RU2791928C1 - Fibre concrete mix preparation method - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to construction, in particular to fibre concrete mix preparation method. A fibre concrete mix preparation method includes preparing an aqueous solution, which includes SiO₂ (pH>7), in advance and a protein-based foam concentrate. In the first stage, the fibre is hydrotreated in the aqueous solution. In the second stage, the dosed dry components, the aqueous solution and the fibre are mixed in a mixer after hydrotumbling.

EFFECT: invention provides possibility to increase the fibre concrete mixture fibre distribution uniformity.
1 cl, 3 dwg

Description

The invention relates to the field of construction and can be used in the manufacture of fiber-reinforced concrete products and structures, during repair work, as well as directly on the construction site.

There is a known method for the preparation of fiber-reinforced concrete mixtures in which, at the first stage, fine aggregate, water are dosed separately and fed into the mixer, and at the second stage, fiber and cement are introduced into the mixture prepared at the first stage together - in the form of finished dosed soluble fiber cement granules with a specific (given) content they have fibers. (RU, No. 2725054, В28С 5/40 (2006.01), 06/29/2020).

The disadvantage of this method is the increased complexity of the operation.

A known method of preparing a fiber-reinforced concrete mixture, including the supply of a mineral binder, fine aggregate, fiber, mixing water to the mixer, subsequent mixing until homogeneous and unloading (AS USSR 663586, class B28C 5/40, 1977).

The disadvantage of this method is the low homogeneity of the resulting mixture due to the formation of lumps in the process of mixing the components and the uneven distribution of fibers in the hardened fiber-reinforced concrete.

The closest technical solution is a method for preparing fiber-reinforced concrete mixtures, including the supply and forced mixing in two stages in the mixer of its components, at the first of which fine aggregate with non-metallic fiber in the form of mineral fiber is fed and forcibly mixed, and at the second stage into the mixture prepared at the first stage components, a mineral binder is introduced (AS USSR 1765018, class B28C 5/40, 1990).

The disadvantages of this method are the heterogeneity of the prepared fiber-reinforced concrete mixture due to the formation of lumps in the process of mixing the components, the uneven distribution of fibers in the hardened fiber-reinforced concrete, as well as increased energy and labor costs.

The objective of the present invention is to develop a more efficient method for the preparation of fiber-reinforced concrete mixtures by simplifying the method of introducing fiber and improving the structure of the resulting fiber-reinforced concrete mixture, without clumping and with a uniform distribution of fibers in the volume of hardened fiber-reinforced concrete, as well as reducing energy and labor costs.

The technical result of the invention is to increase the efficiency of the preparation of fiber-reinforced concrete by reducing the energy and labor costs of the process of preparing the fiber-reinforced concrete mixture, reducing clumping and increasing the uniformity of fiber distribution in the fiber-reinforced concrete mixture and in the hardened fiber-reinforced concrete.

The task is achieved by the fact that the method of preparing a fiber-reinforced concrete mixture includes two stages:

1. At the first stage, hydrofluffing (uniform distribution of bundles into individual fibers) of the dosed fiber in an aqueous solution is performed.

2. At the second stage, mixing of the dosed dry components, the specified aqueous solution and fibers after hydrofluffing is carried out in the mixer.

The introduction of fiber into the fiber-reinforced concrete mixture after hydrofluffing allows, firstly, to evenly distribute the fiber without the formation of lumps, secondly, to avoid the appearance of bundles of undistributed fiber in the hardened fiber-reinforced concrete and, thirdly, to reduce energy and labor costs of the process of preparing the fiber-reinforced concrete mixture.

The method is implemented as follows.

Preparation of an aqueous solution for hydrofluffing dosed fiber, which includes a SiO ₂ sol (pH> 7) and a protein-based foam concentrate in a ratio of 1: 0.003: 0.003 (water : sol : foam concentrate). The ratio of aqueous solution to fiber is 1:0.044 (aqueous solution:fiber). Hydrofluffing is done within 5 minutes. After preparation of the aqueous solution, the batched dry components (binders, fillers, necessary additives), the specified aqueous solution and fibers after hydrofluffing are mixed in the mixer.

