Concrete formwork is the use of support structures and moulds to create structures out of concrete which is poured into he moulds.
There are many different types of formwork used in construction, usually differing according to what the building requirements and challenges are. Formwork is used by creating moulds out of wood, steel, aluminium or prefabricated forms into which the concrete is poured. This is then allowed to harden and set after which it is stripped, or in the case of stay-in-place formwork it is left as part of the structure.
Formwork allows contractors to cast and construct the main parts of a building which are required to be strong and support the structure such as floors and walls, as well as smaller parts of a building such as stairs relatively quickly.
Types of Formwork
There are many different types of concrete formwork used in construction. Traditional timber formwork uses timber and plywood to form the moulds for pouring. This method is cheaper than other methods, yet not as effective because wood is not as strong as metal or steel. However, on complicated sections of buildings which need great attention to detail, timber formwork is still widely used.
Engineered formwork systems use prefabricated moulds made from a metal frame, usually either steel or aluminium. Engineered formwork is much cheaper and quicker to use than traditional formwork. The frames are extremely strong and rarely need replacing, reducing costs. Due to the formwork systems being engineered, their construction is faster and requires less manpower, again saving money. Simple structures can be built with re-usable plastic formwork systems (a type of engineered formwork), which consist of strong, lightweight, interlocking systems.
Stay–in-place formwork is used generally for the supporting parts of a structure. This type of formwork consists of insulating concrete forms which are filled with reinforced concrete and once set, are left in place.
When concrete is mixed, the success and quality of the concrete in structures is known as workability. Concrete can be made to different qualities depending on the amount of water, the type of water, the shape of the mould, how long the cement has been hydrating for and amount and type of cement contained in the mixture. The quality of the cement is reduced if too much water is included, causing the cement to separate from the other substances which make up the concrete mixture.
Concrete can crack, which was problematic for constructions throughout history as they ran the risk of collapse. Today reinforced concrete is used which is a much stronger substance and rarely cracks. When concrete is reinforced, it is filled with metal rods and reinforcing bars with other materials such as glass and plastic fibre.
Concrete formwork is widely used in present day construction. With the many different types of formwork available, any building project is more easily achievable because different methods can be used to achieve the desired result. When reinforced, concrete is a virtually indestructible material, perfect for major construction work, as well as small, detailed and complex structures.
About the Author:
Cape Formwork Contractors (CFC) is a scaffolding and formwork contracting company, providing high quality concrete formwork services for construction which are safe and reliable, whether dealing with simple or complex structures.