The Development of Steel Fiber

Steel fibers are short and thin fibers that are made of steel materials through a certain process and can be randomly distributed in concrete or mortar. According to the process type, it is divided into 5 categories, which are steel wire cold drawn type, steel plate shear type, steel ingot milling type, steel wire scraping type and melt extraction type. According to the shape, it is divided into straight type and special type. According to the molding method, it is divided into a bonded row type and a single bulk type.

Steel fiber directly replaces the steel bars in traditional concrete, reduces the amount of steel and concrete, and improves the concrete's compression, impact, crack resistance, impermeability and wear resistance.

1. The development and status quo of the world steel fiber material industry

The development of steel fiber has a history of 100 years. At present, the global output reaches hundreds of thousands of tons. Many developed countries have large-scale production of steel fiber, using advanced technology and equipment. These equipment have the characteristics of high linear speed, low noise, small size, and high degree of automation. Bonded rows of cold drawn steel wire fibers have become the world's largest use type due to their high tensile strength, high aspect ratio, good bondability with concrete, good workability and no agglomeration for mixing.

In the past ten years, foreign theoretical research on steel fiber concrete has developed rapidly. The steel fiber product quality standard ISO13270 has been formulated and published in the steel fiber-related concrete structure design model standard Model Code 2010 for Structure. Many countries have also released steel fiber concrete design standards, such as Germany, Netherlands, Denmark, etc.

Steel fiber of our steel fiber company is widely used in infrastructure projects such as industrial floors, subways, tunnels, structural components, cement products, and water conservancy projects.

2. The development and status quo of China's steel fiber material industry

The research and application of steel fiber in China has been developed for half a century, and good achievements have been made. Steel fiber is used in fields such as building floors, water conservancy projects, and traffic tunnels. Steel fibre material standards and various related steel fiber application standards are formulated, such as product quality standards Steel Fiber for Concrete, test standards Fiber Concrete Test Method Standards, application standards Fiber Concrete Structure Technical Application Regulations, Building Ground Design Code, Technical Specification for Steel Fiber Concrete Pile Bearing Floor, etc.

At present, there are more than 100 steel fiber manufacturers in China, the production process and quality of which are uneven. Most of the steel fiber production is small-scale or even workshop-style production, which cannot achieve large-scale production. The manufacturers do not have strict control systems of raw materials, production processes, and product quality. Some steel fiber manufacturers mainly produce bonded rows of steel fibers, but due to the lack of strict quality control and glue quality problems, the quality of fibers in rows is poor and the dispersion is uneven. At present, only a few steel fiber manufacturers in China have obtained ISO9001 quality certification, ISO14000 environmental system certification and CE first-level certification, ensuring stable production processes and product quality.

3. Comparison of domestic and foreign steel fiber industry level

The current design method of steel fiber concrete in China is still at the level more than ten years ago. The theoretical calculation adopts the influence coefficient and is limited by the test sample. The influence coefficient cannot completely scientifically reflect the reinforcing performance of steel fiber, so the design result is either conservative or unsafe, which hinders the application of steel fiber concrete in many fields.

For most manufacturers with unstable quality of raw materials, backward production process, simple equipment, they are still at the stage of small workshops, lacking inspection methods for the strength of steel fiber and steel fiber reinforced concrete.

At present, both theoretical research and production levels in China are lagging behind developed countries, and resources need to be invested to quickly catch up and surpass the level of developed countries.

4. The future development trend of steel fiber

As an energy-saving and environmentally friendly product, steel fiber has huge development potential in the future. In China, the steel fiber floor area accounts for about 4% of the total industrial floor area, so there is a lot of room for future development. In addition, fields such as airport construction and nuclear power facilities will also become new application areas. Besides floors, pavements, and tunnels, the application of foreign steel fiber is moving towards building structure fields, such as floor structures, seismic structures, steel fiber concrete 3D printing components, and so on. The mixed application of steel bars and steel fibers can double the performance of concrete, which will also be the direction of future research and application.

5. The development goals of steel fiber

In order to accelerate the application and development of steel fibers in China, it is necessary to upgrade the production methods of small workshops, improve production quality through large-scale production, and ensure stable steel fiber performance. Manufacturers work with universities to do more researches, revise outdated standards, formulate truly scientific and practical design and construction specifications, and develop advanced, accurate and easy-to-use steel fiber quantity and dispersion testing equipment to ensure stable mechanical properties of steel fiber reinforced concrete.