KR101736367B1 - Grounting composition for high pressure injection soil solidification method - Google Patents

Abstract

The present invention is characterized in that a 0.045 mm (45 탆) sieve residue is judged to be less than 10%, or a 0.045 mm (45 탆) sieve residue is judged to be less than 10% with respect to 100 pbw of fine pulverized slag powder, And 50 to 100 parts by weight of the reinforcing reinforcing material. The present invention also relates to a grout composition for a high pressure injection soil improvement method.
According to the present invention, the vitrified CaO and SiO ₂ components of the blast furnace slag fine powders are activated to the compound stimulus by the active magnesia and the sulfate which are the auxiliary components of the strength, and can exhibit the strength equal to or higher than that of the one kind ordinary cement. The present invention was filed as a result of a project to develop induction technology for establishing a company-affiliated research institute / research department of Ulsan Metropolitan City and Ulsan Technopark.

Description

Technical Field [0001] The present invention relates to a grout composition for a high-

The present invention relates to an eco-friendly grout composition for a high pressure spray ground improvement method using a blast furnace slag fine powder as a main material, and more particularly to a green grout composition using a blast furnace slag fine powder as a main material without using cement, The present invention relates to an eco-friendly grout composition for a high pressure injection soil improvement method capable of replacing one kind of ordinary portland cement most widely used as a grouting material for a high pressure injection soil improvement method.

The high pressure injection soil improvement method is a method of forming high consolidation within the planned direction or range by cutting the ground with the force of air or water and injecting the grout material at a high speed to replace the soil with the soil or mixing with the soil. The high pressure injection soil improvement method has an advantage that it can be applied only to a specific stratum requiring improvement, and it can be improved by adhering it to a previously constructed structure or a lower part.

In addition, unlike a general chemical injection method in which grout material is injected into a substrate, the gap is artificially created, and the grout material is injected into the generated gap. Therefore, There is almost no impact on the burials. In addition, unlike the slurry injection method, chemical injection method, compaction grouting method, etc., the high pressure injection ground improvement method can be improved from the low permeability clay soil to the highly permeable sand and gravel ground It is widely applied.

Next, FIG. 1 shows the construction procedure of a general high-pressure injection soil improvement method. Referring to FIG. 1, the excavation is performed by using the equipment, and the soil of the object range is stirred with cement suspension, air or water, (Drawing) process while rotating the lot while forming a columnar reformer in the ground.

Various methods have been developed for the improvement of high pressure spraying ground by using equipment, injection pressure and construction method. CCP method, jet grouting method, JSP method, RJP method, SIG method, SRC method, CJP method, DCC method Are generally known.

Although these methods differ slightly depending on the type of grout material used, the method of excavation, the multiple structure of the injection pipe, and the injection position, as shown in FIG. 1, the nozzle is located at the lower end of the injection pipe, The principle that a grooved material is injected at a high pressure to form a columnar reformer is the same.

If the high pressure injection soil improvement method is classified according to the structure of the lot and the injection pipe, it is classified into a) single-pipe high-pressure injection method, b) double pipe injection method, and c) triple pipe injection method as shown in FIG.

That is, the construction method is classified according to whether the structure of the excavation and agitation lot is a single pipe, a double pipe or a triple pipe. As shown in FIG. 2 a), the single pipe injection method is a method in which a cement suspension is injected at a high pressure of about 200 kgf / And stirring mixing to form a columnar reforming material having a diameter of 300 to 500 mm in the ground, and a CCP (Chemical Churning Pile) method is a typical method.

2 (b) is a method for forming a reformer by injecting air (air jet) or cutting water (water) into a single pipe injection method as a double pipe injection method. Since the double pipe injection method uses cutting water or high pressure air in parallel with the single pipe injection method, the cutting force is relatively high, and the diameter of the reforming body is about 800 to 1,200 mm, and the soil of the cement suspension and the ground are uniformly It is mixed to make more efficient construction. A typical construction method is J.S.P (Jumbo Special Pattern) method, which is the most common construction method since the first introduction to Korea in the late 1970s.

