KR101816937B1 - Hydraulic cement composition for injection into soil, and method for improvement in soil using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic cement composition for ground penetration excellent in penetration resistance and excellent flowability (overflow) prevention performance, sufficient strength development and long term durability, and a ground improvement method using the same.
[MEANS FOR SOLVING PROBLEMS] An alkali metal silicate as a blast furnace slag fine powder, a classification cement, a polyacrylic acid type dispersant and a first-rate inhibitor, wherein the alkali silicate metal salt has a molar ratio (n) in the following general formula (1) , And 0.2 to 7 parts based on 100 parts of the total amount of the blast furnace slag fine powder and the classification cement is a hydraulic cement composition for ground injection.
R ₂ O · nSiO ₂ (R: alkali metal) (1)

Description

Technical Field [0001] The present invention relates to a hydraulic cement composition for ground injection, and a method for improving the soil using the same.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic cement composition for ground penetration and a soil improvement method using the same.

As a kind of soil improvement method, there is a chemical solution injection method for injecting a hardening agent into the ground through a rod in order to strengthen a soft ground, and a lot of chemical solution injection materials are known. For example, water-based fillers, special silica fillers, polymeric fillers, and suspension fillers such as cement, clay, and slag. Unlike the method in which the soil is disturbed by a high-pressure jet (jet flow) as in the jet grout method, the chemical solution injecting method using the chemical solution injecting material can be improved without disturbing the high ground and the equipment is compact There are many achievements in terms of features.

The solution injecting material may be a solution type or a suspension type, and a solution type may be used when high permeability is required. However, the solution-type drug solution injection material has high permeability, but the strength of the obtained cured product itself is small, and the shrinkage of the cured product is large, so that there is a problem in long-term durability. On the other hand, in the case of the suspension-type drug solution injection material, the use of cement or slag, which exhibits hydraulic properties, has the advantage that relatively high strength development can be expected and long-term durability can be easily ensured. Therefore, in the suspension type, development of improved permeability is mainly performed. However, in the improvement of the ground in the harbor and the coastal area, there was a problem in that the injected medicine is liable to overflow due to the tide of the tide.

As the above-mentioned suspension-type chemical solution injection material, there is known an injection material composition comprising a polycarbonate-based dispersant as an essential component in a cement clinker and a blast furnace slag made into a fine powder (see, for example, Patent Documents 1, 2 and 3). These techniques are to provide a filler composition having improved permeability by using a specific polycarboxylic acid-based dispersant. There is no description about first-rate (overflow) prevention performance, and there is no example of durability.

On the other hand, as an injection material having a gelling time, an injection material containing waterglass, solidifying agent, and blast furnace slag having a Blaine ratio (specific surface area value) of 8,000 cm2 / g or more is also known (See, for example, Patent Documents 4, 5 and 6).

Patent Document 4 shows that a cured body having a high gel strength is obtained at a moisture level at a level of several tens of seconds by using a fine-grained slag in combination, but it is an evaluation only of the compressive strength and there is no description of permeability, .

Patent Document 5 discloses a waterglass having a molar ratio in a range of 2.8 to 4.0 and a particulate slag having an average particle diameter of 10 μm or less and a bane specific surface value of 5,000 cm 2 / g or more, preferably 8,000 cm 2 / g or more, Accordingly, it is a technique relating to an injection material which further contains cement. In this document, there is a description of the use of water glass, the compression strength and permeability, but there is no mention of the first-class prevention performance.

Patent Literature 6 discloses a slag cement which is composed of a suspension type grout containing a mixture of fine particle slag and fine particle cement, wherein the slag and cement have an average particle diameter of 10 mu m or less and a baine specific surface value of 5,000 cm & Characterized in that the mixing ratio is 50% or less, wherein the suspension type grout further contains water glass and / or an alkali material. In this document, similarly to Patent Document 5, there is a description of the use of water glass and the penetration property, but there is no description about the first-class preventive performance, and evaluation of the cured product is only an evaluation of compressive strength.

