Colossal potential modern technologies And a wide range of construction materials are provided practically unlimited possibilities professional and private construction sectors. Wall blocks are budget analogue expensive bricks and imply a significant simplification of installation work.
The production of wall blocks allows you to implement any construction projects without significant financial costs, while satisfying all construction requirements at different sites under any conditions.
Production
The production process of wall blocks involves the use of concrete mixtures, followed by the addition of special solutions, the composition of which determines the characteristics of the future material. Various technologies (casting, vibrocompression) can be used in the manufacturing process.
To a large extent, the formation of the properties of concrete blocks is influenced by temperature conditions and pressure indicators at which the material hardens and takes on its final shape. At different conditions mixtures of identical composition have various characteristics strength and uniformity. For example, when a concrete mixture spontaneously hardens in natural conditions the material will have lower properties than when creating optimal temperature parameters and using an autoclave.
Today, there are several types of wall blocks, each of which has special properties:
- Expanded clay concrete blocks - construction material oriented towards construction small buildings, and industrial facilities. The concrete mixture contains high-strength clay granules, which provides high heat-saving properties and sufficient strength indicators. Expanded clay-based wall blocks do not freeze, condensation does not collect on their surface, and fungi and mold do not spread.
- Polystyrene concrete blocks are a composite material, the production of which uses concrete mixtures based on polystyrene granules. They can be produced directly on construction sites, because the manufacturing process does not involve the creation certain conditions for hardening. Polystyrene concrete has good heat and sound insulation properties, but is extremely vulnerable to fire.
- Foam concrete blocks are a type of lightweight wall blocks, the production of which uses standard concrete mixtures based on a strong foaming agent. The manufacturing process is quite simple, does not require the use of hard-to-find components and the creation special conditions for hardening. The material does not have high strength indicators and requires additional finishing erected walls.
- Aerated concrete blocks are a durable and homogeneous material from the category of light cellular blocks, in the production of which autoclaves are used. High strength, excellent heat and sound insulation properties, fire resistance and frost resistance are the main advantages of aerated blocks. Objects built from aerated concrete blocks practically do not shrink.
Inexpensive composite materials include concrete based on sawdust. Such blocks have high environmental friendliness, good thermal insulation and fire resistance. The disadvantages of sawdust concrete include a long period drying and increased water permeability.
Advantages of producing expanded clay concrete blocks
The production process of expanded clay concrete blocks involves the use of special concrete mixtures based on environmentally friendly expanded clay and fired clay granules in a special way. The correct ratio of the components of the solution and the use of special equipment make it possible to obtain light and high-strength blocks for the construction of walls.
Expanded clay blocks, manufactured in accordance with established standards, are superior to some types of wall blocks both in chemical indicators and in operational characteristics. Of the benefits composite material based on expanded clay there are:
- high thermal conductivity coefficient;
- active air exchange and vapor permeability;
- versatility of use in any climatic conditions;
- fair durability;
- corrosion resistance;
- fire resistance;
- environmental friendliness;
- ease of storage and transportation;
- relatively low cost.
Expanded clay blocks speed up the process of wall construction by 4-5 times, which allows you to significantly save time without losing quality. Installation of expanded clay-based wall blocks is quite simple and does not require special professional skills.
Construction is perhaps the most developed industry. Naturally, experts are constantly developing new equipment, as well as different materials. Thanks to this, it is possible to reduce the cost of building construction and make it more productive. Wall blocks are a very popular material. What this is, you will find out further.
Advantages of blocks and features of their use
So, presented building elements are very popular, especially in the construction of small buildings. At the same time, you can implement almost any project.
The production of wall blocks can become a profitable business. For the manufacture of such elements are used natural materials: sand, cement, lime. Naturally, to improve the properties of this type of product, various plasticizers and additives are used. In any case, this material has the following advantages:
Reasonable cost and inexpensive production;
Various ingredients for making;
Good strength and others specifications ready-made blocks;
High speed of construction of buildings;
Excellent thermal insulation of premises.
Varieties of elements
Before choosing equipment for the production of wall blocks, you need to understand what they are. So, there are these types of building materials:
1) aerated concrete - made from cement, water, sand and lime, in addition, a plasticizer is added to the composition;
2) slag - this material is durable and light, it has a porous structure, which helps make the house more energy efficient;
3) expanded clay concrete - an excellent material for construction and arrangement of thermal insulation of premises;
4) foam block - made from a standard solution with the addition of a foaming agent.
