the laboratory to determine the strength.
You can also check the strength of the resulting concrete yourself using the method of shock impulse action, using for this either a special Kashkarov hammer or improvised means.
All of these methods are based on the assessment of the impact impression on the concrete surface. Only in the first case, the impact assessment is made relative to a special standard, and in the rest - "by eye", which affects the accuracy. With improvised means, the result will be quite approximate, but for private construction it is quite acceptable.
One of the handy ways is to use a hammer with a weight of a working metal blank of 400 - 500 g and a chisel. If, after the impact, the chisel entered the concrete by 1 cm or more, then its grade is not higher than M75, if it sank no deeper than 0.5 cm - M100 - M150, if small dent with breaking off small pieces - at least M200, and if damage is not visible - M350.
Another similar method is a medium-strength blow to a concrete blank with a metalwork hammer with a convex spherical head. If after that a dent 1 mm deep remains on the surface, then concrete grade M50 - M75, if lesser depth - M75 - M100, and if it does not remain at all - M150 - M200.
In the following parts of the educational program, the main characteristics of crushed stone will be considered, which determine the scope of its application and are determined as geometric parameters grains (), and the physical properties of the material itself ().
The article presents the main characteristics of crushed stone as a building material. We will talk about how different types of gravel differ, what each of them is intended for. You will learn how to determine the main performance indicators (fraction, strength) depending on the purpose of the work.
Crushed stone is a building material obtained by crushing and screening rocks, heavy industry waste or processing. Represents individual stones different size(fractions). It is widely used in construction as a structural and bulk material. An individual rubble stone is called a grain. The quality and scope of natural crushed stone is standardized by GOST 8267-93 "Crushed stone and gravel from rocks for construction work."
The main parameter of crushed stone
Flakiness is the main indicator for crushed stone of any origin. It reflects the presence of relatively even flat faces on individual stones. The larger such faces are, the higher the flakiness is considered. Grains with faces of a relatively large area have an acicular (acicular) or lamellar shape. Other grains (with conditionally identical faces) are called cuboid. The percentage of content of such grains depends operational properties mass, especially in a "dry" bulk form.
Groups of crushed stone in the form of grains
|
Group (characteristic) |
Group (designation) |
|
|
cuboid |
Up to 15% |
|
|
improved |
Up to 25% |
|
|
Plain |
Up to 35% |
The ability to determine flakiness by eye will help in choosing crushed stone for your own needs. To do this, it is enough to know how this indicator is reflected in the properties of the material:
1. Cube-shaped grains perceive tamping better, resulting in a denser base. This is important when arranging a foundation pad and bedding under the road. They are also the most durable (compared to other forms).
2. Needle grains create voids in the mass of stone. While creating concrete structure more mortar will be needed to prepare the mixture, and the compressive strength will be somewhat less.
3. At the same time, voids are useful for drainage. Providing sufficient packing density, crushed stone of the usual group removes atmospheric water.
Characteristics of crushed stone
This material has two main performance indicators that you should be guided by when choosing for your own construction - frost resistance and strength.
Frost resistance
By resistance to freezing cycles, grains are divided into 3 categories. They are marked with the letter F and a number indicating the number of freezing cycles:
1. Highly resistant. Brand F200, F300, F400. It is used for all types of critical structures, bridge supports, reinforced concrete products, high-rise construction, outdoor dumps, offshore facilities and for the Far North.
2. Resistant.Grades F150, F100, F50. Used in construction in the southern regions and the Middle Strip.
3. Unstable.Grades F50, F25, F15. They are introduced as bedding and drainage to a level below the GWL. Is used for internal works and heated structures.
It should also be noted that laboratory studies of the frost resistance of crushed stone are carried out on a separate grain. In a structure (in concrete), the grain receives a plus of 30–40% to frost resistance due to pressure inside the structure.
Strength
This most important indicator is determined by simulating the actual operation of the embankment - crushing, wear and crushing. Thus, the ability of the material to resist these influences is revealed.
