RU223072U1 - COMBINED METAL FIBER COMPOSITE REINFORCEMENT - Google Patents

Abstract

The utility model relates to construction, specifically to the production of reinforcing products for reinforced concrete structures. The purpose of the utility model is to increase strength and reduce deformability by organizing the joint work of the composite core and metal winding; This increases the crack resistance of reinforced concrete products and reduces their fragility; reducing the metal consumption of the product by reducing the density of the double-sided wire braid; reduction in labor intensity due to the possibility of manufacturing on one pultrusion molding line. The technical result of the utility model is the creation of a building product with improved technological and operational properties with the possibility of being used for the manufacture of combined metal-fiber composite products with increased strength and deformability for reinforcing conventional and prestressed concrete structures that are economically competitive in the construction market. The problem is solved due to the fact that the known reinforcing rope, consisting of a straight-line power core of individual fiberglass rods and a continuous metal winding of several metal wires wrapping around the core in one direction, for the purpose of using non-tensioned concrete structures as reinforcement, is made in the form of a combined metal-composite rod, and the elements of the rod are impregnated and glued together during manufacture with a polymer or mineral binder and are used for reinforcing monolithic and prefabricated cement concrete, gypsum concrete, polymer concrete, asphalt concrete, sulfur concrete, soil cement and other structures. Metal winding is made in the form of double-sided wire braiding made of various types of steel and non-ferrous metal alloys with a high tensile modulus of elasticity. By adjusting the ratio of the material and the geometry of the braided wires, 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 main advantage of a combined metal-composite rod, compared to all known ones, is the manifestation of a synergistic effect of increasing the strength and ductility of a brittle composite material, for example, glass-polymer or carbon-polymer. An increase in the ultimate tensile strain of a glass-polymer composite rod occurs due to the “healing” of the resulting local breaks of individual fibers by the presence of a solid metal wire in this place. The increase in the strength of the combined metal-composite element is explained by the effect of transverse compression of the section by turns of wire, which occurs when the wire stocking is stretched on the surface of the rod.

Description

The utility model relates to construction, specifically to the production of reinforcing products for reinforced concrete structures.

Glass-composite reinforcement is known for reinforcing concrete structures (V.S. Plevkov, A.G. Tamrazyan, K.L. Kudyakov. 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. A circular cross-section is formed during the manufacture of reinforcement by wrapping it with fiberglass strand. Composite reinforcement has high tensile strength.

Disadvantages - low (compared to reinforcing steel) tensile modulus of elasticity and increased fragility (ultimate strain at break - no more than 2.5%). When testing tensile strength, the reinforcement is divided by longitudinal cracks into numerous fragments and crushed into pieces.

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). The surface relief of the rod is created by a winding harness. The power rod is made of glass fibers impregnated with a binder and applied to a steel core. In contrast to standard glass-composite reinforcement produced using pultrusion technology (V.S. Plevkov, A.G. Tamrazyan, K.L. Kudyakov. Strength and crack resistance of bending elements with prestressed glass-composite reinforcement. Tomsk, TGASU 2021), the reinforcement in question is more rigid tensile due to the higher (up to 3 times) elastic modulus of the metal core.

The disadvantage of the known solution: low strength (compared to a solid glass-composite rod), since fiberglass composites made of unidirectional fibers begin to collapse when stretched 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 shell material.

A combined metal-composite reinforcing rope is known, consisting of a fiberglass core and an external winding of metal wire (Patent RU No. 2569650 Reinforcing rope. Published: November 27, 2015 Bulletin No. 33), characterized in that the core is made in the form of a bundle of individual straight rods of circular cross-section made of low-modulus high-strength composite material. The rope is intended for reinforcing prestressed concrete structures. At the same time, continuous metal winding facilitates technological operations for fixing the rope during tension.

Disadvantages of the rope: low strength (compared to solid fiberglass or steel rope), since it is not possible to organize joint tensile work of elements of different lengths: straight ones made of fiberglass and spiral ones made of metal wire; increased metal consumption in continuous winding; the inability to effectively use non-prestressed concrete structures as reinforcement, since the elements of the reinforcing rope are not interconnected by a common matrix; The rope is quite labor-intensive and requires the use of several production lines during production.

What is known and is the closest in essence is a combined metal fiber rope (Application No. 2023119416 dated July 24, 2023), twisted from at least three twisted strands of glass, basalt, carbon or other synthetic fiber, which has a central metal core, and the core is made rectilinear, and the bundles are wound around it with a calculated pitch, and which is taken as a prototype of a utility model.

The disadvantage of this metal fiber rope is still insufficient strength when used as non-tensioned reinforcement and increased deformability.

The purpose of the utility model is to increase strength and reduce deformability by organizing the joint work of the composite core and metal winding; This increases the crack resistance of reinforced concrete products and reduces their fragility; reducing the metal consumption of the product by reducing the density of the double-sided wire braid; reduction in labor intensity due to the possibility of manufacturing on one pultrusion molding line.

The technical result of the utility model is the creation of a building product with improved technological and operational properties, with the possibility of being used for the manufacture of combined metal-fiber composite products with increased strength and deformability, for reinforcing conventional and prestressed concrete structures that are economically competitive in the construction market.

