JPH1053763A - Slag-based grout - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a grout which forms, in a certain time, a solid body having strengths similar to those of a hardened cement body and undergoing no degradation with time and which is suitable for a ground improvement method by suspending water-granulated slag and an alkali metal pyrophosphate in water. SOLUTION: This grout of suspension type contains 10-1,500kg/m<3> water- granulated slag, 20-250kg/m<3> (solid basis) alkali metal pyrophosphate, and water. The slag is pref. a by-product of a metal smelting process in a blast furnace, a converter, an electric furnace, an open hearth furnace, etc., and one finely ground into a Blaine value of 8,000-30,000cm<2> /g is still pref. Though inexpensive, sodium pyrophosphate is limited in solubility; and therefore the joint use with potassium pyrophosphate is pref. Water available on site, such as river water, underground water, rain water, tap water, or water contg. sea water, can be used without any limitation. This grout enables a ground improvement excellent in permanency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension type grouting composition containing slag as a main component and capable of arbitrarily adjusting gel time from tens of minutes to several hours, and a ground improvement method using the composition. More specifically, a grouting agent composition comprising a slag and an alkali metal pyrophosphate, the consolidated body of which can achieve a consolidation strength similar to that of cement, and a ground or rock improvement method using the composition, a continuous underground pile or The present invention relates to a method for constructing a continuous underground wall and the like.

[0002]

2. Description of the Related Art Grouting compositions are widely used for the purpose of strengthening and stabilizing soft ground. Various grouting agent compositions (ground injection chemicals) and ground injection methods have been proposed so far, but currently the most frequently used grouting agent compositions are mainly composed of water glass. For example, JP-A-7-166163 discloses a grouting agent containing water glass having a SiO ₂ / Na ₂ O molar ratio of 1.5 to 2.8 and fine particle slag as effective components. As a hardening agent for water glass, inorganic acids such as phosphoric acid and sulfuric acid, bicarbonates such as sodium bicarbonate and sodium bicarbonate, calcium-containing inorganic substances such as cement, lime and slag, and organic acids in alkalis such as glyoxal and ethylene carbonate. Organic monomers to be released and the like are already known.

[0003] In many of the known grouting compositions containing water glass as a main component, the alkali component or the silicate component of the consolidated body is eluted and degraded by groundwater, and the problem of inevitable deterioration of the consolidated strength with time is unavoidable. There is. Therefore, many water glass grouting compositions are generally used as agents for temporary ground improvement for a single period, and are not suitable for long-term temporary or permanent ground improvement.

As a solution to the above-mentioned problem of the time-dependent deterioration of the water glass-based grouting agent composition, for example, JP-A-59-1529
No. 84, JP-A-59-152985 and the like disclose a silica sol grouting agent which can reduce the elution of alkali components into groundwater without using water glass. However, they generally have low consolidation strength and are positioned as temporary or soil stabilizers for temporary use for a relatively short period of time, from several weeks to less than one month.

On the other hand, as a grouting agent composition having a relatively high strength of a consolidated body, for example, a suspension type grouting agent composition mainly composed of cement, as disclosed in JP-A-1-133965, is known. However, it is known that general-purpose cement has a relatively large primary particle diameter of 40 to 60 μm on average, and thus lacks permeability to the ground. In recent years, a method using so-called ultrafine cement with an average of 10 μm or less has been proposed, but there is a problem that only a small amount of the fine cement is still produced and the price is expensive.

On the other hand, a method of using a water-soluble polymer such as polyacrylamide and urea resin as a grout agent for stabilizing the ground has been known for a long time. There are concerns about effects on the human body, and its use is severely restricted.

In recent years, there has been a strong demand for a high strength grouting agent composition which is particularly excellent in durability or durability, and in response to the demand, for example, slags such as granulated blast furnace slag and converter granulated slag. Some so-called slag-based grout compositions containing powder as a main component have been proposed. Typical examples are described in JP-A-6-219796 and JP-A-6-228.
558 and JP-A-7-119138. In these techniques, as an alkali stimulant for realizing the latent hydraulic property of the slag powder, for example, an alkali water glass solution, a sodium aluminate solution, or sodium hydroxide is used. Solution or the like is used. However, most of the solidified slag-based grouting agent compositions using these alkali stimulants have a uniaxial compressive strength of about several tens Kgf / cm ² at the highest, and further strengthening is desired. . At the same time, the alkali stimulants shown in these known techniques can basically be handled only in an aqueous solution. That is, typical known alkali stimulants such as water glass solution Nos. 1 to 3 and sodium aluminate solution are decomposed or deteriorated in a solid state, or are remarkably lacking in resolubility in water. For example, prior dry blending with slag powder is not possible. Therefore, it is necessary to separately measure, mix, and disperse each of them at the injection site, and there are often problems such as measurement errors and addition errors.

