Table of Contents
Since development of the first concrete articles has passed 100 years, but still this construction material has not lost relevance, and every year products are modified. The main advantages which the concrete slab has, – long life cycle under different conditions without loss of qualities and also ability to resist to corrosion and rotting. Therefore plates are applied not only to construction, but also to laying of roads, mounting of engineering networks.
Production, structure and scope of concrete slabs of overlapping and other types of products
Construction plates are made at the specialized enterprises or the plants which are engaged in release of steel concrete products. The range of goods is provided to thicket not only by different types of overlappings, but also other products among which:
- blocks and pillows for the base;
- flights of stairs;
- paving slabs;
- wall panels.
Properties and characteristics of products from concrete depend on basis of design, quality of the used concrete mix and other materials, and, above all – on observance of production technique. Generally technical parameters of goods depend on properties of two main components of elements:
- the steel reinforcing parts.
It is interesting! Concrete in itself is considered quite brittle, its main advantage – not exposure of corrosion. Steel is material which is subject to destruction under the influence of moisture. However in combination these two elements form ideal tandem because steel increases concrete durability, and concrete, in turn, protects steel from rust formation and corrosion.
Depending on type of product the brand of the used iron fittings and concrete is chosen and also the quantity of layers of reinforcing, diameter of wire and step of grid is defined. Than more armature was applied, especially the final product differs in high strength characteristics. For strengthening of floor slabs or other products certain types of armature which designation contains in marking of each product are used:
- BP-II – high-strength wire;
- A-IV, A-V, A-VI – hot-rolled bar;
- At-IV, At-VI, At-V – the bar differing in the increased durability;
- K-7 – the reinforcing rope having the best characteristics of durability.
Refer the next moments to features of production:
- The base concrete slab has bigger section in comparison with normal floor slabs.
- Multidirectional laying of the reinforcing profile improves load properties of products, especially it concerns load of bend.
- For prevention of cracking in leveling fix points on perimeter of plates the strengthened basic belt is laid.
- For more convenient transportation and laying on surface of plates load-lifting loops are mounted.
Durability of finished products depends on grade of the used concrete. The concrete mix of M-200 or M-300 having strength class is usually applied B-22.5 is not lower. In case of use of special types of concrete additional marking is put: foam mortar – I, heat-resistant – porous – the Item.
On private and industrial buildings the following types of plates are applied:
- wall interior or outside panels;
- slab roofs.
These types of concrete goods make building frame basis. In addition, sidewalk concrete slabs and road are made. In separate group it is possible to allocate the concrete articles applied to creation of fences and other barriers.
Pluses and minuses of use of plates of overlappings of concrete goods and other concrete articles
No construction can be provided without application of concrete products because first of all they differ in the affordable price and wide circulation. Other essential plus can be considered the fact that some types of plates can be made independently as the basis of concrete is water and cement, and as armature it is possible to use scrap of ferrous metal. At the same time it is necessary to consider that it will be difficult to define load bearing capacity of independently made elements. For production it is better to employ the specialist who will monitor production process.
As other advantages of concrete slabs are considered:
- Easy availability of goods. The plants on production of ZhB of plates are practically in each city.
- Standard dimensions. The sizes of plates, as well as other parameters, are accurately regulated by standards of state standard specification that allows to calculate exact quantity of products which will be necessary at construction. At the same time plates differ in big variety of dimensions.
- Higher speed of work. Laying of floor slabs gives the chance to considerably reduce time spent for work.
- Long term of operation. As interfloor overlappings also wood beams are sometimes used, however the house from concrete slabs will be not only is stronger, but also is more long-lasting.
- The improved consumer properties. Thanks to features of production which are constantly improved use of concrete slabs helps to improve sound insulation and heat insulation of the ready building or engineering communication. Also plates ensure additional fire safety because concrete – non-combustible material.
- Smooth surface. Plates of overlappings differ in plain surface which at stage of interior finish is easier for processing that does products attractive to house construction.
It is interesting! High rates of resistance to vibrations are considered as additional benefits of concrete articles that allows to apply them at construction of industrial capacities and also gives the chance to build constructions in zone of the increased seismic activity.
Despite large amount of advantages, in application of concrete articles it is possible to allocate also such shortcomings:
- Big weight. Because of the considerable mass of plates at construction it is required to use the additional load-lifting equipment that is especially difficult at construction of high-rise buildings.
- Costs of delivery. As for floor slabs, they often differ in large volume that does not allow to bring for once necessary quantity of plates for construction of owner-occupied dwelling from the concrete goods panels.
- Need of exact calculations. Before beginning construction, it is necessary to define correctly future load of overlappings and, proceeding from it, to buy certain types of panels.
Concrete slab: kinds of products, their distinctive features
Different types of concrete slabs differ among themselves with construction features, form, assignment, way of operation and also texture of surface.