In Patent Document 7, there is proposed a method for producing a water-soluble polymer by mixing water, a fine particle water slag, an alkali stimulant, a dispersant, a high molecular substance which is dissolved or dispersed in water to impart viscosity, The present invention relates to a suspension type soil conditioner. This document discloses permeability and sedimentation preventing performance but does not disclose the properties of the cured product so that the reinforcement performance and the first-class prevention performance when the cement is poured into the ground and solidified are known I can not.

Patent Document 8 discloses a technique relating to an injection material containing wet-milled slag, a polyacrylic acid-based dispersant, and sodium silicate. In this document, there is a description of improvement in castability and compressive strength, but there is no description of permeability and first-class prevention performance.

Japanese Patent Application Laid-Open No. 2007-238428 Japanese Patent Application Laid-Open No. 2007-238925 Japanese Patent Application Laid-Open No. 2004-175989 Japanese Patent Application Laid-Open No. 02-167848 Japanese Patent Application Laid-Open No. 07-229137 Japanese Patent Application Laid-Open No. 07-286173 Japanese Patent Application Laid-Open No. 2005-344078 Japanese Patent Application Laid-Open No. 2002-212556

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic cement composition for ground injection which is excellent in permeability and first-class preventive performance, exhibits sufficient strength and long-term durability, and a ground improvement method using the same. .

In order to solve the above problems, the present invention adopts the means of the first to fourth embodiments described below.

The present invention 1 comprises a blast furnace slag fine powder, a classification cement, a polyacrylic acid-based dispersant, and an alkali metal silicate salt as an anticancer agent, wherein the alkali silicate metal salt has a molar ratio (n) in the following general formula (1) ) Is 3.5 or more, 0.2 to 7 parts by mass based on 100 parts by mass of the total amount of the blast-furnace slag fine powder and the classification cement, and the blast-furnace slag fine powder and the classification cement have a Blaine specific surface area value of 7,000 to 16,000 cm2 / g , And a median diameter of 1 to 7 mu m.

R ₂ O · nSiO ₂ (R: alkali metal) (1)

The present invention 2 is a hydraulic cement composition for ground injection according to the first aspect of the present invention, wherein the polyacrylic acid-based dispersant is a copolymer containing a monomer of the following general formula (2) to be.

CH ₂ = C (R ¹ ) COO (R ² O) n R ³ (2)

R ₂ O is an oxyalkylene group having 2 to 4 carbon atoms; n is an integer of 5 to 40; and R ³ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms (wherein R ¹ is a hydrogen atom or a methyl group Lt; / RTI >

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The present invention 3 is a ground improvement method in which the hydraulic cement composition for ground injection according to the present invention 1 or 2 is injected into a ground.

The present invention 4 is a ground improvement method of the present invention 3, which is used for soil improvement for preventing liquefaction.

Herein, "parts" and "%" in this specification refer to mass parts and mass% unless otherwise specified.

INDUSTRIAL APPLICABILITY The hydraulic cement composition for ground injection of the present invention is excellent in permeability and first-class prevention performance, and can exhibit effects such as ground improvement.

The hydraulic cement composition for ground injection of the present invention is composed of a blast furnace slag fine powder, a classification cement, a polyacrylic acid-based dispersant, and an alkali metal silicate as a first-class inhibitor. High Strength and Long-term Durability In order to achieve high permeability, blast furnace slag and classification cement are used.

The blast furnace slag fine powder is used as an admixture for general blast furnace cement or concrete produced by crushing steel slag generated in the production of pig iron.

The blast furnace slag powder is preferably 7,000 cm 2 / g or more, more preferably 7,000 to 16,000 cm 2 / g, and most preferably 9,000 to 13,000 cm 2 / g as the blaine specific surface area value . If it is less than 7,000 cm < 2 > / g, sufficient permeability may not be obtained, and if it exceeds 16,000 cm < 2 > / g, The blaine value is a value measured in a blanket air-permeable device of JIS R 5201.