2 (c) is a schematic drawing of the triple-tube injection method. Unlike the single-tube and double-tube injection method, cutting is performed by using cutting water and high-pressure compressed air in a preceding process, and the cement suspension is filled. The triple-tube injection method can improve the soft ground with a larger diameter and higher strength than the single- and double-tube injection method, and RJP (Rodin Jet Pile) method is a typical method.

In order to prevent the problem of surrounding ground uplift due to injection of high-pressure injection, which is a problem of the existing high-pressure injection soil improvement method, and to prevent the softening of the ground surface due to the jetted water, (For example, SIG method) filling the slurry with only grout material, and a method (for example, SRC method) in which the slurry is greatly reduced by recycling gypsum as an injection material by solid-liquid separation of the cut soft soil.

Despite the classification and functional distinction by the high-pressure spraying equipment as shown in FIG. 2, the grout materials mostly used in all the high-pressure sprayed soil improvement methods are the cement suspension and the sodium silicate solution as the dispenser. In some cases, only the cement suspension is injected. In the case of urgent order or urgency (urgent gel formation), cement suspension and sodium silicate solution are used at the same time. Depending on the conditions of the site, Sodium silicate) may be alternately injected.

As is well known, there is a problem that the above-mentioned cement is not environmentally friendly as a product manufactured by calcining at 1,450 ° C using imported bituminous coal as a raw material, such as limestone, iron ore, clay, and silica. According to the LCI database in Korea, 944 kg of carbon dioxide is emitted when 1 ton of cement is produced. Carbon dioxide is the primary contributor to global warming, and each country is making every effort to suppress the generation of carbon dioxide.

In addition, Korea is mining about 55 million tons of limestone to produce 45 million tons of cement every year. In addition to the damage of Baekdudaegan in Korea, the limestone reserves will be exhausted in about 35 years.

Therefore, the development of eco-friendly injection materials that minimize the amount of cement that gives enormous environmental load is urgently needed. In addition, in the case of large permeable ground or a lot of underground water, excessive cement is added to the ground because the cement is changed to desalination considering the loss of cement. In addition, when the water contained in the cement suspension is lost to the adjacent ground, in addition to the volume of the water, the cement itself shrinks as it hydrates, causing another void between the ground and the reformer, It also happens when you can not.

In addition, cement has been reported to cause environmental pollution caused by strong alkali and hexavalent chromium in the ground.

Recently, several techniques for improving the problem of using such conventional cement as an injection material have been proposed.

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 concern that even when it is used as a foaming agent in mortar, it is a substance to be handled in a limited work space provided with a dustproof facility and has a small specific gravity, which may cause a problem of not mixing with bentonite when producing a suspension mixed with water.

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.

Also, Korean Patent No. 10-0834923 discloses a technique in which mortar is used as a grouting filler, and mortar has a water blending ratio of 65 to 70% and a slump of 5 to 8 cm. In general, mortars are used for various purposes such as plastering, wall-wicking, and fire-proofing, and the composition of the mortar varies depending on the type of mortar. The composition of the mortar used as the grout material is not precisely shown, can do.

Also, in Korean Patent No. 10-0804807, 35 to 65% of a quick-setting component pulverized to have a powder degree of 4,500-5,500 cm2 / g, 15-30% of a calcium sulfoaluminate powder, A filler composition (A) comprising 50 to 70% of cement powder and 5 to 15% of anhydrous gypsum, 5 to 15% of a gypsum plaster, 5 to 15% of loess powder, 3 to 10% of a reaction modifier, and 0.3 to 1.0% , 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 the heat 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.

In Korean Patent No. 10-1377552, 100 to 300 parts by weight of blast furnace slag fine powder, 20 to 100 parts by weight of petroleum coke desulfurization gypsum and 20 to 100 parts by weight of a sulfate stimulant are added to 100 parts by weight of coal ash having a calcium oxide content of 30 to 60% The present invention also provides a milk injection material for cement pile construction, which comprises 40 to 100 parts by weight of an expanding material based on 100 parts by weight of coal as a filler having a composition ratio by weight.

Also, in Korean Patent No. 10-1402877, it is disclosed 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 to 20% by weight of paper ash sludge incineration ash.

