RU2818634C1 - Combined metal-fiber rope - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to production of reinforcement articles for reinforcement of concrete structures. Disclosed is a combined metal-fiber rope twisted from at least three twisted bundles of glass, basalt, carbon or synthetic fiber, wherein includes a central straight metal core, around which bundles are wound with a calculated pitch, wherein the twisting around the core is made in the opposite direction from the bundles twisting, cross-sectional area of the metal core is from 2 to 25 % of the total cross-sectional area of the rope.

EFFECT: reduces fragility of the rope, which can take any shape when bent and enables to use it for making composite polymer articles for reinforcing conventional and prestressed concrete structures.

5 cl, 4 dwg

Description

The invention relates to construction, specifically to the production of reinforcement products for reinforcing concrete structures.

Glass-composite reinforcement is known for reinforcing concrete structures (V.S. Plevkov et al. Strength and crack resistance of bending elements with prestressed glass-composite reinforcement. Tomsk, TGASU, 2021). The reinforcement consists of a bundle of glass fibers impregnated with a binder, usually epoxy resin. The reinforcement has high tensile strength.

The disadvantages of composite reinforcement are the low tensile modulus of elasticity and low ultimate strain at break (no more than 2%).

There is known “hybrid” composite reinforcement for reinforced concrete products, consisting of a mixture of glass and carbon fibers impregnated with a polymer binder (RU Patent No. 2612374 Hybrid composite reinforcement. Published: 03/09/2017 Bulletin No. 7). Carbon fibers are introduced to increase the tensile modulus of elasticity in order to increase the compatibility of the reinforcement and concrete matrix in products, with the volume content of the binder being 13-17%, carbon fibers being 3-15% of the volume of the composite rod, and the carbon fibers being evenly spaced along the contour of the section on distance from the edge 2-3 mm. The modulus of elasticity of hybrid reinforcement increases in proportion to the amount of high-modulus carbon fibers introduced into the mixture.

The disadvantage of hybrid composite reinforcement is the low ultimate strain at break (no more than 2%). The increased fragility is explained by similar properties of glass and carbon fibers.

Reinforcing ropes are known, consisting of a low-modulus fiberglass core and an external winding of metal wire (Patent RU No. 2569650 Reinforcing rope. Published: November 27, 2015 Bulletin No. 33). A reinforcing rope containing a core and wire strands twisted in the longitudinal direction and wound onto the core, characterized in that the core is made in the form of a bundle of individual straight rods made of low-modulus high-strength composite material.

Disadvantages of the known reinforcing rope: low strength (compared to solid fiberglass or steel rope), since it is not possible to organize joint tensile work of different length elements - straight ones made of fiberglass and spiral ones made of metal wire.

There is known metal-fiberglass reinforcement, consisting of a composite load-bearing rod and a metal core placed in the center of the cross-section (Patent RU No. 120984 Composite glass-metal-plastic reinforcement. Published: 10.10.2012 Bulletin No. 28). Composite metal-fiberglass reinforcement, contains a load-bearing rod, the surface relief of which is created by a winding strand, the load-bearing rod is made in the form of a “composite matrix”, consisting of a steel core and fiberglass threads, impregnated with a composite binder and applied to the steel core, a winding fiberglass strand with using multi-pass winding, it is wound onto the outer surface of the rod impregnated with epoxy compound.

The disadvantage of the known solution is low strength (compared to a solid glass composite rod), since fiberglass composites made of unidirectional fibers are destroyed in tension due to longitudinal cracks, as a result of which the rod delaminates in the transverse direction, disrupting the adhesion of the smooth metal core and the fiberglass material .