[0008] In the above-mentioned homogel compact of the known slag-based grout composition, a so-called self-disintegration phenomenon, in which cracks generally occur due to repeated dry and wet cycles, is often observed. This phenomenon is a serious problem from the viewpoint of permanence. Yes, there is a strong need for improvement. Also, regarding the gel time control method of these compositions, it is clear that those that can be easily adjusted in a wider range are more excellent from the viewpoint of construction management at the actual injection construction site, and in recent years, particularly, There is a strong need for new grouting agents that can be solved.

The Great Hanshin-Awaji Earthquake that occurred in January 1995 caused a great deal of damage to important structures that had been built on soft ground. It can be said that issues such as a method of ensuring safety for all important structures and a method of permanently strengthening earthquake resistance were also raised. In particular, there is an urgent and strong demand for ensuring the seismic safety of important structures constructed or about to be constructed on liquefied ground in major urban areas. The use of underground space is also being actively used in soft ground, but it is essential to strengthen and stabilize the ground during underground construction work, and there is a strong demand for medium- and long-term advance ground stabilization and stabilization.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a grouting agent composition having excellent compaction strength characteristics for various types of ground and capable of arbitrarily adjusting the gel time within a range of several minutes to several hours. The present invention also provides a novel slag suspension grout agent having a uniaxial compressive strength of the homogel and the sandgel compact as high as that of the cement compact and having high durability and free from problems such as a self-disintegration phenomenon. That is.

Another object of the present invention is to allow safe handling and, at the same time, dry-blend the active ingredients of the grout agent composition in a predetermined amount and supply them in a one-pack package. Another object of the present invention is to provide a highly reliable grouting agent that can reduce compounding errors and complexity of drug preparation. Still another object of the present invention is to provide a method for strengthening and stabilizing soil with unstable soil such as soft ground or rock crack using the grout composition.

[0012]

Means for Solving the Problems The present inventor added an aqueous solution of an alkali metal pyrophosphate to granulated slag, whereby slag particles having no self-hardening property were gradually gelled and solidified within a certain period of time. That, to confirm that a solid compact comparable to the hardened material whose main component is the same as the suspended component of the cement is formed, and that no self-disintegration phenomenon is observed, etc. The present invention has been completed. That is,
The invention 100~1,500k a 1 m ³ per slag
g, alkali metal pyrophosphate in an amount of 20 to 25 in terms of solid content.
It is a suspension type grouting agent composition containing 0 kg and water.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The granulated slag of the present invention is preferably a granulated slag of a metal smelting by-product such as a granulated blast furnace slag, a converter granulated slag, an electric furnace granulated slag, and a flat furnace granulated slag. can give. More preferably, 30 to 35 wt% as SiO ₂ minutes, 35 to 45 wt% as CaO content, 13 to 20 wt% as Al ₂ O ₃ minutes, 5 to 8% by weight MgO component, several weight and other components % Blast furnace granulated slag composed of various composition ratios such as slag.

As the granulated slag, metal smelting slowly cooled slag is excluded from the present invention. The reason is that the slowly cooled slag is a crystalline slag and has no latent hardening property. However,
In the granulated slag component of the present invention, a small amount of a crystalline component may be mixed, and it is basically preferable to use an amorphous granulated slag obtained by a so-called slag method of a water cooling method. it can.

Generally, granulated slag (also referred to as slag slag, hereinafter simply referred to as slag) does not exhibit self-hardening by itself. However, in an aqueous solution in the coexistence of alkali or in a high humidity environment, SiO ₂ and Al ₂ O ₃ components are eluted, and then Ca ions are eluted to form calcium silicate hydrated crystal gel on the surface of slag particles. However, it is well known that the particles gradually solidify and gel to form a solidified body over time, whereby a consolidated body is finally obtained, and the uniaxial compressive strength characteristics of the consolidated body increase with time. Have been. At this time, if the amount of alkali used is too small, gelation does not take place at all, and if it is too large, the slurry viscosity is too high and the liquid cannot be pumped due to poor fluidity, or the viscosity change is remarkable. For this reason, it is a general fact that the ground injection is interrupted or impossible at all, and the alkali metal pyrophosphate of the grout composition of the present invention is no exception.

The preferred primary particle size distribution of the granulated slag which can be used in the present invention is 3,000 cm in Blaine value which is an index indicating the specific surface area of the fine powder obtained by the cell aeration method recommended by the Concrete Association. ² / g or more, and the maximum particle size is 300μm or less, also 5,000 cm ² / g or more preferably in Blaine value, 30,000 more preferably 8,000Cm ² / g or more ² /
g or less, and the maximum particle size is 10 μm.
m or less, more preferably 8 μm or less, and still more preferably 6 μm or less.
It is preferable that the particles are ultrafine particles having a size of not more than μm.

