Concrete forms are temporary frames that hold wet concrete in shape until it dries and hardens. They can be made out of wood or steel and allow the builders to easily pour concrete into certain shapes.
Concrete forms also allow the wet mix to retain its strength and cure properly, giving the structure durability. The forms need to have tight joints to prevent wet concrete from seeping through the frame.
They also need to be strong enough to support the weight of the concrete – small household projects, such as driveways, use wooden forms but larger projects need to use steel forms. The forms should have enough bracing and support to help them keep their shape once the cement is poured in.
They also need to be able to withstand the weather without bending or warping. You can guarantee that your projects will be strong and durable if you have used proper concrete forms.
Concrete forms can be made from various materials
The most common material used to make concrete forms is wood. These forms are usually constructed on-site from plywood or timber. Wooden forms are cheap and are ideal for flat concrete structures such as floors, steps or driveways.
Metal is another common material for creating forms. These steel moulds are usually used on larger construction sites, such as commercial buildings and skyscrapers. They are ideal for creating vertical columns and pillars for tall structures.
Some forms are created from fibreglass, reinforced plastic, ceramic or aluminium. All of them have their benefits and disadvantages but their purpose remains the same – to create moulds for concrete structures.
Two types of concrete forms
Construction projects are three-dimensional and, as such, need vertical and horizontal forms. Vertical forms are needed for building concrete walls, columns, pillars and stairs. These forms need to support the lateral pressure of the concrete, so they should be anchored or bolted to the soil or floor to keep them in place.
Horizontal forms are used to build beams, ceilings, floors and paths. They need to support the weight of wide concrete structures, so should be reinforced with braces, struts or metal pegs.
Components of concrete forms
Concrete forms are made up of various components. The form that comes into direct contact with the concrete is called the formwork sheeting. This mould is responsible for the precise look and shape of the finished concrete surface. It needs to be water-resistant or have its own moisture content so as not to suck water out of the concrete and leave it too dry.
The elements that support and connect the formwork sheeting are known as the formwork bearers. These include steel or wooden beams and clamps that connect and support the formwork sheeting. They provide structural strength to the form and support the weight of the heavy concrete.
Lastly, formwork ties are the steel wire components that bind two forms together. The ties are usually wrapped around the formwork bearers then guided through drilled holes in the formwork sheeting. The wires are then tightened by twisting.
Concrete is then poured into the formwork structure and left to cure for a few weeks. The formwork can then be stripped and deconstructed once the concrete has set properly. Avoid using too many ties or nails in the formwork as this will make it hard to deconstruct later.
Concrete forms are a vital component of any construction project. When assembled properly, the forms will hold concrete in shape for up to four weeks while the concrete cures. This allows the concrete to reach its optimal strength and durability.
LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges.
LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in the Mbeya Region at Songwe in Southwest Tanzania.
At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.