In addition, in Korean Patent Application No. 2013-147586, which is a prior patent of the present inventor, 5 to 200 parts by weight of petroleum gypsum desulfurization gypsum and 50 to 300 parts by weight of compounding water are added to 100 parts by weight of the blast furnace slag fine powder, And 5 to 100 parts by weight based on 100 parts by weight of the fine powder.

These techniques are based on the theory of alkali activated slag that activates blast furnace slag fine powders as a byproduct of the desulfurization process by alkali and sulfate stimulation by gypsum and is a technical content of utilizing high calcium incineration as an expansion material. 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.

Korean Patent No. 10-0699430 Korean Patent No. 10-0886220 Korean Patent No. 10-0834923 Korean Patent No. 10-0804807 Korean Patent No. 10-1377552 Korean Patent No. 10-1402877 Korean Patent Application No. 2013-147586

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and it is an object of the present invention to provide a cement mortar composition, which does not use cement but utilizes blast furnace slag fine powder as a main material of a grout composition, Which is capable of exhibiting a strength equal to or higher than that used as a grout material in a high-pressure sprayed soil improvement method, by providing a grout composition for a high pressure sprayed soil improvement method.

In order to solve the above technical problems, the grout composition for a high-pressure injection molding method according to the present invention is characterized in that 0.045 mm (45 탆) sieve residue is judged to be less than 10% (45 탆) sieve residue is judged to be less than 10%, or 50 to 100 parts by weight of the pulverized and classified pulverized auxiliary material.

Wherein the strength auxiliary material is a ferronickel slag fine powder having an active magnesia content of 30 to 40% by weight and a 0.045 mm (45 탆) sieve content of less than 10%, Fine particles of lightweight dolomite having an active magnesia component of 20 to 35% by weight and a 0.045 mm (45 탆) sieve fraction of less than 10%, And a calcium oxide content of 50 to 75% by weight, a sulfate oxide content of 15 to 30% by weight and a 0.045 mm (45 탆) sieve fraction of less than 10% Gypsum, or a mixture of two or more thereof.

According to an embodiment of the present invention, the grout composition for the high pressure injection soil improvement method is characterized in that at least one 45 mu m body residue selected from portland cement and blast furnace slag cement is judged to be less than 10% or crushed and classified cement .

The cement is preferably contained in an amount of 50 to 100 parts by weight based on 100 parts by weight of the blast furnace slag fine powder.

According to another embodiment of the present invention, the grout composition for a high pressure injection soil improvement method is characterized in that the silicon dioxide (SiO ₂ ) content is 30 to 65 wt%, the 45 μm sieve fraction is less than 10% And may further include classified coal-fired fly ash.

The fly ash may be contained in an amount of 10 to 100 parts by weight based on 100 parts by weight of the blast furnace slag fine powder.

According to the present invention, the vitrified CaO and SiO ₂ components contained in the blast furnace slag fine powders are activated by stimulation of alkali and sulphate included in the strength auxiliary material, and the strength auxiliary material is activated to exhibit the strength, It is possible to develop a high-pressure injection injection method utilizing an environment-friendly grout material since the same strength as that of the grout material for injection injection method can be exhibited.

1 is a schematic diagram showing a construction procedure of a general high-pressure injection soil improvement method,
Fig. 2 is a view showing the JET grouting method according to the structure of the lot and the injection tube.

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

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a,""an," and "the" include singular forms unless the context clearly dictates otherwise. Also, " comprise "and / or" comprising "when used herein should be interpreted as specifying the presence of stated shapes, numbers, steps, operations, elements, elements, and / And does not preclude the presence or addition of one or more other features, integers, operations, elements, elements, and / or groups.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eco-friendly grout composition using a blast furnace slag fine powder used in a high-pressure injection soil improvement method, and each component and action included in the eco-friendly grout composition will be described below.

Generally, ordinary Portland cement and blast furnace slag cement manage the particle size by the specific surface area (blaine method). However, to control the content of the normal granulated powder, 0.045 mm (45 μm) Of the total. This is because the degree of powder has an important influence on the expression of the strength, that is, the activity index. Therefore, the granularity of each material must be clearly controlled in order to achieve a predetermined purpose.