The median diameter of the blast furnace slag fine powder is preferably 1 to 7 mu m, more preferably 2 to 5 mu m. For example, the median diameter can be measured by a laser diffraction particle size distribution meter. If the thickness is less than 1 mu m, the manufacturing cost is too high to be practical, and if it exceeds 7 mu m, the permeability may be deteriorated.

Classification cement is obtained by adjusting the granularity of cement using a classification facility. As the cement to be classified, it is possible to use Portland cement such as ordinary Portland cement, early strength Portland cement, low heat Portland cement, moderate heat Portland cement, and sulfated cement, The same applies to mixed cements such as fly ash cement and silica cement, as well as refractory cements such as alumina cement.

Classified cement also includes cement, other than cement, which contains dihydrate (gypsum) or calcium carbonate added in the cement manufacturing process. The inclusion of small particles of calcium carbonate by classification is advantageous in terms of strength development.

As with the blast furnace slag fine powder, the blast cement powder preferably has a blast value of 7,000 cm 2 / g or more, more preferably 7,000 to 16,000 cm 2 / g, and most preferably 9,000 to 13,000 cm 2 / g. If it is less than 7,000 cm2 / g, sufficient penetrability may not be obtained, and if it exceeds 16,000 cm2 / g, the manufacturing cost is too high, which is not practical.

The median diameter of the classified cement is preferably 1 to 7 mu m, more preferably 2 to 5 mu m. For example, the median diameter can be measured by a laser diffraction particle size analyzer. If the thickness is less than 1 mu m, the manufacturing cost is too high to be practical, and if it exceeds 7 mu m, the permeability may be deteriorated.

The proportion of the classification cement is preferably 5 to 30 parts, more preferably 10 to 25 parts, per 100 parts of the blast furnace slag fine powder. If the amount is less than 5 parts, sufficient strength development can not be obtained. If the amount is more than 30 parts, there is a fear of impairing permeability.

In the present invention, a polyacrylic acid-based dispersant is used. The polyacrylic acid-based dispersing agent is characterized by being a copolymer containing the monomer of the following general formula (2) to give an effect of suppressing sedimentation of the particles when the suspension solution is prepared and permeability.

CH ₂ = C (R ¹ ) COO (R ² O) n R ³ (2)

In the formula (2), R ¹ represents a hydrogen atom or a methyl group, and R ² O represents an oxyalkylene group having 2 to 4 carbon atoms, such as -CH ₂ CH ₂ O-, -CH ₂ CH ₂ CH ₂ O -, -CH ₂ CH (CH ₃ ) O-, -CH ₂ CH (CH ₂ CH ₃ ) O-, and -CH ₂ CH ₂ CH ₂ CH ₂ O-. n represents an additional moles of the oxyalkylene group and is an integer of 5 to 40; If the addition mole number (n) is too small, the dispersing ability becomes insufficient. On the other hand, if it is too large, it becomes a solid having a high melting point, and handling becomes difficult.

R ³ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, and a butyl group.

Examples of the monomers include polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polybutylene glycol mono (meth) acrylate, and methyl methacrylate having an addition mole number n of alkylene oxide of 5 to 40 moles. Methoxypolyethylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) (Meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, and propoxypolyethylene glycol (meth) acrylate. These may be used singly or in combination of two or more. If a monomer represented by the general formula (2) is contained, a copolymer obtained by combining with a monomer component having another chemical structure may be used.

Among these, a copolymer containing methoxypolyethylene glycol (meth) acrylate or methoxypolypropylene glycol (meth) acrylate is preferable in terms of sedimentation preventing ability and penetration performance.

The weight average molecular weight of the polyacrylic acid-based dispersant is preferably 5,000 to 100,000, more preferably 20,000 to 80,000.

The amount of the polyacrylic acid-based dispersant to be used is not particularly limited, but is preferably 0.1 to 3 parts, more preferably 0.3 to 2 parts, per 100 parts in total of the blast furnace slag fine powder and the classification cement.

In the present invention, a melamine-based dispersant may be used in combination with the polyacrylic acid-based dispersant of the present invention.

The alkali metal silicate is to impart first-class preventive performance to the hydraulic cement composition for ground injection. The first-class prevention performance can be achieved by making the hydraulic cement composition for ground injection into thixotropic.

