RU2810345C1 - Composite element for reinforcement of ice structures - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: design and production of composite elements for reinforcing ice structures. A composite element for reinforcing ice structures contains a reinforcing component, which is a rope made of mineral fibers, and a binder - water cooled below freezing temperature. The reinforcing component is made with a metal core to allow electrical heating when it is removed from the ice.

EFFECT: increase in the strength and ductility of reinforced ice structures, as well as the possibility of manufacturing reinforcement products directly at the site of use.

1 cl, 4 dwg

Description

The present invention relates to construction, specifically to the design and production of composite elements for the reinforcement of ice crossings, winter roads, airfield runways, ice coverings of sports arenas, skating rinks and other ice structures, to the protection of water spaces from unpredictable disturbances of the ice surface.

An ice-soil composite is known (Vasiliev N.K., Shatalina I.N. Methods of ice reinforcement for creating ice and ice-soil composites // News of the All-Russian Scientific Research Institute of Hydraulic Engineering named after B.E. Vedeneev. 2011. T. 264. P. 119 -129). Dispersed reinforcement of ice with fiber, sawdust or sand allows you to increase the strength and deformation properties of ice several times. The disadvantages of the known material are the huge consumption of reinforcing material, since it is almost impossible to selectively reinforce only those areas of the ice mass where it is required by calculation; increased labor intensity of creating an ice-ground structure.

A composite fibrous material based on an ice matrix is known (Patent RU 2679726, IPC V32V 23/00, published 02/12/2019, Bulletin No. 5). A method for producing a composite material based on ice, including layer-by-layer freezing of layers of ice from water in molds, characterized in that layer-by-layer freezing of layers of ice is carried out at a temperature from minus 10 to minus 17 ° C, the thickness of the ice layer does not exceed 1.2 mm, the time interval between pouring does not exceed 30 minutes; in the process of freezing layers of ice, the resulting composite material is reinforced by laying at least two layers of a reinforcing component, which is used as RUSAR-S threads of 5 or 25 threads per layer, on the surface of the frozen layer with further pouring a new layer of ice.

The material is obtained by layer-by-layer freezing of layers of ice 1.2 mm thick with alternating layers of reinforcing fabric. Disadvantage: the method is not suitable for implementation in natural conditions of rivers, lakes, skating rinks, etc.

It is known to use fiberglass mesh for reinforcing ice Yakimenko O.V., Sirotyuk V.V. Strengthening ice crossings with geosynthetic materials (monograph. Omsk. SibADI, -2015. - 168 pp. URL: http://bek.sibadi.org/fulltext/ESD56.pdf/). Contents of work using a known method. After the formation of an ice coating of sufficient thickness for people and vehicles to work (at least 15 cm), ready-made fiberglass meshes are delivered to the site of the future crossing and laid out along the route. Then, layer by layer 1-2 cm thick, fill the surface of the ice with water and wait for it to freeze. The process is repeated until the calculated thickness of the ice coating is frozen.

The nets are laid on top of the ice covering and an additional layer of ice is frozen on top. Disadvantages of the known solution: complex technology of work with great dependence on weather changes; the need for warehouse space for storage in the summer.

Composite fiberglass reinforcement with a polymer binder is known (Stepanova V.F., Stepanov A.Yu., Zhirkov E.P. Composite polymer reinforcement: monograph. M.: ASV, 2013). The polymer binder, usually epoxy resin, is a fairly viscous material, so special equipment is required for high-quality impregnation of thin fiberglass strands and their subsequent connection before heat treatment into a single rope, i.e. into the future reinforcing bar. In this case, the consumption of the viscous binder reaches 25-30% in the volume of the rod due to the increased thickness of the binder film on the surface of each fiber, which is inevitable with the impregnation technology. Considering that the strength of a composite is determined primarily by the properties of the fiber, and the binder is a matrix and is necessary only for the formation of a single material, an excess amount of binder inevitably leads to a decrease in the specific strength and deformability of the composite.

The reinforcement is manufactured by heat treatment of a fiber tow, pre-impregnated with epoxy thermosetting resin, at a temperature of 180°C. The manufacturing process is energy-intensive, the reinforcement is quite fragile, and the maximum strain at break does not exceed 2%. Reinforcement and reinforcing cages and meshes are not adapted to shape changes; the thermosetting binder does not allow large-sized products to be disassembled for transportation, storage and reuse.

Composite fiberglass reinforcement with a sulfur thermoplastic binder is known (Patent RU 216986 U1, IPC E04C 5/07, publ. 03/13/23, Bulletin No. 8). The reinforcement is made by impregnating the fiber tow with a melt of sulfur binder at a temperature of 130-140°C. The process of manufacturing reinforcement is quite energy-intensive, the reinforcement is very fragile, cracks that form in the sulfur matrix during loading do not “heal”, which reduces the strength of the composite.

A general disadvantage of known fiber reinforcing materials is the impossibility of producing composite reinforcement directly on the construction site and the need for a factory process for producing a composite product from them.

Fiber ropes and rope reinforcement are known, obtained by impregnating them with a polymer binder (Patent RU 2482247 C2, IPC E04C 5/07, publ. 05/20/2013, Bulletin No. 34). A reinforcing element with a periodic surface, including interconnected strands of long mineral fibers, characterized in that it is made in the form of a rope woven from tape strands consisting of longitudinal fibers with a thickness of 5-50 microns, or threads of them, with a fiber density in the cross-section tow 2-20 thousand tex, tensile strength 0.6-2.0 GPa and cross-sectional area not more than 1.2 nA, where n is the number of strands, A is the cross-sectional area of one strand.