In principle, the equipment used for the production of wall blocks of all these types is the same. The appropriate parameters are simply set.
What equipment is needed for the job?
Now let’s figure out what kind of equipment is actually needed for the production of wall blocks. So, you need to purchase:
Vibrating table;
Vibropress;
Device for mixing ingredients;
Forms for filling.
In principle, only one brick making machine is sufficient. It can be equipped with removable or non-removable molds. If necessary, you can purchase other equipment for the production of wall blocks, which will perform additional functions. You also need machines for stacking and storing finished products.
Features of use and types of brick making machines
The presented device is the most important part of the line, so it’s worth talking about it in more detail. Such equipment for the production of wall blocks has a very simple principle of operation: the semi-dry mixture is poured into molds and, through constant movement of the press, it is compacted to form a finished block that must dry.
Now let's look at what a brick press for producing wall blocks is like.
1. If possible, move:
Stationary;
Mobile.
2. By degree of functionality:
Specialized;
Universal.
3. By degree of automation:
Automated.
It should be noted that the presented equipment for the production of wall blocks makes it possible to make a very durable building material. It's all about the ratio of water and cement. The less liquid you use, the stronger the block will be. Such hard concrete cannot be prepared using a concrete mixer, which is why a brick press is used.
Another advantage of this device is that all work is performed automatically, without human physical labor. The operator only has to control the process using the remote control.
How to choose effective equipment?
In order for the manufacturing procedure to be continuous and the equipment to work long time without breakdowns, you need to choose it correctly. First of all, pay attention to the performance of the units. The higher it is, the faster you can produce the required volume of goods. In addition, you should decide whether the device will be stationary or mobile. If you are making blocks at the construction site, then it is better to give preference to a mobile device.
A machine for the production of wall blocks must be multifunctional and of high quality. You should buy the presented device only at certified points where you can receive a warranty from the manufacturer.
Of course, you need to consider your financial capabilities. If you don't have enough money, try purchasing equipment that has already been used. Over time you will be able to replace it.
Building blocks are a common material for the construction of structures for various purposes. They differ in size, components, manufacturing method, but all are popular wall structural material. Building blocks are made in industrial conditions, V household They also make concrete products and cinder blocks, which requires a DIY building block maker. Based on the material used, these products are divided into the following types:
- slag concrete;
- concrete;
- aerated concrete;
- fiber foam concrete;
- polystyrene concrete.
Cinder blocks as a building material
Cinder block is a standard concrete product, but instead of heavy gravel and crushed stone, aggregate in the form of waste slag is used. This replacement gives the material lightness compared to concrete and additional thermal insulation properties, since slag compares favorably with heavy and dense crushed stone in terms of thermal conductivity.
The production of cinder blocks requires precise dosage of components in the solution, namely:
- cement grade not lower than 400 or 500, take one part (bucket);
- quarry sand, mix 3 parts (buckets);
- slag, burnt out brick, expanded clay, this material is added in the amount of 5 parts (buckets);
- water.
To obtain cinder blocks of the same quality as in the factory, use a solution of medium viscous consistency. A liquid solution will reduce the strength of the blocks, and a thick solution will create uncontrollable voids inside when it hardens.
Concrete blocks
Building blocks made of cement, sand and crushed stone are used for the construction of wall and other structures, if required increased strength. The ratio of components for standard concrete is taken in the ratio 1:3:6; other options for the concrete mixture are described in the builder's handbooks and depend on the brand of cement used, the size of the aggregate and the type of sand.
Construction sawdust blocks
For construction residential buildings, dachas, cottages use light and warm wall material made of sawdust, sand and water. The binding component in the solution is lime. The amount of material added to the solution changes the properties of the final product. An increase in sawdust mass leads to an increase thermal insulation properties, but contributes to a decrease in strength. With an increase in the amount of sand in the solution, the strength increases, while the frost resistance limit increases, which increases the performance properties of the material. Blocks are widely used in private housing construction as cladding for insulating structures.
The main advantages of the blocks are the availability of materials and low price, long term use without destruction, environmental friendliness of the material, ease of production. The installation for the production of building blocks with your own hands is available in manufacture and is popular among home craftsmen. Sawdust concrete has an increased drying time, so several through holes are made inside the product to improve air flow.
