1. Explore the mechanical properties of the template
All of the above plastic building formwork have high bending strength and elastic modulus, and the mechanical properties can meet the requirements of the plastic building formwork for bending strength and elastic modulus. Among them, the mechanical properties of the plastic building formwork based on PE and PP-R are good, and the mechanical properties of PVC are slightly lower than the other three plastic building formwork. However, the density of three kinds of plastic building templates based on PP, PE and PP-R is relatively high, between 1.0 and 1.3, far higher than that of PVC building templates from 0.63 to 0.7.
Through the above information comparison, it can be seen that although the mechanical properties of PVC plastic building formwork are slightly lower than those of the other three base materials, the weight of PVC plastic building formwork is lower than that of the other three base materials, which is close to the password of wood plastic and conforms to the operation habits of the construction personnel. Saws, nails and wood formwork are very close. The formworks of the other three kinds of base materials are heavy and increase labor intensity, which is not conducive to construction. The formworks of the other three kinds of base materials are very difficult to saw and nail, which is also not conducive to construction operation.
2. Temperature expansion performance of formwork
The results show that the thermal expansion coefficients of PE, PP, PP-R and PVC are 11.88 × 10-5 / ℃, 15.2 × 10-5 / ℃, 12.6 × 10-5 / ℃, 1.8 × 10-5 / ℃, respectively. It can be seen that the thermal expansion coefficient of PVC based plastic building formwork is small, which is very close to the thermal expansion coefficient of concrete.
Take the formwork with a length of 1.83M as an example. If the temperature difference is 30 ℃, the length of various formworks will be extended by 6.52mm, 8.34mm, 6.92mm and 0.98mm respectively. It can be seen from this that if the slab joint is not reserved during the low-temperature construction of the plastic building formwork with PP, PE and PP-R base materials, the formwork will be arched and warped after the temperature rises. Because the temperature change of PVC based plastic building formwork is very small, there will be no arch up phenomenon.
Although the mechanical properties of PVC based plastic building formwork are slightly lower than those of other three base materials, its weight and operation performance are better than those of other base materials. Especially when the temperature changes, there will be no arching, warping, waves and other phenomena. PVC plastic building formwork is a more suitable building formwork at this stage. Shandong green palstic formwork is a good choice for the contractors and building materials.
