Removable Formwork Systems
It becomes clear that the formwork is a special shield shielding made of various materials, the internal volume of which is the future element of the structure and is intended for filling concrete solutions. In this volume are often placed metal structures, providing the ability to withstand loads and very high structural strength of products.
There are a lot of forms and materials of formwork. The most traditional and, probably, the first formwork can be considered ordinary trenches in the ground. According to this technology, casting of concrete for simple strip foundation is still carried out. Laying of concrete in the formwork from board boards is also known for a long time.
The use of wooden boards and boards in the form of prefabricated and collapsible structures makes it possible to repeatedly use such a system. Knowing how to pour concrete into the formwork, you can use the well-known technology of building a wall, which assumes that after setting the mortar, you can move the enclosing elements of the formwork to the right, to the left or above, and top up the next portion.
In addition to natural boards and boards, magnesite boards are widely used, which are more resistant to moisture and prolonged repeated use.
A practically unrestricted resource is possessed by industrially-constructive types of removable metal formwork of shield type with the strengthened working planes and the unified systems of fastening for assemblage. These collapsible elements allow for quick installation, multiply increase the speed of construction and are especially good at building houses on frame-wool base.
Representatives of non-removable formwork
There are a number of technologies using fixed formwork techniques. Thermodomain( rational) construction systems have become very popular. The non-removable elements of thermal house formwork are a box structure made of expanded polystyrene without a bottom and an upper cover, but with internal partitions that provide the required rigidity.
Each such element has on the upper and lower perimeter a system of protrusions and holes that provide a very accurate assembly according to the principle of the famous children's designer. After the assembly of a number of blocks and installation in the internal cavities of metal reinforcement elements, nothing else is needed, except for pouring the formwork with concrete mortar.
As a result, a monolithic wall with a ready-made thermal stabilization and thermal protection system is formed, more than three times more efficient than traditional brick-and-stone walls. With all the advantages of this technology allows you to significantly and( up to 40%) save on the cost of materials.
We share tips on how concrete is poured into
formwork. When carrying out concrete work, it is recommended to fulfill the requirements on how to properly fill the formwork. For this, in the most general case, it must first be properly installed and strengthened using special fights, struts and clamps. In the carefully installed and calibrated formwork, it is necessary to place the elements of the reinforcing cage of the future design. After this, you can pour the previously prepared mortar mixture.
As the latter, ordinary heavy concretes of 200 or 300 grades are used, which include fractions of rubble from one and a half to two and a half centimeters, but pure sand can be used in a standard ratio of 1: 3( cement and sand).It is important to properly observe the proportion by adding water( about 680 liters per ton of cement-sand mixture).
As a rule, in the conditions of industrial construction, the filling operation is performed on the entire volume of the prepared formwork. But in terms of home construction, hands may simply not be enough to prepare and fill the entire volume. Then, layerwise filling of the entire perimeter is performed( providing sufficient thickness of each such layer) or filling the section of the formwork to the full height.
In the latter case, it is better to make an oblique edge, which ensures in the future greater strength of the entire structure. At the same time, if for any reason the works on pouring the formwork are stopped for a day or more, they can be renewed only after the previously filled concrete has become stronger.
The important point of the correct filling, whatever the manufacturers say, is the maximum removal of air from the laid mass, which contributes to its maximum compaction. On construction sites and production, submersible vibrators are used. In the absence of such, you can use the usual piece of reinforcing bar, carefully pierce the mass of the mortar, allowing the air to escape.
In this case, the presence of a second employee tapping a sledge hammer( without fanaticism) on the formwork will significantly accelerate the compaction process. The laid concrete must "mature", which lasts up to 30 days. It is necessary to cover it from direct hit and sunlight( covered with films), periodically moistened with water to ensure its uniform drying: first four hours later, and three days later( and a whole week) three times daily.