Table of dependence of the field of application on the grade of strength
|
Brand |
Group characteristic |
Application area |
|
M1600 - M1400 |
heavy duty |
Foundations of bridge supports, towers, derricks |
|
M1400 - M1200 |
high strength |
Bridge supports, foundations of high-rise buildings, embankments, hydraulic structures, towers |
|
M1200 - M800 |
Lasting |
Load-bearing walls of buildings, industrial structures, piles, columns, foundations, fences, supports, filling under the railway track |
|
M800 - M600 |
Medium strength |
Unloaded structures, walls, backfill limited on 4 sides |
|
M600 - M300 |
Weak strength |
Unloaded dumping, unloaded (open) drainage, filters, treatment facilities |
|
M200 |
Very weak strength |
The strength grade depends on the amount of admixture of weak rock in the mass of crushed stone. In this case, the prototype is subjected to a load of 20 MPa. Permissible content of weak breeds:
1. M1600 - less than 1%.
2. M1400 - M1000 - no more than 5%.
3. M800 - M400 - no more than 10%.
4. M300 - M200 - no more than 15%.
Rock with a weak rock content of more than 20% is called gravel and is used mainly for backfilling local roads, change houses, creating temporary structures and other non-critical work. It is quite acceptable to use washed gravel as crushed stone in private construction (except for foundations).
Varieties of crushed stone
Each of the items has its own classification according to strength, size, frost resistance and other indicators. We will focus only on the practically useful aspects of the description.
gravel crushed stone
This type of crushed stone is obtained by sifting quarry rock and explosive mining of stone rock. It is somewhat less durable than granite (limiting grade M1200) and has an unsightly gray look. At the same time, its advantages are undeniable:
1. More quarries, competition.
2. The cost price is lower (due to the distribution of raw materials).
3. Mining is easier (granite is harder than rock).
4. Extremely low radioactive background.
At the same time, the limiting grade and other properties of crushed gravel make it possible to use it for critical structures in all sectors of the national economy. There are four fractions of this material:
1. 3–10 mm - elimination.
2. 5–20 mm - "seed". Used for small items paving slabs etc.).
3. 5–40 mm - used for medium-sized factory products - concrete and well rings, curbs, lintels, etc.
4. 20-40 mm - the main material for the production of concrete and road filling.
Limestone (dolomite) crushed stone
Carbonate calcite (CaCO 3), compressed by time to a state close to a rock mass. According to the main indicators, it is identical to the gravel. It is applied to concrete goods and road construction. Distinctive feature- White color.
Granite crushed stone
Obtained by the explosion of a granite massif, crushing and screening the mass. In most cases, it has a red tint. The torn edges of the grains provide the best adhesion to the mortar. The shiny texture gives a good appearance to polished monolithic floors and other concrete products on crushed granite.
This type of crushed stone is recognized as the most popular, because it has the highest strength. Accordingly, companies offer the largest assortment screening fractions - from 0–5 mm to 70–120 mm. For each faction, there is a whole set of applications.
Slag crushed stone
This material is the result of crushing and screening of metallurgical dump slags and melts. Concrete products based on this crushed stone are 20–30% cheaper than conventional ones.
Secondary crushed stone GOST 25137–82
The material that is obtained from the targeted processing of construction waste. It is produced in the same way as natural, only as a raw material it is not a piece of rock, but a monolithic element. After the initial split, they extract from it steel elements(reinforcement), then it goes to the screen.
Such a material could save a lot of money: energy costs are up to 8 times less, and the cost of concrete with such crushed stone is 25–30% less. On sale, artificial crushed stone is 2 times cheaper than granite. Although its strength and frost resistance are inferior to natural ones (maximum M800 and F150), there are many areas of application for such indicators.
Having the necessary knowledge about the choice and merits different types crushed stone, you can accurately determine its quality and purchase exactly what you need.
Vitaly Dolbinov, rmnt.r
http://www.rmnt.ru/ - siteRMNT.ru
Building material produced by crushing various hard rocks or processing industrial waste is called crushed stone. This inorganic, outwardly resembling a small chipped stone, is widely used in many areas of human activity. Different kinds crushed stone, depending on its physical and technical characteristics, are used in the capital and restoration construction of buildings, roads, railways, the production of reinforced concrete products, and landscape planning.
and where each type is used
Crushed stone is classified by origin. This is, first of all, the type of rock from which it is made. Manufacturers always provide the necessary information. The origin of crushed stone characterizes its qualities, and hence the scope of its application. The main types of crushed stone by origin are divided into:
- granite. This is one of the most durable types of gravel. It is obtained from hard rock, one of the most common on Earth. Granite rock refers to igneous (primary) rocks and represents ejected to the surface and solidified magma. Granite is formed from a number of crystals: quartz, spar, mica, etc. It has a red, pink and gray color. Gravel types of crushed stone are used for construction and landscape planning, road and railway equipment, drainage, and decorative design.
