KR100502243B1 - Hardening composition for concrete and concrete surface treatment method - Google Patents

Abstract

The present invention relates to a composition used as a concrete inorganic hardening additive and a method for treating a concrete surface. In particular, in solidifying cement for recycling industrial waste, it is possible to significantly reduce the elution of harmful elements and to increase the internal strength of concrete. A composition for concrete inorganic hardening additives and a surface treatment method. The composition for the concrete inorganic hardening additive according to the present invention is sodium carbonate 5 to 15% by weight; 2 to 8% by weight potassium chloride; 2 to 6 weight percent of ammonium chloride; Borax 0.1 to 4 weight percent; And 90.9 to 77% by weight of distilled water, and the concrete treatment method according to the present invention includes 40 to 60% by weight of sodium silicate (Na ₂ O · 3SiO ₂ ), silicon or fluorine on the surface of the solidified concrete structure. Uniformly applying a composition consisting of 0.05 to 1.0 wt% surfactant and 39.0 to 59.95 wt% distilled water; And uniformly applying nitric acid, sulfuric acid or citric acid to the surface to which the composition is applied.

Description

Composition for concrete inorganic hardening additives and concrete surface treatment method {HARDENING COMPOSITION FOR CONCRETE AND CONCRETE SURFACE TREATMENT METHOD}

The present invention relates to a composition used as a concrete inorganic hardening additive and a method for treating a concrete surface. In particular, in solidifying cement for recycling industrial waste, it is possible to significantly reduce the elution of harmful elements and to increase the internal strength of concrete. The present invention relates to a composition for hardening concrete and a surface treatment method.

Recently, with the development of the industry, the generation of various wastes is rapidly increasing, which has a serious impact on environmental pollution. Industrial waste generated during the manufacturing process of various products can be treated by incineration, but most of the inorganic industrial waste is disposed of. The treatment by landfill is difficult to secure landfill and even if it is landfilled, secondary soil pollution is a problem. In addition, the treatment by incineration has emerged as a serious problem due to the emission of toxic substances such as dioxin, which causes the destruction of environmental hormones, especially environmental hormones.

In particular, when landfills of household waste and industrial wastes are landfilled without any treatment, the landfills are treated by vinyl sheet lining (polyethylene sheet lining) and earth lining (low viscosity, bentonite). Although they were landfilled, their construction method had various problems in preventing the construction of the pulp and required excessive facility expenses. In other words, although the vinyl sheet lining method and the earth lining method are generally used in practical use, problems remain in precision construction. Not only can it be installed on soft ground such as coastal landfills, but also after the construction, it can't withstand the load of landfills such as household waste and various industrial wastes, and the sheet tends to be damaged, especially various damages included in the landfill. Harm generated by the decay of various wastes by forming holes by sharp metal fragments, sharp stone debris, etc. causes damage to the sheet, which causes a problem.

In order to reduce environmental problems and economic losses caused by landfill and incineration, wastes from industrial sites are recycled. In particular, industrial wastes are incinerated and used as cement admixtures or sand substitutes.

In general, cement solidification is most commonly used to recycle industrial waste. The purpose of cement solidification is to decontaminate heavy metals contained in hazardous wastes so as not to contaminate groundwater or soil through the medium (e.g. water) in the environment, or to change them into forms that are difficult to dissolve. In the case of oxidative waste, the harmful substances contained are solidified or eluted to the outside when used as a concrete inorganic additive, and in some cases, many harmful damages to the human body are caused by the food chain because certain eluted substances generate secondary pollutants. Will be given.

Concrete structures should contain essentially cement and sand. The sand used at this time is commonly used river sand containing less chlorine ions, but in some cases sea sand is used. In case of using sea sand, the water should be washed several times with less chlorine ions.In order to reduce the cost, the concrete structure is built without washing the sand with large amount of chlorine ions to accelerate the deterioration and damage of the concrete structure. Let's do it.

More specifically, cement or concrete has a very low tensile strength but a very high compressive strength. Therefore, reinforcing bars are inserted to increase the tensile strength. Make a compound called ferric iron. This can be interpreted as the melting of iron, which is a metal, and the strength of the reinforcing bar is weakened, which increases the probability of collapse of the building structure. In order to prevent this, the construction regulations and many studies have been made, but the results are still insufficient.

