silicate brick.
This wall material is one of the most popular and loved by many generations of professional builders and private developers of building materials for the construction of load-bearing walls. One of its main disadvantages is fragility and low thermal insulation characteristics, while it has excellent sound insulation characteristics, high resistance to adverse weather conditions and sufficiently high strength. In addition, silicate brick has a high accuracy of geometric dimensions, which greatly facilitates the masonry process, allows you to build walls while maintaining their geometry and straightness, especially when erecting right corners of buildings.
In the construction market of Ukraine and Russia, silicate products are represented exclusively by silicate bricks. In a number of Western European countries, in addition to silicate brick, large-format silicate blocks are widely used.
Sand-lime brick is a completely environmentally friendly building wall, which consists of a mixture of lime, sand and water. The production process is simple and not labor intensive. During the production process, the prepared mixture is placed in a special reactor, in which the lime slaking process actually takes place, as a result of which an alkaline reaction occurs, accompanied by the release of a significant amount of heat. With such a thermal reaction, sand grains, losing their crystalline structure, form a silicate. Further, the silicate mass is molded and baked in an autoclave oven. The baking process takes place in an environment saturated with water vapor at a temperature of 170-2000C and a pressure of 8-12 MPa.
As a result of this manufacturing technology, a building material is obtained that is highly resistant to adverse atmospheric effects, capable of resisting the emergence and development of various microorganisms. In addition, autoclave processing eliminates shrinkage of the material, which in turn gives the sand-lime brick a presentable appearance and accuracy of linear dimensions.
Silicate brick has the following advantages:
• resistance to various kinds of atmospheric influences,
• sufficient frost resistance, • high compressive strength,
• excellent noise insulation characteristics,
• high resistance to fire (when exposed to high temperatures, there is no release of harmful and dangerous substances, toxins),
• environmental friendliness,
• the ability to accumulate moisture and heat, which in turn affects the comfort in the house, creates an optimal indoor climate.
Along with this, silicate brick has several disadvantages, namely:
• low thermal insulation characteristics, allows to build only multilayer external walls,
• high brittleness of the material, which in turn requires additional measures during transportation and handling operations.
As a rule, silicate bricks are produced in white color. Currently, some manufacturers also offer tinted bricks, which are dyed using a special pigment added to the initial mixture during the production process. In addition, along with a brick having a smooth outer surface, there are bricks with chipped structure on the market.
According to the requirements of DSTU B V.2.7–80–98, this brick is produced in the following strength grades: M75, M100, M125, M150, M175, M200, M250, M300. Silicate brick is excellent for the construction of load-bearing walls and the construction of partitions for various functional purposes. It should be noted that, since it is capable of decomposing under the influence of high temperatures and has low moisture resistance, it is strictly forbidden to use it when laying fireplaces, stoves, pipes, as well as in the construction of basement and foundation parts of buildings.
Having a high density of the material, silicate brick has a fairly large weight, has high noise insulation and storage properties, but at the same time low thermal insulation characteristics.
Silicate brick can be either full-bodied or one that has internal voids (hollow). Solid brick has a heavier weight and high thermal conductivity, so it is mainly used in the construction of internal walls and partitions. Hollow brick is used mainly in the construction of external walls, it has less weight, it is much easier to work with it. Hollow silicate brick walls are slightly warmer, they create less stress on the foundation. Currently, hollow silicate bricks are produced, which have voids of various locations and shapes. It is necessary to carry out the laying of hollow bricks with voids down, so that during the laying process, masonry mortar does not get into them.
Silicate brick is available in three sizes:
• ordinary brick – has linear dimensions of 250x120x65 mm,
• brick one and a half – with linear dimensions 250x120x88 mm,
• double brick (silicate stone) – with a size of 250x120x138 mm.
A commercially available silicate brick may differ in surface smoothness and color, but this does not affect its physical and technical characteristics to any extent. This difference in the appearance of the wall material is associated with the characteristics of the raw materials used in the production, for example, the presence of certain minerals in the sand.