Here, thixotropy is a property that is difficult to flow like a solid at first, but it is a property that fluidity is obtained like a liquid when a force is applied, and becomes solid again when a force is subtracted. Therefore, in the chemical solution injection method, the fluidity becomes high due to the injection pressure at the time of injection, so that it becomes high permeability that easily penetrates the ground. After injection, the fluidity is lowered because there is no pressure load, and in the hydraulic gradient (hydraulic gradient) of the tidal level of the tide, )I never do that.

The larger the hydrodynamic gradient (hydrodynamic gradient, the water pressure per unit distance in the direction of water flow: the hydrodynamic gradient = the water level / the distance over which the water flows), the more easily the chemical becomes prone. In the case of not using the alkali metal silicate salt, In many cases, drugs are first-class. However, by using the alkali metal silicate in a specific amount in combination, it is possible to prevent the first class of the chemical even if it is 0.1 or more.

In the hydraulic cement composition for ground injection according to the present invention, the alkali metal silicate is an alkali metal silicate having a molar ratio (n) of 3.5 or more in the following general formula (1).

R ₂ O · nSiO ₂ (R: alkali metal) (1)

Examples of the alkali metal silicate include sodium silicate, potassium silicate, and lithium silicate. Among them, sodium silicate is most suitable in terms of stability of supply and cost. As the form of the alkali metal silicate, there are an aqueous solution and a powder. The aqueous solution is mainly used when it is used for a chemical solution injection material because the aqueous solution has many types of commercially available products and good workability.

With respect to the molar ratio (n), when the ratio is less than 3.5, the first-order blocking performance is small and the amount of alkali is large, so that the hydration reaction of the cement is inhibited and the compression strength is lowered. Therefore, the molar ratio (n) needs to be 3.5 or more, preferably 3.7 to 5.0. When the molar ratio (n) is 3.5 or more, the amount of alkali in the alkali metal silicate decreases and the load on the environment is also reduced.

The content of the alkali metal silicate is 0.2 to 7 parts (in the case of an aqueous solution, 0.2 to 7 parts by solid content) relative to 100 parts of the total amount of the blast furnace slag fine powder and the classification cement, preferably 1 to 4.5 parts. When the amount is less than 0.2 part, the first-rate preventive performance is small. On the other hand, if the amount exceeds 7 parts, the viscosity is lowered and the first-stream preventing performance is further reduced, and the permeability is lowered due to the aggregates formed by the alkali metal silicate and cement.

However, the hydraulic cement composition for ground injection of the present invention can be used in combination with a known cement admixture (ash) in a range not adversely affecting the original performance. As the known cement admixture (ashes), there may be mentioned, for example, AE agents, AE water reducing agents, high performance water reducing agents, high performance AE water reducing agents, fluidizing agents, coagulation retarders, crude coagulants, defoamers, thickeners, waterproofing agents, , A shrinkage reducing agent (ash), an antirust agent, a polymer emulsion for cement admixture, and clay minerals.

The hydraulic cement composition for ground injection of the present invention is formed into a milky phase by adding water.

As the amount of water to be added increases, the permeability improves, but the material separation is promoted and the material may block in the press feed hose. The smaller the amount of water, the more the viscosity of the cement milk becomes too large. The optimum range of water to be used is preferably from 400 to 1,500 parts, more preferably from 700 to 1,200 parts per 100 parts by weight of the blast furnace slag fine powder, the classification cement and the polyacrylic acid-based dispersant.

The ground improvement method of the present invention is not particularly limited as long as the soil is improved as long as it is an improvement of a weak ground. For example, various structures such as harbors, shore protection and airports, It can be applied to the ground in which the waterproofing and waterproofing grout, the heaving preventing grout, the settlement preventing grout, the blowing preventing grout, the earth pressure reducing grouting, the supporting force increasing grouting, Can be used. Since the permeability is good, it can be applied to the ground of sandy soil (including sand) and effectively functions as a countermeasure against liquefaction.

