A cement strand plate is a composite sheet material made from a mixture of wood shavings and cement. Due to this, partly contradictory combination, the DSP stove has gained valuable characteristics and widespread use in construction.
Cement-particle mixture from which DSPs are made is a kind of concrete based on a mineral binder. Only instead of sand and rubble as filler in it serves small wood chips. The introduction of wood into the composition of the slab reduced its density, but the main thing is that the chips played the role of not only lightweight filler, but also fiber - an additive that creates bulk reinforcement, which perceives tensile loads.
The mixture for the manufacture of plates includes:
The preparation of the mixture begins with the grinding of chips to the desired size. After that, it is divided into two factions on the Sith. Small is used to form the outer layers of the sheet, the larger - for the middle layer. Then it is treated with calcium chloride, "liquid glass", chloride or aluminum sulfate. This is necessary to protect the material from rotting and fungal damage.
Sieved and mineral-treated chips are mixed with water and cement. Additives that accelerate the hardening of cement dissolve in water. In addition to these components, fuel oil and I-20 industrial oil can be added to the mixture in small quantities to reduce internal friction and facilitate pressing.
The prepared mixture is spread on pallets in three layers, the pallets are piled up and placed in a cold press, where this “bag” is compressed to a pressure of 1.8-6.6 MPa and fixed in this state with locks. A special locking system maintains pressure in the mold after removing it from the press.
Compressed packages are heated for 8 hours. During this time there is an accelerated hydration of cement and its hardening. Wood chips due to its elasticity compensates for cement shrinkage, therefore, the specified dimensions of the plates do not change. The unlocking of the molds and the release of pressure also occurs in the press. After that, the bag is opened, and the plates are removed and placed for 1-2 weeks in a buffer storage.
For the final ripening of the material, it is blown with air with a temperature of 70-100 o C. After that, the sheets are cut to size, sanded, sorted and transferred to the warehouse of finished products.
According to GOST 26816-2016, cement particle boards of two grades are produced - TsSP-1 and TsSP-2. They are distinguished by dimensional accuracy, durability and other quality parameters.
|Deviations dimensions of plates (mm)||3.0||5.0|
|Deviation of the thickness of unpolished slabs (mm)||0.7-1.5||0.8-0.16|
|Flexural strength (MPa)||9.0-12.0||7.0-9.0|
|Delamination Strength (MPa )||0.50||0.35|
|Roughness of polished slabs (µm)||80||100|
|Stains on the surface||Not allowed|| Not allowed more than 1 pc . Di |
The meter is more than 20 mm per 1 m 2 .
|Dents||No more than 1 piece is allowed, with a depth of more than 1 mm and a diameter of more than 10 mm by 1 m 2 .||Not allowed more than 3 pcs. a depth of more than 2 mm, a diameter of more than 20 mm per 1 m 2 .|
The deviation limits in thickness and flexural strength are set separately for different thickness ranges. The plates are made with a thickness of 8 to 40 mm with a gradation of 2 mm.
The sizes of DSP sheets of both brands are the same:
In addition to these two brands, there are "related" materials that have similar composition and properties.
These are slabs filled with wood fiber, the so-called wood wool. The filler of this form provides better fibration, which has a positive effect on the strength of the material and its resistance to cracking. Fiberboard is relatively soft, has a relatively low density and is often used for thermal insulation and as a sound absorber.
Material related to lightweight concrete. It uses wood chips, chips, chopped reed stems and rice straw as a filler. Wood concrete has low strength and is used in structures that do not bear loads, for example, internal partitions.
This material is made using magnesia binder - Sorel cement. Insensitive to water.It is used for covering floors, roofs and other structures where frequent wetting of the plates is possible.
The main characteristics of a DSP are determined by its constituent components. For example, the gravity of the cement stone is partially compensated by the ease of filler - chips.
Physical and mechanical indicators of DSP according to GOST 26816-2016:
|Flexural modulus, MPa||4500||4000|
|Hardness, MPa||45 - 65|
|Heat conductivity, W / (m · 0 C)||0.26|
|Specific heat capacity, kJ / (kg · 0 C)||1.15|
|Specific resistance to pulling screws from the plate, N / m||4 - 7|
|Class of biological resistance||4|
|- the number of cycles of variable freezing / thawing without visible signs of destruction||50|
|- residual strength,%||90|
|Resistance to cyclic temperature and humidity changes:|
|- reduction in strength when after 20 cycles of temperature and humidity effects,%||30|
|thickness swelling, field 20 cycles of temperature and humidity effects,%||5|
DSP density is 1100-400 kg / m 3 - this is less than the density of most cement-based materials. The slab with dimensions 3200x1200x10 mm weighs from 42 to 54 kg, depending on the density.
DSP is resistant to moisture and biological factors. Biostability is provided by special processing of chips - mineralization. Moisture resistance is the merit of cement. Cement stone does not lose strength with any moisture. Water absorption during prolonged immersion in water does not exceed 16%, and the swelling of the plate in thickness is within 1.5%.
