Composition and main characteristics of the material
Shell rock is a limestone composed of calcium salts. Moreover, regardless of the place of extraction, the composition remains approximately the same: calcium carbonate - 52.06-55.66%, magnesium oxide - 0.19-0.71%, carbon dioxide - 41.16-43.62%. Under the influence of acidic water, calcium, which is part of the shells, decomposes, releasing carbon dioxide. This determines the presence of pores in the structure of the shell rock and the emergence of mineral springs. The main color is white-yellow, light yellow. Depending on the presence of impurities, the color may be different: iron gives the shell rock pink shades, copper - blue, coal - from gray to black.
Due to the fact that the shell rock was formed in the places of the former seas and from the remains of marine animals, it emits vapors of iodine and sea salt, has good antibacterial properties. In a room decorated with this material, a specific composition of air appears, strengthening immunity and strengthening health in general. It especially helps people with cardiovascular diseases and those who have problems with the upper respiratory tract, with the thyroid gland. Many resorts in the world are known for their coquina beaches with healthy air.
Shell rock is a natural stone, therefore it is an environmentally friendly material. Compared to others, it has a neutral background radiation of 13 μg / h, with the minimum allowable level of 25 μg / h. At the same time, it perfectly protects against dirty air, radiation and other harmful radiation by 100%. This is the only material capable of this.
Another very important advantage over other building materials is that mice and rats do not like a shell rock house. For a country house, this is a significant indicator.
The presence of pores is the reason for the low thermal conductivity of shell rock - 0.2-0.6 W / m-С °, while in brick - 0.55-0.64, more than two times more. The situation is the same with soundproofing. Therefore, the use of this material eliminates the need to additionally insulate and protect the walls of the house from noise, which gives significant savings in construction. In addition, the shell rock has a very high frost resistance - up to 70 cycles, so you can not be afraid for the integrity of the exterior decoration of the walls of the house, unless you go to change it yourself. Shell rock is very inert, therefore it does not react with other building materials, therefore, it will not collapse on its own and will not deform other substances.
According to their density, three brands of shell rock are distinguished:
M15 is the least dense, with large pores, very loose in appearance. It can be of different colors - from white to brown, but most often yellow, for which he received the nickname "yellowish". The yellowish tint is given by the presence of impurities of sand, which has a higher thermal conductivity compared to the shell rock itself. Therefore, this brand is the coldest among other brands. When hitting a hard surface, the M15 block breaks up into several parts. By weight, these blocks are the lightest (8-12 kg), therefore, during loading and unloading operations, their surface may be disturbed. Subsequently, in order to level the surface, it may be necessary to carry out a large amount of plastering work. Despite this, it is successfully used in the construction of garages, utility blocks, fences, baths, upper floors.
M25 is a shell rock with medium density and porosity. The main color is light yellow, sandy. If dropped, it rarely breaks in half, even less often into three parts. The most popular brand in construction, as it surpasses brick, gas and foam concrete in strength.It is widely used for the construction of two-three-story houses. In frame and panel construction, interior partitions are placed from this brand of shell rock. Block weight - 14-17 kg.
M35 is the densest and strongest grade of stone, has the lowest porosity. The color is almost white, yellow-white. The heaviest of all brands (22-25 kg), therefore ideal for laying a foundation, basement, basement. White shell rock is stronger than yellow shell rock.
Where is it used?
Rakushnyak from Crimea has found application in the construction industry, while calculating the required material consumption is not difficult.
A standard block has dimensions of approximately 18x18x38, each square meter of surface will require 30 typical modules when building masonry in one brick, when laying in half a brick, only 18 blocks are needed. For the construction of low houses in the middle climatic zone, the width of the walls in one block will be sufficient. When installing the wall in a half-brick, the building will need additional insulation.
Shell rock walls are able to withstand all types of floors - steel, reinforced concrete, as well as wood. But if you want to live in an environmentally friendly home, then preference should be given to wooden beams. But in seismically unfavorable areas, it is worth using monolithic reinforced concrete structures.
In the process of performing construction work, there is often a need for additional processing of limestone, making lintels, laying beams or bandaging elements. Limestone processing is quite simple, so all the necessary elements can be cut out with the most ordinary household saw.
Some homeowners leave clam shell interior walls unfinished. This stylistic solution allows you to emphasize the concept of an eco-house and the connection between the home and nature.
For the benefits of shell rock and the construction of houses from it, see the video.
Advantages and disadvantages
The advantages of using the Crimean shell limestone are undeniable:
- under the influence of oxygen, the shell rock does not oxidize and does not react with any other substances, it belongs to inert substances;
- does not melt, does not ignite under the influence of elevated temperatures, does not emit toxic fumes;
- due to the presence of useful elements in the chemical structure, it creates a healing microclimate, saturates the air with ionic particles and disinfects it;
- is processed with the most standard tools, thanks to which the blocks can be given various shapes;
- it is highly resistant to adverse natural factors;
- characterized by high strength;
- the pores provide high heat and sound insulation, and in addition, they release condensate from the room to the outside;
- the material does not transmit radiation;
- has a unique texture, presented in more than 10 natural colors.
Due to its high operational characteristics, shell from the Saki quarry is often used for the construction of buildings; it is widely used for finishing all kinds of structures.
Nevertheless, there are subtleties here and some limitations that you need to be aware of.
- Shell rock has a relatively low bearing capacity, therefore, it is most often used in low-rise construction.
- The material does not firmly hold fasteners, especially blocks of the M15 brand. To cope with this problem, you need to use only the most modern fasteners.