When recycling wastes from industrial sites using solid cement additives, asphalt-based resins, silicone oils, urethanes as polymers, chloroprene rubber latex, Polyvinyl alcohol, polyvinyl acetic acid, and organic acids are emulsified and mixed and used for water repellent effect for waterproofing, ie prevention of elution of harmful substances and immobilization of chlorine ions. However, because these materials are organic materials, they not only reduce the strength of the cement but also create a non-uniform phase due to specific gravity during the mixing process.

As described above, in the conventional method, it is difficult to prevent the elution of harmful substances contained in the inorganic oxide to be recycled after disposal while maintaining high strength, and to make chlorine immobilization difficult, and there is a demand for a method to solve such problems. .

In order to solve the above problems, the present invention increases the strength of building structures by suppressing the elution of harmful substances by the external environment and inhibiting the corrosion of sand and reinforcing bars containing a large amount of chlorine ions, thereby developing the national economy. And it is an object of the present invention to provide a concrete surface treatment method and a concrete inorganic hardening additive used therein, which can improve the quality of the environment.

In order to solve the problems as described above, the inventors of the present invention, in order to solve the technical problem of the present invention, as a result of intensive inorganic hardening that can maintain a high strength while suppressing the corrosion of sand and reinforcing bar containing a large amount of chlorine ions The present invention has been completed by focusing on coating an cement surface with an additive and a silica sol capable of preventing the neutralization of cement such as acid rain.

The present invention is 5 to 15% by weight sodium carbonate; 2 to 8% by weight potassium chloride; 2 to 6 weight percent of ammonium chloride; Borax 0.1 to 4 weight percent; And preparing a concrete structure by mixing the composition for the concrete inorganic hardener additive consisting of 90.9 to 77% by weight of distilled water; On the surface of the prepared concrete structure, a composition comprising 40 to 60% by weight of sodium silicate (Na ₂ O ₃ SiO ₂ ), 0.05 to 1.0% by weight of a surfactant containing a silicon or fluorine component, and 39.0 to 59.95% by weight of distilled water To apply; And it provides a concrete manufacturing method comprising the step of applying an acid (acid) on the surface to which the composition is applied.

The invention also relates to 5 to 15% by weight sodium carbonate; 2 to 8% by weight potassium chloride; 2 to 6 weight percent of ammonium chloride; Borax 0.1 to 4 weight percent; And 90.9 to 77% by weight of distilled water. Sodium carbonate, potassium chloride, ammonium chloride and borax in the present invention are components used to cure concrete minerals. If the composition ratio of each component in the composition does not reach the lower limit, the effect is not properly exhibited, and if the amount exceeds the upper limit, there is a risk that alkali aggregate reaction of concrete occurs by alkali metal. Alkali aggregate reaction is a phenomenon in which concrete expands and destroys the structure of concrete, and in the composition according to the present invention, the composition ratio of components is determined by experiment to determine a range in which a hardening effect can occur best without such a reaction. .

In addition, the present invention consists of 40 to 60% by weight of sodium silicate (Na ₂ O ₃ SiO ₂ ), 0.05 to 1.0% by weight of surfactant containing silicon or fluorine component and 39.0 to 59.95% by weight of distilled water on the surface of the solidified concrete structure Uniformly applying the composition; And applying an acid to the surface to which the composition is applied. It provides a concrete surface treatment method comprising a. Here, the composition to be applied on the surface of the concrete structure consists of sodium silicate, surfactant, and distilled water. Sodium silicate penetrates into the concrete and reacts with the concrete hydration product to condense concrete structures or fix harmful substances. If the amount of sodium silicate is too small, the effect is lowered. If the amount of sodium silicate is too large, it is difficult to expect a large effect increase.

In addition, among the types of surfactants, the most effective in the case of a surfactant containing a silicone or fluorine component, if the amount of the surfactant is too small, the performance of the composition penetrates into the concrete deterioration, the amount of the surfactant If too much, there is no economy, the surface tension is increased, the effect is rather deteriorated. When less than 0.05% by weight, the effect of the addition did not appear much, it was shown that the effect up to 1.0% by weight. Also, considering both economic and effect aspects, 0.1 wt% is the optimum content.

Hereinafter, the present invention will be described in more detail.

The inventors of the present invention suggest that when recycling industrial wastes and household wastes, the concrete surface treatment method capable of forming silicon-gel (Si-gel) on the surface of the solidified cement structure and the additive for the inorganic hardener according to the present invention, It was confirmed that the strength in the structure was kept high, and the effect was excellent in preventing elution of environmentally harmful substances and immobilization of chlorine ions.