Also in the present invention, powderiness of raw material particles is very important. When a large amount of granular particles are contained in the powder, the timing of the expression of the strength is delayed (the activity index is lowered), and the desired strength can not be obtained at a desired time. However, depending on the process operation of the plant that manufactures the powder, the powderity of each raw material varies widely, and it is very important to adjust it uniformly. Therefore, it is a matter of fact that each component included in the composition of the present invention must satisfy the particle size.

The grout composition for a high-pressure injection injection method according to the present invention is characterized in that 0.045 mm (45 mu m) sieve residue is less than 10%, or 0.045 mm (45 mu m) sieve residue is 10 %, Or 50 to 100 parts by weight of the pulverized and classified strength auxiliary material.

The main ingredient of the grout composition of the present invention is a blast furnace slag fine powder, which is obtained by rapidly cooling the slag generated in a blast furnace of a steel mill and pulverizing the slag. In the present invention, the vitrified CaO and SiO ₂ components contained in the blast furnace slag are activated by the stimulation of alkali and sulfate contained in the strength auxiliary material by using such blast furnace slag fine powder as the main raw material. Therefore, it is possible to exhibit a strength equal to or higher than that of using cement without containing cement.

In addition, the above-mentioned strength auxiliary material included in the grout composition according to the present invention assists in the development of strength of the blast furnace slag fine powder with activated magnesia and sulfate and at the same time, it rapidly inflates and generates heat to stabilize the ground rapidly, . The raw materials included in the strength auxiliary material of the present invention should also be examined and judged to be less than 10% of the 45 μm sieve residue or grind-classified.

Wherein the strength auxiliary material is a ferronickel slag fine powder having an active magnesia content of 30 to 40% by weight and a 0.045 mm (45 탆) sieve content of less than 10%, Fine particles of lightweight dolomite having an active magnesia component of 20 to 35% by weight and a 0.045 mm (45 탆) sieve fraction of less than 10%, And a calcium oxide content of 50 to 75% by weight, a sulfate oxide content of 15 to 30% by weight and a 0.045 mm (45 탆) sieve fraction of less than 10% Gypsum, or a mixture of two or more thereof.

Ferronickel slag fine powder as one of the above-mentioned reinforcing materials is a by-product generated in the ferronickel manufacturing process, and as of 2014, 2 million tons per year is being produced in Korea. Ferronickel is a term for alloy iron containing 80% of iron and 20% of nickel and is mainly used as a raw material of stainless steel. The raw material of ferronickel is nickel oxide light with serpentinite as a parent rock. In general, the quality of pure nickel is as low as 2 ~ 3% of the ore, and after refining process at 1,500 ℃ or more, about 30 tons of ferronickel slag Is known to occur.

This ferronickel slag is partially recycled as a raw material for sintering, or as a part of road aggregate or aggregate for cocrit, but most of the ferronickel slag is disposed of by landfill.

The cooling conditions for the ferronickel slag according to the present invention are water-chain ferronickel quenched by water with slag, and the material used is powdered quench-hardened ferronickel slag. It is generally known that quenching is a prerequisite for increasing the amount of amorphous material and that the greater the amount of amorphous material, the greater the chemical activity.

The chemical composition of the ferronickel slag powder used in the present invention is shown in Table 1 below in%.

content(%) Chemical composition SiO ₂ MgO CaO Al ₂ O ₃ T-Fe T-Ni Fe-Ni slag 52.4 35.6 0.9 1.6 4.6 0.03

Referring to Table 1, the main chemical components of the ferronickel slag powder are vitrified SiO ₂ and MgO. As is well known, SiO ₂ The rate at which the strength is developed is activated later than CaO or Al ₂ O ₃ . Also MgO is a substance that reacts with water and expands when it is transferred to Mg (OH) ₂ . It is known that the limit of MgO content in cement is also due to its swelling property.

Therefore, in the present invention, the content of MgO contained in the ferronickel slag fine powder is 30% by weight or more, preferably 32 to 40% by weight in order to realize expandability and to serve as a strength auxiliary material for blast furnace slag fine powder through alkali stimulation desirable. The main components of the ferronickel slag are active magnesia and silicon dioxide. These two components are more than 85% and the iron and aluminum oxide components are considered to be the remaining impurities.