The problem is solved due to the fact that the well-known reinforcing rope (RU Patent No. 2569650 Reinforcing rope. Published: November 27, 2015 Bulletin No. 33), consisting of a straight power core of individual fiberglass rods and continuous metal winding of several metal wires entwined in in one direction, the core, for the purpose of using non-prestressed concrete structures as reinforcement, is made in the form of a combined metal-composite rod, and the elements of the rod are impregnated and glued together during manufacturing with a polymer or mineral binder and are used for reinforcing monolithic and prefabricated cement concrete, gypsum concrete, polymer concrete, asphalt concrete, sulfur concrete , soil-cement and other structures. Metal winding is made in the form of double-sided wire braiding 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 double-sided wire braid can vary from 2 to 5% of the total cross-sectional area of the rope, depending on the purpose of the reinforced product. At the same time, increased consumption of ductile metal increases the ultimate tensile strain, while increased consumption of mineral fiber increases tensile strength. By adjusting the ratio of the material and the geometry of the braided wires, 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 main advantage of a combined metal-composite rod, compared to all known ones, is the manifestation of a synergistic effect of increasing the strength and ductility of a brittle composite material, for example, glass-polymer or carbon-polymer. An increase in the ultimate tensile strain of a glass-polymer composite rod occurs due to the “healing” of the resulting local breaks of individual fibers by the presence of a solid metal wire in this place. The increase in the strength of the combined metal-composite element is explained by the effect of transverse compression of the section by turns of wire, which occurs when the wire stocking is stretched on the surface of the rod.

The contents of the utility model are explained

in fig. 1-3. Figure 1 shows the appearance of the combined metal-fiberglass rod;

Fig.2 - section A-A according to Fig.1

Fig. 3 is a load-deformation graph for a fiberglass reinforcing bar in combination with a metal double-sided wire braid and a core made of low-alloy hardening steel wire.

Legend in the figures:

1 - combined metal-composite reinforcement

2 - double-sided wire braid

3 - metal core

4 - composite rod

Reinforcement 1 consists of a composite rod 4, a metal double-sided wire braid 2 and a core 3. Reinforcement 1 is manufactured on equipment for pultrusion production of composite reinforcement (V.S. Plevkov, A.G. Tamrazyan, K.L. Kudyakov. Strength and crack resistance of bending elements with prestressed glass-composite reinforcement. Tomsk, TGASU 2021), and instead of a device for winding the forming tow of their glass fiber, drums with thin metal wire are placed to obtain braiding 2. The metal fiber reinforcement semi-finished product is impregnated with a binder and heat treated using well-known pultrusion technology / (V.S. Plevkov , A.G.Tamrazyan, K.L.Kudyakov. Strength and crack resistance of bending elements with prestressed glass-composite reinforcement. Tomsk, TGASU 2021). An additional metal core 3 of one or two wires is used for large diameter reinforcement (more than 12 mm). 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 less viscous and does not require heat treatment.

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

Let's consider a sample of reinforcement 1, which consists of a fiberglass rod 4, a double-sided wire braid 2 and a steel core 3. To determine the mechanical properties of the reinforcement, it is necessary to subject the sample to tension in a tensile testing machine.

The sample is a combined metal-glass-composite reinforcement reinforced with a metal double-sided wire braid around the perimeter and a low-carbon wire core in the center of the section. The properties of the reinforcement components differ quite significantly. The tensile strength of glass composite is up to three times higher than that of steel, while the elastic modulus of steel is approximately 4 times higher than that of glass composite. Fiberglass is very brittle, and steel has a pronounced yield point. In fig. For comparison, Fig. 3 shows the load-strain curves for a metal rod (curve A), for a glass composite rod (curve B) and for a combined element consisting of a fiberglass rod with a metal double-sided wire braid and a core with an area ratio of 4: 1 (glass composite : metal) curve C. All samples have the same cross-section. The fiberglass sample is the strongest and most fragile, breaking at an elongation of less than 3%. The metal sample is ductile and deforms to an elongation of more than 20%. As the tensile load increases, the metal-glass-composite rod obeys the “mixture rule”; the elastic modulus in the initial load range is proportional to the volume ratio of the glass-composite and steel in the cross-section of the rod. When a certain stress level is reached (point E), the steel of the wire elements (braid and core) 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 absorb its part of the load until an elongation of 10-20%. At the same time, the total resistance of the combined reinforcement continues to remain close to the maximum value for the glass-composite rod (point D) up to an elongation of 7-8%. Thus, when the yield limit of the metal double-sided wire braid and core is exceeded, the rod continues to work with the formation of plastic deformations that are unusual for a “pure” glass composite, i.e. the material acquires the property of “pseudoplasticity” with a significant increase in the ultimate strain at break.

The effect of reinforcement with such reinforcement 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" ).

Literature

1. V.S. Plevkov, A.G. Tamrazyan, K.L. Kudyakov. Strength and crack resistance of bending elements with prestressed glass-composite reinforcement. Tomsk, TGASU 2021.

2. Patent RU No. 120984 Composite glass-metal-plastic reinforcement. Published 10.10.2012 Bulletin. No. 28.

3. Patent RU No. 2569650 Reinforcing rope. Published: November 27, 2015 Bulletin. No. 33).

4. Application No. 2023119416 dated July 24, 2023.

5. GOST 13771-86 SCREW CYLINDRICAL COMPRESSION AND EXTENSION SPRINGS, CLASS II, FROM ROUND STEEL. Basic parameters of turns.

6. Code of rules SP 14.13330.2014 "SNiP II-7-81* Construction in seismic areas."

Claims (1)

Combined metal-fiber composite reinforcement, consisting of a glass-polymer or carbon-polymer composite rod, having a central metal core, characterized in that it has a metal double-sided wire braid along the surface.