Concrete production today has been mastered not only by professionals, but also by private developers, this has made available a monolithic technology of housing construction. Such buildings are more durable than all other types of buildings. Previously, industrial technology and high-rise buildings were built using this technology . Today, this technique is known to private craftsmen who use it to build their own houses and cottages. Using monolithic technologies, you can realize incredible and bold design ideas.
Future homeowners are increasingly thinking about building monolithic houses, since such buildings are surprisingly strong. They are able to undergo even a small earthquake. And the work does not involve large labor costs in the construction process. It is not necessary to use expensive materials, and during operation the house is durable and reliable. You can finish such buildings with any facing material, it is permissible to immediately erect walls with additional thermal insulation.
Features of removable formwork
Monolithic reinforced concrete can be poured into removable or non-removable formwork. The first variety is more common and famous. After the initial setting of the solution, the craftsmen will need to dismantle the material, leaving the structure to dry completely.
If reusable formwork will be used, then it will be possible to form a variety of forms for pouring concrete. You can build the foundation, form the frame of a multi-story building, equip monolithic walls and stairways, as well as create interior and exterior decor elements. Walls of cast reinforced concrete are poured into a removable formwork, for which it is used:
- solid wood;
- steel sheets;
- combined variations;
- aluminum molds;
- sheets of plywood.
PVC coating is quite common, which facilitates the dismantling of multi-turn formwork. Metal options are used for the construction of complex structures and in cases where massive construction technology is used. To create the formwork of the foundation, it is best to use plywood, boards or wooden boards. It is possible to facilitate the installation process by using metal frames in which wooden boards are installed. Plywood for removable formwork can only be used to create a small concrete structure or thin partition.
Rules for the construction of removable formwork
If you want to fill in monolithic reinforced concrete, then you can use a removable formwork solution, but certain requirements are imposed on it. The frame must be firmly fixed in place and have the properties of rigidity. The individual elements of the overall design must be precisely matched to each other. At the same time, the gaps should be minimal.
The height of the formwork must withstand significant pressure, which will be the solution after pouring. It is desirable that the removable formwork has poor adhesion to concrete. If it will be used several times, then the structural elements should not be deformed from the effects of the load.
Preparation of wooden elements
If you want to fill in monolithic reinforced concrete yourself, then you should choose wooden boards, the thickness of which can vary from 25 to 50 mm. In width, such elements can be very different, this parameter does not play a special role. However, with increasing width, the likelihood of cracking increases. It is better to choose boards whose width varies from 200 to 300 mm. Boards should be assembled into boards, the height of which should correspond to the future level of concrete pouring. To do this, apply the bars to which the boards are strengthened.
Bars should be placed on the outside, while nails are driven into boards so that the hats are inside the formwork. You should fit the boards together as tightly as possible. If gaps with a width of 1 to 5 mm were formed, then they are covered with tow. If there are cracks of a more impressive size, they should be clogged with slats.
For reference
Monolithic reinforced concrete will not get the required strength if there are cracks in the formwork, since cement milk from the solution will leak through them. In addition to the shields, it is necessary to prepare bars, the length of which should be 1/3 greater than the height of the formwork. To form the spacers, boards and wire are used to bind the walls by installing internal jumpers.
Formwork device
Below we will consider an example of the formation of the formwork design for a strip foundation. These principles will allow you to build fences for most other purposes. First, the surface is prepared, a trench is excavated for the foundation, and a sand cushion is laid at the bottom. The layer of this preparation should be 150 mm. The resulting base is compacted and liberally moistened with water. To simplify the process of determining the correct location of the walls of the formwork, its foundation should be made as strong as possible. To do this, it is covered with a cement-sand mortar or poured with a thin layer of concrete. Horizontalness should be verified using a water-level building.
Formwork for stairs and floors
If the formwork for the staircase is implemented, then at the installation site of the structure, a foundation should be formed, which is connected with the main base of the building. When creating the formwork of floors, it is necessary to create the basis of shields that are supported by telescopic racks. The base area is not fixed by beams, but by I-beams and wooden beams.
