KR101840470B1 - Grouting agent and method - Google Patents

Abstract

The present invention relates to an eco-friendly ground grout material eliminating the risk of heavy metal leaching and a ground grouting method using the same. More specifically, the eco-friendly ground grout material can utilize the bottom ash and fly ash discharged from a circulating fluidized bed boiler and a byproduct from a desulfurization process in a steel mill called sodium sulfate as a complex stimulant of alkali and sulfate salt to exercise the potential hydraulic properties of fine blast furnace slag powder. With respect to 100 parts by weight of the fine blast furnace slag powder, the ground grout material includes: 0.5-1,000 parts by weight of bottom ash from a circulating fluidized bed boiler having the CaO content of 15-70 wt% and SO_3 content of 3-30 wt%; 0.5-1,000 parts by weight of fly ash from a circulating fluidized bed boiler having the CaO content of 15-60 wt% and SO_3 content of 3-20 wt%; and 0.5-1,000 parts by weight of sodium sulfate, which is a byproduct from a desulfurization process in a steel mill, with the Na_2O content of 10-50 wt% and SO_3 content of 10-50 wt%.

Description

TECHNICAL FIELD [0001] The present invention relates to an eco-friendly ground grout material free from heavy metal leaching and a grouting method using the same.

The present invention relates to an eco-friendly ground grout material free from heavy metal leaching and a ground grouting method using the same. More particularly, the present invention relates to a bottom ash and fly ash discharged from a circulating fluidized bed boiler, Which is a byproduct of the desulfurization process, as an alkali and sulfate complex irritant, and a method for grouting the ground using the same.

During the use of civil engineering and architectural structures, it is often necessary to reinforce the foundation and reinforcements due to tunnel construction, expansion or remodeling, change of purpose, increase of load.

The grouting method is used as a method for improving the ground which is expected of these problems and as a means for eliminating the safety problems such as order and reinforcement in constructing any objects.

The chemical solution injection method at the time of grouting construction injects the filling material such as cement liquid into the soft ground by the pressure of the pump to fill the pores or cracks in the ground to prevent the water from flowing out or to harden the ground layer by hardening And a chemical solution such as a cement liquid, a mortar liquid or a water glass liquid is used as an injection material.

Therefore, the chemical solution injection method has a complex effect such as prevention of scarring by increasing the strength of the ground by injecting a solution liquid and a solution-type chemical solution, which originally has fluidity but can be solidified after a predetermined time, Is one of the improvement methods of the ground that expects.

Generally, cement is used as a main binder in grouting chemical injecting method. Cement can cause environmental pollution due to strong alkali and hexavalent chromium in the ground, and excessive volume shrinkage occurs during hydration reaction. In particular, cement must contain hexavalent chromium because the cement kiln has refractory clay bricks at the front of the low temperature furnace, and the temperature is high and the chemical reaction with the clinker of the abrasive and semi-molten state of the clinker And a mag-chrome brick containing magnesia and chromium is used for the part to be formed. In this process, chromium contained in the refractory bricks is known to be contained in the process of clinker formation.

Several techniques have been proposed to improve the problem of using such conventional cement as an injection material for grouting. For example, Korean Patent Registration No. 10-0699430 discloses a technique for reducing the occurrence of bleeding by adding cement to a grout (liquid A) containing bentonite, a dispersant and a retarder as an admixture, and aluminum sulfate as a coagulant, Bentonite and aluminum powder (liquid B) were added to the grout (liquid A) to give the inflatability by using the foaming effect due to the chemical action of the aluminum powder and the cement.

However, the bentonite presented in this technology is also a natural product that is not available in Korea, and it is an expensive product which is dependent on the whole import. Aluminum powder is a fine particle and light weight property, There is a fear that a problem of not being mixed with bentonite may occur when a suspension mixed with water is produced because the material is a material to be handled in a limited working space equipped with a dustproof facility even when it is used as a foaming agent in mortar and the like.

Further, in Korean Patent No. 10-0886220, a grout material (liquid A) is composed of a mixture of portland cement or portland cement and blast furnace slag cement, and the quick-setting liquid (liquid B) is prepared by mixing sodium silicate with an acidic chemical liquid Technology.

This technique is a technique to neutralize the acid solution mixed with acidic solution to lower the alkali of sodium silicate used as a quick-setting agent, but the mixing ratio of portland cement and blast furnace slag cement is not presented, and cement is the main material It is not different from the existing technology.

Korean Patent No. 10-0834923 also discloses a technique in which cement mortar is used as a grouting filler and mortar has a water mixing ratio of 65 to 70% and a slump of 5 to 8 cm. In general, cement mortar is used for various purposes such as plastering, wall laying, wall trowel, etc., and its composition varies depending on the type of mortar. The composition of the mortar used as grout material is not precisely shown, .