- gravel. Crushed stone produced by sifting or crushing rock. It has almost the same strength as granite, but has a lower radiation background and is cheaper. Gravel types of crushed stone are used for concrete, the production of reinforced concrete products, foundation work and in road construction.
- Limestone. This crushed stone is a product of crushing sedimentary (secondary) rock - limestone, the main component of which is calcite. Limestone and significantly inferior in strength to gravel and granite. It is applied in road construction and production of reinforced concrete products.
- slag. This is a product of crushing waste from metallurgical production. The main advantage of such rubble is a relatively low cost. Most often used as a binder for the preparation of concrete.
- Secondary crushed stone. The product of crushing construction debris - brick, concrete, asphalt. Such crushed stone is inferior in all characteristics to products from natural materials, but still widely used as a filler for concrete, road facilities, strengthening weak soils, landscaping.
crushed stone production
The production of crushed stone consists of several stages:
- rock mining;
- transportation (if necessary);
- several stages of crushing;
- fraction sorting.
The main stage of crushed stone production is crushing. The shape and size of the resulting grains depend on this operation. Crushing is carried out in 2-4 cycles on special equipment - crushing machines. Depending on the grinding method, there are different types of crushed stone crushers:
- Cheek- are established at the first stage of crushing. The principle of operation is shockless crushing of rock between two plates.
- Centrifugal. These crushers are most often used for the production of fine crushed stone of any hardness used in road construction.
- Cone crushers are one of the most expensive crushed stone production machines. Their main advantage is versatility. Such crushing machines can produce crushed stone of any fraction and even artificial sand.
- Rotary. In these machines, the crushing of rock is carried out by impact energy. The rock being filled at high speed repeatedly hits the impact plates and is crushed until it falls into the calibrated exit slots.
At the last stage, before shipment of products to consumers, crushed stone is divided into fractions. The operation is carried out on equipment called a screen. These machines can be stationary or suspended. During the screening process, the crushed rock passes through several vibrating sieves with holes of various diameters. On each of them, the crushed stone of the established fraction is separated.
Fractions of rubble
At the exit after crushing, grains of various sizes are obtained. For further implementation, crushed stone is sorted based on particle size. Fraction - the maximum allowable value of a single grain (stone). Types of crushed stone according to fractions are divided into main and accompanying. The main ones are from 5 to 70 mm in size. The sizes of the accompanying fractions and elimination - from 0 to 40 mm. For special applications, types of crushed stone of special fractions are produced: 70-120 mm and 120-150 mm.
Crushed stone is the main natural stone material. Granite crushed stone 5-20 mm in size is in the greatest demand. Such material is used in the production of concrete, asphalt and reinforced concrete products. Granite crushed stone of large fractions (20-45, 20-65, 25-60, 40-70 mm) is also quite in demand on the market, it is used for railway embankments, in construction when strengthening foundations and laying foundations, as a cushion layer in the construction of roads .
gravel and crushed stone
For the production of concrete, such large aggregates are used: natural stone and gravel crushed stone; aggregate from gravel used in construction can be mountain, river and sea. The last two, due to their smooth polished surface, have the worst adhesion. Stone crushed stone for construction is produced by crushing natural rocks. Such types of crushed stone have a rough surface and an acute-angled shape, due to which they have better adhesion to binders than gravel. The quality of gravel and crushed stone is characterized by:
- strength;
- grain size and shape;
- frost resistance;
- content of harmful impurities.
Physical properties of crushed stone
Much more attention is paid to the physical characteristics of the material than to the origin. It is on the basis of these properties of crushed stone that the scope of its use is determined. All types of crushed stone are characterized by the following main indicators:
- strength;
- flakiness;
- frost resistance;
- water absorption;
- grain shape;
- radioactivity.
