RU2619607C1 - Propytic composition for protection of concrete on the basis of hexafluorosilicate of divalent metal - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: impregnating composition for protecting concrete comprises, by wt %: 5.0-26.0 divalent metal hexafluorosilicate; oxalic acid 3.0-5.0; surfactant 0.1-2.0; water the rest.

EFFECT: increase the depth of penetration of the impregnating composition in the treated concrete, reducing the viscosity of the impregnating composition, protection against the penetration of treated concrete chemicals and oil, reducing its peeling.

2 cl, 6 dwg

Description

The invention relates to the chemical industry, namely to impregnating compositions, and can be used to protect the surface layer of concrete, cement-concrete and asphalt concrete coatings.

Concrete structures during operation are subjected to numerous destructive influences, including cyclic freezing and thawing, dynamic loads, the effects of natural atmospheric phenomena, etc.

Due to this, in actively exploited concrete structures, for example, such as roads, significant surface defects will form in a year. In the future, if repair and restoration measures are not carried out, irreversible destructive processes develop in the surface layer of concrete structures, leading to intensive destruction.

To increase the efficiency of the content of concrete structures, preventive measures are taken to protect them from destruction.

Protection methods include such types of application of protective materials as hydrophobic impregnation and impregnation on an organo-polymer and cement-water basis.

Silanes and siloxanes can be used as hydrophobic impregnating compositions, which are of high cost and ineffective in conditions of salt corrosion of concrete.

Impregnation on an organo-polymer basis when applied to concrete penetrates into the pores and capillaries of the surface layers of concrete, followed by polymerization without direct chemical attack with the mortar part of the concrete. Therefore, it is possible to exfoliate the polymer film and further develop corrosion.

As a result of physicochemical interaction with cement stone, impregnating-clogging compositions form crystalline insoluble or poorly soluble neoplasms, clogging pores and capillaries, which is a promising method for protecting concrete structures.

The prior art "Impregnating composition based on a polymer based on the clogging action of ultra-cord to protect the surface layer of concrete, cement-concrete and asphalt concrete coatings" (see patent for invention RU 2516397 C1, published on 05/20/2014), which includes an oil-polymer resin , solvent, toluene and antioxidant. The main disadvantage of this impregnating composition is the difficulty of obtaining and the high cost of its components, and, as a consequence, the impregnating composition itself.

The prior art also known "Composition for hydrophobization of silicate building materials", taken as a prototype (see patent for the invention RU 2273623 C1, published 10.04.2006), which contains, by weight. %: sodium methylsiliconate 10-15, sodium hexafluorosilicate 0.8-1.2, phosphoric acid 0.2-0.25, talc 0.15-0.25, alumina 0.25-0.5, water - the rest . The specified composition has cheap starting components and is easy to prepare, however, it does not have high penetration depth and moisture protection, leads to poor frost resistance and compressive strength of the impregnated material. In addition, the composition has a high viscosity.

The well-known "Method for producing magnesium hexafluorosilicate" (see patent BY 7658 C1, published December 30, 2005) with a maximum yield of the target product.

The objective of the invention is the creation of an impregnating composition for concrete based on divalent metal hexafluorosilicate with an increased penetration depth of the impregnating composition into the treated concrete.

The invention provides the following technical results:

- increasing the penetration depth of the impregnating composition in the treated concrete;

- decrease in the viscosity of the impregnating composition;

- protection against penetration of chemicals and oils into the treated concrete, reducing its peeling.

The problem is solved in that the impregnating composition for protecting concrete, including an aqueous solution of divalent metal hexafluorosilicate, additionally contains oxalic acid and a surfactant in the following ratio, wt.%:

divalent metal hexafluorosilicate 5.0-26.0 oxalic acid 3.0-5.0 surface-active substance 0.1-2.0 water rest

OP-7, OP-10 can be used as a surfactant (see GOST 8433-81).

The specified composition with the described ratio of components allows to reduce the peeling of the treated concrete, to protect against penetration of chemicals and oils, as well as to increase the penetration depth of the impregnating composition into the treated concrete and reduce the viscosity of the impregnating composition.

Brief description of the figures:

In FIG. 1, 3 show the outer and inner surfaces of an untreated concrete sample;

In FIG. 2, 4 show the external and internal surfaces of a sample of concrete treated with an impregnating composition;

In FIG. Figures 5 and 6 show a radiographic image and its interpretation (visualization).

The impregnating composition is prepared as follows: dosed components, divalent metal hexafluorosilicate (magnesium hexafluorosilicate MgSiF ₆ , calcium CaSiF ₆ , zinc ZnSiF ₆ can be used as divalent metal hexafluorosilicate), oxalic acid ((COOH) ₂ ) and surfactant ( surfactants can be used OP-7, OP-10 according to GOST 8433-81) are loaded into a container with water with the stirrer turned on. The loading begins with divalent metal hexafluorosilicate, after which oxalic acid and surfactant are added sequentially. The mixture of the above components is mixed until smooth at a temperature of at least 19 ° C.

Impregnation Technology:

The treated surface is cleaned and dried, then, at a temperature of at least 14 ° C, an impregnating composition is applied to the treated surface, then the treated surface is aged without use for 24 hours, after which the quality of the impregnation is monitored.

In the course of experimental studies using the above technology, an impregnating composition consisting of, wt. %:

magnesium hexafluorosilicate - 24;

oxalic acid - 4.6;

OP-10 - 1.1;

water is the rest.

The depth of surface fluating of concrete depends on its density and structure of cement stone. Studies conducted on high-density concrete (SNiP 2.03.11-83) showed that the maximum impregnation depth is 7 mm.

In addition, the optical analysis of the microstructure of the samples revealed the following:

- the outer surface of the untreated sample (Fig. 1) has a uniform light yellow color, the air pores are completely open both on the outer surface and inside (slice - Fig. 3);

- on the surface of the treated sample (Fig. 2) there is a light coating, consisting of the products of the fluating reaction. The same products filled many air pores, including inside the sample (section - Fig. 4).

The distribution of the impregnating solution along the depth of the sample from the treated surface was analyzed according to x-ray and optical analysis — by luminescence in ultraviolet using double monochromatization. The photographs are shown in Figures 5 (where the white dots reflect the depth distribution of the fluid) and 6 (visualization of the depth distribution of the fluid).

Thus, the present invention allows to reduce the viscosity of the impregnating composition, to increase the depth of penetration of the impregnating composition into the surface to be treated, to reduce peeling of concrete, to provide protection against the penetration of chemicals and oils into the processed concrete.

Claims (3)

1. Impregnating composition for the protection of concrete, containing an aqueous solution of divalent metal hexafluorosilicate, characterized in that it further contains oxalic acid and a surfactant in the following ratio, wt.%: divalent metal hexafluorosilicate 5.0-26.0 oxalic acid 3.0-5.0 surface-active substance 0.1-2.0 water rest 2. An impregnating composition for protecting concrete according to claim 1, characterized in that OP-10 is used as a surfactant.

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