In Korean Patent No. 10-0804807, 35 to 65% of an acicular component, 15 to 30% of a calcium sulfoaluminate powder, and a calcium sulfate component are pulverized so that the aluminate is heat treated at 600 to 700 ° C to have a powder degree of 4,500 to 5,500 cm 2 / (A) composed of 5 to 15% of anhydrous gypsum, 5 to 15% of gypsum, 5 to 15% of loess powder, 3 to 10% of a reaction modifier and 0.3 to 1.0% of a surfactant, , And a microcement composition (B) composed of 30 to 50% slag fine powder.

The micro cement proposed by this technology generally means a product having a powder degree of 6,000 cm 2 / g or more. Although it is quite expensive, it is used as a material for filling microcracks in a chemical solution injection method in which only a crack part is injected without disturbing the paper sheet It is common. In addition, there are 7 kinds of raw materials in the case of the water - dispersible material (liquid A), so it is considered that there are many problems in manufacturing the product for practical use.

Also, in Korean Patent No. 10-1402877, it is described that 55 to 65 wt% of blast furnace slag fine powder, 10 to 20 wt% of F grade fly ash, 10 to 20 wt% of C grade fly ash having a calcium oxide content of 20% To 5% by weight of pulp slurry and 10 - 20% by weight of paper ash sludge incineration ash.

Also, Korean Patent Application No. 2016-1631467, which is a prior patent of the present applicant, discloses that the content of calcium oxide is 50 to 80% by weight based on 100 parts by weight of fine blast furnace slag having a specific surface area of 3,500 to 8,000 cm ² / g, 1 to 200 parts by weight of a desulfurization by-product generated in the combustion of petro coke having a sulfur oxide content of 10 to 40% by weight and a specific surface area of 2,000 to 8,000 cm ² / g, and 5 to 200 parts by weight of cement Is injected together with liquid sodium silicate.

These techniques are based on the theory of an alkali activated slag which activates the blast furnace slag fine powder by alkali and sulphate stimulation caused by gypsum generated as a byproduct of the desulfurization process which occurs during the combustion of Petro coke and uses a high calcium incineration as an expansion material Content. That is, the above-mentioned patents can be regarded as a technique for early stabilizing the ground by utilizing the strength development of the alkali activated slag and the expandability of the high calcium incineration ash.

However, some of the above technologies have not been commercialized due to reasons such as the complexity of the manufacturing process and the cost of expensive raw materials such as the use of more than five types of raw materials to be mixed or the use of expensive drugs as sulfite stimulants.

On the other hand, fly ash, which accounts for about 80% of the coal combustion by-products discharged from the pulverized combustion boiler of a thermal power plant, generates vitreous (amorphous) components when burned at a high temperature of about 1,350 ° C. The bottom ash, which is about 20% of the byproducts, is also used as cement and concrete raw materials. It also means coal ash that has fallen on the bottom of the boiler due to its own weight attached to the wall and the like during pulverized coal combustion. And is a porous material containing a large amount of vitreous. The pulverized coal boiler bottom ash has a particle size similar to that of fine aggregate and coarse aggregate for concrete, and is included in the structural lightweight aggregate of KS F 2534; it is estimated that it has enough lightweight and toughness to be used as structural lightweight aggregate And studies are being actively carried out to utilize these as aggregates. In recent years, studies have been actively carried out to induce geopolymer polymerization reaction by destroying the bottom ash glass film with a chemical such as sodium hydroxide after finely pulverizing the bottom ash of the pulverized coal boiler of the thermal power plant into ultrafine particles to physically activate it Is in progress. In this connection, the term " binder containing bottom ash " of Korean Patent No. 10-1339332, and " cementless concrete by a binder including bottom ash " of Japanese Patent Application No. 10-1410056 and No. 10-1366293 "blast furnace slag and bottom ash The present invention relates to a concrete composition comprising a cement mortar composed of a cement mortar composed of a cement mortar and a cement mortar and a method of producing the cement mortar. In Korean Patent No. 10-1312562 entitled " Binder composition for concrete containing bottom ash ", bottom ash is finely pulverized with a vibration mill at a rate of 6,000 to 8,000 cm ² / g to activate the particle surface, Respectively. All of these patents are intended to utilize a bottom ash of a pulverized coal-fired boiler of a thermal power plant.

On the other hand, coal combustion by-products discharged from the circulating fluidized-bed combustion of medium and small-sized cogeneration plant have low pozzolanic reactivity because the combustion temperature is low at about 850 ° C and no vitreous is formed. In the case of the circulating fluidized bed boiler fly ash, the content of CaO and SO ₃ was higher than that of fly ash from the pulverized coal boiler and the recycled content was insufficient due to insufficient SiO ₂ content. However, as the KS L 5405: 2016 fly ash standard was revised, And a recycling plan was prepared so that it can be mixed with some. However, the bottom ash of the circulating fluidized bed boiler is not as porous as that of the pulverized coal boiler bottom ash because it is very small and has a small particle size and is burned at a low temperature. Therefore, it is difficult to use as a lightweight aggregate like a pulverized coal boiler bottom ash, It is being processed. In addition, some recent research data on the bottom ash of pulverized coal bed boiler fly ash and thermal power plant pulverized coal boiler have been reported, but the data on the bottom ash of the circulating fluidized bed boiler has not been reported so far.

