RU179075U1 - Flexible Concrete Slab Rope - Google Patents

Abstract

The utility model relates to the construction of engineering protection against the negative effects of water (hydraulic engineering). A flexible concrete slab consisting of concrete blocks (position 2) connected by a rope of a cable lay (position 4, 5). The rope is made of a combination thread, which includes polypropylene and polyethylene. During the operation of a flexible concrete slab in the section of the rope passing through the gap between the concrete blocks (position 4), under the influence of sunlight and oxygen (position 6) a polyethylene “crust” is formed, which protects the rope from further destruction. A useful model is aimed at increasing the term operation of a flexible concrete slab.

Description

The utility model relates to the construction of engineering protection to prevent the negative impact of water (hydraulic engineering).

Flexible concrete slab (GBP) is a set of concrete blocks interconnected by a flexible connection (AC 251463). Thus, in general terms, GBP is a structure containing the following essential features:

1. Concrete blocks, mainly two rectangular truncated pyramids having a common larger base, ensure the safety of the protected object;

2. A flexible connection, made mainly from a rope, cable or other flexible rod element (hereinafter referred to as the rope), which is monolithic in the body of each concrete block, ensures the connection of concrete blocks into a single structure.

The disadvantage of GBP during operation, for example, when protecting the coast, is the destruction of the rope under the influence of sunlight and oxygen (air).

In accordance with GOST 30055-93 “Ropes made of polymer materials and combined”, the country's industry produces artificial ropes from the following materials:

- polyamide;

- polypropylene;

- polyester.

Due to their technical characteristics, ropes are not made of polyethylene.

According to the set of mechanical characteristics in the production of GBP, the most commonly used polypropylene rope.

However, these materials have low resistance to sunlight and oxygen.

During the operation of polymeric materials under the influence of sunlight and oxygen, their gradual destruction occurs - destruction. This process proceeds with the breaking of bonds of the main macromolecular chain.

To reduce degradation, special substances (stabilizers) are added to the polymer (to polypropylene - almost always), for example, soot, for example carbon technical grade K354 (GOST 7885-86 “Technical carbon for rubber production”). However, the addition of stabilizers only slows down the destruction, and does not exclude it.

Conventionally, the rope in the GBP can be divided into two parts (Fig. 1).

One part of the rope (position 1) is monolithic in the body of the concrete block (position 2). This part of the rope is protected by a layer of concrete from exposure to sunlight and oxygen (position 3).

The other part of the rope (position 4) passes through the gap between adjacent concrete blocks. Despite the fact that the gap between adjacent blocks does not exceed 8-10 mm, sunlight and oxygen act on this section of the rope and lead to destruction of the rope material.

From a technical point of view, the destruction can be excluded, if before laying the rope is placed in a cover (braid) made of an elastic protective material that would protect the rope material (polypropylene) from exposure to sunlight and oxygen, then the destruction problem would be solved.

However, it is known (patent RU No. 121266) the effect of slipping under load from the body of a concrete block of a rope having a cover (braid).

Thus, a technical contradiction arises. If the rope is placed in a cover (braid), then the rope material (polypropylene) will be protected from sunlight and oxygen, but it will not be tightly fixed in the body of the concrete block.

If you use a rope of cable lay (do not use a protective cover), then the rope will be firmly fixed in the body of the concrete block, but will be exposed to sunlight and oxygen.

The objective of this utility model (technical result) is to change the design of flexible communications so that:

- on the material of the rope was not exposed to sunlight and oxygen, on the one hand;

- the rope retained its properties to be securely fixed in the body of the concrete block (to have a cable lay), on the other hand.

The solution to this problem is achieved by manufacturing a rope from threads made of low pressure polypropylene grade 21030 (GOST 26996-86 "Polypropylene and copolymers of propylene") coated with a substance that would protect the polypropylene threads from exposure to sunlight and oxygen.

In particular, low-pressure polyethylene (gas-phase) grade 276-73 (GOST 16338-85 “Low-pressure polyethylene”), which darkens and hardens, becomes brittle, can act as a polypropylene coating from exposure to sunlight and oxygen.

