Today’s world, concrete is still the most widely used building material in the world. With the continuous development of construction and transportation industry, the requirements for concrete performance are becoming higher and higher, which promotes the research and application of concrete reinforcement materials. Fiber reinforced materials are widely used in concrete materials because of their excellent physical and mechanical properties. Fiber reinforced concrete developed earlier. At present, the research on steel fiber reinforced concrete and polypropylene fiber reinforced concrete has been relatively mature and widely used in engineering practice. However, the research and application of futa fiber, steel wire / steel mesh fiber, polyvinyl alcohol fiber, polyester fiber and Dura fiber on the performance of reinforced concrete are less. This paper introduces the characteristics and applications of the above fiber reinforced concrete, which provides a basis for engineering application.

1 Forta Fiber Asphalt Concrete

With the continuous development of the transportation industry, more and more new materials are used in asphalt concrete pavement, and futa fiber is one of them; It is a new type of polymer organic fiber, which is composed of polypropylene and aramid fiber with a mass ratio of 3:1.
  

In the 1980s, foreign countries began to study the effect of fiber on the performance of asphalt concrete and applied it to engineering practice; However, there is little research on this aspect in China. Adding futa fiber into asphalt mixture can improve its low temperature crack resistance, high temperature stability, fatigue resistance and water stability; Yuan Jun and Cao Liping from Tongji University have made a detailed study on futa fiber in improving the high temperature stability of asphalt concrete, and draw the following conclusions: 1) after adding futa fiber, the high temperature stability and overall stability of the mixture are improved. 2) After adding futa fiber, the permanent deformation resistance of asphalt concrete is significantly improved, and the effect is the best when the content of futa fiber is 0.045%. With the addition of futa fiber, the pavement performance of asphalt concrete has been significantly improved; It adapts to the current development of transportation and has broad development prospects.

2 Steel Wire / Steel Mesh Fiber Concrete

Adding randomly distributed steel fibers into concrete can prevent the development of internal micro cracks and external macro cracks; Enhance the fracture toughness and impact resistance of concrete; Improve the fatigue and durability of the structure; Extend the service life of the structure. However, its high cost limits its application. Steel fiber reinforced concrete (SFRC) is made of waste steel wire rope, which is cut and mixed into ordinary concrete according to a certain amount; It not only has the properties of steel fiber reinforced concrete, but also has low cost; It only needs cutting processing fee, so its economic benefit is good, and the waste is reused.

Steel mesh fiber reinforced concrete is a kind of fiber reinforced concrete with high-strength bi-directional steel mesh, which improves the initial crack strength of concrete and solves the problem of limited orientation and amount of short fiber; Effectively prevent concrete cracks caused by temperature, dry shrinkage, settlement and other factors; It is especially suitable for projects requiring high crack resistance.

3 Polyvinyl Alcohol Fiber Concrete

Polyvinyl alcohol (PVA) fiber is a kind of chemical fiber. Its initial main purpose is to solve people's clothing problems. After decades of development, its application range is more and more extensive: fishery, packaging materials, water-soluble materials and reinforcing materials. As a reinforcing material, PVA fiber has its main advantages, which can be seen in literature [3]. After adding PVA fiber into concrete, the mechanical properties of concrete are improved mainly as follows: 1) the tensile strength of concrete is improved due to the addition of PVA fiber; The increase of compressive strength is small. 2) The toughness of concrete is improved by adding PVA fiber; The impact resistance is obviously improved. 3) The addition of PVA fiber improves the ductility and anti-destructive ability of the structure. 4) With the addition of PVA fiber, the durability of components is greatly improved.

At present, PVA fiber concrete has been widely used in earthquake resistance, repair Engineering (spraying method can be used) and engineering to improve structural durability.

4 Polyester Fiber Asphalt Concrete

Adding polyester fiber into asphalt concrete has the following properties: 1) it can adsorb and stabilize asphalt, so as to increase the cohesion of asphalt and improve the rutting resistance of the mixture. 2) Low temperature crack resistance, water damage resistance and fatigue resistance are enhanced. 3) The service life of the pavement is prolonged. The addition of polyester fiber can obviously improve the performance of the mixture, and it will be widely used in future maintenance projects and new projects.  