Korean Patent No. 10-0699430 Korean Patent No. 10-0886220 Korean Patent No. 10-0834923 Korean Patent No. 10-0804807 Korean Patent No. 10-1402877 Korean Patent Application No. 10-1631467 Korean Patent Registration No. 10-1339332 Korean Patent Registration No. 10-1410056 Korea Patent No. 10-1366293 Korean Patent Registration No. 10-1312562

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a method of manufacturing a cemented carbide- Which is the most widely used in the grouting work for soft ground reinforcement by utilizing hydroponics and activity as a stimulant of the blast furnace slag fine powder as a byproduct of the desulfurization process of the steel mill, and eco-friendly ground grout And a grouting method using the same.

In order to solve the above-mentioned technical problem, a circulating fluidized bed boiler having a CaO content of 15 to 70% by weight and an SO ₃ content of ₃ to 30% by weight with respect to 100 parts by weight of fine powdered blast furnace slag, 0.5 to 1,000 parts by weight of bottom ash, 0.5 to 1,000 parts by weight of a circulating fluidized bed boiler fly ash having a CaO content of 15 to 60% by weight and an SO ₃ content of 3 to 20% by weight, an Na ₂ O content of 10 to 50% _And 0.1 to 500 parts by weight of a manganese oxide produced as a by-product in a steel desulfurization process in which the content is 10 to 50% by weight.

The pulverized coal boiler fly ash may further comprise 0.5 to 400 parts by weight of pulverized coal boiler fly ash per 100 parts by weight of the blast furnace slag fine powder, and the pulverized coal boiler fly ash has a SiO ₂ content of 35 to 60% by weight and a CaO content of 0.5 to 10% And the SO ₃ content is 0.1 to 3% by weight, and is discharged from the pulverized coal-fired boiler dust collecting facility of the thermal power plant.

The gypsum may further contain 0.5 to 400 parts by weight of gypsum based on 100 parts by weight of the blast furnace slag fine powder, and the gypsum may further comprise any one or a mixture of two or more of natural anhydrous gypsum, petroleum coke desulfurized gypsum, have.

The cement may further comprise 0.5 to 200 parts by weight of cement based on 100 parts by weight of the blast furnace slag fine powder. The cement may be selected from the group consisting of first cement, third cement, CSA (Calcium Sulfur Aluminate), blast furnace slag cement and fly ash cement And may further comprise one or a mixture of two or more.

Further, 0.01 to 20 parts by weight of a liquid and powder type fluidizing agent may be added to 100 parts by weight of the blast furnace slag fine powder in order to improve fluidity.

In order to prevent underwater separation, 0.01 to 20 parts by weight of a water-insoluble agent may be further added to 100 parts by weight of the blast furnace slag fine powder.

Further, 0.01 to 20 parts by weight of a foaming agent or foaming agent may be added to 100 parts by weight of the blast furnace slag fine powder to form pores.

Also, the eco-friendly grout grouting method using the grout material according to the present invention is characterized by comprising the steps of: 1) preparing a ground grout material including a blast furnace slag fine powder, a fluidized bed boiler bottom ash, a fluidized bed boiler fly ash, and a gravel; 2) mixing 50 to 300 parts by weight of water with respect to 100 parts by weight of the grout material to prepare a slurry; 3) injecting the slurry prepared above to fill the gap or mix with the gravel; 4) curing the filled slurry and the mixed soil.

According to the present invention, in order to replace one kind of ordinary cement which is most widely used in soft ground grouting, bottom ash and fly ash discharged from a circulating fluidized bed boiler and manganese as a by-product of a steel desulfurization process are used as a stimulant for blast furnace slag fine powder It is possible to provide an eco-friendly ground grout material free from leaching of heavy metals and a ground grouting method using the same by replacing one kind of ordinary cement which is most widely used in soft ground grouting work by improving hydration reaction and activity.

Hereinafter, an eco-friendly ground grout material free from heavy metal leaching and a ground grouting method using the same will be described in detail.

The eco-friendly ground graft material according to the present invention is characterized in that it comprises a circulating fluidized bed boiler having a CaO content of 15 to 70% by weight and an SO ₃ content of ₃ to 30% by weight based on 100 parts by weight of the granulated blast furnace slag fine powder, 0.5 to 1,000 parts by weight of bottom ash, 0.5 to 1,000 parts by weight of a circulating fluidized bed boiler fly ash having a CaO content of 15 to 60% by weight and an SO ₃ content of 3 to 20% by weight, an Na ₂ O content of 10 to 50% _And 0.1 to 500 parts by weight of a manganese oxide produced as a by-product in a steel desulfurization process in which the content is 10 to 50% by weight.

