Plastic concrete spacers, also known as form spacers or void formers, are crucial components in concrete formwork, playing a pivotal role in ensuring the proper placement and spacing of reinforcing bars and maintaining a consistent concrete cover. These spacers, strategically positioned between the formwork and reinforcing bars, create voids for various purposes, including:
Plastic concrete spacers ensure the correct distance between the reinforcing bars and the concrete surface, also known as concrete cover. This adequate concrete cover protects the reinforcing steel from corrosion, safeguarding the structural integrity and durability of the concrete structure.
Plastic concrete spacers can be used to create voids or gaps within the concrete structure to accommodate electrical conduits, plumbing pipes, or other mechanical elements. This allows for the efficient installation and maintenance of these utilities without compromising the structural integrity of the concrete.
Plastic concrete spacers can be used to form joints or expansion joints in concrete slabs or walls. These joints allow for controlled movement of the concrete due to thermal expansion or contraction, preventing cracking and ensuring the long-term performance of the structure.
Plastic concrete spacers can provide support for formwork, especially in curved or complex shapes, preventing formwork deflection and ensuring the desired concrete shape is maintained.
This type has high compressive strength and minimizes damage to concrete. At the time of production, this spacer is considered to be the same as the concrete of the building so that their heat coefficient is the same. The price of this type is higher than other types, especially the plastic type.
Application:
Concrete assessor is used to cover rebar in slabs, walls, building foundations, tunnels, dams and similar things.
Suggested reading: To learn more about Concrete Grout click.
This type, like the concrete type with high compressive strength, should be carefully designed so that the rebars can be placed on it easily.
Application :
This type of spacer itself is used as a wire or sometimes a bent rebar.
The plastic spacer is cheaper than the other two types and therefore has many fans. But the resistance of this type is less and it may not stick well to concrete. On the other hand, its thermal coefficient is also different from concrete.
Application:
This type is very widely used in the construction industry and is used in concrete structures with different formats.
Plastic concrete spacers come in various shapes, sizes, and designs to cater to diverse construction requirements. The most common types include:
Chair Spacers: These spacers resemble chairs, with a flat base and a raised top, providing support for horizontal reinforcing bars.
Bar Spacers: These spacers are typically cylindrical or rectangular in shape and fit around vertical reinforcing bars, maintaining the desired spacing between bars.
Distance Tubes: These spacers are hollow tubes that create voids for pipes, conduits, or other utilities.
Slab Spacers: These spacers are designed for use in concrete slabs, providing support for both horizontal and vertical reinforcing bars.
Wall Spacers: These spacers are specifically designed for concrete walls, ensuring proper concrete cover and spacing of reinforcing bars.
Plastic concrete spacers are relatively inexpensive compared to other spacer materials like metal or ceramic.
Their lightweight nature makes them easy to handle and install.
Plastic spacers are not susceptible to rust or corrosion, unlike metal spacers, making them suitable for use in marine or coastal environments.
Plastic spacers are generally simple to install and require minimal preparation.
The wide range of shapes and sizes available caters to diverse construction needs.
Strength Requirements: Ensure the spacer strength is adequate for the weight and load-bearing capacity of the concrete structure.
Environmental Conditions: Consider using spacers made from UV-resistant plastic if exposed to direct sunlight.
Fire Resistance: If fire resistance is a concern, choose spacers made from flame-retardant plastic.
Compatibility with Concrete Mix: Check the compatibility of the spacer material with the specific concrete mix being used.
Follow Manufacturer’s Instructions: Each spacer type may have specific installation guidelines.
Proper Placement: Position spacers accurately to maintain consistent spacing and concrete cover.
Secure Fastening: Use appropriate methods to secure the spacers in place, preventing them from dislodging during concrete placement.
Inspect Regularly: Check for any damaged or misplaced spacers during construction.
Spacer literally means spacer. There are standards for building a structure and covering rebars and reinforcement. Using this part helps a lot to improve these standards. Failure to comply with these standards may cause problems such as the options below.
Adhesion of rebars and reinforcement to concrete
Extrusion of rebars and reinforcements
When one of these problems occurs, the rebar will be corroded and the project will face a lot of costs; Therefore, the use of spacers on the one hand helps the speed of work and on the other hand increases the quality of work.
1.The diameter of the rebars should be four thirds of the largest nominal size of the aggregates.
2. The thickness of the concrete cover: the rebars should be suitable for the environmental conditions and the type of the desired part and should not be less than certain values.
3. If the concrete is applied next to resistant soil, it must be in vertical contact and the thickness of the concrete cover must not be less than 75 mm.
4. If the concrete has a concave and prominent surface, the thickness of the coating should be measured in the depth of the depressions.
5. If surface protection is done, it is possible to reduce the concrete cover up to 20 mm.
If the concrete grade is about 50 MPa more than the minimum size, it is possible to consider the concrete cover 5 mm less and things like this.
Plastic concrete spacers play an essential role in modern construction practices, ensuring the proper placement and spacing of reinforcing bars, maintaining concrete cover, and creating voids for various purposes. Their cost-effectiveness, lightweight nature, corrosion resistance, and versatility make them a preferred choice for a wide range of concrete applications. By carefully selecting the appropriate spacer type and following proper installation guidelines, contractors can achieve high-quality concrete structures with enhanced durability and long-lasting performance.
