EA024383B1 - Method for treatment of building materials with polysulphide solutions - Google Patents

Abstract

The invention relates to a method for treatment of major building materials: concrete, foamed concrete, brick, roofing slate, etc., with water solutions of calcium and potassium polysulphides with addition of alcohols and surfactants. The invention can be used in civil engineering for increasing water resistance and durability of products made of inorganic porous materials such as concrete, foamed concrete, brick, limestone, gypsum, etc., and structures based on such materials used in conditions of exposure to weather effects and ground water. The impregnating composition contains calcium and potassium polysulphides, monobasic alcohol of normal structure or iso-structure, surfactants and water, contents of components being as follows, wt.%: x∙(CaS)+(1-x)∙(KS) - 20-40, alcohols - 2-5, surfactants - 0.1-0.5, water - the balance, where x is mass fraction of calcium polysulphides in polysulphide mixture that varies within a range of 0.1 to 0.9. Sulphanol or neonol are used as surfactants. Treatment is performed at atmospheric pressure and a temperature of 20-50°C by application with a brush, sputtering or immersion of specimens with consumption of the impregnating composition of 1.0-2.5 kg/mor by specimens immersion under rarefaction within 0.1-0.2 atm. at a temperature of 30-50°C during 0.5-1 h, consumption of the impregnating composition being 1-3 kg/m. The technical result is provision of a durable, stable in storage and efficient composition for treatment of building materials.

Description

The invention relates to a method for processing basic building materials: concrete, aerated concrete, brick, slate, and other sulfur-containing compositions based on aqueous solutions of calcium and potassium polysulfides and their mixtures, with the addition of alcohols and surface-active substances (surfactants), allowing deep impregnation of building materials at room and elevated temperatures, at atmospheric and reduced pressure, which leads to the formation in the pores of building materials of a hydrophobic mineral coating, consisting of fine particles of sulfur. The invention can be used in construction to improve the quality and durability of products of inorganic porous building materials: concrete, aerated concrete, brick, limestone, gypsum, as well as structures based on them, operated in atmospheric conditions.

It is known that one of the ways to increase the durability of concrete and other porous materials is to reduce its porosity. As methods that increase the density, methods of processing the hardening phase are used, for example, low-viscosity liquid monomers such as styrene, methacrylate and other polymerizable compositions, allowing to obtain concrete polymers [Pokrovsky N.S. Impregnating concrete waterproofing. - M .: Energy. 1964, 112 p.]. However, the use of these monomers as an impregnating composition and their wide distribution in the production of concrete and reinforced concrete products is largely hindered by their high cost and the complexity of the impregnation technology.

As a method of processing concrete, significantly improving its operational characteristics, sulfur melt impregnation is used [Paturoev VV, Volgushev AN Main characteristics of sulfur impregnated concrete. - M .: TsINIS Gosstroy of the USSR. - 1976 - 15 p.]. As a result of sulfur melt impregnation, the density and mechanical characteristics of concrete significantly increase, and water resistance, frost resistance and chemical resistance increase. However, the use of a sulfur melt means the use of relatively high temperatures (130-150 ° C) and an increase in energy costs. In addition, heating products to such temperatures can cause stresses in the material and lead to a decrease in strength. It should be noted that the process is sensitive to temperature fluctuations, since sulfur is liquid only in a certain temperature range. The high viscosity of the sulfur melt does not allow efficient processing at atmospheric pressure and requires preliminary evacuation of products in a sealed bath, which also significantly limits the widespread use of the method.

A known method of processing slate with a sulfur-containing solution in order to hydrophobize it [RF patent No. 2243191, class. С04В41 / 50, publ. 12/27/2004]. The method of hydrophobization of slate involves treating it with an aqueous solution of sodium polysulfide prepared from pre-crushed sulfur and an aqueous solution of sodium hydroxide by boiling until complete dissolution, followed by the introduction of polyalcohol as a stabilizer, cooling to room temperature and filtering, and processing the products from slate by immersion and keeping for 1-24 hours. An increase in water resistance of slate products is achieved. The coefficient of water absorption when processing slate with sodium polysulfide is reduced to values less than 0.5%. At the same time, the processing of other building materials with sodium polysulfide does not lead to a significant decrease in the coefficient of water absorption, and when treated with concrete it leads to the destruction of the latter.

