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Russian engineers strengthen rebar beams using moss-based carbon nanotubes

The nanotubes were produced from brown moss

MOSCOW, June 30. /TASS/ Researchers from the Far East Federal University’s School of Engineering (SE FEFU) have invented a new way of making fiber-reinforced plastic rebar more durable, the press office of FEFU said. To do so, they have suggested using carbon nanotubes produced from moss by mechanical, thermal, and chemical treatments.

The authors of the development, the Dean of FEFU’s School of Engineering Alexander Bekker and Andrey Umansky a research assistant at Research and Educational Center "R&D Center "Arktika", have already taken out a patent for their innovation.

"Concrete products with fiber-reinforced plastic rebar tend to warp out of shape in a more pronounced way than those with steel reinforcement do, with the deformation being accompanied by a formation of wide splits. We solved this issue by strengthening the structure of FRP rebar by means of nanotechnologies," Bekker stated.

In contrast to steel reinforcement, the FRP rebar does not consist of metal but of roving, basaltic or glass fibers bonded together by a binding agent, for example, with epoxide resin which fastens the fibers and protects them from any aggressive impact by its surroundings. The inventors added carbon nanotubes to epoxide. On a micro-level, the nanotubes act as reinforcement material and due to their special properties they serve as pockets of directional crystallization.

The nanotubes were produced from brown moss (Sphagnum fuscum) collected in the wetlands of the Lower Amur River region. The scientists chose this type of moss because of its low thermal conductivity and has a very high degradation resistance. After mechanical treatment the moss which had first been exposed to the degradation at a high temperature, multilayer carbon nanotubes having a diameter 10-20 nanometers are produced. Scientists suggest applying these nanotubes to strengthen the reinforcement.

"Carbon nanotubes provide a better coupling of components and consequently strengthen the durability of materials," Bekker explained.

According to the scientists, when compared to usual rebar materials, this breakthrough reinforcement with nanotubes resists stretching more effectively by 75-97% and is more resistant to any sort of deformation by 7-15%.