The blast furnace slag is a by-product obtained by quenching slag in a high-temperature molten state generated as a by-product in a steelmaking blast furnace process with water. The blast furnace slag fine powder is called a latent hydraulic material because the amorphous coating is formed when it comes into contact with water and the hydration reaction does not occur by itself. The amorphous film must be destroyed in order for the latent hydraulic properties to be exhibited. The blast furnace slag fine powder can be used if it is a commercially available product having a specific surface area of 3,000 cm ² / g or more.

The circulating fluidized bed boiler bottom ash is generated in a circulating fluidized bed boiler using coal as the main fuel and in the lower part of the boiler in a manner of desulfurizing in the furnace together with limestone. In the desulfurization process of the circulating fluidized bed boiler, limestone is injected into the combustion chamber and burned together with the fuel, so that sulfur oxide and limestone in the combustion gas react in the furnace to remove sulfur in the combustion gas and produce anhydrous gypsum. It is carbonated and transferred to the quicklime component and discharged. Particularly, circulating fluidized-bed boiler bottom ash is burned at a temperature of about 850 ° C, and thus can not cause a pozzolanic reaction because there is no vitreous component. However, the CaO and CaSO ₄ components are higher than fly ash collected at the top, It can be said that it has a more excellent composition as a stimulant for fine powders. Therefore, it is a strong alkali substance having a pH of 11.5 or more and has a property of acting as a stimulant when used in the same manner as the blast furnace slag fine powder.

When water is added to ordinary blast furnace slag fine powder, an amorphous film is formed on the surface, and the internal Ca ²⁺ , Al ^{3 +,} etc. are not eluted. However, when water is introduced after mixing the circulating fluidized bed boiler bottom ash, the CaO component contained in the bottom ash reacts with water to convert it into Ca (OH) ₂ , resulting in OH ^- and SO ₄ ^{2 - The} component destroys the amorphous film of blast furnace slag fine powder, facilitating the elution of Ca ^{2 +} , Al ^{3 +,} etc., and the elution ions generate CaO-SiO ₂ -H ₂ O-based hydrate, (3CaO.Al ₂ O ₃ .3CaSO ₄ .32H ₂ O) having an acicular structure, the surplus sulfur oxide densifies the structure in the hydrated body to improve the compressive strength of the hardened body . Since the bottom ash generally has a particle diameter of 5 mm or less and its particle size is larger than that of cement and fly ash, it has a stimulating effect on the blast furnace slag itself, and thus can act as a stimulant and a fine aggregate. It can be used directly as paste and mortar when mixed with water without adding aggregate. However, in order to further enhance the stimulating effect of the blast furnace slag, it is preferable to classify and grind it to 1 mm or less.

The bottom ash preferably has a CaO content of 15 to 70% by weight. If it is less than 15% by weight, the content of CaO existing in the form of pure CaO itself is insufficient, except for about 10% by weight of CaO present in the form of CaCO ₃ and CaSO ₄ . That is, since the pure CaO reacts with water and is converted into Ca (OH) ₂ and the amount of OH ^- ion generated is insufficient, the amorphous film of the blast furnace slag fine powder is difficult to break down in a short period of time. The pure CaO present in the bottom ash reacts with water and absorbs, exotherms and expands to form Ca (OH) _2. The reaction equation is as follows. The volume expands about 1.99 times.

CaO + H ₂ O-> Ca (OH) ₂ + 15.6 kcal mol ^-1

Therefore, the pure CaO component reacts with water to convert it into calcium hydroxide, and it also acts as an alkali stimulant of fine powdered slag powder. However, due to the increase in temperature due to heat generation, the hydration reaction of the blasted slag powder is promoted and the effect of compensating the volumetric shrinkage Role and so on. On the other hand, if the CaO content is more than 70% by weight, the CaO content existing in the pure CaO form is excessively absorbed, excessively absorbing the water, and excessive heat generation and expansion may occur and cause cracks. Therefore, it is necessary to perform the chemical quantitative analysis before the raw materials in the bottom ash, and the CaO content should be 15 to 70% by weight.

The bottom ash preferably has an SO ₃ content of ₃ to 30% by weight. If it is less than 3% by weight, the content of SO ₃ capable of stimulating slag is insufficient, so that the strength is difficult to manifest. If it exceeds 30%, the content of SO _{3 which} does not react with the excess amount of slag is present. It is preferred to analyze the chemical composition to use the bottom ash within the above range.

It is preferable that the bottom ash is mixed with 0.5 to 1,000 parts by weight with respect to 100 parts by weight of the blast furnace slag fine powder. When the blending amount is less than 0.5 parts by weight, the effect thereof is not exhibited. When the blending amount is more than 1,000 parts by weight, The irritant component is excessive and the strength is greatly lowered.