The flakiness of the rubble
In crushed stone, the content of lamellar and needle-shaped grains is normalized, whose thickness or width is three times greater than the length. This is an important characteristic, which is first of all paid attention to when using crushed stone in construction and the production of reinforced concrete products. In the presence of a large number of grains of lamellar and needle shape in the total mass of crushed stone concrete mix may be of poor quality and require additional sealing. A large number of grains of this shape leads to the formation of numerous voids. According to the percentage of lamellar and needle grains in the mass, crushed stone is divided into groups:
- I - up to 15%, cuboid;
- II - 15-25%, improved;
- III and IV groups of usual flakiness - 25-35% and 35-50%, respectively.
Cuboid crushed stone is most suitable for the preparation of concrete due to the absence of problems with voids.
crushed stone strength
This property of crushed stone is characterized by the strength limit of the original rock. The strength of this natural stone material is determined by the imitation of mechanical effects on compression, crushability during crushing in the cylinder, abrasion in the shelf drum. Granite has the highest strength. The most demanded is crushed granite M1200 with a content of stones of weak rocks no more than 5%. Its main application is the construction of foundations, the production of high-strength concrete and load-bearing structures.
Frost resistance of the material
The property of a material to maintain integrity, strength and mass after repeated freezing and thawing is called frost resistance. This characteristic is especially important for crushed stone used in the construction of foundations in regions with low temperatures. Materials with high density and low porosity have high frost resistance.
Activity of radionuclides of crushed stone
One of the most important characteristics of any material used in construction is the radioactivity of rubble. It determines its suitability for all types of construction work and must comply with sanitary and epidemiological standards, which is confirmed by the relevant conclusions and certificates. The first class of radioactivity of high-strength crushed stone corresponds to a value of less than 370 Bq / kg. For the second class - more than 370 Bq/kg.
Crushed stone is a loose building material of inorganic origin. It is obtained as a result of industrial processing of various rocks. When buying, the consumer is primarily interested in the fraction and breed. The price, purpose and scope of the material depend on this.
In the process of processing, crushed rock particles are sifted through special sieves (screens) and sorted by size and shape. A fraction is a range of sizes of individual grains, they are usually indicated in millimeters.
Conditionally divided into two groups:
1. Standard - dimensions in accordance with GOST.
2. Non-standard - parameters for special purposes, produced in agreement with the customer.
Screenings (granite chips) and various mixtures are also used in the construction industry. Within each species, a narrower classification of fractions is possible.
| Dimensions | Fraction, mm | View |
| Standard | 5-10 | small |
| 5-20 | ||
| 10-20 | ||
| 20-40 | average | |
| 25-60 | ballast | |
| 20-70 | large | |
| 40-70 | ||
| non-standard | 10-15 | small |
| 15-20 | ||
| 70-120 | BUT | |
| 120-150 | ||
| 150-300 | ||
| Other | 0-5 | screening |
| 0-40 | mixtures | |
| 0-60 | ||
| 0-80 |
Description of varieties
Depending on the raw material, several breeds are distinguished:
- Granite - obtained as a result of undermining and crushing monolithic rocks. The grains can be gray, red or pink. The main advantages of crushed granite include increased strength, durability and lightweight processing. These characteristics are due to the content of quartz, mica and feldspar.
- Gravel - mined by crushing. Another method is to screen large rocky debris in the quarry area. The main characteristics include a reduced level of radioactivity, moderate resistance to mechanical damage and an affordable price.
- Limestone is the result of industrial processing of sedimentary calcite rocks. Differs in ecological cleanliness, low density and excellent frost resistance. Due to the wide availability of raw materials and simple production technology, it is the cheapest of all types.
- Slag - a product of processing waste from metallurgical, chemical enterprises, incineration solid fuel in boiler rooms. Crushed stone mass shows excellent characteristics of durability, tensile strength and mechanical shock. The rough surfaces of the grains provide increased adhesion to the binder component (cement).
- Secondary - obtained after processing various construction waste: fragments of bricks, asphalt, concrete products.
Specifications and properties
1. Strength.
It is determined by the volume of inclusions of brittle rocks. Their content in durable grades of crushed stone should not exceed 5%. This indicator is of great importance in the construction of roads and railways, bridge supports, heavy foundations. In residential construction, the use of M800-M1200 is recommended.