The dimensions of sawdust blocks are not strictly regulated; their width is taken as a multiple of the wall thickness. If we talk about standard sizes, then the blocks are made according to twice the thickness of the brick (140 mm - 65x2 + 10 cm). When making sawdust stones, the dry ingredients are first mixed, then water is added, and mortar mixers are used for the work.
Aerated concrete building blocks
Their preparation involves a complex process of saturating the solution with gases, which is difficult to reproduce at home. Aerated concrete building blocks are distinguished by their lightness, high noise-insulating and heat-insulating properties.
Fiber foam concrete products for masonry
Fiber foam concrete is inherently an environmentally friendly wall material containing sand, foam and cement. High-tech machines for building blocks spray foam into the mass of the solution, it forms uniform closed particles of space. To increase the strength of the blocks, manufacturers use polyamide fiber reinforcement throughout the entire mass. This wall material is very durable, does not rot, is lightweight and durable.
Their fiber foam concrete blocks are produced in various sizes. For load-bearing walls use 20x30x60 cm, which weighs 22 kg. To build a brick wall of the same size, you will need 18 stones, they will weigh 72 kg. Blocks of smaller thickness (10 cm) are used in the construction of walls inside a building, partitions, and they are used to insulate floors and walls. The thermal conductivity of fiber foam concrete is 2.7 times less than that of brick and 2 times less than that of slag concrete and shell rock.
Large block sizes reduce application cement-sand mortar for masonry 20 times compared to building a wall from small stones. Fiber foam concrete does not burn when exposed to high temperatures does not change shape and does not emit harmful impurities when heated.
Polystyrene concrete blocks
The material is classified as another type of light wall concrete blocks. It differs from standard concrete in better performance qualities and reducing production costs. The innovative wall material surpasses all known lightweight concrete in weight, even foam concrete is one and a half times heavier. Thanks to this indicator, houses are built without the usual massive foundation, and the cost of transporting material is reduced.
The production of polystyrene foam blocks involves carefully combining cement, sand, polystyrene foam particles and special additives to retain air in the total mass. Other physical characteristics material puts it a step above conventional materials. Low water absorption and vapor permeability make expanded polystyrene concrete resistant to repeated freezing and thawing, which affects the durability of constructed structures. After the construction of the walls standard materials slight shrinkage occurs throughout the year. In the case of polystyrene foam blocks, they do not wait this long.
Installation for the production of building blocks with your own hands
For the manufacture of building structures A special device is used that operates on the principle of a vibration processor.
Such a vibrating machine or vibrating table is designed independently. A self-made installation for the production of building blocks significantly reduces the cost of the blocks and, accordingly, the walls of the house.
Preparation of the solution
The solution is prepared from sand, cement, water and filler, which is used as various materials, as written above. To check the consistency of the solution for fluidity, throw a small amount onto the ground. A high-quality mixture does not spread in watery streams; when clenched in a fist, it sticks together into a lump.
The production of cinder blocks involves thorough cleaning of the slag from foreign debris; chips and unburned parts of coal are not allowed to get into the solution. Sometimes gypsum is added to the solution. In this case, three parts of slag and one part of gypsum are mixed, and water is introduced at the same time. This solution is quick to use as the plaster hardens in minutes. The slag is pre-soaked with water before mixing. To improve the quality of output products, modern plasticizer additives are added to the solution. Their action increases the frost resistance, water resistance and mechanical strength of the blocks.
Depending on the purpose, two types of concrete blocks are made - solid and hollow. The former are used for the construction of durable structures, load-bearing walls, and foundations. The second type of blocks is used as partition material; it insulates well from cold and extraneous sounds.
Making concrete blocks without a vibrating table
Of the two technologies, the use of a wooden form, which is designed to allow the solution to flow naturally without vibration, is in undiminished demand. Placing the solution into the prepared form is carried out in several stages. First, the container is filled with a third of the solution, after which the walls of the mold are carefully tapped with a hammer around the perimeter for high-quality shrinkage. concrete mortar. In the next two stages, the solution is added according to the original technology until the mold is filled. The production of building blocks with voids involves inserting two plastic bottles with water, which remove it after setting.
The forms are left to dry for 2-5 days. Then the blocks are carefully removed from the collapsible structure and laid out on pallets until completely dry. With this method of production there is no need to purchase.
The following tools and equipment will be needed: a sieve for sifting sand, molds for mortar, a trough for mixing or a concrete mixer, a hammer for tapping, a bucket, a shovel, a trowel, and drying trays.
