In the case of beams or slabs, the cement concrete structure is reinforced using plywood formwork. It is beneficial to support the mold where concrete needs to be poured. The plywood boards are commonly made up of pine, spruce, poplar, or birch material.
However, there are multiple other materials being used for manufacturing plywood across the world depending upon the availability and suitability of wood in various regions.
The film is applied on the plywood surface to prevent the concrete from sticking to the plywood. After the concrete gets hardened, the plywood is removed from the supports given to the structure, and thus for that purpose shuttering oil is being used.
Advantages of plywood formwork:
Plywood generally absorbs moisture which is its natural property which results in a sponge effect. Plywood causes panel movement to disturb the weight and mechanical properties of the material, and thus eventually affects its life cycle.
The advantages of plywood are as follows:
- It provides a high-quality concrete cast surface.
- It is suitable for weight-to-strength ratio.
- It has minimal deflection due to inherent stiffness.
- It has high durability.
- The material can be reused at different construction sites.
- This crossed-laminated structure provides nearly doubled panel shear to plywood when compared to solid timbers.
- It is easy to fix by using machining and fastening methods.
- It is easy to handle on the site.
- It has good chemical resistance.
- There are a wide variety of different overlays and sizes available.
- It has ecological importance.
Description of different types of plywood formwork panels:
The panels of the plywood are used as forming panels or else as form liners. Forming panels not only impart the desired texture or pattern to the concrete surface but also provide structural strength and stiffness to hold the concrete in place. A form liner can only import the desired texture and pattern to the concrete; a backing panel carries the load of the concrete.
The different types of plywood are mentioned below:
Film-faced plywood:
Film-faced plywood is amongst the most used plywood in the construction industry. A surface film is a piece of paper being soaked with glue or resin. It has improved resistance to abrasion, chemicals, insects, fungi, and moisture penetration. They have a smooth, hygiene and easy-to-clean surface.
HDO plywood:
This kind of panel is known as a high-density overlay that has a greater amount of resin inside the overlay, its surfaces are harder and more impervious to water and impact the MBO forming panels. A higher number of uses and a smoother finish can be achieved.
MDO plywood:
The MDO stands for medium density overlay and is of better quality but is also more expensive than ordinary plywood. This quality surface on the concrete is derived from the MDO’s ability to mask imperfections and reduce the transfer of the wood grain onto the concrete surface. The output of the medium-density overlay is to gain consistent color and smoothness which is ideal for coating or else painting.
A wood veneer faced plywood:
A wood veneer plywood is amongst the cheapest category of plywood compared to any other plywood category. During manufacturing, people will print some kind of glue/oil to the face or back of wood veneer-faced formwork plywood to use the formwork easily.
Specialty plywood:
Specialty plywood forming panels with unique overlays are also available. The overlay materials include epoxy resin, laminated plastic, metal, and glass fiber-reinforced plastics.
The metal and fiberglass overlays can add strength and stiffness to the panel. The manufacturer shall check on the design specifications and surface treatment recommendations for the proprietary panels.
Plywood form grades and categorization:
Plyform is manufactured with exterior bond classification plywood; restriction to certain categories of woods/veneer grades can provide high performance.
Applications of plywood formwork:
Plywood formwork represents a wide-ranging construction formwork system that can be manufactured easily and are economical to use.
- Wall and column: The plywood formwork is used for giving support to various concrete structures. These formworks are used to give support to the columns and beams of the building.
- Slabs: Plywood formworks are used in different shapes of the building. The formworks are used for various slab tables, drop beams, and ceiling slabs. Etc.
- Uses in infrastructure projects: In the case of infrastructure projects while doing the construction of bridges and tunnels, the building process is the factor that affects the choice of plywood sheets. When a continuous flow of concrete is planned and multiple concrete pouring is done, the plywood sheet should be strong and durable.
Thus, customized plywood formwork is used. Plywood formwork is used in different forms such as crane climbing formwork, configured tunnel systems, shaft platforms, and customized steel forms. Etc.
Conclusion:
With the help of plywood formwork, the concrete is poured, and shuttering is done inside the molds. As it has the properties of plywood it does not stick to the concrete and is weather resistant.
The plywood formwork is used to give support to the structures so that the structures can withstand the load of structure while the concrete inside of the slabs and columns gets hardened.
The shuttering oil is used for the plywood to avoid the sticking of concrete while the concrete is getting hardened. The shuttering oil can help in the easy removal of the plywood from the concrete structure.
The use of plywood is being done in building construction for the support of the columns and beams. It is also useful in infrastructure projects like the construction of flyovers, tunnels, and dam walls. Etc. as support needs to be given to these structures.
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