Application of basalt fiber cloth in building reinforcement

                                Application of basalt fiber cloth in building reinforcement

1. Preface
With the development of the times, many building structures built in the 1980s and 1990s have gradually stepped into aging. For the need to improve the seismic and compressive performance of buildings, strengthening buildings has become a general trend. Reinforcement technology is emerging in endlessly. This paper introduces a method of strengthening buildings with basalt fiber cloth, introduces the basic properties of basalt fiber cloth, analyzes and summarizes the reinforcement principle of basalt fiber cloth, and discusses the broad prospect of the application of basalt fiber cloth in building reinforcement.
2. Introduction of fiber materials for reinforcement
Fiber reinforcement technology is a new technology rising in the 1980s. Due to the excellent mechanical and chemical properties of fiber composites, it has been favored by the engineering community and widely used in engineering reinforcement. Among them, basalt fiber, aramid fiber, carbon fiber and glass fiber are the most widely used fiber reinforcement materials. However, the mechanical property parameters of various fiber materials are different, and their designability and processability are also different.
2.1 basalt fiber
Basalt fiber is a new type of mineral fiber, which is made of basalt raw materials by high-temperature melt line drawing. With high strength and modulus, it can be compatible with concrete, and its price is between aramid fiber and glass fiber. Because its raw material comes from natural basalt, it is environment-friendly and pollution-free, and its product performance is better than glass fiber, it has been used as reinforcement material in engineering.
2.2 aramid fiber
Aramid fiber has excellent properties of high strength, high modulus, low elongation, good electrical insulation, good impact resistance, softness and processability, and simple construction. It is complementary to carbon fiber in many aspects and is also an important fiber reinforced material. Aramid fiber can be used alone or mixed with carbon fiber and glass fiber. Abroad, aramid fiber is widely used. However, in China, the application of aramid fiber as structural reinforcement material is still in its infancy.
2.3 carbon fiber
As a reinforcement material, carbon fiber has certain inherent defects, such as low impact strength, low shear strength, strong conductivity, will produce electromagnetic interference, and its application range is limited. Because of its excellent mechanical properties such as high strength, high modulus and simple structure, it is still widely used in construction engineering. China's annual consumption of carbon fiber accounts for one quarter of the world's total output. Carbon fiber is the fastest-growing and most promising fiber-reinforced composites.
2.4 glass fiber
Glass fiber includes high-strength glass fiber (s glass fiber) and alkali free glass fiber (E glass fiber). The elongation and tensile strength of glass fiber are low and the price is cheap, but the elastic modulus is poor, the alkali resistance is poor, the corrosion by salt is poor, and the construction operation is poor. Therefore, the scope of application is more limited, and it is suitable for occasions with low reinforcement requirements.
3. Characteristics of basalt fiber cloth
Basalt fiber cloth should be combined with resin to give play to its excellent tensile strength, elastic modulus, creep resistance and seismic performance. Table 1 below shows the comparison between basalt fiber cloth and steel plate.
Table 1 Comparison between basalt fiber cloth and steel plate
name
Basalt fiber cloth
steel plate
Tensile strength (MPA)
≥2000
≥400
Modulus of elasticity (GPA)
≥80
one hundred and forty
Elongation (%)
≥2.2
-
It can be seen from the above table that the tensile strength of basalt fiber cloth is 5 times that of steel plate. The low density of basalt fiber cloth reduces its own weight, which makes the construction process simpler and lighter, and reduces the difficulty of transportation and construction.
In addition, the excellent chemical properties of basalt fiber cloth are also one of the important factors that make it superior to other reinforcement methods. Basalt fiber cloth has excellent chemical corrosion resistance. It can enhance the corrosion resistance of the matrix and prolong the service life of the building, whether in the long-term sun and rain or in the harsh acid-base environment. In a sense, it reduces the maintenance cost and maintenance cost of the project.
Figure 1 basalt fiber cloth
Figure 2 basalt fiber cloth
4. Reinforcement principle of basalt fiber cloth
In the reinforcement process, basalt fiber cloth and resin are pasted on the structure to be reinforced along the tensile direction or perpendicular to the crack direction, including beams, columns, cantilever beams, slabs and other projects that need reinforcement and change, so that the basalt fiber cloth and the reinforcement matrix form a new composite, so that the basalt fiber cloth and the original reinforced concrete structure are stressed together, increasing the crack resistance or shear resistance of the structure, and improving the strength, stiffness Crack resistance and extensibility.
5. Overview of the application of basalt fiber cloth in building reinforcement
The excellent properties of basalt fiber cloth, such as low density, high strength, good durability and strong resistance to acid and alkali chemical corrosion, determine that basalt fiber cloth will be widely used in the reinforcement of building structures. When strengthening concrete structures, basalt fiber cloth does not need to add bolts and willow nails for fixation, which has little disturbance to the original concrete structure. Compared with replacement concrete reinforcement method, chemical grouting construction and other reinforcement methods, the construction process of basalt fiber cloth is simple and convenient. Compared with other reinforcement methods, basalt fiber sheet reinforcement has obvious advantages, and as a new technology, it has been favored and affirmed by more and more people.