Method for making blocks using a vibration machine
To do this, purchase or make your own vibrating machine for cinder blocks. A special metal mold is installed on the plane of the machine, and a concrete mixture with slag filler is poured into it to one third. After this, a vibrating table is connected to the action for up to 20 seconds, which allows you to remove all unnecessary air bubbles from the solution, and the cement will receive good shrinkage. The solution is poured into the mold three times. The blocks are removed from the mold in the same way as with the vibration-free manufacturing method.
Cinder block does not tolerate drying out hot weather in the open rays of the sun, so on hot days it is sprinkled with water and covered with oilcloth or cellophane so that moisture does not evaporate so actively. Formed, completely dried concrete blocks gain 100% strength on the 28th day, and after that they are ready for use in construction.
Features of making cinder blocks
The molds are made independently, using metal or wood; the width of the boards is at least 190-200 mm. They are connected into a prefabricated structure, the side parts of which are detached to remove the finished block. IN general design no more than 6 cells are combined to lay concrete. Ready design installed on a dense, waterproof material, such as oilcloth, forming the bottom of the mold.
If wood is chosen as the material for the mold, it is pre-treated with impregnations or primers to increase moisture resistance. The molds are made from dry wood. These conditions are met, otherwise during the work the wood will move away from the water and the geometric size of the block will change. Standard sizes stones are considered 400x200x200 mm, but each private manufacturer makes blocks for his own construction.
For metal matrices, sheets with a thickness of no more than 3-4 mm are taken. When welding a structure, everything welds done from the outside so as not to round the corners of the block. The voids inside the cinder block are made using segments metal pipes suitable diameter, for example 80 mm. The distance between the pipes and the distance from the walls are controlled, the composition is welded in strips for rigidity and fixation.
If equipment is being made for the production of building blocks, then when attaching the vibrator to the table, after tightening the nuts, they are still lightly welded. The motor must be covered with a protective casing made of any material against splashes of solution, water, and dust.
Technology for the production of sawdust concrete blocks
The available materials are not pre-processed, and you can buy them at any hardware store, therefore, the production of blocks from sand, lime and sawdust begins immediately after purchase. To mix the solution, use a concrete mixer or mortar mixer, since mixing by hand wood waste difficult.
Dry sawdust, passed through a coarse sieve, is mixed with sand and cement. Lime or prepared clay dough is added to the solution. The resulting mixture is mixed well and only after that water is added, gradually pouring it in small portions. To determine the readiness of the solution, squeeze it in your hand, after which fingerprints should remain on the lump, which indicates the correct proportions.
Before filling the molds with the solution, they are lined with a thin layer of sawdust. Internal holes in the blocks are made using wooden plugs about 70-80 mm in size, which are installed in the matrix before pouring the solution. The material of the building blocks is placed tightly into the mold using a special tamper. The container is filled to the top and left to dry for three days. After this period, the solution gains about 40% of its required strength.
The molds are disassembled, and the blocks are dried for another four days, after which the strength becomes 70% of the required limit. Finished products are transferred to pallets and protected from direct sun rays. Drying of blocks is faster if you leave gaps between the products during storage. It is advisable to place the trays in a draft or use a fan for forced ventilation.
Sawdust concrete blocks gain 100% strength after drying for 3 months, but they can be used after a month of ventilation. At this time their strength is 90%.
Machines and equipment
To make the number of blocks required for construction, a ready-made vibroforming machine is purchased. The TL-105 brand has good performance. And although its power is only 0.55 kW, it produces about 150 concrete blocks with different aggregates per hour of operation. Its approximate cost on the market is approximately 42,800 rubles. Modern manufacturers of machine tools produce many types of machines for the production of blocks with additional functions. Prices for machines are different, and the cost of building blocks directly depends on this.
For small private construction, a 1IKS vibration machine is suitable; it costs about 17,000 rubles, the power is only 0.15 kW, such equipment produces 30 blocks per hour. When buying a machine, take into account the level of production of blocks for construction needs.
In conclusion, it should be noted that making building blocks with your own hands will greatly save money on the production of products. Cost does not take into account wages, which is paid to the employee. The cost of the block does not include overhead and production costs, taxes and other deductions, therefore, making the building material cheaper than the house.
It is not difficult to organize a cinder block manufacturing business: the technology is simple, the raw materials are cheap. However, careful calculation of profitability is required. This niche cannot be called free, which means that the products must be competitive in quality and price.
