Fiber Reinforced Polymer/Plastic (Fiber Reinforced Polymer/Plastic, referred to as FRP), FRP composites are high-performance materials formed by mixing the fiber material with the matrix material (resin) in a certain ratio. Light and hard, non-conductive, high mechanical strength, less recycling, corrosion resistance.
FRP, fiber reinforced composite plastics, is the English (Fiber Reinforced Plastics) abbreviation, the existing CFRP, GFRP, AFRP, BFRP and so on. In Chinese, FRP refers to GFRP. FRP composite material is a high-performance type material formed by mixing fiber material with matrix material in a certain proportion. Among them, GFRP has polyester FRP, epoxy FRP, phenolic FRP and other types depending on the variety of resin used. General FRP is light and hard, non-conductive, high mechanical strength, less recycling, corrosion resistance and other characteristics.
Tensile strength
High tensile strength, FRP tensile strength are significantly higher than steel, and high strength steel wire tensile strength is about the same, generally 2 times or even up to 10 times the steel. But FRP material in the tensile strength before, almost no plastic deformation, tensile stress, strain was line elastic rise until brittle, so FRP composite materials in the process of action with the concrete structure ****, often not due to the FRP material was pulled off the damage, but due to the lack of strength of the FRP-concrete interface leads to the interface of the concrete structure was peeled off the damage, so the FRP-concrete interface bonding performance has become the most important issue of the concrete structure. Therefore, FRP-concrete interface bonding performance has become a key and difficult point for future engineering applications.
Thermal expansion coefficient
The coefficient of thermal expansion of FRP composites is similar to that of concrete, so that when the ambient temperature changes, FRP and concrete work in coordination with the two will not produce large temperature stress.
Modulus of elasticity
Compared with steel, most FRP products have small modulus of elasticity. It is about 25% to 75% of that of ordinary steel. Therefore, the design of FRP structures is usually controlled by deformation.
Shear strength
Because FRP is fiber polymerization through the matrix, the strength of the inter-fiber is determined by the matrix (strength is generally weaker than the fiber), so perpendicular to the direction of the fiber is weaker.FRP's shear strength is low, and the strength of its tensile strength of only 5-20%, which makes FRP members in the connection process need to develop a special anchorage, jigs and fixtures. This also makes the moderation of FRP members become a prominent issue in research.
Corrosion resistance, anti-fatigue properties
FRP material corrosion resistance, anti-fatigue properties, can be in the acid, alkali, chlorine salts and moisture in the long-term use of the environment, and thus can improve the service life of the structure, which is difficult to compare with the structural materials. But at the same time, compared with the general concrete, FRP composite fire performance deviation, which also restricts the popularization and application of this type of structural products, become one of the problems to be solved in the future.
Weight
Specific strength is very high, that is, often referred to as lightweight high-strength, so the use of FRP materials can reduce structural self-weight, easy to construct, and its weight is generally 20% of the steel.
Good designability
FRP belongs to the artificial material can be used according to the needs of the project with different fiber materials and fiber content and spread the way of different processes to design different strength indicators, modulus of elasticity and special performance requirements of the FRP products, and FRP shovel shape can be flexibly designed.
Factory production, on-site installation, is conducive to ensuring the quality of the project to improve labor efficiency and construction industrialization.
Other advantages
Insulation, heat insulation and permeability to electromagnetic waves, etc., so it can be used in some special occasions such as radar stations geomagnetic observatory medical nuclear magnetic *** vibration equipment structure.
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