Closest to the described in technical essence and the achieved result is a known method of processing building materials [RF patent No. 2416589, class. С04В41 / 45, publ. 04/20/2011] a composition containing calcium polysulfide and water, which additionally includes monohydric alcohols with the following content, wt.%: Calcium polysulfide 15-20, monohydric alcohols of normal or isostructure 0.02-0.05, water - the rest. The samples are processed at atmospheric pressure and room temperature by impregnation, immersion, spraying or brushing in the amount of 2-2.5 kg / m ² for 1-5 hours. The method is universal and suitable for processing all known building inorganic materials (concrete , aerated concrete, ceramic and silicate brick, gypsum, asbestos cement, etc.). Moreover, this method provides increased strength, frost and chemical resistance of building materials, a significant reduction in their water absorption, allows you to apply to structures and products in the same way as conventional paints and varnishes (brush, roller, spray, dipping). The known invention solves the technical problem of simplifying the method of processing building materials, reducing energy intensity and increasing processing efficiency.

However, the known processing method has disadvantages. Calcium polysulfide-based solutions are destroyed during long-term storage, so they must be stored in an airtight container and under a thin layer of oil or kerosene. In addition, varying the concentration of the solution based on calcium polysulfide in the range of 15-20 wt.% Does not give a noticeable improvement in the coefficient of water absorption. There are also disadvantages of the method in the processing of small-sized products - bricks, paving slabs, curbs, etc. When conventionally applied by brush to the surface of the products or dipping at atmospheric pressure, the composition penetrates to a depth of about 1 cm. In some cases, this is not enough, since to increase the service life building materials, it is necessary to increase the penetration depth of the protective solution into building products more than 1 cm.

- 1,024,383

The aim of the invention is the creation of a more stable and effective impregnating composition for the treatment of building materials.

The goal is achieved in the proposed method for processing building materials by impregnating with a composition containing calcium polysulfide, monohydric alcohols of normal or isostructure and water, characterized in that it uses a composition further comprising potassium polysulfide and surfactant, with the following components, wt.%:

x- (Ca5 ₄ ) + (1-x) - (K ₂ 8 ₃ ) 20-40, alcohols 2-5,

Surfactant 0.1-0.5, water the rest, where X is the mass fraction of the content of calcium polysulfide in the mixture of polysulfides, which varies in the range from 0.1 to 0.9; and the processing is carried out at atmospheric pressure and a temperature of 2050 ° C by applying with a brush, spraying and immersion of samples with a flow rate of the impregnating composition in an amount of 1.0-2.5 kg / m ² .

According to the second variant, the processing of the samples is carried out by impregnation with a composition containing calcium polysulfide, normal or isotropic monohydric alcohols, and water, characterized in that they use a composition additionally comprising potassium polysulfide and surfactant, with the following content of components, wt.% X- {Ca5 ₄ ) + (1-x) - (K ₂ 8h) 20-40, alcohols 2-5,

Surfactant OD-0.5, water is the rest, where x is the mass fraction of the content of calcium polysulfide in the mixture of polysulfides, which varies in the range from 0.1 to 0.9; and the processing is carried out for 0.5-1 h by immersion of the samples under vacuum within 0.1-0.2 atm. at a temperature of 30-50 ° C with a flow rate of the impregnating composition in an amount of 1-3 kg / m ² .

As surfactants use sulfanol or neonol.

The use of a mixture of polysulfides, as well as the expansion of the methods of application of the impregnating composition, can significantly improve the operational characteristics of building materials. It is proposed to use a mixture of calcium polysulfide and potassium polysulfide, alcohols and surfactants as an impregnating composition. An aqueous solution of potassium polysulfide is stable even after prolonged storage in a wide range of concentrations, up to 45 wt.% (Solution densities 1.45 g / cm ³ ). The introduction of potassium polysulfide in an aqueous solution of calcium polysulfide leads to a significant increase in the stability of the mixture of calcium polysulfides and potassium. Moreover, the introduction of potassium polysulfide provides an increase in sulfur content in a solution of a mixture of calcium and potassium polysulfides, the effectiveness of its use.