In the present invention, the construction method is not particularly limited, and the construction equipment used in the usual chemical solution injection can be used, and it is possible to comply with the injection design and the construction method usually used. For example, a suspension solution prepared by a mixer is pumped through a hose by a pump, and the injection material is injected through a rod disposed in the ground. The rod to be used at that time is not particularly limited, but a single pipe rod, a single-pipe strainer rod, a double pipe rod, and a double pipe type double rod type double rod can be used.

Basically, the hydraulic cement composition for ground injection according to the present invention is injected in one shot. However, depending on the condition and purpose of the ground, a commercially available condensation accelerator and various other admixtures are separately fed under pressure so that 1.5 shots or 2 It is also possible to construct by shot method.

Example

Hereinafter, the present invention will be described in detail by way of examples.

Experimental Example  One

1 part of polyacrylic acid type dispersant and water shown in Table 1 were mixed with 100 parts of blast furnace slag fine powder and blast furnace slag fine powder of 100 parts in total of 20 parts of classification cement and blast furnace slag fine powder and classifying cement, Kneaded with a grout mixer for a minute, and mixed to obtain a kneaded product (kneaded product). Sodium silicate A shown in Table 1 was added as a solid component to a total of 100 parts of the blast furnace slag fine powder and classification cement and kneaded with a grout mixer for 1 minute to prepare an injection material for a hydraulic cement composition for ground injection.

The results of the infiltration (flow down) test for measuring the viscosity, compressive strength, permeability, and the outflow situation, shape, and diameter of the cured product, which serve as evaluation indexes of the first-class preventive performance, are shown in Table 1.

For comparison, 1.0 part of a polyacrylic acid-based dispersant was added to 100 parts of blast furnace slag fine powder, 20 parts of classified cement, 100 parts of blast furnace slag fine powder and classified cement in total, without adding sodium silicate A. Subsequently, 966 parts of water was added to 100 parts of the mixture, kneaded with a grout mixer for 2 minutes and mixed to prepare an injection material for a hydraulic cement composition for ground injection, and the same test was carried out. The results are shown in Table 1.

<Materials Used>

Blast furnace slag fine powder: commercially available blast furnace slag fine powder, blaine value 10,500 cm2 / g, median diameter 3.6 m

Classification Cement: Classified cement which usually classified Portland cement, Blaine value 9,700㎠ / g, Median diameter 4.1 占 퐉, Calcium carbonate content 11.3%

(2), R ¹ is a methyl group, R ² O is an oxyethylene group having 2 carbon atoms, R ³ is a methyl group, R ³ is an alkylene group having 2 carbon atoms, Methyl group, n = 23, and a weight average molecular weight of 42,000. The mass average molecular weight was measured by the GPC method (standard substance: sodium polystyrenesulfonate / water (water)).

Water: Cheongsu

Sodium silicate A: aqueous solution, mole ratio (n) 3.97, SiO ₂ 23.38%, Na ₂ O 6.07%, SiO ₂ + Na ₂ O concentration 29.45%

(N) of 3.69, an SiO ₂ concentration of 21.2%, a K ₂ O concentration of 9.0%, a SiO ₂ + K ₂ O concentration of 30.2%

<Test Method>

Viscosity:

Using a B-type rotational viscometer, the viscosity immediately after completion of the kneading was measured. The temperature at the time of measurement is 25 ° C.

Compressive strength:

80 milliliters of injection material was weighed (referred to as a mold) into a mold having a diameter of 50 mm and a height of 100 mm, and then 306 g of silica sand No. 5 was added. The age of measurement is 28 days.

permeability:

And the preparation method of the stabilized soil by the chemical liquid injection shown in JGS0831-2000. The infiltration state was observed when acrylic resin having a diameter of 50 mm and a height of 1,000 mm was filled with silica sand No. 5 and injected into a simulated ground by hydraulically filling the injection material at a pressure of 0.05 MPa.