Melt of polyethylene and polypropylene are non-miscible liquids. With vigorous stirring, the melt of polyethylene and polypropylene forms an emulsion, that is, a dispersed system consisting of microscopic drops of liquid.

When mixing ceases over time, the emulsion delaminates and individual drops of polypropylene (polyethylene) stick together.

The adhesion of droplets in the emulsion can be significantly reduced by reducing the proportion of one liquid relative to another, for example, mixing molten polymers in a ratio of one to three to one to seven.

Based on the mechanical properties of the polymers (the strength of the future rope), it is advisable to take the melt of polypropylene (65-85 percent) as the basis, and add polyethylene to the melt in the amount of 15-35 percent. Figures are given without stabilizers, the volume of which can reach up to 5 percent.

The technological process for the manufacture of threads consists of the following stages.

The first stage - obtaining a melt of polypropylene (65-85 percent) and polyethylene (15-35 percent), thoroughly mixing it to form an emulsion.

The second stage is the passage of the polymer melt (emulsion) through the die, that is, metal caps with small holes. A polymer melt (emulsion) will pass through each of the holes of the die in a constant time regime.

The third stage is the hardening of the thread, consisting of polypropylene and polyethylene. Due to the small cross section of the thread, spontaneous peeling of the polyethylene part of the thread from the polypropylene part will not occur or peeling will be minimal. Thus, a combined thread is obtained.

Then, in the traditional way, a rope of the required diameter of a cable twist is weaved from combined threads (position 5).

HBP are produced according to traditional technology (pouring concrete into a forming tool with a tucked-in rope rope) with the difference that a rope is twisted from combined threads, that is, threads that include polypropylene and polyethylene.

Thus, the technical result is achieved by a combination of the following features of a utility model:

a) Limiting signs characterizing a flexible concrete slab (generic term):

- concrete blocks;

- flexible connection made of a rope of a cable twist.

b) Distinctive features aimed at achieving the claimed technical result:

- the implementation of the rope from the combined threads, which include polypropylene and polyethylene.

The rope of combined threads in the structure of the GBP works as follows.

Sun rays and oxygen (position 6) begin to act on the material of the rope (position 4), which is in the gap between the individual concrete blocks. Under the influence of sunlight and oxygen, the process of destruction of polypropylene, which is part of the combined threads, and located on the surface of the rope, begins. As a result of destruction, the polypropylene part of the threads is destroyed and weathered. On the surface of the rope, parts of the composite yarn consisting of polyethylene remain. Under the influence of sunlight and oxygen, the polyethylene part of the thread darkens and hardens. Over time, the process of destruction of polypropylene ceases, since a “crust” of darkened and hardened polyethylene filaments forms on the surface of the rope.

A “crust” of hardened polyethylene filaments on the outer surface of the rope can be relatively easily peeled off mechanically. However, the space between the concrete blocks makes it difficult to exfoliate under the influence of such natural factors as wind and abrasion by abrasive particles (sand, etc.) carried by the wind. Thus, the outer threads of hardened and darkened polyethylene reliably protect the inner threads of the rope from destruction.

The service life of a rope made of combined yarns is significantly extended, which allows you to meet the requirements for building materials for the construction of shore protection structures according to the criterion of "lifetime".

Claims (6)

1. A flexible concrete slab containing a plurality of concrete blocks interconnected by a rope of rope lay, characterized in that the rope is made of threads obtained from a melt of a mixture of polypropylene and polyethylene. 2. The flexible concrete slab according to claim 1, characterized in that the polymer ratio (excluding the stabilizer) is: polypropylene - from 65 to 85 percent; polyethylene - from 15 to 35 percent. 3. The flexible concrete slab according to claim 1 or 2, characterized in that the number of stabilizers can be up to 5 percent. 4. The flexible concrete slab according to claim 3, characterized in that soot (carbon) is used as a stabilizer.

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