As a prototype of the proposed invention, fiber reinforcing ropes were adopted, consisting of several bundles of glass, basalt or carbon roving, twisted or twisted into one element (Patent RU No. 164110 Reinforcing rope, Published: 08/20/2016, Bulletin No. 23). A reinforcing rope made of continuous glass or basalt fibers with a thickness of 9 - 25 microns, collected into bundles, is twisted from 3-4 bundles in 30 - 300 twists per linear meter, and the bundles are twisted in 20-200 twists per linear meter in the opposite direction of twist of the rope , with the possibility of subsequent impregnation with a binder and the formation of composite reinforcement. Laying the strands and rope in different directions makes it possible to ensure the stability of the section of the unimpregnated rope from spontaneous unraveling. Thus, the rope is a semi-finished product for the manufacture of polymer composite reinforcing products of any shape, from straight rods to spirals, springs, clamps, ties, broken and curved shapes after impregnation and hardening of the binder material.

The disadvantage of the known rope design, adopted as the prototype of the proposed invention, is the low (compared to reinforcing steel) tensile modulus of elasticity, which reduces the crack resistance of reinforced concrete products, and increased fragility (ultimate tensile deformation does not exceed 2.5%).

The purpose of the invention is to eliminate the shortcomings of the prototype: increasing the tensile modulus of elasticity, increasing the crack resistance of reinforced concrete products by reducing the fragility of the rope: - with the simultaneous use of all its positive qualities.

The technical objective of the invention is to create a building product with improved technological properties (flexibility, ability to take any shape) and increased strength and deformability, as well as the possibility of use for the manufacture of composite polymer products for reinforcing conventional and prestressed concrete structures.

The problem is solved due to the fact that the well-known rope (RU Patent No. 164110 Reinforcing rope, Published: 08/20/2016 Bulletin No. 23), consisting of several twisted bundles of fiber roving or threads twisted into a rope in the direction opposite to the bundles, is additionally equipped with a metal a core in the form of one or more metal wires, a rod or a flexible cord. The core is made straight, and the fiber bundles wrap around it with a certain step along the length. The rope can be impregnated with a polymer or mineral binder and used for reinforcing monolithic and prefabricated concrete, gypsum concrete, polymer concrete, asphalt concrete, sulfur concrete, soil cement and other structures (including structures made of heavy, light, cellular concrete, etc.). The metal core can be made of various types of steel and non-ferrous metal alloys with a high tensile modulus of elasticity. The cross-sectional area of the metal core can vary from 2 to 25% of the total cross-sectional area of the rope, depending on the purpose of the reinforced product. Increased consumption of metal in the section increases the tensile modulus of elasticity of the reinforcement, while increased consumption of mineral fiber increases tensile strength. By adjusting the ratio and geometry of laying the composite and metal in the cross-section, as well as the type of metal and fiber, it is possible to obtain a material with specified properties in a wide range of tasks.

The content of the invention is illustrated in Fig. 1-4.

Figure 1 shows the appearance of a rope made of three bundles and one wire.

1 – rope

2 – metal core

3 – composite harness

Figure 2 – cross-section of a combined metal-fiberglass rope.

Figure 3 – cross-section of a combined metal-fiberglass rope made of four bundles and four rolled wires.

Fig. 4 – graph of the “load-deformation” relationship for a fiberglass reinforcing rope in combination with metal wire made of low-alloy hardening steel.

Fig. 2 and Fig. 3 is considered as a usage example.

The technical result of the claimed solution is the creation of a building product with improved technological properties (flexibility, ability to take any shape) and increased strength and deformability, as well as the ability to be used for the manufacture of composite polymer products for reinforcing conventional and prestressed concrete structures.

Implementation of the invention.

Rope 1 can be processed into a reinforcement product on equipment for pultrusion production of composite reinforcement, additionally equipped with a torsion-winding machine. First, strands of roving are twisted into bundles (3) with a designed number of twists per meter of length, with simultaneous winding on coils or drums. Then the rope (1) is twisted from several strands (3) and a core (2), and the twisting around the core (2) is performed in the opposite direction from the twist of the strands. This ensures resistance to unraveling of the fiber part of the rope.

A combined metal fiber rope, twisted from at least three twisted strands of glass, basalt, carbon or synthetic fiber, characterized in that it includes a central straight metal core, around which the strands are wound with a calculated pitch, and the twisting around the core is made in the opposite direction from the twist bundles, the cross-sectional area of the metal core is from 2 to 25% of the total cross-sectional area of the rope.