The final cost of concrete slab is influenced by the following parameters:
- grade of the used concrete. It can be light, heavy or silicate material;
- features of the internal building. The plate can be characterized by presence of through channels (multihollow designs) or to be monolithic, that is continuous or corpulent;
- product parameters. According to standards of state standard specification of product have standard indicators of length, thickness and width. However monolithic constructions can be not only standard, but also executed in individual parameters;
- way of installation depending on depth of opiraniye of floor slabs on walls. Console panels demand two points of support and are used for construction of portable designs – balconies or hoods. Joist ceilings are established in the presence of two, three or four support;
- section profile. Concrete articles can be the correct geometrical form, for example, rectangular or square and also mown or having edges;
- way and production technique. Integral seamless options or precast structures which are made in the vibration, molding way or by method of continuous formation are allocated;
- reinforcing type. Concrete products can be normal not intense or previously intense;
- type of cementing agent. The cement, plaster or concrete mix can be the cornerstone of production of panels.
What is monolithic reinforced concrete slabs of overlapping
Monolithic plates of overlappings are applied generally to creation of interstorey partitions and the organization of heating mains. The manufacturing techniques are regulated by the statutory act. Thanks to lack of joints and seams monolithic constructions differ in the increased characteristics of durability and are used both for housing, and for industrial construction.
Depending on way of production continuous plates are planimetric, demanding presence of support on all contour of plate and also three – and bilateral. The main difference of monolith from other type of concrete articles – the largest weight which on average reaches value of 300 kg on square meter of overlapping. For this reason often continuous plates cast directly on construction site in folding contours which can even be rented. It helps to save time and means on transportation, loading and unloading of panels.
Monolithic plates, besides in view of features of production, are characterized by good waterproof and frost-resistant properties that plays significant role in operation of ready construction. Customers also show increased requirements to exterior of products because their surface has to be ideally equal, not have flows and the sticking-out ends of iron fittings.
Important! The main minus of monolith – the long term of hardening. According to norms the monolithic plate is considered completely stiffened only 28 days later after filling, and the house from plates of concrete goods will be exposed long time to shrinkage.
As for dimensions of continuous plates, in this case both standard, and other options of the sizes meet. Thickness of monolith is selected taking into account the maximum longitudinal distance between support. So, at girderless basis of design height of monolith is defined by ratio 1:30, but anyway it is not recommended to use plate which thickness less than 15 cm. In calculations of plates of overlappings these indicators are considered as the most important, affecting load bearing capacity of products. If over 6 meters, irrespective of plate thickness are required to issue flight, carrying out additional reinforcing is required.
Multihollow floor slabs: sizes and features of use of designs
Multihollow series of floor slabs enjoys many years popularity thanks to the fact that panels differ in the increased characteristics of durability, but at the same time have smaller weight unlike monolithic type of overlappings.
By production of hollow type of reinforced concrete slabs the concrete of high specific weight is applied generally, and in each part there are through channels or emptiness concreted from end faces. Both in that and in other case in plate there are air chambers thanks to which multihollow panels get the following advantages:
- Smaller consumption of concrete by production that influences lower price of reinforced concrete slabs.
- Simplification of laying of communications. Emptiness allow to organize not only networks of power supply and water supply, but also other communications.
- Smaller pressure upon the base. Availability of emptiness considerably reduces the weight of products, and respectively, and all design in this connection pressure upon foundation of the building decreases.
- Short terms of construction and lack of shrinkage. Plates are delivered already ready to mounting that allows to conduct continuously construction without temporary expectations.
It is important! If from end face the through outputs of channels are open, it is necessary to close up openings independently, using cement mix and any material for warming.
It is possible to carry only smaller durability to shortcomings of plates (in comparison with monolith) and presence of joints. In general use of multihollow plates positively affects noise isolation and heat insulation of construction.
Differ in standards of state standard specification of plate in such characteristics:
- Thickness. In most cases height of plates reaches 22 cm, but there is facilitated type of hollow products which thickness is 16 cm and also products of the increased durability having height of 30 cm meet.
- Width. Plates 1, 1.2, 1.5 wide are considered as the most widespread, products of 1.8 in size very seldom meet.
- Length. The indicator depends on way of production, for example, the concrete articles made when using timbering have length from 2380 mm to 8980 mm. Length without shuttering options can reach 12 meters in case of the individual order, at the same time the plate can be cut on elements of any length with an accuracy of 10 cm.
- Nominal distance between channels of floor slab. The average distance between centers of emptiness – 185 mm, between edges of channels has to remain not less than 26 mm.
- Diameter of internal opening. The indicator varies from 114 to 203 mm.
