Concrete Construction

Formwork Quality Concrete Control

formwork concrete

For construction, Concrete is the first option to come to mind. Concrete is one of the most used construction material. It gives amazing properties and efficient results. Create building elements with concrete, poured into a specially designed mold. Formwork Relation with Concrete Quality. Formwork is holding and supports wet concrete until such time it cures. Formwork is an important element in concrete construction. Formwork systems affect the cost, time and quality of project delivery.

Formwork Affects Concrete Quality

Formworks are chosen by various conditions like the formwork system, it could lead to a response to sustainable construction. Adopting the modern formwork system encouraging, it also avoids repairs and rehabilitation of structures before its expected life span of the structure. before setting up formwork check quality first. Shuttering must have enough strength to bear all the loads present during casting operations, and must then hold its shape while the concrete hardens. It must stand with high bearing capacity, capable of withstanding dead and live loads. Retaining its shape with adequate props and braces.

Choose always reusable material like timber, iron rod. if formwork is removable, the process must not damage the concrete. Choosing the type of formwork it is important to consider the type of concrete and the pouring temperature. Formwork must be capable of resisting loads of wet and dry concrete. Formwork placement is affected by the alignment of slabs, beams, columns and other concrete structural members. Forms must be built to the correct dimensions. it must be rigid enough under construction loans to maintain the designed shape and alignment of the concrete element.

Formwork must support all loads, which may be applied until these loads can be carried by the concrete structure itself. The concrete is contained in a timber or steel casing for a certain period after its placing. Various types of material used for formwork. This casing is known as the shuttering, centering, form-work or molds and it is to be removed when concrete has hardened sufficiently to support its weight. removing the formwork is known as stripping. Stripped formwork can be reused. Reusable forms are known as panel forms and non-usable are called stationary forms.

Timber Framework: Timber is the most common material used for formwork. The disadvantage with timber formwork is that it will warp, swell and shrink. The application of water-impermeable cost to the surface of wood mitigates these defects. On the process of the development technology in civil engineering works are developed the different types of concrete formwork.

Types of Frameworks

Plywood Formwork
 Steel Formwork
 Aluminum Formwork
 Plastic Formwork
 Vacuumatics 3D formwork
 Fabric formwork

Choosing the Concrete Construction system requirement formwork. The Construction formwork should be designed in such a way that it can be easily removed and used again. Considering easy removal, Smooth surface, Lightweight and rigidity, and the economy as primary considerations for choosing a type of framework used for construction. The formwork should be fixed in such a way that the least hammering is required for its removal. Easy to carrying and setting both are important. The inside surface of formwork should be coated with crude oil or soft soap solution. This will make the removal of formwork easy. The formwork should be sufficiently strong to bear a dead load of wet concrete as well as the impact of ramming or vibrating the concrete. The over-estimation of loads results in expensive formwork and the under­estimation of loads fails formwork.

The main concrete elements for different positions and forms are constructed on the formwork systems:

 Flat slabs
 Columns formwork
 Ribbed and waffle slabs
 Beams and slabs
 Post-tensioned slabs
 Tunnel form
 Table form

It is desirable to bring down the cost of formwork to a minimum consistent with safety. The various steps such as a reduction in a number of irregular shapes of forms, use of parts of commercial sizes, putting the formwork in use again as early as possible, etc. may be taken to effect economy in the formwork.

The formwork should be so arranged that there is a minimum of leakage through the joints. This is achieved by providing tight joints between adjacent sections of the formwork.

Formwork Setting Preparation: One surface of each form was fixed by welding to a supporting structure to make it stable, during the concrete placement process. The other surface of the formwork was mounted by a pin at its upper point to allow it to rotate. The bottom part of this rotatable surface sat on ball bearings to minimize friction. Surfaces of all seven formworks were treated with mold oil. Then, one of each pair of formworks, which had the same surface material (such as Populus nigra timber, pinus silvestris timber and plywood), was watered before concrete was placed.

Temparature Affects Formwork:

Temparature varies also point change in formwork. The rate of hardening of concrete is of course more rapid at high temperatyres and slower at low temperatures, so the head of unhardened concrete in the form will vary with the Tempature. When concreting at low temperatures it is possible for very high hyd rostatic heads to develop because great amounts of Effects of formwork on concrete Many kinds of interaction between concrete and formwork combine to affect the quality of the product Offsets, deflection and tie marks produced from poor-forming materials, leave an unsightly wall or require costly finishings concrete can be placed before the first concrete begins to set. For this reason most form manufacturers publish recommendations on placement rates for use at various temperatures.

Quality Control of Concrete:

The concrete structures like multi-storeyed buildings, skyscrapers or dams are built to last many decades and hence the quality control of concrete during the construction of such important structures is a must and it has to be attended to with intelligent and scientific approach. The specifications of work should be framed with extreme care so as to serve effectively as a guide to get the job done well. As a matter of fact, the specifications are as important as the design of the project.

Other types of Formworks. Different formwork systems provide a wide range of concrete construction solutions that can be chosen to suit the needs of particular developents.

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