The carbon fiber wrap reinforcement method is to stick an epoxy resin with extremely high tensile strength to the structure to be reinforced along the tensile direction or perpendicular to the crack direction to form a whole. The carbon fiber material and the original reinforced concrete are jointly stressed to increase the crack resistance, shear resistance, bending resistance and compression resistance of the structure, and improve the strength, stiffness, crack resistance and elongation of the structure. To achieve the purpose of structural reinforcement and structural stress. Compared with other reinforcement methods, carbon fiber cloth reinforcement has the advantages of space saving, simple construction, easy construction quality assurance, basically no increase in structural size and self-weight, good corrosion resistance and good durability. In addition, using this method can greatly increase the service life of the building and reduce the cost of reinforcement, so the reinforcement process is favored.

When purchasing carbon fiber wrap, some people often ask what is the tensile strength of carbon fiber wrap. Most people will tell you that it is 3400MPa. In fact, this is the standard value of the tensile strength of carbon fiber cloth. There is also a design value for tensile strength that is occasionally mentioned. So what do these two values mean in practice?

Standard value of tensile strength

Generally speaking, the tensile strength indicates the standard value of tensile strength. The tensile strength of carbon fiber cloth indicates the maximum tensile stress that a unit area of carbon fiber cloth can bear. The simple point is that a carbon fiber cloth with a cross section of 1mm² can withstand a force of 3400N. Take a class 300g carbon cloth as an example, its cross-sectional area S = a (carbon cloth width) b (carbon cloth thickness) = 100 * 0.167 (300g carbon cloth thickness) = 16.7mm² if it is 100mm wide. Then it can theoretically withstand F = 3400N * 16.7 = 56780N. The construction unit pays more attention to the tensile strength, because when purchasing carbon cloth, it is required that the tensile strength of the carbon cloth is 3400MPa. If it fails, it means that the carbon cloth is unqualified and cannot be used in this project.

Design value of tensile strength

The tensile strength of the same carbon cloth in different reinforcement members may be different. The design value of the tensile strength of the primary carbon cloth is 1600MPa in important members and 2300MPa in general members. Many people wonder why the design value of the more important component is smaller. First of all, we must understand that the design value of tensile strength is the value calculated during the calculation of the force. The standard value of the tensile strength of the first-class carbon cloth is 3400MPa, which is already determined, so the smaller the value, the more secure it is. Therefore, the design value of the tensile strength of important components is smaller than the design value of the tensile strength of general components. The design unit's tensile strength design value is more concerned, because in the calculation of the force, the tensile strength design value is used.

What is the relationship between the standard value of tensile strength and tensile strength?

First, the carbon fiber cloth can only be calculated according to the corresponding tensile strength design value only when it reaches the standard value of tensile strength of 3400MPa. How much tensile strength can the carbon fiber cloth exert during reinforcement? This is difficult to determine, because the specific conditions of each project are different, and the actual strength of the project is also different. Some structures have large deformation and the use of carbon fiber reinforcement will cause the strength of carbon fiber to be exerted very little, and the strength may even be less than the design value of tensile strength. This structure will have certain safety risks, so this structure is not suitable for reinforcement with carbon fiber wrap.

Strength is a very important parameter of carbon fiber wrap. It is necessary to make full use of the tensile strength of carbon fiber in the reinforcement project to make the structure safer.