The disadvantage of the known rope composite reinforcement, adopted as a prototype, is its fragility; the absence of plastic properties necessary for the redistribution of forces between reinforcement elements. The production of composite polymer reinforcement is carried out in a factory and is impossible when used directly on site. Reinforcing frames and meshes are not suitable for processing for reuse or storage, and transportation of large-sized reinforcement products is expensive.

The technical result of the proposed invention is to expand the scope of application of composite reinforcement, for example, in ice structures, increase the strength and ductility of reinforced ice structures, as well as the possibility of repeated production of reinforcement products directly at the site of use.

The technical result is achieved due to the fact that in an ice-fiber composite element for reinforcing ice structures, including a reinforcing component and a binder, according to the proposed technical solution, the reinforcing component contains a braided or twisted rope made of at least two twisted strands of mineral fibers, and a binder - water or other aqueous solution (for example, starch), cooled below freezing point.

The reinforcing component in an ice-fiber composite element can be made in the form of a mesh of twisted or braided fiber ropes with a cell size from 0.5x0.5 to 5x5 m.

In addition, in the ice fiber composite element, the twisted or braided rope of the reinforcing component may contain a metal wire core to allow electrical heating when the reinforcing component is removed from the ice.

The volumetric weight of the ice fiber composite element is slightly greater than the volumetric weight of water. Therefore, to hold the rope and/or mesh at the calculated depth for positioning when freezing at the desired height of the ice cross-section, they are equipped with floats. Floats can perform a connecting role, combining ropes into meshes.

The contents of the utility model are illustrated by drawings, where in Fig. Fig. 1 shows a reinforcing component made in the form of a braided rope (a) with a metal wire core (b), Fig. 2 shows a plan for reinforcing the ice covering, Fig. 3 and 4 - sections along the ice surface.

Designations on the drawings:

1 - braided rope

2 - twisted tourniquets

3 - wire core

4 - float

5 - ice massif

6 - pond

7 - crack in the ice

The composite element is made from a twisted or braided fiber rope (1), which consists of several, at least two twisted strands (2) of mineral fibers (Figure 1). The rope (1) is made in factories from mineral roving and delivered to the site in the form of skeins or finished meshes (Figure 2). After impregnation with water or another aqueous solution (for example, starch), the rope (1) is frozen and turned into a composite element with an ice binder.

To ensure positive buoyancy, the rope (1) or a mesh of ropes (Fig. 2) is additionally equipped with floats (4).

The rope (1) can be additionally equipped with a metal wire core (3), which makes it possible to shape the rope and, if necessary, remove the reinforcing component from the ice mass (5) by heating the wire with an electric current.

Example No. 1 of the manufacture and use of an ice-fiber composite element. For the longest and safest use of winter ice crossings, the water spaces (6) of rivers or lakes must be prepared during the warm period. Along the route of the future crossing (or the territory of racing competitions, or places of amateur fishing, etc.), the water surface is equipped with a reinforcing component in the form of a mesh (Fig. 2) made of fiber or braided rope (1), equipped with floats (4) for buoyancy. The mesh is stretched over the surface of the reservoir (6) or part of it. The rope (1) is saturated with water due to capillary suction and, as it freezes, is included in the ice mass (5) as a reinforcing composite element. Reinforcement of the ice mass (5) eliminates or limits its splitting into individual ice floes, which is sometimes necessary for the safety of ice crossings. The ice matrix (binder) of the composite element, unlike polymer and sulfur, has the property of creep under load, which reduces the likelihood of brittle fracture. At the same time, the ice matrix of the composite element has the property of resolving, that is, self-healing of “own” cracks directly in the body of the rope.

During the period of ice drift, when the process of crushing the ice mass (5) into individual ice floes begins, reinforcement allows you to extend the time of safe operation of the crossing. After complete thawing of the ice binder, the ice fiber composite element turns into a fiber or braided rope (1) (Fig. 1) or mesh (Fig. 2). Fiber products are easily packed into containers and placed in minimally spaced warehouses until the next season.

Example No. 2 Placement of a reinforcing component at a shallow depth in a lake to ensure the integrity of the ice cover

When the water that has soaked the rope (1) freezes, its ice matrix is deformed similarly to the ice mass (5) in the surrounding water. As the air temperature drops further, ice, like all solid materials, begins to shrink. In this case, tensile stresses appear in the ice mass (5), which can lead to the formation of cracks (7). Reinforcing elements frozen into the ice act as reinforcement that absorbs tensile forces, increasing the crack resistance of the ice mass (5) (Fig. 4).

By adjusting the length of the float (4), it is possible to place ropes or nets at the required depth depending on the purpose of the ice cover and the expected thickness of the ice (Fig. 3)

Claims (1)

A composite element for reinforcing ice structures, including a reinforcing component and a binder, characterized in that the reinforcing component contains a rope made of mineral fibers, and water cooled below freezing temperature is used as a binder, while the reinforcing component is equipped with a metal wire core for the possibility of electrical heating when removing it from the ice.