An increase in the efficiency of the process of impregnation of building materials is also achieved by processing small-sized products (bricks, paving slabs, curbs, pipes, etc.) by immersing the samples under vacuum within 0.1-0.2 atm. at a temperature of the impregnating composition of 30-50 ° C, which allows to increase the depth of penetration of the composition into the material. An increase in the penetration depth of building materials is also achieved by treating the products with an impregnating composition heated to 30-50 ° C. At elevated temperatures, the viscosity of polysulfide solutions decreases, and they penetrate to a greater depth, thereby providing lower values of the coefficient of water absorption of the samples. In addition, the products treated with heated solutions dry out faster, which also allows to increase the productivity of the process by reducing the processing time.

Thus, in the present invention, the technical problem of increasing the efficiency of processing building materials is solved by using a composition consisting of a mixture of aqueous solutions of calcium and potassium polysulfides, as well as using the treatment under vacuum at elevated temperatures.

When conducting experimental studies of the effectiveness of the proposed composition, Portland cements were used as binders: PC 500-DO and PC 400-D20 manufactured by AO Soda (Sterlitamak), satisfying the requirements of GOST 10178-85. Crushed stone (GOST 8267-93), gravel (GOST 8268-93), river quartz sand (GOST 8736-93) were used as aggregates for cement concrete and mortars. Mixing water for concrete and cementitious mixtures met the requirements of GOST 23732-79.

The experiments on the impregnation of samples of cement stone with a water-cement ratio (W / C) of 0.3 and a cement-sand mortar with a composition of 1: 3 at W / C = 0.5 were carried out on samples - cubes 2x2x2 cm ³ in size. Impregnated and tested samples hardening under normal conditions in

- 2 024383 for 23 days. Autoclaved aerated concrete of class B35, in the form of cubes 10x10x10 cm ³ in size, was used as samples of aerated concrete. Slate samples were flat squares measuring ¹⁰ x ¹⁰ cm ² .

The materials were impregnated by spraying, applying with a brush, as well as by immersion and exposure of the test samples at atmospheric pressure and room temperature, they were carried out as well as in the case of a close analogue for 1-5 hours. Based on the results obtained, the optimal consumption of the proposed composition was established, equal to 1.0-2.5 kg / m ² .

The impregnation of materials by immersion in conditions lowered to 0.2 from atmospheric pressure and at a temperature of 30-50 ° C was carried out for 30 minutes. Based on the test data, the consumption of the impregnating composition in the amount of 1-3 kg / m ^{2 was} determined, which ensures effective protection of materials.

The test results of the processing efficiency of the samples of the proposed composition are presented in table. 1-3.

Table 1. The dependence of the coefficient of water absorption of concrete on the ratio of the content of calcium and potassium polysulfides in the impregnating composition

Material samples Composition for processing building materials, mass. % The coefficient of water absorption,% Ca8 ₄ , K ₂ 5 ₃ , Ca5ch + K ₂ 8 ₃ , Surfactant alcohols X the control- ny impregnated ny concrete 0 35 35 0.3 4 0 8.5 4.3 concrete 3 32 35 0.3 4 0.08 8.4 4.3 concrete 5 thirty 35 0.3 4 0.14 8.2 4.1 concrete 10 35 45 0.3 4 0.22 8.6 3.8 concrete fifteen twenty 35 0.3 4 0.43 9.0 3,5 concrete 32 3 35 0.3 4 0.90 8.7 4.3 concrete nineteen one twenty 0.3 4 0.95 8.8 6.3

Table 2. The dependence of the coefficient of water absorption of concrete on the surfactant content in the impregnating composition (15% Ca8 ₄ + 20% K ₂ § ₃ )