Infiltration Test (Flow Down): Outflow situation, shape, diameter of hardened body

The test was carried out in accordance with the permeability test method of the soil indicated in JGS0311-2000. The test conditions were as follows: No. 5 silica sand was charged in a transparent acrylic vessel of φ10 × 23 cm to a porosity of 40.5% to prepare a simulated ground. However, the bottom surface of the acrylic container for making the simulated ground is set with a filter so that water or an injection material flows out. A pipe was set so that the injection material was injected near the center of the simulated ground, and the simulated ground container was immersed in a water-filled container. The simulated soil container immersed in the simulated soil container was set to have a water level difference of 3.5 cm between the top portion of the simulated ground container and the water filled container (water gradient = 0.152) And the outflow state of the injection material from the simulated ground was observed. The state of the injection material cured body retained in the simulated ground is such that the simulated ground container is disassembled after 7 days at the latest and the cured body is taken out from the inside and when the cured body is cured in a substantially spherical shape, Respectively. However, when 120 ml of the injection material is spherical, the diameter of the cured product is 6.1 cm.

Table 1 shows the following.

The viscosity immediately after completion of kneading was 29 to 52 mPa · s in Experimental Nos. 1-2 to 1-8 in which sodium silicate was 0.2 to 7 parts. On the other hand, in Experiment No. 1-1 having no sodium silicate, viscosity was 4 mPa · s, and in Experiment No. 1-9 in which sodium silicate was 8 parts, the viscosity was 5 mPa · s.

The compressive strength was 0.6 to 1.4 N / mm 2 in Experiments Nos. 1-2 to 1-8. On the other hand, the comparative example of Experiment No. 1-1 was 0.5 N / mm 2, and the comparative example of Experiment No. 1-9 was 0.4 N / mm.

With respect to the permeability, in the Experiments Nos. 1-2 to 1-8 and Comparative Example 1-1, which is the comparative example, the acrylic pipe having a height of 1,000 mm was entirely penetrated. On the other hand, in Experiment No. 1-9, which is a comparative example, only the penetration of 760 mm was carried out without permeation.

In Experiment No. 1-9, which is a comparative example in which the content of sodium silicate is 8 parts, which is more than 0.2 to 7 parts per 100 parts in total of the blast furnace slag fine powder and the classification cement, the permeability and the compressive strength are shown in Experiment No. 1-5 , And in the infiltration test, the infusion material was an infinite material because the infusion material flowed out 10 minutes after the infusion and the infusion material did not penetrate uniformly.

In Experiment No. 1-1, which is a comparative example not containing sodium silicate, the same permeability as in Experiment No. 1-5 was obtained, but the compressive strength was somewhat lowered. In the infiltration drop test, Minute, no trace of the cured body was observed, and the ground improvement (reinforcement) effect was not obtained.

Experimental Example  2

The same procedures as in Experimental Example 1 were carried out except that 1.5 parts of sodium silicate shown in Table 2 was used as a solid component in total of 100 parts of the blast furnace slag fine powder and classification cement. The results are shown in Table 2.

<Materials Used>

(N) 4.96, an SiO ₂ concentration of 19.56%, an Na ₂ O concentration of 4.07%, a SiO ₂ + Na ₂ O concentration of 23.63%, a sodium silicate B: aqueous solution,

(N) of 3.74, an SiO ₂ concentration of 24.00%, an Na ₂ O concentration of 6.62%, a SiO ₂ + Na ₂ O concentration of 30.62%

Sodium silicate D: aqueous solution, molar ratio (n) 3.5, SiO ₂ concentration 25.61%, Na ₂ O concentration 7.55%, SiO ₂ + Na ₂ O concentration 33.16%

(N) 3.16, SiO ₂ concentration 28.84%, Na ₂ O concentration 9.43%, SiO ₂ + Na ₂ O concentration 38.27%, sodium silicate E: aqueous solution,

Experiments Nos. 1-5, which contained 1.5 parts of sodium silicate having a molar ratio (n) of 3.5 or more in the general formula (1) as solids of the alkali metal silicate salt in 100 parts in total of the blast furnace slag fine powder and the classification cement, The injection materials of Nos. 2-2 to 2-4 have a high viscosity of 25 to 41 mPa · s immediately after kneading, a high 28-day compressive strength of 0.5 to 0.8 N / mm 2, Furthermore, even in the infiltration test with a relatively large dynamic gradient, there was no leakage, and the cured product was maintained in a substantially spherical shape, which was superior to the first-class prevention performance.