Methodology for the construction of formwork
Once you have leveled and strengthened the foundation in the trench, you can begin work on installing the formwork. Using a rope and pegs, you should outline the perimeter of the formwork elements, following the requirements of the project. On the perimeter of the foundation, pegs and bars are installed on all sides. Surfaces that face the foundation must be removed from the marking line by a distance equal to the thickness of the formwork panels. Pegs are needed to hold the bottom of the shields, while the bars will become the basis for the supports. Wooden shields should be attached to the boards and pegs, fastening with nails. The inner surface of the shields should repeat the external form of the future foundation.
Specialist advice
If after you want to grind on concrete, you should indent the edges of the formwork from the marking by 15 mm. The upper part of the support bars must be additionally fixed with the help of supports. To do this, apply a board whose length should be 1.5 times longer than the height of the foundation. With one edge, it will abut against the upper part of the support beam, while with the other - in the soil. With a large thickness of the foundation, when the supports can not withstand the pressure, you should carry out a bunch of formwork with additional jumpers. They are made of wire rod, which will connect the opposite shields.
Technology for the construction of buildings with fixed formwork
Concrete formwork can also be fixed, this technology is most often used today in the construction of cottages. In this case, the formwork elements will act as an additional layer of thermal insulation. The cost of work will be as low as possible, since labor costs are negligible. After the formation and waterproofing of the base of the building, formwork is installed on it, which has the form of polystyrene foam forms. They are held together by profiles. The forms have a spike-groove locking system that allows you to connect the elements firmly and without gaps. This completely eliminates the possibility of penetration of the solution and the occurrence of sagging at the junction of the forms.
The formwork can have completely different thicknesses, but blocks in which the empty space has a width of 150 mm are considered standard. At the same time, on both sides there is polystyrene foam with a layer of 5 to 7.5 cm. This will be enough to keep the house warm in winter and cool in summer. When buildings are built of reinforced concrete using the technology of creating fixed formwork, after installation, concrete is poured into the latter. As soon as its layer reaches a thickness of 50 cm, the material should be sealed with a deep vibrator.
Important to remember
It should be noted that only concrete is permissible for pouring fixed formwork, the use of warm mixtures is excluded. This is due to the fact that the vapor permeability of expanded polystyrene is low, and the vapor permeability of warm mixtures is higher. If warm concrete is sandwiched between the layers of thermal insulation, condensation will accumulate inside, during which fungus and mold will certainly form. Such technology of monolithic reinforced concrete does not provide for the need for additional insulation. The walls will need to be plastered with a decorative composition or sheathed with siding. The advantages of the technique are the simplicity of the work, low cost and no need for additional insulation. But at the same time, the cottage will not have the ability to breathe.
Precast Concrete Technology
The main difference between reinforced concrete prefabricated elements is that they are not assembled at construction sites, but in the factory. This allows you to achieve higher quality products. At the manufacturing stage, highly mechanized machines are used, as well as fully automated equipment. The price of such structures is lower, since the complexity of the process is minimized. Precast concrete is made taking into account the insignificant costs for the installation of formwork, since in this case it involves reusable use.
Reinforced concrete structures are divided into four classes according to their purpose, namely:
- for industrial facilities;
- Concrete products of various profiles;
- for the construction of civil and residential buildings;
- for engineering structures.
Prefabricated reinforced concrete for civilian use includes ceilings, flights of stairs, panels, platforms, foundation concrete blocks and wall structures. For industrial use, reinforced concrete columns, column foundations, piles and floor slabs are used.
DIY precast
The formwork device will also need to be implemented if you yourself want to make reinforced concrete products. At the same time, some home masters believe that it is not necessary to spend money on reinforcement, since concrete already has high strength and reliability. However, in 90% of cases, combined loads, namely tension and compression, are applied to the bearing elements. The reinforcement will undergo tension, not allowing the structure to break. Concrete will be able to withstand vertical loads only when it has the shape of a regular cube, which can only be achieved in laboratory conditions.
Conclusion
The production of concrete for pouring the foundation must preserve respect for the ratio of ingredients. So, the proportion of cement, sand and gravel is as follows: 1: 3: 5.