Therefore, if the active magnesia component contained in the ferronick slag fine powder contains less than 30% by weight, the expansion may not be sufficient. In the case of the raw material exceeding 40% by weight, the calcium silicate hydrate, which reacts with the cement, There is a fear of a decrease in strength, meaning that the amount of silicon (SiO ₂ ) component is relatively small, which is not preferable.

In the present invention, by using the feronitic slag fine powder to exhibit the strength development by the vitrified SiO ₂ and the heat generation and expansion characteristics by the active magnesia, it is a composite functional material which assists the manifestation of strength of the blast furnace slag fine powder, It has a feature to utilize.

In addition, one of the raw materials for strength reinforcement of the present invention is calcined dolomite, which is produced by calcining dolomite at a relatively low temperature. As the endothermic reaction (Scheme 1) according to the calcination temperature under at a temperature of 600 ~ 800 ℃ the MgCO ₃ is decarbonation first and the transition to the active magnesium in a highly reactive amorphous state, a CaCO ₃ at a temperature of 800 ~ 1000 ℃ Decarboxylated and transferred to highly reactive calcium oxide.

(Scheme 1)

600 to 800 ° C: CaMg (CO ₃ ) ₂ = CaCO ₃ + MgO + CO ₂ ↑

800 to 1000 ° C: CaCO ₃ + MgO = CaO + MgO + CO ₂ ↑

The chemical composition of the light mineral dolomite powder according to the present invention is shown in Table 2 below.

ingredient(%) SiO ₂ MgO CaO Al ₂ O ₃ Fe ₂ O ₃ SO ₃ Light dolomite
(Light Burned Dolomite) 4.3 30.6 52.3 3.7 1.8 0.7

Since the active magnesia of this limestone dolomite exists in an amorphous state with a very high initial reactivity as shown in the following reaction formula 2, it reacts with water and hydration to form crystalline brucite.

(Scheme 2)

As shown in the above hydration equation, a large amount of brucite (Mg (OH) ₂ ) gel is formed at the beginning of hydration, and a large amount of excess water is confined as a crystal water. This is because the ratio of pore hydrates such as ettringite As a result of forming a dense structure and consequently contributing to an increase in compressive strength.

In order for the calcite dolomite powder according to the present invention to function as a reinforcing additive and a composite material expressing strength itself, the content of active magnesia (MgO) contained in the light dolomite is 20 wt% or more, preferably 25 to 35 wt% . The main components of the light dolomite are active magnesia and calcium oxide. These two components are more than 80% and the remaining impurities are silicon dioxide, iron oxide and aluminum oxide.

Therefore, when the active magnesia component in the light weight dolomite fine powder according to the present invention contains less than 20% by weight, expansion may not be sufficient. In the case of the raw material exceeding 35% by weight, calcium hydroxide (CaOH ₂ ) The amount of the calcium oxide component to be formed is relatively small and there is a fear of a decrease in strength due to the lack of the stimulation effect, which is not preferable.

In addition, the gypsum contained in the strength auxiliary material of the present invention breaks down the acid film of the blast furnace slag fine powder and the ferronickel slag fine powder in a short time by the alkali and sulfate complex irritation to accelerate the ion release inside the slag, It is a substance that simultaneously produces a large amount of etrinous gut and simultaneously acts as a stimulant and a binder to generate various hydrates as the age elapses.

The gypsum having such a function is made to have an alkali of pH 12 or more, preferably 12 to 12.5, so that the acidic coating of the blast furnace slag compound is stimulated with an alkali and a sulfate to induce destruction in a short time to obtain a desired effect .

Also, the gypsum according to the present invention has a calcium oxide content in the gypsum of 50 wt% or more, preferably 65 to 75 wt%, a sulfate oxide content of 15 wt% or more, preferably 20 wt% To 30% by weight. Generally, the purity of high grade gypsum means that the calcium oxide content and the sulfate oxide content are 95% or more. Silicon dioxide, ferric oxide, aluminum oxide and the like contained in the gypsum are regarded as impurities.

Therefore, if the content of calcium oxide in the gypsum is less than 50% by weight, the alkali-stimulating effect is not sufficient and the strength development may be delayed. If the calcium oxide content in the gypsum exceeds 75% by weight, The sulfide oxide content is lowered and the sulfate stimulating effect is reduced.