When moistening, the DSP absorbs little water. This determines its good resistance to low temperatures. The cold resistance of DSP is 50 freeze-warm cycles without visible damage and with 90% residual strength. According to this parameter, the plates are suitable for use outside heated premises provided they are protected from moisture accumulation.
Cement-bonded chipboard is a porous material, since wood chips occupy a significant part of the volume in it. Due to this structure, it has a low thermal conductivity - about 0.26 W / (m ∙ ° C). This is 1.5-2 times less than that of a brick and approximately twice as much as that of drywall. Despite the fact that DSPs cannot be fully considered as heat insulating material, its use significantly affects the resulting thermal resistance of external enclosing structures.
The porous structure causes the permeability of the material to water vapor at a level of 0.03 mg / (m ∙ h ∙ Pa). The same vapor permeability has concrete. This parameter is necessarily taken into account when designing multilayer walls. When using DSP slabs for interior decoration of external walls, it can serve as a vapor barrier layer, reducing the accumulation of moisture in the wall and increasing the efficiency of insulation.
The fire characteristics of the DSP are as follows:
By the sum of the parameters, the cement-shaving plate belongs to safe materials. Its use allows to increase the fire resistance of building structures and reduce the fire hazard class of the premises.
This characteristic receives a lot of attention due to the massive use of synthetic materials in the production of building materials. Cement strand board consists only of natural ingredients. It does not contain formaldehyde resins, polystyrene and other substances that can serve as sources of emission of volatile toxic compounds. Thanks to mineralizing additives, the wood component is not susceptible to rotting, which also contributes to the preservation of a healthy atmosphere in the rooms.
The cement-shaving plate is fairly easy to cut and drill, which greatly simplifies working with it. On its surface putties well, it is well painted.
The fields of application of a cement particle board are determined by its properties described above. Especially valuable is the successful combination of valuable qualities that complement each other.Not many materials have strength, moisture resistance, environmental friendliness, fire safety and relatively low weight at the same time.
The shape of the material in the form of plates gives another important advantage - ease of use, manufacturability. The use of DSPs in many cases allows us to speed up the work, to exclude the so-called "wet processes", which require special skills from the masters, are laborious and time consuming, especially considering the hardening time of the building mixtures.
The use of cement-bonded particle boards is reduced to installation work, the large size of the sheets allows you to immediately cover a large area and simplify the alignment of the planes.
Cement-bonded chipboards are very well suited for wall cladding, both solid and framed. Ecological safety makes them a good material for interior decoration, and moisture resistance can be used for wet rooms and for exterior decoration of buildings.
Slabs can be mounted on brick walls instead of regular plaster. This method is called "dry plaster". Facing with plates makes it easy to get a flat surface. The complexity of this work, given the ease of ensuring proper quality, is much lower than with traditional plastering. For these purposes, usually used sheets with a thickness of 8-12 mm.
Cement particle boards are very well suited for frame construction. This technology directly provides sheet plating, which provides high workability and saving time. One of the types of frame structures - internal partitions. DSPs serve as soundproofing material, reducing the acoustic coupling between the rooms, separated by a partition. For cladding frameworks use plates with a thickness of up to 20 mm.
A hinged ventilated facade is one of the natural applications of DSPs. These sheets serve as outer casing, protecting the inner layers from atmospheric moisture and wind. For the ventilated facade is extremely important strength, moisture resistance and fire safety of the material. DSP is able to withstand high mechanical loads, does not deteriorate from moisture and does not spread flame, even in conditions of strong traction in the ventilation gap. Light slabs up to 12 mm thick are used in this area.
DSPs are used when constructing flat roofs, including exploited roofs. Sheets are laid on top of the insulation and then closed with a waterproofing membrane. Due to the rigidity of the plates, the insulation is not subjected to concentrated loads and you can walk on the roof, and even use it, for example, as a summer cafe or a recreation area. Depending on the load in the roofing systems, slabs up to 20 mm thick are used, and in special cases even more.
For the device of the floor, such properties of DSPs as bending strength and moisture resistance are applied. This material is very well suited for the subfloor - the so-called dry screed. Instead of spreading a layer of cement-sand mixture overlap, smooth it out and wait until it hardens, DSP plates are laid on the prepared "beacons" and immediately a smooth and ready for further decoration base is obtained, which also serves as a heat insulator.
Thicker slabs are taken for the frame house or when laying the floor along the logs. The choice of thickness is determined by the upcoming load and the distance between the lags.
Another, often used, construction is a floating floor. For her, the DSP is also perfect, as well as for a flat insulated roof. The choice of the thickness of the plates is influenced by the design loads and the density of the insulation. For the sub-floor used slabs with a thickness of not less than 14 mm.
Typically, in monolithic construction, formwork is a temporary structure that is removed after the initial hardening of the concrete. Using DSP allows you to combine the preparation of formwork with finishing work. Fixed formwork is made of these slabs, which remains in the composition of the wall, immediately forming a flat surface that does not need plastering.
This is one of the possible applications of a DSP board. It comes in its strength and moisture resistance. Laying the plates on the prepared sand "cushion" creates a flat surface that will not crumble, crack, on which there will be no dips or swelling. Of course, to compensate for the frost heaving, you need to take care of the device of high-quality drainage layer.