What is the difference between carbon paper and carbon cloth?
The research on reinforcement and repair of carbon fiber concrete structures began in developed countries such as the United States and Japan in the 1980s. This technology in China started relatively late, but with the rapid development of China's economic construction and transportation, the enhanced application of carbon paper and carbon cloth has been vigorously promoted and developed rapidly. Carbon fiber reinforcement has two application forms: carbon fiber cloth reinforcement and carbon fiber plate reinforcement, and there are differences in the improvement of structural bearing capacity between the two.
When it comes to carbon paper and carbon cloth, they are made of carbon fiber materials, but there are differences between the two. Carbon fiber cloth, as the name suggests, is similar to cloth, light in weight, thin in thickness, soft, and can be cut and woven with carbon fiber. The thickness of the carbon fiber cloth is 0.167mm for 300g and 0.111mm for 200g. Carbon paper and carbon cloth are suitable for reinforcement projects with increased load in buildings, changes in engineering functions, material aging, concrete strength levels lower than design values, structural crack treatment, repair of service components in harsh environments, and treatment and protection. It is of great help in structural shear resistance, earthquake resistance and bending resistance. In use, it can be pasted into multiple layers according to the needs of the project. Carbon fibers are attached to multiple layers at the same time, and the CCM membrane electrode will have a certain waste in the problem of tensile force attenuation, so it is recommended not to exceed 4 layers.
Carbon fiber sheet is a carbon fiber composite material of carbon fiber strands and resin cured, similar to steel plate. The carbon fiber panels are available in thicknesses of 1.2mm and 1.4mm, as well as 2.0mm and 3.0mm. It is better to prevent structural instability and is often used in bridge and other reinforcement projects.
Only in terms of tensile strength, the specification requires that the grade I carbon fiber cloth reaches 3400MPa, which is higher than the 2400MPa grade I carbon fiber sheet. However, in the actual strengthening, the improvement of the bearing capacity of the CCM membrane electrode is also related to the thickness of the section. If such a comparison is made, in the case of the same width of 10cm, the 1.2mm thick carbon fiber plate can provide a force of 1.2 × 2400 ×100=288000N, the carbon fiber cloth of 300g of grade I is 300g. According to the calculation of mechanical properties, one carbon fiber board can be equivalent to 4~8 pieces of carbon fiber cloth. If the number of layers of carbon paper and carbon cloth exceeds 4 layers, it is recommended to replace it with carbon fiber plate reinforcement.
Which is better to use? The specific application varies depending on the actual situation of the reinforcement project, and only which material is more suitable. Because carbon plate is relatively hard and carbon fiber cloth is relatively soft, carbon fiber cloth is sometimes applied to cylindrical or irregular-shaped structures in usage scenarios, and carbon paper and carbon cloth are used in relatively flat places such as bridge bottoms or floors. Each product has its own advantages and disadvantages, but choose according to the situation!