For the same reason, when the content of sulfated iron oxide in the gypsum is less than 15% by weight, the effect of stimulating the sulfate is insufficient and the strength development may be delayed. If the sulfide oxide content exceeds 30% by weight, the relative calcium oxide content in the gypsum is lowered, The effect is reduced.

Specific examples of the gypsum of the present invention having the above characteristics may be one or a mixture of two or more selected from the group consisting of natural gypsum, flue gas desulfurization gypsum, petro coke desulfurization gypsum, and coal coke desulfurized gypsum.

The strength auxiliary material of the present invention having the above-described structure is preferably contained in an amount of 50 to 100 parts by weight based on 100 parts by weight of the blast furnace slag fine powder. When the amount of the reinforcing slag is less than 50 parts by weight, the blast furnace slag is stimulated to exhibit the strength, and the amount of the material exhibiting the strength itself is small, so that the predetermined strength can not be exhibited. If the blending amount exceeds 100 parts by weight, There is also a fear of a decrease in strength.

In addition, the grout composition according to the present invention may further include KS (Korean Industrial Standard) certified product cement which can be obtained in the market in general for the purpose of shortening the air and realizing the early strength. The above cement should also be manufactured by KS certified product and the 45 ㎛ sieve residue at less than 10% in the manufacturing factory.

The cement may be any one or a mixture of two or more selected from the group consisting of portland cement and blast furnace slag cement, and may be included in an amount of 50 to 100 parts by weight based on 100 parts by weight of the blast furnace slag fine powder. When the cement is contained in an amount of less than 50 parts by weight based on 100 parts by weight of the blast furnace slag fine powder, the hydration reaction material becomes less and the desired torsional strength can not be exhibited. When the cement is incorporated in an amount exceeding 100 parts by weight, And the economy is deteriorated.

In addition, the grout composition according to the present invention may further include fly ash exhibiting pozzolanic activity for the purpose of improving fluidity and enhancing long-term strength.

The fly ash should have a 45 mu m sieve residue of less than 10% and be pulverized and classified, preferably 10 to 100 parts by weight based on 100 parts by weight of the blast furnace slag fine powder.

The fly ash is preferably a coal-fired fly ash having a silicon dioxide content of 30 wt% or more, preferably 45 to 65 wt%, which exhibits pozzolan activity, for pozzolan activity expression. In Korea's industrial standard (KS), the content of silicon dioxide in fly ash used as an admixture of concrete is specified to be over 50% (KS L 5405). Suitable for civil engineering purposes, silicon dioxide A content of 45 wt% or more is sufficient. Further, fly ash having a silicon dioxide content exceeding 65% by weight does not occur due to the characteristics of various components included in coal used as fuel.

The fly ash should have a 45 탆 sieve content of less than 10% and be pulverized and classified. It is preferable that 10 to 100 parts by weight of the fly ash is blended with 100 parts by weight of the blast furnace slag fine powder. If the fly ash is incorporated in an amount of less than 10 parts by weight based on 100 parts by weight of the blast furnace slag fine powder, the effect of improving the flowability due to the spherical particles characteristic of fly ash is not exerted and the pozzolanic active material is relatively small, . When the fly ash is incorporated in an amount of 100 parts by weight or more based on 100 parts by weight of the blast furnace slag fine powder, the fluidity is greatly improved but the initial strength is lowered due to a relatively large amount of the pozzolanic active material improving the long-term strength.

The grout composition for a high pressure injection soil improvement method according to the present invention can be produced by compounding the respective components in a predetermined mixing ratio.

Further, water is mixed with the grout composition for the above-mentioned high-pressure injection soil improvement method, water is added to adjust the concentration of water / binder ratio (W / B ratio) And can be used. The mixing ratio of the grout composition and water varies depending on the geotechnical conditions and the like, and ordinarily can be practiced by those skilled in the art.

In addition, if necessary, in addition to the grout suspension (A) of the present invention, a conventional sodium silicate solution or the like can be used as the rapid setting (B). The amount of the rapid setting and the mixing ratio can be generally adjusted by those skilled in the art Therefore, it is not limited to concrete numerical value.