The approximate cost of 1 m2 of a wall 25 cm thick, built from silicate brick, is: from ordinary brick – 146 UAH, one and a half – 150 UAH, silicate stone – 157 UAH.
Expanded clay concrete.
This wall material is a relatively new building material for our market. Expanded clay concrete has high noise and heat insulation characteristics, high fire resistance, and is also able to effectively accumulate heat. Walls built of expanded clay concrete blocks “breathe”, thereby providing an optimal indoor climate. Possessing such a set of unique properties, it is not surprising that this wall material has recently gradually begun to conquer the Ukrainian construction market. Expanded clay blocks are made from concrete with the addition of lightweight aggregate – expanded clay.
Expanded clay is a porous granules of foamed and then fired clay. Blocks made of expanded clay concrete are lightweight, they have high mechanical strength, resistant to the development of microorganisms and moisture. Moisture that gets inside the unit quickly evaporates. Expanded clay concrete perfectly accumulates heat, due to which the heated rooms during the day cool down very slowly at night. Expanded clay concrete wall blocks can be produced both full-bodied and with internal voids, and these voids can be filled with various heat-insulating materials.
The main advantages of expanded clay concrete blocks include:
• high noise and heat insulation characteristics,
• high level of vapor permeability of the material,
• reasonably good fire resistance,
• the ability to perfectly accumulate heat,
• simplicity and ease of masonry work, as the blocks have profiled side faces and large linear dimensions.
Along with this, blocks of expanded clay concrete have the following disadvantages:
• high moisture absorption (during storage at the construction site, they should be protected from various atmospheric precipitation, and immediately after the erection of the walls, the outer surface should be plastered).
According to the current DSTU B V.2.7-7-94, expanded clay concrete blocks should be produced in the following linear sizes: thickness – 18.8 cm, width – 9, 19, 30, 35 and 40 cm, length – 14, 29, 39 and 59 cm. A number of manufacturers produce blocks with the following linear dimensions (length, width, height): 25x20x11 cm, 39.6x20x19 cm, 50x30x24 cm, 50x24x10 cm.
These blocks have a significant weight, they perfectly dampen noise. An order of magnitude better thermal insulation characteristics, along with full-bodied blocks, are precisely hollow claydite-concrete blocks. All currently produced claydite concrete blocks have a non-smooth outer surface, which, when laying them, causes the use of traditional cement-sand mortars and laying on a thick seam (1-1.2 cm thick). In the absence of profiled locks on the ends of the blocks (groove-comb system), vertical seams also require filling with mortar.
The estimated cost of building 1 m2 of a wall 19 cm thick using expanded clay concrete blocks is about UAH 144, and 25 cm thick – UAH 165.
Complementary elements. Regardless of which wall material you have chosen for construction, it is necessary to use special additional elements during masonry. Their use is not necessary, but it makes it possible to facilitate and speed up the masonry process, and also saves wall material (eliminates cutting and gets rid of non-production waste). Additional elements are flat or narrow hollow blocks that are used when laying walls in places under the floor , near lintels and when laying corners. In some cases, they can be replaced with a special modular brick, which must be suitable in height.
A number of important parameters that must be taken into account when building walls.
Walls can have both one-, two-, and three-layer construction. Each type of wall has its own individual characteristics, which must be taken into account when choosing a wall material. So, for example, when choosing a wall material for the construction of a single-layer wall, it is necessary to take into account not only its strength, but also thermal conductivity. At the same time, the thermal insulation properties of a multilayer wall directly depend on the thermal insulation qualities of the insulation used. When choosing a wall material for the construction of a load-bearing outer wall, first of all, it is necessary to pay attention to the ease of work, its durability and reliability.