The fluidized-bed boiler fly ash is discharged from a circulating fluidized-bed boiler dust collecting facility to either or both of coal ash, paper sludge material, coal + solid fuel material, coal + biomass material, solid fuel material and biomass material The above mixture may be used.

The circulating fluidized bed fly ash serves both as a stimulant of blast furnace slag and as a water-absorbing agent in the soil to rapidly solidify the soil particles to physically improve and to prevent shrinkage.

The content of the circulating fluidized bed fly ash CaO is preferably 15 to 60% by weight. If the content of CaO is less than 15% by weight, the effect of stimulating the blast furnace slag and the function of absorbing moisture are insufficient. Conversely, if the CaO content exceeds 60% by weight, the CaO content existing in pure CaO form excessively absorbs moisture, Excessive cracking may occur.

The fluidized bed boiler fly ash preferably has an SO ₃ content of 3 to 20 wt%. If the amount is less than 3% by weight, the SO ₃ content that can stimulate the blast furnace slag is insufficient and the strength is difficult to manifest. If the content is more than 20%, the excess amount of SO ₃ may not be reacted with the slag, . Therefore, it is preferable to use a circulating fluidized bed boiler fly ash having a CaO content of 15 to 60 wt% and an SO ₃ content of 3 to 20 wt% by performing quantitative chemical analysis of raw materials before circulating fluidized bed boiler fly ash.

The circulating fluidized bed boiler fly ash is preferably mixed in an amount of 0.5-1,000 parts by weight based on 100 parts by weight of the blast furnace slag fine powder. If the blending amount is less than 0.5 parts by weight, the effect is not exhibited. If the blending amount is more than 1,000 parts by weight, The amount of the fine powder is relatively decreased, and the latent hydraulic property is lowered, and the fluidity may be lowered due to a relatively large amount of water being absorbed relatively rapidly.

On the other hand, in the desulfurization process for removing sulfur dioxide (SO ₂ ) from the iron and steel industry, a byproduct containing a large amount of impurities (Na ₂ SO ₄ ) is generated, reaching 40,000 tons / year. In industrial terms, a large amount of manganese is produced as a by-product, which is used for builders such as pulp manufacturing glass industry, metal smelting, dye industry, laxative, and the like, which are additives to increase the detergency of synthetic detergents. At present, it has obtained high purity gypsum which is used industrially by refining gypsum, but it is costly. On the other hand, in the case of pulverized mung bean produced in the steel making process, since there are many impurities, suitable use place is not found. In the present invention, as a result of increasing the strength of the blast furnace slag and the ground grout material using the alkaline and sulfate complex irritant, the wastes generated from the waste are selected and used in the steelworks. In addition, the gum can be dissolved well in water to greatly increase the fluidity of the grout material.

The content of Na ₂ O is preferably 10 to 50% by weight. If the content is less than 10% by weight, the stimulus effect of the blast furnace slag is insufficient and other impurities are excessively contained and the strength can not be expressed. Conversely, if the content of Na ₂ O exceeds 50% by weight, the SO ₃ content decreases, And the Na ₂ O component is eluted and bleaching phenomenon occurs. If the content of SO ₃ is less than 10% by weight, the SO ₃ content that can stimulate the blast furnace slag is insufficient and the strength is difficult to manifest. If it exceeds 50%, the SO ₃ content is less than 10% SO ₃ content is present and the strength may be lowered. Therefore, it is preferable that the gypsum generated as a by-product of the steel smelting desulfurization process is subjected to chemical quantitative analysis before the raw material is received, so that the gypsum having an Na ₂ O content of 10 to 50 wt% and an SO ₃ content of 10 to 50 wt% is preferably used.

It is preferable that the gypsum contains 0.1-500 parts by weight of the blast furnace slag fine powder. When the blast furnace slag is less than 0.5 parts by weight, the effect is not exhibited. When the blast furnace slag is more than 500 parts by weight, Is relatively decreased, and the potential hydraulic resistance is lowered, and the excess amount of gum is present, and the strength is greatly lowered.

In addition, the pulverized coal boiler fly ash may further comprise 0.5 to 400 parts by weight of a pulverized coal-fired boiler fly ash, based on 100 parts by weight of the blast furnace slag fine powder. The pulverized coal fly ash has a SiO ₂ content of 35 to 60% 10% by weight and an SO ₃ content of 0.1 to 3% by weight, and is discharged from the pulverized coal boiler dust collector. The pulverized coal boiler fly ash is collected when a combustion gas of a pulverized coal combustion boiler passes through a dust collecting apparatus in a thermal power plant having a separate desulfurization facility. Since the CaO content is less than 10 wt%, the pH is 6 to 11 Of neutral and low alkali materials.