Cheap wall materials are in demand in the construction of dachas, garages, outbuildings, and sometimes industrial facilities. The production of cinder blocks as a business is attractive due to its simple technology, low cost of raw materials and the breadth of the sales market. Currently, not only slag, but other fillers are used for their production. The outdated name is strongly associated with low-grade building materials from Soviet times, from which it was customary to build mainly cowsheds. Modern blocks have little in common with it; they are more often called by the composition of their main components or manufacturing technology.
Raw materials, varieties, certification
In fact, any cinder block is an artificial building stone obtained from concrete mortar. Composition: 80 - 90%: boiler slag, metallurgical waste, granite crushed stone and screenings, broken bricks, sand. Modern environmentally friendly components are becoming increasingly popular: expanded clay (expanded clay), wood concrete (wood pellets, sawdust), polystyrene (porous plastics). Depending on this, a wide variety of names arise finished product. The fastening mass is represented by cement, sometimes with the use of plasticizing additives that accelerate the hardening process (Table 1).
When planning the production of cinder blocks, you need to have answers to three main questions:
- what materials are available for use as filler;
- what types of stone are in demand in a particular area;
- What is more profitable to use as an advantage: price or quality of products.
The most interesting thing is that cinder block is not subject to mandatory certification. Unlike the constituent components: cement, sand, gravel, chemical additives - they must meet established standards. If desired, the manufacturer can pass it in voluntarily in any appropriate laboratory. In this case, the products will be checked for compliance with GOST 6665-91 "Concrete wall stones. Technical conditions." For this you will need:
- certificate of state registration (OGRN, TIN);
- technical specifications, if available (TU);
- application and company details.
The absence of Gost, on the one hand, gives a free hand, but on the other, it gives rise to certain problems. Buyers are critical of the seller’s unfounded statements, and the presence of a certificate is a convincing argument when choosing building materials. The use of industrial waste is especially discouraged - such products are difficult to classify as environmentally friendly materials.
Cinder block production technology
The full production cycle of building stone includes:
- kneading the initial semi-rigid mixture in a mixer or concrete mixer;
- loading concrete into the matrix (with or without a void former);
- leveling the mixture, compacting corners (for manual loading);
- compaction of the solution using vibration (from 2 to 30 sec) and pressure;
- demolding by lifting the matrix; the block remains on the floor or pallet;
- transportation of finished products to the place of final drying.
A rigid solution prevents the block from crumbling after pressing and losing its shape after drying. The temperature in the workroom must be at least 1°C. Hardening to a degree allowing transshipment occurs within 1.5 - 4 days. When adding special plasticizers, it is reduced to several hours. Final ripening is carried out on racks, or outside, at natural temperature for a month. Humidity should be high, sometimes steaming is used.
Common types of equipment
The operating principle, as well as the performance, of most mechanical and semi-automatic machines differs little from each other. Rather, when choosing, attention is paid to the reliability of materials, design features, ease of use. Conventionally, they can be divided into three groups:
- simple mechanical machines using manual labor, (popularly known as “zhivopyrki”); with or without low-power vibrators;
- semi-automatic brick making machines equipped with additional labor-saving elements: lifting mechanism, rollback, etc.;
- automatic lines, including forced-action concrete mixers, buckets with dispensers, conveyors, and vibropresses in one process.
If we talk about small businesses, most of them use mechanical machines and brick making machines. For example, one of the largest online stores offers 175 offers for the sale of equipment for making cinder blocks. Let's look at what manufacturers offer.
1 Mechanical machines with vibrator low power.
They occupy approximately half of the total supply - 80 pieces at a price of up to 50,000 rubles. About 40 models are sold at prices up to 25,000 rubles (RMU-1, Strom-unicum, 1X Universal, Mars, M3 K). The operating principle of “simplified” vibration is that it allows a semi-rigid concrete mass to be shaped using a matrix.
Most of these devices (Fig. 1) have a productivity of 200 - 1,000 blocks per day. Mixing the solution, feeding it into molds, and leveling are all done manually. They differ in the power of the electric motor, the number of matrices (from 1 to 4 pieces), the design of the lifting mechanism, and the possibility of rolling back the machine. Working on them is hard physical labor; it is difficult to maintain the geometry of the products.
This category also includes some machines with enhanced vibration costing 50,000 - 100,000 rubles (Fig. 2). The number of proposals is about 30. Fundamentally, they do not differ from their low-power counterparts. Usually in them large quantity matrices (up to 8 pieces), some models have a table, others have wheel mechanisms, and so on.
