1. The carrying capacity of plastic building formwork is low
At present, the plastic building formwork is mainly used as a roof and floor formwork in the form of a flat plate, and the load capacity is low. As long as the spacing of the secondary beams is properly controlled, the construction requirements can be met. But to be used as a wall column formwork, it must be processed into a steel frame plastic formwork. Therefore, it is necessary to adjust the formula of plastic building formwork, improve the production process, improve the performance of plastic building formwork, and at the same time develop GMT formwork.
2. The strength and stiffness of plastic building templates are too small
The static bending strength and elastic modulus of plastic building templates are smaller than other templates. The strength and rigidity of plastic building templates used in China are lower than that of bamboo (wood) templates, and much lower than that of foreign GMT templates.
3. Welding slag is easy to burn the plastic building formwork
Electric welding slag is easy to burn the surface of plastic building formwork. At present, plastic formwork is mainly used as floor formwork. When laying steel bars, because the temperature of welding slag 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 Surface quality of formed concrete. Therefore, flame retardants can be properly added to polypropylene to improve the flame retardancy of plastic templates. In addition, protective measures can be taken during electric welding operations, such as giving the welder a piece of asbestos cloth, which can be laid flat under the welding spot for the flat formwork, and a small wooden board can be placed next to the welding spot for the vertical formwork, which can solve the problem of electric welding scalding. Problem with bad plastic building formwork.
4. The thermal expansion and contraction coefficient of plastic building formwork is large
The coefficient of thermal expansion and contraction of plastic building formwork is large, and the coefficient of thermal expansion and contraction of plastic plates is larger than that of steel and wood. Therefore, plastic building formwork is greatly affected by temperature. For example, during the high temperature period in summer, the temperature difference between day and night can reach 40°C. According to information, At high temperature, the expansion and contraction of a 3m-long slab can reach 3mm to 4mm. If the slab is laid at night, arching will occur in the middle of the formwork at noon; 3mm ~ 4mm gap.
From this point of view, plastic building formwork still has some shortcomings, so plastic building formwork manufacturers need to upgrade their technology more during the production process.
