Use of plastic formworks for concrete construction has many advantages such as durability, cost and flexibility compared to other materials for concrete formworks.
Formworks are used to hold freshly placed concrete at its position until it attains enough strength and with the help of formworks concrete can be easily manipulated and various shapes and forms can be constructed.
There are different materials which may be used to manufacture formworks for example timber, steel, and aluminum in addition to plastic that offer number of advantages compared to other materials for example durability, cost effectiveness, and flexibility.
It is reported that, not only does the construction of formworks takes time but also spent about 20 to 25% of the total cost of the structure. It is one of the major factors that influence the success of construction of any structure in terms of safety, cost, quality and speed.
It is for these advantages and benefits of plastic forms that will be discussed in the following sections.
Fig.1: Plastic Formwork for Concrete Construction
Objectives of Plastic Formworks in Concrete Construction
Form work is not a permanent construction but it requires careful attention to avoid damages of permanent construction. The formwork design and construction are controlled by three principles:
- Safety: It depends on the formwork strength substantially. Life of labors and public might be in danger if the formwork does not possess adequate strength.
- Quality: Concrete shape accuracy and the quality of final finished surface of concrete element.
- Economy: The structural frame, which is the most critical factor during construction, is most crucial cost component.
Advantages of Plastic Formworks in Concrete Construction
Formworks expend large labor force and total cost of the project that is why efforts have made to introducing a formwork system that is cost effective and can be assembled, dismantled and handled easily by labor.
There are several advantages provided by plastic formworks in concrete construction:
- Cost effective
- Labor friendly
- Eco friendly
- Low maintenance
Plastic Formwork System
It is manufactured from specific grade plastic that neither placed materials adhered to it nor chemical reactions occur between poured materials and the plastic form and consequently there will be no any patch on the surface of reinforced concrete element.
Water or freshly placed concrete leakages from different parts of the form is avoided because of the perfect fitness of various parts of the system. Added to that, it is most labor friendly system because not only does it fit and plugged easily but also it is considerably light weight compare with other types of formwork systems.
Nailing and oiling plates are not required prior to concreting because of auto leveling of plugging system that make plates level automatically and consequently it takes about 30% lesser time during installing and dismantling compare with conventional form systems.
Additionally, after its utilization, the plastic forms can be cleaned with water easily and if it breaks due to bad handling, low voltage hot air gun is used to seal it.
Other formwork materials such as wood, steel, aluminum produce various disadvantages which might outweigh their benefits. For example, the application of wood is considerably costly and create substantial environmental impacts due to deforestation.
With regard to aluminum formworks, it can be employed many times but its high cost makes it as not very suitable option to use. In contrary, plastic forms can be recycled and it is environmentally friendly in addition to reduce handling time and great reusability index.
Table-1 provides a comparison between plastic forms and other form types.
Table-1: Comparison Between Plastic, Traditional, And Steel Formworks
|Items||Plastic formwork||Traditional formwork||Steel formwork|
|Size||Any size can supply||Restricted||Restricted|
|Availability time||More than 100 times||8 times||100 times|
Different Types of Commercially Available Plastic Formworks
Siscon Plastic Formwork System
It is one type of commercially available plastic forms which can be used to construction various structural elements such as walls, columns, and slabs. It provides substantial precision.
Plastic Formworks for Walls
It is used for the construction of boundary walls, retaining walls, shear walls, rainwater drains, flood or storm drain walls, irrigation canals, and in concrete banking.
Fig.2: Wall Plastic Formwork Applications at Different Location of the Structure
Fig.3: Plastic Formworks used for Wall Construction
Plastic Formworks for Floors
Fig.4: Plastic Formwork for Concrete Floor Concrete
Fig.5: Plastic Formwork for Slab Construction
Plastic Formworks for Column
Fig.6: Installation of Plastic Formwork for Column
Nova Plastic Formwork System
It is produced from composite plastic material and it is the only plastic form that can be employed in both salt and fresh water without damage. Various application of NOVA plastic forms are shown in Figure-7, Figure-8, and Figure-9.
Fig.7: Application of Nova Plastic Forms
Fig.8: Application of Nova Plastic Form in the Construction of Column
Fig.9: Use of Nova Plastic Form in Construction of Concrete Walls