According to concrete practitioners, an increase in the number of matrices does not lead to a direct increase in efficiency. Productivity is a relative concept when we're talking about about manual or semi-mechanized labor. Such machines are more difficult to maintain; they must be operated by at least two people. They practically do not reduce costs, but they are more expensive.
2 Semi-automatic hydraulic vibrating presses.
This group includes machines and devices costing from 170,000 to 470,000 rubles (Stroy-Profi-4, Sirgis-3, Rifey, Skala 15ML, Mastek-Meteor, Universal). Usually they are designed to produce 3 - 4 blocks per cycle, the pressure on the concrete mass is 2,000 - 5,000 kg, and the pressing time is up to 30 seconds. Significant advantage(in addition to facilitating physical labor) - high quality products. Form-forming equipment (matrix, punch) ensure precise geometry. Productivity is positioned as 120 - 180 pieces/hour, that is, from 1,000 to 2,000 per shift.
Peculiarities:
- automatic, semi-automatic control; minimum manual labor;
- high quality, good product geometry, different types block;
- additional equipment for the production of curbs and paving slabs;
- unloading bunkers, conveyor belts; shock-absorbing springs;
- the ability to connect in line with other equipment;
- production of blocks with a decorative surface: smooth, corrugated, stone-like.
3 Mini-factories for the production of cinder blocks.
The price of automated lines selling full cycle production from forced mixing of the initial mass in a concrete mixer, with automatic feeding, pressing and drying (steaming) - from 2 to 5 million rubles. They are characterized by high productivity, producing up to 400 finished blocks (80 pallets) per hour of operation; as a rule, they are equipped with a set of replaceable modules for the production of other types of concrete products (up to 350 pieces). The set includes forced-action concrete mixers, high-power brick making machines, vibrating tables, and trestles. Such mini-factories are produced by Mastek LLC and some other manufacturers (Fig. 3).
Investments, payback, profitability
Cinder blocks belong to small-piece concrete products along with cellular concrete (foam and gas blocks). Main advantage - low price. A special feature is seasonal demand, because construction is preferred in the summer. In addition, stone wall materials are not equally in demand across regions. The need can be indirectly assessed by the distribution of the main competitor - brick (Fig. 5).
The size of the investment depends on the type of equipment purchased, the availability of filler (mostly local materials), and the cost of cement - this is the most expensive part of the raw material.
As an example, let’s calculate the cost of 1 cinder block at prices in the Middle Urals in 2015.
- cement - 9.28 rubles. (3.5 kg);
- screening of granite - 1.12 rubles. (9.3 kg);
- sand - 3.16 rubles. (9.3 kg);
- e/energy - 0.44 rubles;
- salary - 2.18 rubles.
Total: costs per unit of production are 16.17 rubles. A year ago it was approximately at the level of 12.24 rubles.
For 9 months of 2015 average price for cement increased by 1.9% and amounted to 3,931 rubles/t in October (2,858 rubles for the same period in 2014). And its consumption decreased by 11% (Fig. 6).
The cost of one standard cinder block ranges from 27 - 29 rubles per piece, expanded clay block is more expensive: 37 - 39 rubles. At first glance, the profitability seems high, but you still need to add costs for equipment, rent of premises for production and storage.
Other things to consider when planning:
- building materials are characterized by inelastic demand - a reduction in price has little effect on sales volumes; the buyer prefers quality, since the period of use is long;
- Do not rely on the equipment performance parameters specified by the manufacturer; in reality it is usually 15-20% lower;
- at the beginning of work, time will be spent on selecting the optimal ratio of components, developing technology - the quality of the product greatly depends on the equipment used and the composition of the mixture.
Summary
It is impossible to say unequivocally whether making cinder blocks is profitable or not. In each specific case, a huge number of local factors must be taken into account: demand, access to cheap (or even free) filler, the number of competitors, the cost of labor in the region, its organization, delivery costs, product quality. It all depends on what the entrepreneur’s goal is: to earn a living for the family, or to reach a certain business level.
The most difficult thing in this matter is to find a niche in the sales market. More successful business It develops for those who leave “on the shoulders of the builders” - that is, they begin work with certain guarantees. For those who rely on the end consumer, it’s more difficult. Although right now, during the crisis, they began to order services less, and build more on their own.