Characteristics of ridge or P-shaped floor slabs, panels of covering and wallboards
If to look at the drawing of floor slabs of this type, the special form of products is evident at once. Because of unusual configuration ridge plates are more used for industrial or uninhabited construction. Availability of stiffening fins provide to the ready building high resistance to any influences, but because of uneven surface on ceiling they will look not esthetically.
To level surface, it is necessary to spend large number of means and materials. At the layout of floor slab can keep within edges up, forming trough, but more often mounting happens in the traditional way – edges down.
According to norms such sizes are characteristic of products:
- height – 40 and 30 cm (for previously strained plates);
- length – 5-5.5 m;
- width – 0.74-2.985 m.
The main advantages of use (in the construction plan) floor slabs of ridge type – opportunity to carry out construction of the building in the temperature range from-40 to +50 ° and also ability to stability at influence of the seismic activity equal to 9 points.
Registration of attic-floor room and roof is considered completion phase of construction of any building. Special panels of covering after which laying the roof with use of the finishing materials, such as bitumen or liquid rubber performing the waterproofing function and at the same time differing in low cost is built are for this purpose used.
Slab roofs are mounted in the standard or ridge way. Intense armature is applied to improvement of durability of design. This type of plates differs in ability to maintain the raised loading to 1500 kg/m ². In structure of plate the mortgage elements executed from iron fittings which connect to the next parts are used.
Such options occur among the most popular sizes:
- width – 2-3 meters;
- length – 6-12 meters;
- thickness varies from 250 to 455 mm.
Wall concrete slabs were developed with the purpose to accelerate rates of construction of the building, for example, the owner-occupied dwelling can be executed from plates in only 2-3 weeks.
It is possible to distinguish the following from main types:
- Single-layer. Are made from the homogenous concrete mix differing in low heat conductivity. Their thickness does not exceed 4 cm.
- Two-layer. The bearing inside layer is executed by the reinforced concrete, and outside – cement – sand solution.
- Three-layered. Are carried out by combination of the first two types of plates for what the welded prefabricated reinforcement cage is used. Between layers the heater layer is usually added.
It is interesting! Depending on bearing capacity wallboards are hinged, self-supported and bearing.
In separate group it is possible to allocate the plates for partitions differing in the large dimensions corresponding to height of floors. Length of such concrete structures usually reaches 6 meters. For production of panels normal or plaster concrete of the increased durability which is characterized by good water proofness and frost resistance is used. Thickness of wallboards should be selected according to weather patterns in the region. Depending on requirements panels 20-50 cm thick are manufactured.
Other options of concrete articles used in the different purposes
At road construction special road concrete slabs by which production high-strength concrete of V-25 or V-30 brand is applied are used. Resistance to tensions in bending is considered distinctive feature of these concrete articles. This characteristic provides durability and high flow capacity of road highways. Concrete road slabs at which production the strengthened reinforcing was applied can keep within during creation of the runways expected the raised loading.
Main characteristics of products:
- ambient temperature range at which it is admissible to use products without loss of their properties, – from-55 to +40 °C;
- erasability indicator – 0.7 g / cм ²;
- frost resistance class – F250.
Depending on configuration road plates are rectangular and also trapezoid or hexagonal. It is important to consider that before putting concrete slabs, it is necessary to prepare the basis correctly. The top soil layer acts for this purpose and leveled, and the site under laying is well rammed. Then the pillow from wet sand which is condensed with skating rink is filled, and only after that it is possible to place plates. Cavities between plates are filled in with quality concrete.
Concrete slabs are made for paths and sidewalks by method of vibrocasting or vibropressing. After the product is given the necessary form and the size, tiles pass steaming stage, there will not occur full crystallization of concrete mix yet. Color is given to tile by means of addition of natural impurity thanks to what they do not burn out and are not abraded over time. On standards of state standard specification concrete walkway slabs have to have single-layer or two-layer structure. Two-layer options differ in presence of top decorative color layer 2 cm thick.
As the main advantages of products are considered:
- high wear resistance to mechanical damages;
- long term of operation;
- attractive exterior;
- easy mounting and dismantling;
- presence only of natural materials at structure.
In addition to the listed products, concrete is used also for production of other elements, such as:
- Fences. The monolithic fence from concrete slabs is cast directly on the site using timbering. This option of barrier differs in the easiest way of mounting. Also concrete and type-setting fences which are characterized by variety of flowers and forms meet.
- Floor slabs of wells. These are the reinforced concrete slabs of overlapping with in advance prepared openings under the hatch having marking of software. Variety of the sizes allows to use the concrete covers intended for wells of different diameters.
The first concrete slab has been made more than a century ago, and since then products are constantly modernized. At the same time not only their exterior improves, but also load bearing capacity of products increases. Producers compete in creating the easiest plate with preservation of its sizes and properties. In general concrete panels are considered as the excellent construction material allowing to create quickly reliable and steady construction. The main thing – is correct to pick up the size and type of plate.