1.1 definition of building formwork
The building formwork is the forming mold of concrete, which is made according to the design requirements, so that the concrete structure and members can be formed according to the prescribed position and geometric size.
Formwork engineering is a complex system engineering with a wide range of contents, including design, material selection, manufacture, formwork support, pouring, demolition and turnover. After more than half a century of development, China's mold base industry has changed from "simple and extensive" to "environmental protection, simplicity and high quality".
With the continuous improvement of formwork construction technology, formwork specifications are developing towards serialization and systematization, formwork materials are becoming diversified and lightweight, and formwork application is becoming multi-functional and instrumental. To develop and apply new building formwork and promote the technical innovation of formwork engineering is an important way to reduce project cost and promote the modernization of construction industry.
1.2 the status of building formwork in the national economy
Formwork scaffolding project is the most important part of cast-in-place concrete structure engineering.
In the construction engineering, the concrete structure occupies the leading position. According to statistics, concrete structures in the United States, Japan and other developed countries account for more than 50% of all projects, and this proportion can reach more than 80% in China. (steel structure, wood structure, etc.)
According to statistics, the cost of the mold base accounts for about 25%-35% of the total cost of the concrete structure project, 30%-40% of the project consumption, and about 50% of the total construction period.
In 2020, China's GDP reached 101.6 trillion yuan, and the total output value of the construction industry was 26.4 trillion yuan, accounting for 25.98% of the GDP.
Formwork scaffolding industry as an important part of the construction industry, it is not only a small industry, but also a large industry. According to statistics, the total output value of the mold base industry accounts for about 5% of the total output value of the construction industry, and the total output value of the mold base industry is about 1.32 trillion yuan in 2020.
1.3 the development of architectural formwork
1.4 main classification of building formwork
In order to meet the needs of construction engineering, the performance and quality of formwork have been continuously developed, and there are more and more types of formwork. At present, formwork can be classified according to different ways: 1 according to production material, 2 according to structural type, 3 according to function, 4 according to construction method, etc.
2 application status and prospect of building magnesium alloy formwork
2.1 introduction of magnesium alloy materials
China is rich in magnesium ore resources, of which it has been proved that more than 20 billion tons of dolomite magnesia ore, more than 3 billion tons of magnesite and more than 4 billion tons of salt lake magnesium chloride reserves can be exploited for more than a thousand years, accounting for more than 70% of the world's magnesium resources. At present, the cumulative identified reserves of magnesium chloride in the Qaidam Basin are 4.281 billion tons, accounting for 99% of the total magnesium salt in salt lakes in the country, ranking first in the country.
2.2 performance comparison of magnesium alloy template
1. Weight comparison
two。 Comparison of mechanical properties of substrate
3. Other performance comparison
2.3 Economic comparison of magnesium alloy formwork
At present, the sharp rise in magnesium prices is directly due to the sharp rise in raw material prices, with coal prices and ferrosilicon rising 4-5 times. This situation will not last, and the Nonferrous Association is also actively coordinating. According to the comprehensive calculation, if the magnesium price returns to the same level as the aluminum price, the magnesium template has the price advantage.
2.4 Technical bottleneck of magnesium alloy template
2.5 main manufacturers and scientific research institutions of magnesium templates
At present, there are four main magnesium template enterprises in China: Jiafeng Industry (Huizhou) Co., Ltd. (die casting technology), Zhejiang Taipson New material Technology Co., Ltd. (extrusion technology), Dongguan Mei Innovation Precision Die casting Co., Ltd. (die casting technology), Shaanxi Suide Zhenmeng magnesium Alloy material Co., Ltd. (extrusion process).
On August 24, China's first "magnesium alloy building formwork R & D center", jointly built by Beijing China Railway Construction Technology Co., Ltd., the National magnesium Alloy Materials Engineering and Technology Research Center, and Shaanxi Suide Zhenmeng magnesium Alloy material Co., Ltd., was established.
2.6 Research and development direction of magnesium alloy template
The main results are as follows: 1) improve the alloy material, increase the elongation, reduce the damage rate and repair rate of magnesium alloy template, and increase the number of use;
2) the die-casting and extrusion processes are continuously improved, giving full play to their respective advantages, and the extrusion process should further reduce the cost;
3) improve the surface treatment to improve the corrosion resistance and weather resistance of magnesium template;
4) all industries need to work together to promote the formulation of industry standards for magnesium alloy templates at an appropriate time;
5) further expand the engineering practice and get the approval of the general contractor.