In particular, when the additive composition according to the present invention is used, the reactivity between chlorine ions and reinforcing bars in cement and concrete structures is remarkably reduced, and the strength of cement by neutralizing concrete structures under acidic and neutral conditions in the external air and water environments. The weakening can be prevented, and the surface of the concrete according to the present invention is uniformly sprayed with a composition containing a surfactant containing sodium silicate and a silicon or fluorine component on the concrete surface, and then the silicon-gel by inorganic and organic acids ( As a method of coating so that Si-gel) can be formed, it was confirmed that harmful metal ions can be effectively prevented from being eluted, and also excellent in fixing chlorine ions.

The inorganic hardening additive which concerns on this invention may be used with an admixture as alkaline solution, and may be used independently.

In addition, the concrete surface treatment method according to the present invention is uniformly sprayed with a composition comprising a sodium silicate (Na ₂ SiO ₃ ) and a surfactant containing a silicon or fluorine component on the surface of the solidified concrete structure, the acid To form silica gel. In this case, the acid to be used may be any organic acid such as citric acid, or an inorganic acid such as nitric acid or sulfuric acid, but it is preferable not to use hydrochloric acid.

Hereinafter, the effect of the inorganic curing additive and the concrete surface treatment method according to the present invention will be described in more detail.

Inorganic curing agents used in the following examples were prepared by mixing and dissolving inorganic salts containing alkali metals, boron groups, nitrogen groups, halogen groups, iron and the like as conventional inorganic curing agents. Water glass was used by diluting more than 5 times that 35% of solid content in the domestic market. Acid was used as sulfuric acid and nitric acid for inorganic acid and citric acid for organic acid.

(Examples 1 to 3 and Comparative Example 1) Preparation and Mixing of Inorganic Curing Additives

An inorganic curing additive was prepared by mixing 5 to 15 wt% of sodium carbonate, 2 to 8 wt% of potassium chloride, 2 to 6 wt% of ammonium chloride, and 0.1 to 4 wt% of borax in distilled water 90.0 to 77 wt%. 2.5%, 5.0%, and 7.5% of the inorganic curing additives thus prepared were mixed with cement, respectively, and cement mortars corresponding to Examples 1 to 3 were prepared according to KS L 5105, which were examples 1, 2, and 3, respectively. .

A cement mortar prepared in the same manner as in Example was used as Comparative Example 1 except that no inorganic curing additive was added for comparison.

Experimental Example 1 Measurement of Compressive Strength and Flexural Strength

The cement mortars prepared according to Examples 1 to 3 and Comparative Example 1 were measured at 7, 14, and 28 days of age, respectively, and the results are shown in Table 1 below.

M / C ratio (%) Compressive strength (kgf / ㎠) Flexural strength (kgf / ㎠) 7 days 14 days 28 days 7 days 14 days 28 days Example 1 2.5 345 396 414 99 123 130 Example 2 5.0 366 411 419 121 171 170 Example 3 7.5 377 421 433 129 182 185 Comparative Example 1 0 313 357 365 65 80 83

M / C ratio: The ratio which mixed the composition for inorganic hardening additives with cement mortar

In the case of the cement mortar to which the inorganic hardening additive was added (Examples 1 to 3), it was found that the compressive strength and the bending strength were significantly increased compared to the cement mortar to which the inorganic hardening additive was not added (Comparative Example 1). As the amount of the inorganic hardening additive increased, it was confirmed that the strength of the cement increased.

Experimental Example 2 Immobilization Test of Chlorine Ion

In order to confirm the immobilization effect of chlorine ions, sodium chloride was added to the sand so that chlorine ions were exactly 500 ppm, and then dried at atmospheric pressure while uniformly mixing. A cement mortar was prepared in the same manner as in Example 2, 50 wt% of sodium silicate (Na ₂ O ₃ SiO ₂ ) on the surface of the solidified cement, 0.1 wt% of a surfactant containing a silicon or fluorine component, and 49.9 wt% of distilled water. The composition, consisting of%, was sprayed and the acid diluted directly to neutralize by spraying, followed by drying to form a silica sol-gel. At this time, when using nitric acid and sulfuric acid was used diluted 25 times, when using citric acid was used diluted 10 times. Extraction method of the chlorine ions mixed in the cement was performed according to ASTM C114, and compared based on the sample without the addition of chlorine ions. The analysis method was performed according to ASTM D512. Water glass was diluted 5 times with 35% solids sold in Korea, and acid was diluted 25 times with sulfuric acid and nitric acid in the case of inorganic acid and citric acid in the case of organic acid. It was used by diluting 10 times. The results are shown in Table 2 below.