5 Dura Fiber Concrete

Dura fiber is a kind of high-strength polypropylene bundle fiber made from 100%pp raw rubber through special production process. It has the advantages of small specific gravity, high tensile strength, anti-aging, corrosion resistance, good adhesion with cement slurry, etc; Adding it into concrete can greatly improve the performance of concrete.

The addition of Dura fiber: 1) prevents the segregation of concrete and ensures the homogeneity of concrete. 2) The bending strength of the component is slightly improved; It has little effect on compressive performance. 3) The durability, impermeability, frost resistance, corrosion resistance and impact resistance of concrete are improved.

Dura fiber concrete has been widely used in construction engineering, airport roads, aqueducts in hydraulic engineering, bridges and other projects because of its excellent physical and mechanical properties.

6 Aramid Fiber Concrete

Aramid fiber concrete is another high-performance chemical fiber used for continuous filament reinforced concrete. It has been successfully developed in the United States as early as the 1960s. It has high tensile strength, high elastic modulus, low density and good thermal stability. Therefore, aramid fiber has been used in concrete composites to meet different requirements.

7 Other Types of Fiber Reinforced Concrete

7.1 Steel Fiber Recycled Concrete

The addition of steel fiber improves the mechanical properties of recycled concrete and makes the original brittle recycled concrete show certain ductility; The toughness of recycled concrete is improved; And its comprehensive benefit is good; Recycled concrete is regarded as an important research object in the "Eleventh Five Year Plan" in China, and steel fiber recycled concrete has a very good development prospect.

7.2 Steel Fiber Lightweight Aggregate Concrete

Similarly, the addition of steel fiber has greatly improved the performance of lightweight aggregate concrete in all aspects, and has been applied to the repair of old bridges.

7.3 Basalt Continuous Fiber Concrete

Literature [7] describes the characteristics of continuous basalt fiber. After being added to concrete, the problem of reinforcement corrosion can be solved, and its price is reasonable. The market prospect is very broad.

8 Conclusion

With the rapid development of China's economy and technology, higher requirements are put forward for the physical and mechanical properties of concrete in construction, transportation, water conservancy and other industries; A single variety of fiber reinforced concrete materials can not meet the requirements of modernization. It is urgent to study and apply new fiber reinforced materials to expand their application range. Scientists and engineers should strengthen the research and application of the above fiber reinforced concrete and formulate corresponding standards and specifications to meet the requirements of high strength and high performance of concrete.

Reference:

[1] Yuan Jun, Cao Liping, Sun Lijun / Research on high temperature performance of futa fiber asphalt concrete [J] Journal of building materials, 2006,9 (4): 436-441

[2] Chen Xiaolian, Li Fengtong / application of steel mesh fiber concrete in engineering [j] Concrete, 2006, 9 (3): 84-96

[3] Wang Xiaogang, Mao Xinxin, Zhao Tiejun / polyvinyl alcohol fiber cement-based composites [J] Journal of Qingdao Institute of architecture and engineering, 2006, 9 (4): 28-31

[4] Li Yegang, An Ping, Wang Guimei / application and performance of polyester fiber in asphalt mixture [j] Jiangsu architecture, 2006, (1): 43-44

[5] Dong Ping / brief introduction to the properties of Dura fiber and its application in construction engineering [j] Post and Telecommunications design technology, 2002, (11): 53-57

[6] Zheng Xiaoguang, Zhao Anfang, Shen Xinyuan / application of chemical fiber in the construction field -- fiber reinforced and crack proof concrete [j] Journal of Henan Urban Construction College, 2006, 8 (2): 44-48

[7] application prospect of Tian Chunzhu / basalt continuous fiber in building structures [J] Heilongjiang water conservancy science and technology, 2006, (3): 80-81

Transferred from - 【 China concrete and cement products network 】