Material samples Composition for processing building materials, wt.% The coefficient of water absorption,% Ca3 ₄ , K ₂ 8 _3> Ca8 ₄ + K ₂ 3s, Surfactant Alcohol, ethanol X the control- ny impregnated ny concrete fifteen twenty 35 0.05 4 0.43 8.8 3.9 concrete fifteen twenty 35 0.1 4 0.43 8.8 3,7 concrete fifteen twenty 35 0.2 4 0.43 8.9 3.6 concrete fifteen twenty 35 0.5 4 0.43 9.2 3.6 concrete fifteen twenty 35 0.6 4 0.43 9,4 3.9

Table 3. The dependence of the coefficient of water absorption of concrete on the alcohol content in the impregnating composition (15% Ca8 ₄ + 20% K ₂ § ₃ )

Material samples Composition for processing building materials, wt.% water absorption coefficient,% SaZd, K ₂ 3 ₃ , Sa8d + K ₂ s ₃ , Surfactant alcohols X the control- ny impregnated ny concrete fifteen twenty 35 0.3 one 0.43 8.8 4.1 concrete fifteen twenty 35 0.3 2 0.43 8.8 4.0 concrete fifteen twenty 35 0.3 4 0.43 8.9 3,5 concrete fifteen twenty 35 0.3 5 0.43 9.2 3.6 concrete fifteen twenty 35 0.3 6 0.43 9,4 3.8

Table 4. The dependence of the coefficient of water absorption of ceramic and silicate brick and aerated concrete, impregnated with a composition containing polysulfides of calcium and potassium, surfactants and alcohols

Material samples Composition for processing building materials, mass. % The coefficient of water absorption,% Ca8 ₄ , K ₂ 8 ₃ , Sa5d + k ₂ s ₃ , Surfactant alcohols X the control- ny impregnated ny brick, silicate fifteen twenty 35 0.3 4 0.43 9,4 4.3 brick, silicate 10 35 45 0.3 4 0.22 10.0 5,0 medium density aerated concrete ϋ500 fifteen twenty 35 0.3 5 0.43 39.2 8.4 medium density aerated concrete 0500 10 35 45 0.3 4 0.22 41.7 8.8 brick, ceramic i fifteen twenty 35 0.3 5 0.43 14.8 4.1 brick, ceramic i 10 35 45 0.3 4 0.22 15.3 4.2

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Table 5. The dependence of the coefficient of water absorption for samples of concrete, brick, autoclaved aerated concrete and gypsum, treated under various conditions with a composition containing 15% Ca8 ₄ + 20% K ₂ 8 ₃ (total content of polysulfides 35%, x = 0.43), 4 % alcohol, 0.3% surfactant

Sample Materials Sample Processing Conditions Immersion treatment at room temperature and atmospheric pressure Processing of samples by immersion at a vacuum of P = 0.1P, ™ at a temperature of 40 ° C Immersion processing of samples at atmospheric pressure and temperature 40 ° C Brushing samples at atmospheric pressure and temperature 20 ° C Sa§4 (close analogue) Proposed composition fine-grained cement concrete class B10 control 8.2 9.0 8.7 8.9 9.1 processed offers composition 6.3 3,5 1.8 3.2 5,4 ceramic brick brand M100 control 15.1 14.8 15.4 14.8 15,2 processed offers composition 9.7 4.1 3.6 4.3 7.8 silicate brick of the MIO brand control 9.6 9,4 9.6 9.7 9.5 processed offers composition 6.5 4.3 2.7 3.9 5.2 плотности500 grade aerated concrete control 38.8 39.2 39.5 39.0 38.9 processed offers composition 18.1 8.4 5,0 8.1 12.9 gypsum brand G-5 control 40,2 41.1 41.3 processed offers composition 20.5 8.7 - - 6.5

The choice of the range of x in the range from 0.1 to 0.9 means that in the formula unit almost any content of potassium polysulfide is possible, starting from 0.1 (or starting from 2 or 4 wt.%) In a mixture of polysulfides. In this case, potassium polysulfide begins to act as a stabilizer of the mixture during prolonged storage. A value of x greater than 0.9 means an excess of the content of potassium polysulfide above 36 wt.%, With a given content of the indicated component in the mixture of polysulfides, the processing efficiency decreases, and the composition also becomes more expensive (see Table 1-5). The use of a polysulfide content of less than 20 wt.% Reduces the processing efficiency due to a decrease in sulfur content, and an increase in the polysulfide content of more than 40 wt.% Leads to the precipitation of part of the polysulfides. The introduction of surfactants in the impregnating composition in an amount of less than 0.1 wt.% Does not reduce the surface tension of the solution and does not have a positive effect, and an increase in the content of surfactants above 0.5 wt.% Does not further increase the penetrating ability of the composition. The alcohol content in the impregnating composition of less than 2 wt.% Does not lead to a noticeable decrease in the surface tension of the solution and does not have a positive effect, and an increase in the alcohol content above 5 wt.% Does not lead to an increase in the penetrating ability of the composition, and also increases the cost of the solution (see table . 1-5).