In Experiment No. 2-1 in which the molar ratio (n) of sodium silicate was less than 3.5, the permeability was the same as in Experiment No. 1-5, but the compressive strength was somewhat lowered. In the infiltration- Was a cured product which was irregularly shaped after 10 minutes from the injection.

Experimental Example  3

The procedure of Experimental Example 2 was repeated except that 1.5 parts of sodium silicate A as solid content was used and 100 parts of the blast furnace slag fine powder and classification cement were used and the polyacrylic acid type dispersant shown in Table 3 was used. The results are shown in Table 3.

In Experiment No. 3-1 in which the polyacrylic acid type dispersant was not used, there was no outflow of the injection material in the infiltration test, but permeability was only 500 mm in the permeability test.

Experimental Example  4

The procedure of Experimental Example 2 was repeated with the exception that 1.5 parts of solid sodium silicate A was used in a total amount of 100 parts of the blast furnace slag fine powder and classification cement, and the blast furnace slag powder and classification cement shown in Table 4 were used. The results are given in Table 4.

The permeability of the injection material with the blast value of 7,300 cm2 / g, the blast furnace slag fine powder with the median diameter of 6.3 ㎛, the bane value of 9,700 ㎠ / g and the median diameter of 4.1 ㎛ was 900 mm penetration.

Experimental Example  5

The same procedures as in Experimental Example 2 were carried out except that 1.5 parts of sodium silicate A as a solid component and 100 parts of blast furnace slag fine powder were used for the total of 100 parts of the blast furnace slag fine powder and classification cement . The results are shown in Table 5.

In Experiment No. 5-1 in which no classification cement was used, all penetration was observed in the permeability test, but in the infiltration drop test, the injection material flowed out 5 minutes after the injection, and there was no trace of the cured body, I did.

From the above results, it was confirmed that the blast furnace slag fine powder, the classification cement, the polyacrylic acid-based dispersant, and the alkali metal silicate salt as the antifogging agent, the alkali silicate metal salt had a molar ratio (n) in the general formula (1) The hydraulic cement composition for ground penetration of the present invention, which is 0.2 to 7 parts by weight based on 100 parts of the blast furnace slag fine powder and the classification cement in total, is excellent in permeability and first-class preventive performance and excellent in strength development and long-term durability .

The hydraulic cement composition for ground penetration according to the present invention is excellent in permeability and first-class prevention performance, and is excellent in strength development and long-term durability. Therefore, it can be used for reinforcement of various soft grounds such as measures for liquefaction of sandy soils such as harbors and coastal areas Can be applied.

Claims (5)

Wherein the alkali metal silicate has a molar ratio (n) in the following general formula (1) of not less than 3.5 (inclusive), and the alkali metal silicate as the first- 0.2 to 7 parts by mass based on 100 parts by mass of the total amount of the blast furnace slag fine powder and the classification cement, and the blast furnace slag fine powder and the classification cement have a Blaine specific surface area value of 7,000 to 16,000 cm 2 / g , And the median diameter is 1 to 7 mu m.
R ₂ O · nSiO ₂ (R: alkali metal) (1) The method according to claim 1,
Wherein the polyacrylic acid-based dispersant is a copolymer containing a monomer of the following general formula (2).
CH ₂ = C (R ¹ ) COO (R ² O) n R ³ (2)
(Wherein R ¹ is a hydrogen atom or a methyl group, R ² O is an oxyalkylene group having 2 to 4 carbon atoms, n is an integer of 5 to 40, and R ³ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms) A ground improvement method for injecting a hydraulic cement composition for ground injection according to claim 1 or 2 into a ground. The method of claim 3,
A method for improving the soil properties, characterized in that the method is used for improving the soil to prevent liquefaction. delete