- There is no geometry standard in the shell rock blocks, since when the stone is mined, even forms and exact dimensions are not always obtained - here deviations of a couple of centimeters are allowed.
- High water absorption. To get rid of this drawback, the material of the shell walls must be properly protected from the outside, treated with special water-repellent impregnations, insulated and plastered.Before moving on to the interior decoration of the shell building, it is necessary to carry out insulation and complete decoration of the facade. If this step is neglected, homeowners will have to deal with dampness in the room and increased heating costs during the winter.
Peculiarities
As you know, most of the building materials go through several stages of processing from natural raw materials. So, red brick goes through firing, aerated concrete undergoes autoclave hardening, and cinder blocks are obtained by mixing cement mortar and mineral filler.
It is an accumulation of shell fragments and ancient molluscs. Over millions of years, they accumulated at the bottom of ancient oceans and transformed into solid rock. All that remains for people is only to dig it up and cut it into separate blocks.
Separate crushed and whole parts of the shells of mollusks are fastened together with lime cement, thanks to this chemical composition, this stone acquires a number of useful characteristics:
- porous structure provides high diffusion parameters;
- the presence of iodine and salt in the chemical composition of the rock saturates the air with compounds beneficial to health, exhibits pronounced antibacterial properties;
- shell rock has zero background radiation;
- has an increased filtering ability;
- does not corrode and rot.
The material has the following physical characteristics:
- thermal conductivity - 0.3-0.8 W / m2;
- frost resistance - 25 cycles;
- material density - about 2 100 kg / m3, water absorption - 15%.
The most famous deposits of the Crimean shell rock are located in Sake. It is mined using open technology without special energy costs, which is why the selling price of such blocks at the field is quite low. However, with distance from the quarry, the price of shell rock increases many times over, since the cost of transportation is added to the cost of the material.
The use of shell rock
Due to its exceptional qualities, this natural stone is simply irreplaceable both in housing construction and for other purposes. But there are several nuances that you need to know. Due to the difference in density, strength, color, structure of shell rock, when buying, you must look at each block for through holes and check the brand of the product. The brand is easy to check for impact: how much the block will crack.
The weight of the block must be at least 16 kg, as a guarantee of the required strength and density. The most extensive application is, of course, in the construction of houses. Blocks with an untreated sawn surface can be used in the construction of walls, fences, arches. Low thermal conductivity of shell rock walls will provide the room with comfortable warmth in winter and refreshing coolness in summer. For areas with an average climate, a wall width of 40 cm is sufficient. This material is "breathable", so excess moisture can easily evaporate through it, the house is always dry and optimal air humidity is maintained. This prevents mold from forming. Good sound insulation will not allow street noise to distract you from enjoying your vacation. The healing properties guarantee improved well-being and good mood.
The strength and inertness of the stone are the key to the durability of the building. There are many architectural monuments in history, built of shell rock and preserved in excellent condition to this day.
The porosity of the surface contributes to strong adhesion to concrete, and the layer of mortar can be minimal, practically seamless masonry. And this again has a positive effect on the cost of construction.
Thanks to the large size of the blocks, it is easy to work with them: you do not need such skill as when working with bricks, you can do it yourself. It is enough to set the level correctly. You can put it on any foundation, there are no special requirements for it.
Another plus in favor of shell rock: the block can be easily cut into pieces of the required size with an ordinary grinder with a circle of at least 180 mm. They will be required at the junction of walls and floor beams, in door and window openings.
Shell rock tiles are ideal for outdoor facades. Low weight does not create additional load on the foundation. Its polished surface does not need additional processing.
The natural color is in harmony with the surrounding nature. Before cladding, the walls also do not require special preparation: the high degree of adhesion of the shell rock to the concrete guarantees reliable fastening to the facade and hides its irregularities. Only for concrete mortar it is necessary to use fine river sand. If desired, the slabs can be easily painted in any color. The porous structure absorbs paint well and for a long time.
Polished slabs are also used in interior decoration, fireplaces and stoves. Ease of sawing allows you to give fireplaces any shape and shape. Low thermal conductivity will provide pleasant warmth to the outer surface of the block, despite the heat inside the hearth.
In areas with high humidity, frequent rains, heavy snowfalls, after the completion of construction, the walls must be treated with waterproofing agents, or cladding made of wood, brick with a gap for ventilation. You can also use mineral wool insulation or vapor-permeable plaster. If a road passes next to the house, then you can treat the facade with a special compound that prevents the settling of combustion products. There are also remedies for those who like to paint on the walls.
Various decorative items can be cut from shell rock: sculptures, flowerpots, various stands.
The unique pattern of curls of shells on the cut will add elegance and lightness to the products. Having treated the surface with a protective compound, you can provide them, without exaggeration, eternal life.
The rough (cobbled) surface of shell rock slabs is resistant to abrasion and therefore is used for facing steps of stairs, porches, paths, areas inside the courtyard. Where it is necessary to reduce or completely eliminate slip.
Summarizing all of the above, shell rock is an excellent material for creating a beautiful, reliable and comfortable home for years to come.
Making shell rock
The material is mined in a quarry with special machines that cut shell rock layers. Even in one quarry, the structure and color of the stone changes depending on the depth of the layer. Despite its strength, shell rock is easily sawn even with a hand saw and you can easily get slabs and blocks of various sizes without much difficulty. For the same reason, it is possible to manufacture parts of various shapes and sizes, for example, columns. The standard size of the blocks is 18x18x38 cm, or 20x20x40 cm. There are 5.5 bricks in one shell rock block. When processing boards, they are given different types of surfaces: ordinary sawn, polished, rough.