The proposed method for preparing a fiber-reinforced concrete mixture by the method of preliminary hydrofluffing of the fiber (uniform distribution of bundles on individual fiber fibers) in an aqueous solution can be implemented more efficiently than in known technologies, since the proposed technology provides the possibility of better obtaining a finished fiber-reinforced concrete mixture and uniform distribution of fibers in the hardened fiber-reinforced concrete, due to the fact that the SiO ₂ Sol together with the foam concentrate contribute to the increase in the hydrophilicity of the fiber.

Thus, a method for preparing a fiber-reinforced concrete mixture has been developed, the effectiveness of which consists of the following factors:

- refusal from mechanical operations for the introduction of fiber due to preliminary soaking in an aqueous solution;

- refusal to use energy-intensive high-speed mixers;

- the possibility of using a simplified technology for the rapid preparation of a fiber-reinforced concrete mixture, due to the use of hydrofluff in the specified aqueous solution with the inclusion of SiO ₂ sol (pH> 7) and protein-based foam concentrate;

- the possibility of achieving a higher uniformity of the fiber-reinforced concrete mixture, by reducing the clumping during mixing and increasing the uniformity of the distribution of the fiber in the hardened fiber-reinforced concrete.

To substantiate the performance of the proposed technical solution - a method for obtaining a fiber-reinforced concrete mixture of increased efficiency, the following laboratory tests were performed.

The method was tested using basalt fiber brand BS17-12.7(1/2") r-KV-13 with a fiber length of 12 mm. (Produced by Kamenny Vek LLC, Moscow region) in a fibrous concrete mixture. following sequence:

1. The water-cement ratio was set to 0.45;

2. Preparation of an aqueous solution followed by hydrofluffing of the fiber. The aqueous solution includes SiO ₂ sol (pH>7), "KS-K", pH>7 (Produced by SITEK LLC, St. Petersburg) and Foamcem protein-based foam concentrate (Laston SPA) in ratio 1:0.003:0.003 (water : sol : foam concentrate). The ratio of aqueous solution to fiber is 1:0.044 (aqueous solution:fiber). Fiber hydroflux was carried out for 5 minutes.

3. After preparation of the aqueous solution, mixing of dosed dry components (binders, fillers, necessary additives), the specified aqueous solution and fibers after hydrofluffing is carried out in a mixer.

It was noted that the fiber after hydrofluffing is well distributed in the fiber-reinforced concrete mixture, in which there is no clumping, (Fig. 1) and as a result, the uniformity of the distribution of the fiber in the hardened fiber-reinforced concrete (Fig. 2, 3) increases.

Taking into account the obtained positive test results of the method for obtaining a fiber-reinforced concrete mixture of increased efficiency due to the use of fiber fiber hydrofluff in the specified aqueous solution, the following results were obtained:

1. Simplified method of introducing fiber.

2. Improved the structure of the resulting fiber-reinforced concrete mixture, without clumping (Fig. 1)

3. The fiber is evenly distributed in the volume of fiber-reinforced concrete after hardening (Fig. 2). Fiber-reinforced concrete with an undistributed fiber bundle (fiber without hydrofluff) after hardening is shown in Fig. 3.

4. Reduced energy and labor costs by simplifying the process of preparing fiber-reinforced concrete mix.

Taking into account the obtained positive test results of the method for obtaining a fiber-reinforced concrete mixture of increased efficiency, due to the use of preliminary hydrofluffing of fiber in an aqueous solution, it can be concluded that the use of the proposed technology will allow to achieve a higher quality of fiber-reinforced concrete mixtures and hardened fiber-reinforced concrete and simplify the process of preparing a fiber-reinforced concrete mixture.

Claims (1)

A method for preparing a fiber-reinforced concrete mixture, characterized in that an aqueous solution is preliminarily prepared, which includes a SiO ₂ sol (pH> 7) and a protein-based foam concentrate in a ratio of 1: 0.003: 0.003 (water: sol: foam concentrate), then at the first stage the fiber is hydrofluffed in the specified aqueous solution at a ratio of the aqueous solution and the fiber 1:0.044, and at the second stage, the dosed dry components and the fiber are mixed in the mixer after the hydrofluff.

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