At the next stage, the rope (1) is impregnated with a binder and heat treated using known pultrusion technology. Reinforcing products can be made from rope, for example, clamps for rectangular, square or round piles. To do this, impregnated ropes are wound onto forms and heat treated. For impregnation of reinforced frames or other large-sized products that do not fit into reinforcement production lines, cold-curing compounds should be used. Many polymer resins with high viscosity do not saturate finished ropes well. In this case, it is advisable to perform melt impregnation with modified sulfur, which is low-viscosity and does not require heat treatment.

The rope is distinguished by the fact that the core is made of rolled metal wire, the rope is twisted into 5-40 twists per linear meter, and each bundle is 10-60 twists in the opposite direction, impregnated with a polymer or sulfur binder.

In addition, the rope is given a curved shape before heat treatment.

An example of the design of combined metal-composite rope reinforcement for reinforcing a concrete product.

The reinforcing composite rope (1) consists of three fiberglass strands (3) and a steel core (2). The bundles are impregnated with a polymer binder. Let us consider the behavior of samples of rope reinforcement if they are subjected to tension in a tensile testing machine.

The sample is glass-composite polymer reinforcement, round cross-section, reinforced in the center with low-carbon wire. The mechanical properties of reinforcement components differ dramatically. The tensile strength of glass composite is up to three times higher than that of steel, while the modulus of elasticity of steel is approximately 4 times higher than that of glass composite. The glass-polymer composite is very brittle, and steel has a pronounced yield plateau. In fig. Figure 4 shows load-deformation graphs for a metal rod (curve A-A), for a glass composite rope (curve B-B) and for a combined element consisting of a glass composite rope with a metal wire core with a ratio of 3:1 (glass composite: metal ) (C-C curve). All samples are of the same cross-section.

In this option, as the tensile load increases, the elongation of the metal-glass-composite rod obeys the “mixture rule”; the elastic modulus in the initial load range is proportional to the volumetric ratio of the glass-composite and steel in the cross-section of the rod. When a certain stress level is reached (point E), such steel begins to “flow”, but does not collapse. After this, the contribution of the steel wire to the total resistance remains practically constant for some time; the steel continues to resist and take its part of the load until the elongation is 10-15%. At the same time, the resistance of the combined rope continues to remain close to its maximum value (point D) until an elongation of 7-8%.

Thus, when the yield limit of the metal core is exceeded, the rod continues to work with the formation of plastic deformations that are not characteristic of “pure” glass composite - the material acquires the property of “pseudo-plasticity”, i.e. with a significant increase in the ultimate strain at break.

The effect of reinforcing concrete structures with such steel is to eliminate the possibility of brittle fracture when the maximum deformation of the glass composite is exceeded. With certain combinations (glass composite: metal), such reinforcement can meet the requirements for reinforcement for construction in seismic areas, which distinguishes it from conventional glass composite reinforcement (Code of Rules SP 14.13330.2014 “SNiP II-7-81* Construction in seismic areas. ")

The technological effect additionally lies in the fact that a rope reinforced with plastic wire can be given any complex shape before or after impregnation with a binder (before heat treatment) and obtain reinforcement products of complex shapes for concrete structures.

Claims (5)

1. A combined metal fiber rope, twisted from at least three twisted bundles of glass, basalt, carbon or synthetic fiber, characterized in that it includes a central straight metal core, around which the bundles are wound with a calculated pitch, and the twist around the core is made in the opposite direction from twisting of bundles, the cross-sectional area of the metal core is from 2 to 25% of the total cross-sectional area of the rope. 2. The rope according to claim 1, characterized in that the core is made of flattened metal wire. 3. The rope according to claim 1, characterized in that the rope is twisted in 5-40 twists per linear meter, and each bundle is 10-60 twists in the opposite direction. 4. Rope according to paragraphs. 1-3, characterized in that the rope is impregnated with a polymer or sulfur binder. 5. The rope according to claim 4, characterized in that the rope is given a curved shape before heat treatment.