Fly-ash coal-fired power plant pulverized coal boiler fly ash is partially replaced with Portland cement. Since fly ash has a spherical shape, its fluidity is increased and its pozzolan-reactive property is increased to increase strength in long-term age. . That is, when mixed with Portland cement, fly ash is stimulated and hardened after the hydration product of cement, i.e., calcium hydroxide, is produced. As a result, the reaction of fly ash starts secondarily. For this reason, when fly ash is mixed with Portland cement, problems such as delayed coagulation, initial strength reduction, and neutralization are caused. Due to such a phenomenon, there may arise problems such as delays in form deformation, deterioration in initial strength, and deterioration in long-term durability due to neutralization at the construction site, and the content of fly ash relative to 100 wt% of Portland cement is used as 5 to 20 wt% . In the present invention, the CaO component of the bottom ash and fly ash of the circulating fluidized bed boiler is reacted with water to produce Ca (OH) ₂ And the pozzolanic reaction of pulverized coal boiler fly ash is initially activated by the stimulating effect of NaOH produced by the reaction of the Na ₂ O component of the moss with water.

It is preferable that the pulverized coal boiler fly ash is mixed with 0.5 to 400 parts by weight with respect to 100 parts by weight of the blast furnace slag fine powder. If the pulverized coal boiler fly ash is less than 0.5 part by weight, the effect is not exhibited. If the amount is more than 400 parts by weight, Of the fly ash is present in a large amount.

Further comprising 0.5 to 400 parts by weight of gypsum based on 100 parts by weight of the fine powdered blast furnace slag for enhancing the strength, and further comprising any one or a mixture of two or more of natural anhydrous gypsum, petroleum coke desulfurized gypsum, .

It is preferable that the gypsum is mixed with 0.5 to 400 parts by weight with respect to 100 parts by weight of the blast furnace slag fine powder. If the amount is less than 0.5 part by weight, the effect is not exhibited. If the amount is more than 400 parts by weight, And the strength is greatly lowered.

The cement may further comprise 0.5 to 200 parts by weight of cement based on 100 parts by weight of the granulated fine powder of the blast furnace slag to improve the initial strength. The cement may be one kind of cement, three kinds of cement, , Blast furnace slag cement, fly ash cement, or a mixture of two or more thereof. It is preferable that the cement is mixed with 0.5 to 200 parts by weight with respect to 100 parts by weight of the blast furnace slag fine powder. If the blending amount is less than 0.5 parts by weight, the effect is not exhibited. When the blending amount exceeds 200 parts by weight, Hazardous substances can be eluted and economic efficiency is also insufficient.

Further, it is preferable to further include liquid and powder type fluidizing agents in order to improve fluidity. The fluidizing agent is preferably one selected from the group consisting of naphthalene type, melamine type, amine type, lignin type and polycarboxylic type, or a mixture of two or more thereof. When the amount of the fluidizing agent is less than 0.01 parts by weight, the fluidity is not improved. When the amount of the fluidizing agent is more than 20 parts by weight, the fluidity is excessively improved, It is not economical.

In addition, it is preferable to further include an in-water insolubilizing agent to prevent underwater separation. The water-in-oil separating agent is selected from the group consisting of HYDROXY PROPYL METHYL CELLULOSE (HPMC), HYDROXY ETHYL CELLULOSE, HEC, CARBOXY METHYL CELLULOSE, CMC, ETHYL HYDROXY ETHYL CELLULOSE, EHEC), POLYACRYL SALT, POLY SACCARIDE, HYDROXY ETHYL METHYL CELLULOSE, HEMC, POLY ETHYLENE OXIDE, PEO, ETHYLENE VINYL ACETATE, EVA), or a mixture of two or more thereof. If the amount is less than 0.01 part by weight, the effect of improving the water-insolubilization is not exhibited. If the amount of the water-insolubilizing agent is more than 20 parts by weight, the viscosity is excessively increased. do.

Further, it is preferable to further include a foaming agent or a foaming agent in order to form pores. A foaming agent and a foaming agent are further added to minimize the load on the lower structure by replacing the volume of the fine aggregate and the coarse aggregate while reducing the weight. The foaming agent is a foaming agent used in concrete, and foaming agents such as animal and vegetable foaming agents and aluminum powders commonly used in Korea can be used. The foaming agent and the foaming agent are preferably incorporated in an amount of 0.01 to 20 parts by weight based on 100 parts by weight of the blast furnace slag. When the blending amount is less than 0.01 parts by weight, the pore generating effect is insufficient. When the blending amount is more than 20 parts by weight, It is not economical.

Hereinafter, the ground grouting method according to the present invention will be described.

