CS205320B1 - Concrete reinforced by scattered fibres,especially made of steel - Google Patents

Description

The invention relates to concrete reinforced with scattered fibers, in particular steel.

The current technology of concrete production searches for optimal methods of increasing the compressive strength of concrete and in particular of tensile strength and replacing the laborious classical method of reinforcing reinforced concrete structures by another way, which would allow the production of homogeneous material resistant to different pressures and tensile strengths.

The use of conventional conventional reinforcement of reinforced concrete structures creates difficulties in the design of structurally complicated structurally and dynamically stressed elements.

The production of conventional reinforcement is very laborious and requires a highly skilled workforce and considerable investment in machinery, vehicles and warehousing and production space.

Industrial production of reinforcement requires a continuous supply of reinforcement plants with a wide assortment of ooeli profiles in order to avoid wasting steel by replacing smaller profiles with larger ones.

Further steel losses are due to the fact that short bars are also present in hot-rolled steel supplies, which, together with technological shearing, are scrapped and losses resulting from excessive positive weight tolerances. These losses can reach up to 20% by weight of steel.

One of the ways in which current technology is able to cope with these challenges is to reinforce concrete with scattered fibers, especially steel fibers. Concrete reinforced in this way is characterized by high strength and overall resistance to various influences. ^for its production can

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205 320 utilizes existing machinery, especially mixers and does not require new investments in production and transport equipment. Reinforcement processing does not require special machinery, construction investment or qualified personnel. Metal consumption is a fraction of metal consumption compared to the classical method.

Based on these assumptions, the inventive concrete is designed to improve the bond between the fibers and the concrete. This is achieved in that the fibers are spatially curved or expanded at the ends. This treatment results in better adhesion of the dispersed fibers to the concrete.

The filament according to the invention may, for example, be a steel wire having a length of 30 mm and a cross section

Λ mm. For example, the fiber may have a spatially wavy shape, optionally bent into a hairpin, the arms of which may still be spatially open. Similarly, the fiber may have the shape of a collar. With this embodiment, the possibilities are far from being exhausted. The fiber may also be flattened, for better adhesion to the concrete, the fibers may be provided with irregularities on the surface.

At the ends, the fibers may be provided with wave and hook curvature, anchor heads, or other extensions. The ratio of length to diameter or recalculated fiber diameter can be more than 100 times. Recalculated average means the circular diameter calculated from the actual cross-section if the cross-section is other than the circular one. The length then corresponds to one to five times the largest diameter of the aggregate grains.

Fibers can be obtained in metallurgical secondary production in the manufacture of cold drawn wires or articles thereof. They can also be obtained from shavings and other wastes which occur in the engineering and metallurgical production and which allow the production of steel fibers. ^{For the} production of fibers it is also possible to use equipment for the production of staples for office staplers, equipment for the production of needles, pins or nails 1 treatment machines for scrap processing.

Fiber is introduced into the concrete mixture consisting of water, sand, cement and lime during the spreading and the mixture thus treated is distributed and poured into the formwork, where it solidifies. The result is reinforced concrete.

Fiber reinforcement delays the formation of cracks in concrete and, if they occur, hinders their development. The tensile strength of the failure increases almost linearly with the increase of the prooent reinforcement. By reducing the fiber spacing in concrete to about 10 mm, the concrete's tensile strength is significantly increased by two to three times. Also, flexural strength, shear strength increases to one and a half to two times, impact strength and energy absorption to ten to threefold.

The fatigue strength increases by 60%.

In addition to steel, other suitable natural or synthetic materials can be used for the production of fibers.

The reinforced concrete according to the invention can be used in the construction of pavements, airfields, prefabricated elements and monolithic concrete and reinforced concrete structures. Everywhere, the concrete according to the invention brings savings in reinforcing material, investment costs, accelerated construction, reduced construction costs and savings in skilled workers.

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Claims (1)

SUBJECT OF THE INVENTION Scattered fiber reinforced concrete, in particular steel, characterized in that the fibers are spatially curved or expanded at the ends.