Eluted Chlorine Ion (ppm) No treatment Chlorine ion content: 500ppm Silicone surfactant Fluorinated Surfactant H ₂ SO ₄ 78 101 103 HNO ₃ 107 108 Citric acid 98 99

Chlorine ion elution amount in the original sand sample without chlorine ions was 78ppm, and when the inventors added to the sand so that the content of chlorine ions is 500ppm, the amount of chlorine ions is 98 ~ 108ppm, trace amount of chlorine ion of about 20 ~ 30ppm It was confirmed that only further eluted. According to the present invention, it can be seen that the effect of immobilizing chlorine ions in cement is very excellent, which is due to the neutralization of concrete structures due to acid rain since the surface of cement is coated with silica (SiO ₂ ) inorganic oxide having strong acid resistance. Explain that it represents the fact that it can prevent collapse.

Experimental Example 3 Heavy Metal Dissolution Test

To confirm the dissolution of heavy metal ions, a 1,000 ppm stock solution for the atomic absorption spectrometer was added to the cement mortar so that the concentration in the solid state was 50 ppm. The target element in this experimental example was Cd, Cr, Cu, Pb, As, Hg, cement mortar was prepared as in Example 3. The dissolution test method of each element was carried out by the dissolution test method in the waste process test method, Cd, Cr, Cu, Pb of the analysis items by Perkin-Elmer 2380 Atomic Absorption Spectrophotometer, As, Hg is Perkin-Elmer 2380 Analysis was performed by Atomic Absorption Spectrophotometer and MHS-10 Mercury / Hydride System. The results are shown in Table 3 below.

CD Cr Cu Pb As Hg Concentration 50 ppm 50 ppm 50 ppm 50 ppm 50 ppm 50 ppm Elution concentration 1.2 ppm Not detected (0.1 ppm or less) Not detected (0.1 ppm or less) Not detected (0.5 ppm or less) 14 ppb 7.2 ppb

As a result of the experiment, it can be seen that in the cement mortar prepared according to the present invention, most heavy metals are not eluted or only very small concentrations are detected to have a very large effect on the prevention of heavy metal dissolution.

The concrete surface treatment method according to the present invention can obtain the effect of preventing heavy metal leaching and reinforcing the concrete structure according to the immobilization of chlorine ions even when used alone, but when used simultaneously with the composition for the inorganic hardening additive according to the present invention, You can get it.

According to the concrete manufacturing method according to the present invention, the strength of the cement is increased according to the use of the inorganic hardening additive, and the composition of sodium silicate and the surfactant is applied to the solidified cement surface, and then silicon-gelation is formed by acid. Accordingly, it is possible to significantly reduce the dissolution of harmful substances such as heavy metal-containing materials, and to increase the strength of concrete structures due to the excellent immobilization effect of chlorine ions, which can contribute to the production of solid and permanent building structures. Therefore, according to the present invention when recycling industrial waste, it can contribute to the creation of a clean and more comfortable environment free of secondary pollution, and can have a great effect, especially in the prevention of neutralization of concrete.

Claims (4)

delete Sodium carbonate 5-15 weight percent; 2 to 8% by weight potassium chloride; 2 to 6 weight percent of ammonium chloride; Borax 0.1 to 4 weight percent; And preparing a concrete structure by mixing the composition for the concrete inorganic hardener additive consisting of 90.9 to 77% by weight of distilled water; On the surface of the prepared concrete structure, a composition consisting of 40 to 60% by weight of sodium silicate (Na ₂ O ₃ SiO ₂ ), 0.05 to 1.0% by weight of a surfactant containing a silicon or fluorine component, and 39.0 to 59.95% by weight of distilled water is uniformly Applying; And Applying an acid to the surface to which the composition is applied; Concrete surface treatment method comprising a. The method of claim 2, The acid is characterized in that selected from nitric acid, sulfuric acid and citric acid How to Treat Concrete Surfaces. On the surface of the solidified concrete structure, a composition comprising 40 to 60% by weight of sodium silicate (Na ₂ O ₃ SiO ₂ ), 0.05 to 1.0% by weight of a surfactant containing a silicon or fluorine component, and 39.0 to 59.95% by weight of distilled water is uniform. To apply; And Uniformly applying an acid selected from nitric acid, sulfuric acid and citric acid to the surface to which the composition is applied; Concrete surface treatment method comprising a.