The ground grout method comprises the steps of 1) fabricating a ground grout material including a blast furnace slag fine powder, a fluidized bed boiler bottom ash, a fluidized bed boiler fly ash, and a mortar; 2) mixing 50 to 300 parts by weight of water with respect to 100 parts by weight of the grout material to prepare a slurry; 3) injecting the slurry to fill the gap or mix with the gypsum; 4) curing the filled slurry and the mixed soil. The slurry discharged in the step 3) should be maintained so that a certain amount of the slurry is normally sprayed, and a bulb should be formed at the tip of the slurry, or a site requiring infiltration to the microvoids should be consolidated at a high pressure and injected, If the site is filled with voids, it is preferable to inject it at low pressure. In case of mixing with slurry and on-site soil, the rotational speed of the ogre should be adjusted according to the N value of the soil so that homogeneous mixing can be achieved. It is preferable to give a rotation time of at least 1 minute.

In the step 4), the ground grout material is cured, and it is preferable that the material is not subjected to an external impact before the curing is sufficiently performed, and the curing at room temperature or the curing at a temperature is preferably carried out sufficiently.

Hereinafter, preferred embodiments and comparative examples of the present invention will be described. The following examples are intended to illustrate the invention and should not be construed as limiting the scope of the invention.

Comparative Example

100 parts by weight of the first kind of cement was charged with 300 parts by weight of fine powder of not more than 5 mm, followed by dry mixing, 80 parts by weight of water was further added to 100 parts by weight of the mixture, and wet mixing was performed again to prepare a homogeneous slurry mixture Respectively. Nine specimens of Ø10 cm × 20 cm were prepared and cured at 20 ° C., and the strengths were measured at 3 days, 7 days and 28 days.

Example 1

200 parts by weight of coal combustion circulating fluidized bed boiler bottom ash having a CaO content of 46.7% by weight and an SO ₃ content of 16.8% by weight of 5 mm or less with respect to 100 parts by weight of the blast furnace slag fine powder having a specific surface area of 4,360 cm ² / g, 100 parts by weight of a circulating fluidized bed boiler fly ash having 36.5% by weight and an SO ₃ content of 9.2% by weight, 20 parts by weight of manganese produced as a by-product in a steel desulfurization process having an Na ₂ O content of 43.9% by weight and an SO ₃ content of 43.9% After the addition, 80 parts by weight of water was further added to 100 parts by weight of the mixture, followed by wet mixing to prepare a homogeneous slurry mixture. Nine specimens of Ø10 cm × 20 cm were prepared and cured at 20 ° C., and the strengths were measured at 3 days, 7 days and 28 days.

Example 2

200 parts by weight of coal combustion circulating fluidized bed boiler bottom ash having a CaO content of 46.7% by weight and an SO ₃ content of 16.8% by weight of 5 mm or less with respect to 100 parts by weight of the blast furnace slag fine powder having a specific surface area of 4,360 cm ² / g, 100 weight parts of circulating fluidized bed boiler fly ash having 36.5 weight% and SO ₃ content of 9.2 weight%, 20 weight parts of manganese produced as a by-product in a steel desulfurization process having an Na ₂ O content of 43.9 weight% and an SO ₃ content of 43.9 weight% 80 parts by weight of pulverized coal boiler fly ash having an SiO ₂ content of 51.2% by weight, a CaO content of 1.9% by weight and an SO ₃ content of 0.8% by weight was charged and dry mixed. Then, 80 parts by weight Followed by wet mixing again to prepare a homogeneous slurry mixture. Nine specimens of Ø10 cm × 20 cm were prepared and cured at 20 ° C., and the strengths were measured at 3 days, 7 days and 28 days.

Example 3

200 parts by weight of coal combustion circulating fluidized bed boiler bottom ash having a CaO content of 46.7% by weight and an SO ₃ content of 16.8% by weight of 5 mm or less with respect to 100 parts by weight of the blast furnace slag fine powder having a specific surface area of 4,360 cm ² / g, 100 weight parts of circulating fluidized bed boiler fly ash having 36.5 weight% and SO ₃ content of 9.2 weight%, 20 weight parts of manganese produced as a by-product in a steel desulfurization process having an Na ₂ O content of 43.9 weight% and an SO ₃ content of 43.9 weight% 60 parts by weight of petroleum coke desulfurization gypsum and 20 parts by weight of the first kind of cement were dry mixed, 80 parts by weight of water was further added to 100 parts by weight of the mixture, and wet mixing was performed again to prepare a homogeneous slurry mixture. Nine specimens of Ø10 cm × 20 cm were prepared and cured at 20 ° C., and the strengths were measured at 3 days, 7 days and 28 days.

Test methods and results of specimens

As shown in Table 1 below, the compressive strength test was carried out by the uniaxial compressive strength test method of KS F 2343. The heavy metal elution test was carried out by taking a part of the sample after measuring the compressive strength at 28 days.