2. Flakiness.
Classification according to the shape of the grains, the parameter shows the ratio of length to width and thickness of individual particles. It depends on the density of the concrete. The more cube-shaped grains in the crushed stone, the more evenly they are distributed in the solution and fill all the voids. The normal content is limited to the range of 15-85%. A high percentage of flakiness confirms the good drainage properties of concrete.
3. Frost resistance.
The number of complete freeze-thaw cycles is between F15 and F400. In the construction industry, F300 grades are usually used.
4. Adhesion.
The maximum degree of adhesion of binders with crushed stone particles is observed in gravel.
5. Class of radioactivity.
The indicator depends on the source of extraction of raw materials and is confirmed by GOST. In residential and industrial construction crushed stone of the 1st class of radioactivity is allowed, for road works - the 2nd.
Areas of use
1. Screening - is selected as a filler when mixing concrete, masonry mortars, for the preparation of dry mixes, for the construction of footpaths, sports and children's playgrounds.
2. Road mixes - active use in the production of asphalt concrete, for laying the foundations of highways, runways, railway tracks, backfilling roadsides.
3. Small fractions are the most demanded types of bulk material. This the best way for concrete and casting of structures from it, laying the foundation, blind area, road works.
4. Medium - are used in the construction of industrial facilities, reinforced concrete structures, laying tram lines, roads and railways.
5. Large fractions - mainly in demand in the manufacture of large volumes of concrete. Also selected as a drainage, in the construction of urban roads and foundations for them.
6. BUT (building stone) - sometimes selected for laying massive foundations or strengthening coastline. Main application as decorative elements at finishing of protections, reservoirs, pools. Waste after crushing can be used as a concrete aggregate.
Crushed stone 25-60 is purchased for laying the ballast layer of the railway track. Narrower fractions (5-10, 5-15, 10-15, 15-20) are in demand in the production of asphalt concrete, processing of various surfaces, patching, the device of a blind area around buildings.
Purpose
For concrete - it is recommended to use gravel, granite or limestone fine crushed stone as a filler. Small particle sizes ensure minimal porosity and excellent product strength. In the production of medium and heavy concrete, it is better to choose a slag mass.
For the foundation - in most cases, gravel is used, the main properties of which are strength and affordable price. When building multi-storey buildings or massive objects, it is better to choose crushed granite. When constructing lightweight buildings (arbor, garage, shed), cheap limestone material is suitable. Optimal fractions for bookmarking: 5-20 and 20-40.
For drainage - rubble stone is the most suitable. It is resistant to moisture, temperature changes and soil acidity. Using standard types it is better to select large fractions. In order to save money, you can buy recycled materials. Despite the low price, they have all the properties of primary crushed stone.
For blind area - the best choice will be gravel with a particle size of 5 to 40 mm.
Price overview of popular factions
| rubble | Price *, rub./m3 | ||
| 5-20 | 20-40 | 40-70 | |
| gravel | 1580-3000 | 1530-2850 | |
| granite | 1850-3300 | 1600-3100 | 1700-3070 |
| Limestone | 1100-2700 | 1170-2500 | 1170-2500 |
| slag | 1000-1500 | 800-1200 | 800-1200 |
| secondary concrete | 1020-1250 | 800-1000 | 800-1000 |
* The table shows the cost with delivery in Moscow.
For the manufacture of concrete elements of small thickness, it is better to use crushed stone with a grain size of up to 10 mm. By production of massive products it is possible to apply 10-20 and above.
Before you buy gravel of a certain fraction, you need to require a passport. A conscientious manufacturer always lists the main features, characteristics and applications.
In an attempt to save money, some customers seek to purchase cheap material with low flakiness characteristics. Most of it is made up of needle-like or lamellar grains. Such a choice is justified if it is intended for filling footpaths, playgrounds, decorative works or drainage system. When it comes to laying a foundation or blind area, it is better to buy crushed stone with the maximum flakiness. Otherwise, you will have to spend extra on sand and cement, which in the end is much more expensive.
Recycled gravel allows the developer to reduce costs by 35-50%. This helps to solve the problem of waste disposal. In construction work, it is possible to use not only individual fractions of recycled material, but also non-fractional with a grain size of 0-70 mm.
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