Types of building templates in the construction industry and characteristics of PP hollow building templatesTypes of building templates in the construction industry and characteristics of PP hollow building templates
At present, the main types of building templates used in the construction industry, product types, wooden templates, bamboo plywood, clear water templates, steel templates, cast aluminum templates, plastic steel templates, plastic steel square wood, plastic steel angles, plastic steel cylindrical templates, plastic steel bridge templates Isometric template.
Plastic template can be divided into polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), polycarbonate (PC), acrylic eye, butadiene-styrene (ABS), high density Polyethylene (HDPE), etc. According to the appearance, it can be divided into solid board, hollow board, buckle rib board, module assembly board, plastic square wood, plastic yin and yang corner.
The advantages of plastic PP hollow building templates.
1. Flat and smooth. The splicing of the template is tight and smooth, and the surface degree and smoothness of the concrete structure after demoulding exceed the technical requirements of the existing clear water formwork, without the need for secondary plastering, saving labor and materials.
2. Lightweight and easy to install. Light weight and strong process adaptability, can be sawed, planed, drilled, nailed, can be formed into any geometric shape at will, to meet the needs of various shapes of building support molds.
3. Simple demoulding. The concrete does not stick to the board surface, no mold release agent is needed, and the mold is easily demolded and the dust is easy to clean.
4. Stable weather resistance. High mechanical strength, no shrinkage, no swelling, no cracking, no deformation, stable size, alkali resistance and corrosion resistance, flame retardant and waterproof, mouse and insect resistance under the temperature conditions of -20 ℃ to +60 ℃.
5. Conducive to maintenance. The template does not absorb water and does not require special maintenance or storage.
6. Strong variability. The types, shapes and specifications can be customized according to the requirements of construction projects.
7. Reduce costs. There are many turnovers, the plane die is not less than 50 times, the column beam die is not less than 40 times, and the use cost is low.
8. Energy saving and environmental protection. All scraps and waste templates can be recycled and recycled, with zero waste emissions.
What are the types of plastic PP hollow building templates
1. The strength and rigidity of the plastic PP hollow building template is too small
The static bending strength and static modulus of elasticity of plastic PVC foamed building templates are smaller than those of other templates. The plastic building templates used in China are lower in strength and rigidity than bamboo (wood) templates and lower than foreign GMT templates. Many, according to the city's feedback, PP hollow building templates are now launched to solve this problem.
2. The carrying capacity of plastic building templates
At present, plastic building templates are mainly used as flat and roof slab templates, and the carrying capacity is low. As long as the spacing of the secondary beams is properly controlled, they can meet the construction requirements. However, to be used as wall column templates, they must be processed into steel frame plastic templates, so It is also necessary to adjust the formula of the plastic PP building template, improve the production process, improve the performance of the plastic building template, and also develop the GMT template. This problem of the load capacity of the road can also be solved after the PP hollow building template is introduced.
3. Thermal expansion and contraction coefficient of plastic PP hollow building template
The thermal expansion and contraction coefficient of plastic flat building templates is greater than that of steel and wood, so plastic building templates are greatly affected by air temperature, such as the high temperature period in summer, and the temperature difference between day and night is 40°C. According to data, at high temperatures, 3m long plates The amount of expansion and contraction can reach 1mm～2mm. If the board is constructed at night, the middle of the formwork will arch at noon; if the board is constructed at noon, the formwork shrinks at night to produce a gap of 1mm~1mm between adjacent boards. The problem of large expansion can be reduced by adjusting the material formula and improving the processing technology. In addition, you can choose an average temperature time to lay the board during construction, or add a sponge strip between the board and the board to eliminate the template. The gap ensures that the cast concrete does not leak, and it can solve the problem of arching at high temperature. The PP hollow building template used now is a well-shaped structure, which is affected by the temperature inside and outside. The deformation is small, the expansion rate is small, and the slab The surface is flat and does not deform, which improves rigidity and hardness.
4. Electric welding slag is easy to burn plastic construction template
At present, plastic formwork is mainly used as a floor formwork. When laying steel bars, the welding slag temperature of electric welding is very high when the steel bars are connected.It falls on the plastic formwork, which is easy to burn the board surface and affect the surface quality of the formed concrete. Properly add flame retardant in polypropylene to improve the flame retardancy of the plastic template. In addition, protective measures can be taken during electric welding operations, such as sending a piece of asbestos to the electric welder, and the flat template can be laid under the welding point. Erecting the formwork can put a small wooden board next to the welding point, which can solve the problem of electric welding scalding the plastic construction template