Experiment Way Remarks Compressive strength KS F 2343 Uniaxial Compressive Strength Test Method Heavy metal leaching Waste process test standard Heavy metal dissolution test method

division Compressive strength 3 days
(MPa) Compressive strength 7 days
(MPa) Compressive strength 28 days
(MPa) Comparative Example 3.56 8.46 14.20 Example 1 4.78 9.64 17.43 Example 2 3.82 8.67 16.90 Example 3 5.21 10.90 20.54

(1) Change in uniaxial compressive strength

Table 2 shows the uniaxial compressive strengths of Comparative Examples and Examples 1, 2 and 3. As can be seen from the results, Example 1 using the blast furnace slag fine powder and the circulating fluidized bed boiler bottom ash, circulating fluidized bed fly ash and mortar showed a strength equal to or higher than that of Comparative Example 1 using the cement and the stearic powder, Example 2 including the pulverized coal boiler fly ash exhibited similar strength to that of Comparative Example 1 on the 3rd and 7th days, but exhibited an increase of about 20% on the 28th day when compared with Comparative Example 1.

Example 3, which further includes Petro coke desulfurization gypsum and one kind of cement, shows higher strength in all ages than the comparative example using only one type of cement at all ages. Thus, it can be seen that the eco-friendly grout material of the present invention can replace the first grade cement used in the ground grouting method.

(2) Extraction of heavy metals

KSLT Hexavalent chromium Copper Mercury cadmium lead arsenic Acceptance criteria 1.5 3.0 0.005 0.3 3.0 1.5 Comparative Example 1 0.813 0.676 Non-detection 0.359 0.158 0.087 Example 1 Non-detection Non-detection Non-detection Non-detection Non-detection Non-detection Example 2 Non-detection Non-detection Non-detection Non-detection Non-detection Non-detection Example 3 Non-detection Non-detection Non-detection Non-detection Non-detection Non-detection

The results of the heavy metal leaching experiment shown in Table 3 show that the comparative example satisfies the allowable reference value, but in the case of hexavalent chrome, the amount exceeding 50% of the reference value is eluted. All of the examples of the present invention, however, did not detect any heavy metals as well as hexavalent chromium.

 Therefore, the ground grout material of the present invention and the ground grouting method using the same, by using the industrial by-products generated in the circulating fluidized bed boiler and the steel desulfurization process as the stimulant of the fine powder of the blast furnace slag, It can usually replace cement or minimize its use. It is also an eco-friendly grouting material and grouting method that can solve the problem of natural resources and energy exhaustion, carbon dioxide emission, and environmental pollution caused by leaching of harmful heavy metals as well as cost reduction by cement usage reduction.

Claims (8)

With respect to 100 parts by weight of the blast furnace slag fine powder,
0.5 to 1,000 parts by weight of a circulating fluidized bed boiler bottom ash having a CaO content of 15 to 70% by weight and an SO ₃ content of 3 to 30% by weight, the particle diameter being adjusted to 0.01 mm to 5 mm,
0.5 to 1,000 parts by weight of a circulating fluidized bed boiler fly ash having a CaO content of 15 to 60% by weight and an SO ₃ content of 3 to 20% by weight,
0.1 to 500 parts by weight of a manganese oxide produced as a by-product in a steel desulfurization process having an Na ₂ O content of 10 to 50% by weight and an SO ₃ content of 10 to 50%
Wherein the circulating fluidized-bed boiler bottom ash is generated in a circulating fluidized-bed boiler using coal as fuel, and is generated from the lower part of the boiler in a manner of desulfurizing the furnace in a coarse manner with limestone.
The method according to claim 1,
Further comprising 0.5 to 400 parts by weight of pulverized coal boiler fly ash per 100 parts by weight of the blast furnace slag fine powder,
Characterized in that said pulverized coal fly ash fly ash has a SiO ₂ content of 35 to 60% by weight, a CaO content of 0.5 to 10% by weight and an SO ₃ content of 0.1 to ₃ % by weight and discharged from a pulverized coal- Eco-friendly grout material without leaching.
3. The method of claim 2,
Further comprising 0.5 to 400 parts by weight of gypsum based on 100 parts by weight of the blast furnace slag fine powder,
Wherein the gypsum further comprises any one or a mixture of two or more of natural anhydrous gypsum, petroleum cokes desulfurization gypsum, and hydrofluoric acid gypsum gypsum.
3. The method of claim 2,
With respect to 100 parts by weight of the blast furnace slag fine powder,
0.5 to 200 parts by weight of cement;
0.01 to 20 parts by weight of a liquid and powder type fluidizing agent for improving fluidity;
0.01 to 20 parts by weight of an underwater dispersant to prevent underwater separation; And
0.01 to 20 parts by weight of a foaming agent or foaming agent to form pores,
Wherein said cement further comprises any one or a mixture of two or more of cement, cement, CSA, blast-furnace slag cement and fly ash cement.
delete delete delete 1) fabricating the ground grout material of claim 4;
2) mixing 50 to 300 parts by weight of water with respect to 100 parts by weight of the grout material to prepare a slurry;
3) injecting the slurry produced in the step of preparing the slurry to fill the gap or mix with the gravel; And
4) curing the filled slurry and the mixed soil, and eco-friendly ground grouting method without heavy metal elution.