The stones are made in the form of solid and hollow rectangular parallelepipeds.
The average density of hollow stones should not be more than 1650 kg/m3, and that of solid stones - 2200 kg/m3.
The weight of one stone should not be more than 31 kg.
The deviation of the actual sizes of stones from the nominal ones should not exceed: length - ± 4 mm, width - ± 3 mm, height - ± 4 mm.
Indicators appearance stones must comply with GOST 6133-99 “Concrete wall stones”.
The tempering strength of the stone must be: at least 50% of the design grade - for stones of grade 100 and above; 75% - for stones of grade 75 and below; 100% - for stones of grade 25.
Raw materials
Portland cement containing up to 20% active mineral additives is used as a binder.
Expanded clay gravel of 5-10 mm fraction (or 10-20 mm fraction after crushing procedure) and construction sand are used as fillers.
Fillers must meet the requirements:
Expanded clay gravel and sand -
The largest grain size of coarse aggregate should be no more than 10 mm.
Preparation of concrete mixture
For the manufacture of wall stones by volumetric vibrocompression, concrete mixtures are used.
The concrete mixture is prepared in accordance with the requirements.
Forced mixers are used to prepare the concrete mixture.
Light aggregates are dosed by volume-weight or volumetric method, dense aggregates, cement, water - by mass. It is allowed to dose water using the volumetric method. Dosed materials are loaded into a concrete mixer in the following sequence: coarse aggregate, fine aggregate, cement, water. The volume of the batch should not be more than 0.75 and not less than 0.4 usable capacity mixer
The mixing time should be 4-5 minutes, including 2-3 minutes after adding mixing water.
Transportation of the concrete mixture from the mixer to the hopper of the brick making machine is carried out directly from the mixer.
The concrete mixture is regularly fed into the hopper of the vibropress, so that its level is 0.6-0.8 of the height of the hopper.
The time elapsed from preparing the concrete mixture to its use should not be more than 45 minutes.
Forming wall stones
At the same time, from 3 to 10 stones are formed, depending on the standard size of the block being produced. The process of forming wall stones is carried out manually or automatically on metal pallets in the following sequence:
The empty pallet is installed on the vibrating table of the forming unit by the pallet feeding mechanism;
The lower matrix is lowered onto the pallet, fixing it on the vibrating table;
The concrete mixture from the hopper of the vibrating press is supplied by a measuring box to the molding zone and fills the matrix.
Uniform distribution and preliminary compaction of the mixture dosed in the matrix is ensured by the simultaneous influence of vertically directed vibration with a frequency of 50 Hz and an amplitude of vibrations of up to 1.5 mm, as well as the reciprocating movement of the measuring box with a span of up to 200 mm and agitation of the mixture inside the measuring box with a movable grid.
The duration of vibration dosing of the concrete mixture should be determined from the condition of ensuring the specified height of the product. Recommended duration is 4-6 seconds.
After the measuring box returns to its original position, the upper traverse with the punch is lowered and the mixture is compacted under the influence of pressure and vibration.
The pallet with freshly molded products is pushed out of the molding zone onto the receiving table by the pallet feeding mechanism, and an empty pallet is fed in its place; the formation cycle repeats.
Pallets with freshly molded products are removed from the receiving table using a hydraulic lifter and installed in cassettes. Filled cassettes enter the hardening zone.
Hardening of freshly formed wall stones
Hardening of products is carried out in heat treatment chambers.
Before heat treatment, the products are preliminarily kept at a temperature of 20±5°C for at least 1 hour.
The temperature rise to the level of isothermal heating should be carried out at a rate of no more than 25°C per hour.
The isothermal heating temperature should be no higher than 75±5 oC. The warm-up period should be at least 6-8 hours.
The temperature reduction should be carried out at a rate of no more than 35°C per hour.
Hardening of products from lightweight concrete on Portland cement for 24 hours under conditions production premises, then for 5 days (until the release strength is reached) in an unheated warehouse in summer time year and in a heated room in winter.
The hardened products are separated from the molding trays, grouped into a bag on a transport pallet and sent to the finished goods warehouse.
Packages of wall stones should be stored in stacks, placed on level areas with drainage.
Transportation and storage of stones must comply with the requirements of GOST 6133-99. Loading stones in bulk and unloading them by dumping is prohibited.
TPA Unite LLC produces expanded clay concrete and sand cement wall blocks of the following standard sizes:
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Expanded clay concrete wall blocks |
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