Modified carbon fiber, preparation method thereof and modified carbon fiber reinforced cement-based material

Abstract

The invention discloses a modified carbon fiber, a preparation method thereof and a modified carbon fiber reinforced cement-based material. The modified carbon fibers are carbon fibers with nano silicon dioxide and carbon nanotubes grown on the surfaces in situ. The preparation method of the modified carbon fiber comprises the following steps: (1) removing an epoxy coating on the surface of the carbon fiber; (2) oxidizing the surface of the carbon fiber; (3) performing in-situ growth of nano silicon dioxide on the surface of the surface-oxidized carbon fiber; and (4) growing carbon nanotubes on the surface of the product obtained in the step (3) in situ. The nano silicon dioxide and the carbon nanotubes simultaneously grow on the surfaces of the carbon fibers in situ, the modified carbon fibers combine the pozzolanic effect of the nano silicon dioxide and the bridging nucleation effect of the carbon nanotubes, and the modified carbon fibers are doped into the cement-based material, so that the interfacial strength of the carbon fibers and the cement-based material can be remarkably improved. Pores of the cement-based material are filled with the modified carbon fibers, so that the structure of the cement-based material is more compact, and the early-stage shrinkage performance of the cement-based material is effectively improved.

Description

technical field [0001] The invention relates to a modified carbon fiber, a preparation method thereof and the modified carbon fiber reinforced cement-based material, belonging to the technical field of carbon fiber modification. Background technique [0002] Cement-based materials are the most widely used traditional materials, which have the advantages of low price, good fire resistance, and can be cast into various shapes according to the formwork. However, traditional cement-based materials are brittle materials. Due to factors such as early self-shrinkage, temperature drop shrinkage, and drying shrinkage, micro-cracks will appear, and then develop into macro-cracks. For extra-long basement structures and roof structures, it is more likely to crack due to shrinkage. Once the cement-based material cracks, it will inevitably deteriorate its durability. [0003] Nanomaterials have the characteristics of small particle size and large surface energy, which can make the micro...

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Problems solved by technology

[0006] Purpose of the invention: Aiming at the problems of existing cement-based reinforcing materials such as low interfacial bonding strength with cement matrix or poor dispersion in cement matrix, the present invention provides a kind of cement-based reinforcing material that can effectively enhance the interfacial bonding strength with cement-based materials. Modified carbon fiber, and provides a kind of preparation method of this modified carbon fiber; In addition, the present invention also provides a kind of this modified carbon fiber reinforced cement-based material

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