Hereinafter, a method for improving the high-pressure sprayed ground using the eco-friendly grout composition according to the present invention will be described.

The high pressure injection soil improvement method according to the present invention includes the steps of calculating a reference injection amount by calculating a volume of an underground augmentor to be constructed; Firstly drilling at a planned depth and a planned angle using a high pressure injection soft ground improvement device; Drawing the compressed air and the cutting water by rotating injection and simultaneously excavating the ground and discharging the slime; And injecting the grout composition through an injection port provided in a lower portion of the lot to form an upgrading body.

The high pressure spray ground improvement method utilizing the environmentally friendly grout material according to the present invention can select various kinds of high pressure spray ground improvement equipment suitable for the conditions of the site, and can be used for discharging and recycling the floating soil (slime), using the double pipe equipment The use of the triple pipe equipment, the use of the hardener, and the blending ratio are not specifically specified since they are ordinarily practicable by those skilled in the art.

Hereinafter, preferred embodiments and comparative examples of the grout according to 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.

Example

A calcium oxide content of 65% by weight and a sulfoxide oxide content of 20% by weight were measured as 100 parts by weight of a blast furnace slag fine powder which was judged to be less than 10% % Of petroleum gypsum desulfurization gypsum, and that the amount of the active magnesia component is 30% by weight and the 0.045 mm (45 탆) sieve fraction is less than 10% 70 parts by weight of a 1: 1 mixture of lightweight dolomite fine powder were uniformly mixed to prepare a grout composition (high fire).

Next, water was added to a water / high fire ratio (W / B ratio) of 120%, and mixed thoroughly with a forced mixer to prepare a grout injection solution.

Next, in consideration of the fact that the grout injection solution is mixed with the soil of the perforated hole and the recycled slime during the actual construction, the compressive strength specimen containing 50%, 70%, 100% Was measured.

Comparative Example  : 1 species Usually Portland  Examples of using cement

First, water was added so that the water / high fire ratio (W / B ratio) was 120%, and the mixture was thoroughly mixed with a forced mixer to prepare a grout injection solution.

Next, in consideration of the fact that the grout injection solution is mixed with the soil of the perforated hole and the recycled slime during the actual construction, the compressive strength specimen containing 50%, 70%, 100% Were compared with those of the examples.

Experimental Example  : Uniaxial Compressive Strength Test Method and Result

The compressive strength test was carried out according to KS F 2343 (unconfined compressive strength test method of soil cement) and the results of unconfined compressive strength tests according to ages according to the mixing ratio of soil in the examples and comparative examples are shown in the following Table 3.

Young 3 days 7 days 28th Soil weight ratio (%) 50 70 100 50 70 100 50 70 100 Example
Compressive strength (MPa) 10.1 9.1 8.7 16.3 13.8 12.1 24.7 21.8 19.4 Comparative Example
Compressive strength (MPa) 12.5 11.7 8.9 15.5 13.2 12.7 20.4 20.1 18.0

Referring to Table 3, the strength of the three-day cement was slightly lower than that of the one-kind cement of the comparative example, but the strength was remarkably high over time, especially at 28 days. This is a result that the blast furnace slag fine powder is subjected to alkali stimulation and latent hydraulic stability is started relatively late. That is, the amorphous material of the blast furnace slag fine powder continuously produces hydrates by the combined alkali and sulphate stimuli of the reinforcing additive, and the reinforcing additive itself is considered to be a result of manifesting the strength itself.

Claims (6)

100 parts by weight of a blast furnace slag fine powder obtained by pulverizing and classifying a 0.045 mm (45 mu m) sieve residue of less than 10% and powdered with a water-quenched blast furnace in which slag was quenched by water,
The active magnesia component is 20 to 35% by weight, the 0.045 mm (45 탆) sieve fraction is judged to be less than 10%, or the finely divided dolomite fine powder
Wherein the calcium oxide content is 65 to 75 wt%, the sulfate oxide content is 20 to 30 wt%, the calcium oxide content and the sulfate oxide content are 85% or more, and 0.045 mm ) 50 to 100 parts by weight of a reinforcing auxiliary material obtained by mixing or grinding classified gypsum at a ratio of 1: 1 or less. delete delete delete delete delete

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