When processing at atmospheric pressure by brushing, spraying and immersing the samples, the optimal temperature of the impregnating composition is 20-50 ° C. At temperatures in the indicated range, the viscosity of the solution decreases, and it penetrates deeper into the depths of building materials. An increase in the processing temperature above 50 ° C leads to too quick drying of the solution at the stage of drying the products and the deterioration of the properties of the impregnated samples of building materials.

When processing samples by immersion under vacuum, the optimal process conditions are a duration of 0.5-1 h, a vacuum value of 0.1-0.2 atm, and a temperature of 30-50 ° C. The choice of the temperature range is based on the fact that at 30 ° C and higher, a decrease in the viscosity of the composition begins, which allows to increase the penetration depth of the composition and, accordingly, increase the water resistance of the treated sample. An increase in temperature above 50 ° C, although it leads to a further decrease in viscosity, the composition evaporates too quickly during drying, which reduces the protective properties of the composition. When using rarefaction, atmospheric pressure decreases below 0.1 atm. does not provide the required value of the coefficient of water absorption. Using a vacuum of more than 0.2 atm. complicates the penetration of the composition deep into the samples. When using a vacuum of 0.1-0.2 atm. it is enough to process the samples for 0.5-1 hours. An increase in the processing time over 1 hour does not lead to a noticeable improvement in the water-repellent characteristics of the impregnated samples.

Thus, the selected ranges of indicators of the content of the components of the impregnating composition and the processing conditions for building materials are optimal, provide maximum efficiency of the impregnating composition and technical effect, thereby achieving the purpose of the invention.

The present invention can be used to improve the operational characteristics of concrete and reinforced concrete products, as well as other (aerated concrete, brick, slate, paving slabs) building materials. The processing method allows for repair and restoration work in the field, effective for long-term protection of structures from groundwater, as well as to increase the service life of structures operated in conditions of high humidity.

Claims (3)

CLAIM 1. The method of processing building materials by impregnation with a composition containing calcium polysulfide, monohydric alcohols of normal or isostructure and water, characterized in that they use a composition additionally comprising potassium polysulfide and surfactant, with the following components, wt.%: x- (Ca3 ₄ ) + (1-x) - (K ₂ 8 ₃ ) 20-40, alcohols 2-5, Surfactant 0.1-0.5, water the rest, where X is the mass fraction of the content of calcium polysulfide in the mixture of polysulfides, which varies in the range from 0.1 to 0.9; and the processing is carried out at atmospheric pressure and a temperature of 2050 ° C by applying with a brush, spraying and immersion of samples with a consumption of impregnating composition in an amount of 1.0-2.5 kg / m ² . 2. A method of processing building materials by impregnating with a composition containing calcium polysulfide, normal or isotropic monohydric alcohols, and water, characterized in that it uses a composition further comprising potassium polysulfide and surfactant, with the following components, wt.%: x- (Ca8 ₄ ) + (1-x) * (K ₂ 8h) 20-40, alcohols 2-5, Surfactant is 0.1-0.5, water is the rest, where x is the mass fraction of the content of calcium polysulfide in the mixture of polysulfides, which varies in the range from 0.1 to 0.9; and the processing is carried out for 0.5-1 hours by immersing the samples under vacuum within 0.1-0.2 atm at a temperature of 30-50 ° C with a flow rate of the impregnating composition in an amount of 1-3 kg / m ² . 3. The method of processing building materials according to claims 1 and 2, characterized in that sulfon or neonol is used as a surfactant.