The concept of FRP
FRP is the abbreviation of fiber reinforced composite material, which is composed of multiple strands of continuous fibers such as glass fiber, carbon fiber and Alamede fiber. The production method is to press the glued base material with a professional mold, and repeatedly draw it to form a composite glass-shaped steel material. Compared with traditional materials, this material has many advantages, such as high strength, light weight, and durability. Corrosion and easy construction and other characteristics.
This kind of material has been favored by various civil engineering projects in recent years because it has more advantages than traditional civil engineering materials. It is generally used in bridges, various civil buildings, marine engineering, underground engineering and other projects, and can be applied to various projects at the same time, indicating that FRP materials can withstand the construction conditions of various projects, which is of great significance for the development of modern construction engineering institutions. Great boost.
Features of FRP
Because different fibers have different chemical compositions, the performance of their characteristics is not the same. Commonly used FRP materials such as glass fiber, carbon fiber, and Alamede fiber have different characteristics in practical applications.
1. In terms of tensile strength and ductility
Compared with steel bars, these three materials have more obvious tensile properties, and their strength is 50 times stronger than that of steel. The use of this material has a more obvious effect in reducing its own weight. According to relevant research reports, it can be seen that within the range of tensile strength, there will be no obvious deformation and poor ductility. Therefore, it can be known that the material is tensile in terms of tensile strength. Relatively strong, poor ductility.
2. Corrosion resistance and durability
FRP materials are more corrosion-resistant than steel, can withstand the erosion of various acids, alkalis and other environments, and resist the corrosion of chemical substances very well. In contrast, the corrosion resistance of traditional civil engineering materials is relatively poor. It is easy to be corroded by various chemical substances, which is not conducive to the improvement of the life of the structure, and the cost of maintaining the structure is relatively high, especially in a highly corrosive state, it is easier to shorten the life cycle of the structure. The FRP material has many advantages in this regard, and has a unique effect on maintaining the quality of the engineering structure.
3. Self-weight
Since the density of FRP material is much smaller than that of steel, it is suitable for various construction conditions and environments. Therefore, in order to reduce labor costs and labor intensity during civil engineering construction, this method is generally used. Materials can guarantee the quality of the project and reduce the cost of the project, and in the aspect of old building reinforcement, the advantages of using FRP materials are more prominent.
4. Coefficient of thermal expansion and elasticity
This kind of material needs to be mixed with concrete during civil engineering construction. Since the thermal expansion coefficients between the two are close to each other during mixing, there will not be a relatively large temperature difference, which is convenient for the solidification of the mixture. After solidification, cracks will not occur due to internal temperature differences. . At the same time, this material has a smaller elastic modulus than steel bars.
5. Other aspects
FRP material also has this certain disadvantage. Due to its production and processing procedures, the price is high. At the same time, this material is not good enough in terms of fire resistance, strength perpendicular to the fiber direction, and elastic modulus. Insulation, heat insulation and other obvious advantages, but often can not play the effect in every occasion.
Application of FRP Material in Civil Engineering
Due to its unique advantages, FRP materials are used in various types of civil engineering projects, making the application of materials gradually increase.
1. Construction Engineering
FRP materials have been used in construction engineering since 1986. With the development of the construction engineering industry, the requirements for performance design and material performance have increased for modern construction engineering. In the process of engineering construction, it is generally used in the design of engineering structural frames to improve the performance of buildings. There is a six-story building in the United States. This building is completely made of separated glass fibers and processed by a special process. Finally, the two-component oxygen resin tightly bonds the structural components together. The splicing method generally used in the frame is multi-layer splicing, so that the number of components used is less than the number of components used in ordinary splicing methods, which is different from traditional splicing. The wooden structure is somewhat similar. In the design of the floor beams, box-shaped components are used, so that the cross-section of the column is different from the traditional one. It is a channel-shaped cross-section, which is reflected in the whole process of the building.
2. Geotechnical Engineering
Because FRP material has good corrosion resistance, can resist the erosion of chemical substances in various chemical environments, and protects the structure, so this material is used in reinforced soil. Generally speaking, construction units that use this material for engineering construction use the shield tunneling method in the excavation method, because if the traditional method is used for excavation, the material is easily cut off, so the shield tunneling method is used. Retaining walls, foundation anchors, etc. are generally constructed using glass fiber composite materials, because this material is low in cost, easy to install, and durable, and meets the quality requirements of these projects.
3. Bridge Engineering
Since the 1970s, FRP composite materials have been used in bridge engineering, generally used in cables on bridges, prestressed tendons and the entire bridge system. The use of this material can make the bridge corrosion-resistant, high-strength , The structure is relatively light in weight, so that the seismic capacity of the bridge is improved. The use of this material in the reinforcement of old bridges can reduce the cost of processing, and the construction is more convenient, and the interval between subsequent reinforcements will be significantly increased. In this way, the bending resistance of the bridge will be improved and the use of the bridge will be increased. life.
With the rapid development of the economy and the rapid development of the civil engineering industry, the market demand for FRP materials will also increase. The technical level of FRP materials will be greatly improved, and the industrialization process will gradually accelerate, and it will be used in various aspects of civil engineering, which will bring huge economic benefits and social benefits will also increase. In order to make better use of this new material, relevant research units still need to do in-depth research on the improvement of the material's performance.