Strength. This parameter characterizes the resistance of the wall material to the perception of compression forces. This parameter is indicated by its strength grade (strength class) which is measured in kgf / cm² (MPa). Sand-lime bricks have the highest strength (from 7.5 to 30 MPa), and blocks of cellular concrete have the lowest strength (from 1 to 3.5 MPa). Many modern manufacturers of wall materials consider the high level of strength of their products to be one of their main advantages, while assuring that hollow or solid blocks can withstand significant loads, even those that can occur in the walls of six-story buildings. It is good if these properties of the wall material are of natural origin, and are not connected in any way with its so-called “improvement”, and, consequently, with a significantly higher price. In this case, you should not give in to temptation. In low-rise private construction, a strength of several megapascals is sufficient, and those places that require increased attention and strength can be reinforced with reinforced concrete or made of ordinary building bricks.
Specific gravity. The mass of all structural elements of the wall determines its total weight, noise and heat insulation characteristics. Heavy volumetric walls are always able to effectively dampen noise, but at the same time, heavy massive elements greatly complicate the masonry process, since heavy structural elements are always very exhausting to lay and carry. In addition, it is necessary to take into account the fact that the total weight of the wall structure takes into account not only the weight of the blocks, but also the mass of the mortar and reinforcing elements. Some of the lightest are walls built from cellular concrete blocks (from 104 to 270 kg / m2), heavier walls built from expanded clay concrete blocks (from 130 to 290 kg / m2), from porous ceramics (from 220 to 280 kg / m2), and the heaviest are considered to be walls erected from silicate bricks (from 365 to 415 kg / m2). When planning the foundation of a house, it is the total weight of the wall structure that must be taken into account.
bulk density. This parameter is determined by the ratio of the mass of the wall element to its volume and characterizes the degree of porosity of the material. The bulk density of wall blocks is directly related to the bearing capacity. In most cases, these indicators are not indicated together, while focusing only on the strength class. So for wall blocks made from cellular concrete, the density and at the same time their brand is always known (from M400 to M600). Hollow blocks, depending on the volume of voids, their shape and the degree of porosity of the material, can have indicators of conditional density and brand that are significantly different. As a rule, such a wall material has a conditional density, taking into account voids, in the range from 760 to 950 kg/m3.
Thermal conductivity coefficient λ. One of the main characteristics that you should pay attention to when choosing a wall material for exterior walls is the coefficient of thermal conductivity. It characterizes the ability of a given wall material to transfer heat through itself. The higher this indicator, the lower its thermal insulation characteristics. This indicator is constant for a solid wall material and does not depend on its thickness. In a wall material that has internal voids in the form of slots, everything is different. In such a material in different directions (perpendicular or parallel to the placement of slots) the value of λ is different. That is why, if such blocks are laid with the long side of the internal cavities parallel to the front surface of the wall, then its heat-insulating ability will be lower than if they are laid perpendicularly. Such products in their characteristics have two indicators λ.
Sound insulation coefficient RA2. This indicator of the wall material characterizes its noise-absorbing ability. The higher this indicator, the better its sound insulation characteristics. Wall materials that have a high weight (heavy) are best able to dampen noise. It should also be noted that in no case can one judge the soundproofing properties of a wall based solely on its mass, since the acoustic characteristic of a wall structure also depends on the amount of mortar in the joints and its type. So, for example, walls built from lightweight structural elements using a thick jointed cement-lime mortar can absorb noise much better than walls built from heavy blocks with a thin layer of adhesive mortar. In addition, the method of pairing the walls with other structural elements of the building (internal walls, partitions, ceilings), their total area and the height of the room are of great importance. If these circumstances are not taken into account, then the soundproofing characteristics of even the best wall material can be nullified.
Summing up, it should be noted that the choice of wall material for your home must be approached responsibly, in no case neglecting such parameters as strength, reliability, noise and heat conductivity, as well as durability. We recommend entrusting this choice to a qualified specialist with experience in this field, it is best to seek help from a specialized design organization.