PLASTIC SPACER
Concrete plastic spacer
Description:
Concrete plastic spacers can be used to cover rebars in reinforced structures such as slabs and walls, foundations and other reinforced concrete volumes and are used in projects such as dams and tunnels and other buildings and constructions.
Workers are able to carry all kinds of them in the workshop in a short time. The minimum concrete cover on the reinforcements, which is a protection for the reinforcements against air and other effects, is calculated from the surface of the concrete to the outer surface of the steel on which the coverage rule is applied. In the case where the minimum cover is stated for a type of construction member, the minimum concrete cover is measured to the outer edge of the anchors, tights and spirals if the transverse reinforcement covers the main bars, and if more than one row of the main reinforcement without anchors or tights used, it is measured to the outer surface of the outermost row of rebars. While increasing the quality of structures, spacers help to speed up the implementation of sharp construction operations.
Plastic spacer
Concrete plastic spacers are among construction spacers that are widely used in the construction industry. Spacer literally means a transition distance that generally provides the space between the rebar and the mold. As it is said, for every two mm reduction in the thickness of concrete on the rebar, the life of the structure will be reduced by 5 years and it will reduce the durability and reliability of the structure. Spacers are the most important tools to achieve the required concrete cover. One of the common and preventable weaknesses in reinforced concrete structures is the influence of surrounding destructive factors and elements. The oxygen and moisture of the environment can penetrate into the concrete and reach the rebars to accelerate the corrosion of the rebars and reduce the useful life of the structure. This is despite the fact that the concrete coating on the rebar can be considered as the most important factor to prevent corrosion, and when the rebar is visible on the concrete surface, the chemical effect of moisture is very fast. By using spacers, the required concrete coverage on the rebars is observed. What is expected from a space builder is that it matches with the rebar networks and the task of maintaining the rebar networks during the concreting of the reinforced structure is well done. This task is made possible by durable retainers made using non-corrosive materials that are very easy to produce.
Increase the life of concrete structures. Plastic spacers with special design, raw materials compatible with concrete, convenient transportation and reasonable price are used in different shapes, types and sizes for applications such as foundations, roofs, walls, columns, etc.
Round wall spacer:
This spacer is for vertical surfaces, which is called solar or wheel spacer.
Applications and amount of consumption: It is used on vertical surfaces such as walls, columns and circular sections, and even this spacer can be used in all types of prefabricated concrete. And the amount of use of this spacer on the walls is 3 pieces per square meter of the wall surface and 16 pieces are recommended for columns with a height of 3 meters and 24 pieces for columns with a higher height.
Double grid spacer:
Excellent resistance and point load tolerance (up to 300 kg).
Applications and consumption: It is used in concrete slabs and second floors. This part is designed as two pieces (male and female), which the female part or the base creates a 25-30 mm cover and the male part. It is designed in sizes of 90 to 150 mm, and their selection is based on the thickness of the roof, and the amount of use of this spacer is 4 pieces per square meter of surface area.
Hard Spacer:
The hard plastic spacer is used for heavy structures such as foundations, heavy beams and floors. These spacers are designed for rebar up to 32 in diameter and have a load capacity of up to 270 kg.
Round wall spacer:
This spacer is for vertical surfaces, which is called solar or wheel spacer.
Applications and amount of consumption: It is used on vertical surfaces such as walls, columns and circular sections, and even this spacer can be used in all types of prefabricated concrete. And the amount of use of this spacer on the walls is 3 pieces per square meter of the wall surface and 16 pieces are recommended for columns with a height of 3 meters and 24 pieces for columns with a higher height.
Light spacer:
Proper strength and point load tolerance (up to 25 kg)
Applications and amount of use: Light structures, composite roofs, prefabricated concrete parts whose rebar diameter is less than 16 mm are used. And the amount of light spacer used is 4 pieces per square meter of surface unit.
Medium spacer:
High strength with the ability to withstand point load (up to 150 kg)
Applications and consumption: It is used in medium-weight structures such as beams, putters and semi-heavy floors whose rebar diameter is 10 to 20 mm. The amount of consumption in medium and semi-heavy floors is 4 pieces per square meter of surface area and 3 pieces per meter length in beams and putters.
Heavy spacer:
excellent resistance and with point load tolerance up to 270 kg
Applications and consumption: It is used in heavy and dense flooring such as foundation and tiro-shenage, whose rebar diameter is from 18 to 32 mm. And the amount of consumption in heavy and dense floors is 4 pieces per square meter of surface area and 3 pieces per meter length in beams and putters.
Double grid spacer:
Excellent resistance and point load tolerance (up to 300 kg).
Applications and consumption: It is used in concrete slabs and second floors. This part is designed as two pieces (male and female), which the female part or the base creates a 25-30 mm cover and the male part. It is designed in sizes of 90 to 150 mm, and their selection is based on the thickness of the roof, and the amount of use of this spacer is 4 pieces per square meter of surface area.
Performance features and tips:
• The spacers must be strong and durable so that they do not cause corrosion or loss of the concrete cover.
• The spacers must not change shape under the incoming loads before and after concreting. Spacers should be selected to maintain the integrity of the concrete. Spacers and rebars must be completely fixed in their position and concreting should not cause them to move.
• The spacers that are made in the workshop (by cement and suitable aggregates) must be durable and non-porous, and its strength should be around the strength of the surrounding concrete. After construction, this type of spacers must be implemented according to the regulations of ABA. The water-cement ratio of the mixture used in the construction of spacers should not be more than the concrete mixture. The amount of water absorption of these spacers should be less than 3.5% of their weight after 30 minutes.
• Usually, when making spacers with a suitable mixture of cement and aggregate, the maximum size of the aggregate should be much smaller than the thickness of the coating on the rebars, and it is recommended to limit it to one third of the thickness of the coating. In this case, in order to achieve the desired ratio of water to cement in the main concrete, the amount of cement and water consumption is increased to ensure proper flow. It is recommended to use a lubricant in the construction of this concrete or mortar to avoid the increase of water and cement.
• In the construction of spacers, reinforcement wire is sometimes used to fasten the bit to the rebar. It should be noted that the distance between the wire head in the bit and the surface of the mold (concrete) does not exceed the maximum allowed coverage.
• Plastic spacers or made of other materials should be chosen so as not to cause harmful substances to penetrate into the concrete. There is doubt about the performance of plastic spacers due to the large difference in its thermal expansion coefficient with concrete.
• The distance between the spacers should be in harmony with the performance of the concrete so that the concrete covers them completely and the continuity of the concrete is not lost.
• In small workshops and for minor works, sometimes cut stones are used instead of spacers, which is not recommended, because due to the difference in the properties and texture of these stones with the aggregates used in concrete, there is a possibility of penetration from these points.
Shelf life:
It can be used for up to 24 months in a covered environment and depending on storage conditions and in the original packaging.
Technical services:
The technical department of Rayehe Beton Sabz Company (technical and specialized concrete clinic of Iran) is ready to cooperate and provide services for the correct use of its materials. For more information, refer to the brochure or specialized catalog of plastic spacers.