[0017] Brain value is 3,000 to 5,000 cm
^{Even if 2} / g is used, it is basically possible to produce a high-strength compact. However, it has poor soil permeability and is unsuitable as granulated slag for pouring ground. However, the granulated slag used in the grouting agent composition for the jet grouting method and the deep mixing treatment method can be used without any problem. From the viewpoint of completely securing the ground permeability, the slag has a Blaine value of 8,000 to 30,000 cm ² /
g, more preferably 10,000 to 3 g.
It was processed to an unlimited fine powder of 000 cm ² / g.

[0018] The amount of granulated slag is a grout total amount 1m ³ per 100~1,500kg. Preferably 150 to
It is 1,000 kg, more preferably 200-800 kg. If it is less than 100 kg, it is difficult to gel within a few hours, and the coagulation is slow, and the strength of the final consolidated body is poor. If it exceeds 1,500 kg, the viscosity of the suspension solution becomes too high. Lack of fluidity and injection workability.

Specific examples of the alkali metal pyrophosphate of the present invention include sodium pyrophosphate, potassium pyrophosphate, lithium pyrophosphate and the like, and one or a mixture of two or more thereof may be used. Among these, potassium pyrophosphate and sodium pyrophosphate are preferred because they are particularly inexpensive and readily available on the market, and potassium pyrophosphate is more preferred because of its high saturation solubility in water.
Sodium pyrophosphate and the like have a great limitation on the solubility in water, and it may be difficult to dissolve the intended use amount alone. In such a case, the undissolved weight may be used in combination with another soluble, for example, potassium pyrophosphate.

There are no particular restrictions on the method for producing the alkali metal pyrophosphate. For example, sodium pyrophosphate is dehydrated by heating and dissolving disodium hydrogenphosphate crystals, and potassium pyrophosphate is dehydrated by heating and dehydrating crystals of dipotassium hydrogenphosphate. It is known that salts are each easily obtained. The alkali metal pyrophosphate may be basically recognized as a food additive, and is preferably used because it has little effect on the human body and has no pollution. In addition, any of an anhydride and a hydrate may be used, and there is no particular limitation.

The content of the alkali metal pyrophosphate is 20 to 250 k / m ^{3 of the} total amount of the grouting agent in terms of solid content.
g, preferably 50-200 kg, more preferably 10
0-200 kg. If it is less than 20 kg, the grout solidification strength is low and the durability is poor, and if it exceeds 250 kg, not only a remarkable effect is not found but also the cost is high. Basically, it is important that the pH value of an alkali metal pyrophosphate when used as an aqueous solution is alkaline, and so-called alkali metal pyrophosphates in which the aqueous solution exhibits acidity are excluded from the alkali metal pyrophosphate of the present invention. Is done.

The fine powder of the granulated slag of the present invention and the solid or powdered alkali metal pyrophosphate may be used by dry blending in advance. Rather, one of the objects of the present invention is to provide a composition for a grouting agent which is highly durable and durable so that the raw materials can be supplied in one-pack packaging. Providing to the ground injection site is for this purpose. After the dry-blended packaged and supplied composition is opened, the grout composition of the present invention can be easily and easily prepared on site by simply dissolving / suspending with a predetermined amount of water. In addition, it can be used as a material for a so-called powder injection stirring method in which the powder is injected and stirred into the ground as it is.

Water is essential for the slag of the grout composition of the present invention to exhibit curability and to form a suspension. Water may be available near the injection site and is not particularly limited. For example, river water, snow, ice, lake water, groundwater,
Spring water, rainwater, tap water, industrial water, seawater-containing water, ion-exchanged water, pure water, and the like may be used. Preferably, tap water, groundwater and river water are used. When the powder is sprayed into the ground and used, the grout of the present invention is suspended by the groundwater.

The grout composition of the present invention basically comprises granulated slag, alkali metal pyrophosphate and water. If necessary, various additives shown in the following (a) to (e) may be used. One or more of the additives, preferably (a) to (c), can be used in combination. (A) Gel time regulator (b) Non-hydraulic inorganic fine particles (c) Water reducing agent for cement (d) Setting retarder for cement (e) Surfactant

As the gel time regulator (a),
Or an inorganic calcium compound such as a tertiary alkali metal phosphate, a second or third alkaline earth metal phosphate, slaked lime powder, quicklime powder, cement fine powder, gypsum fine powder, or a water-soluble material such as calcium lactate or calcium tartrate. Examples thereof include organic calcium salts of carboxylic acids or dicarboxylic acids, and calcium complexes such as calcium saccharate, and one or more of these can be used. Preferred are second or third alkali metal phosphates and second or third alkaline earth metal phosphates. Examples of the second alkali metal phosphate include disodium hydrogen phosphate, dipotassium hydrogen phosphate, and dilithium hydrogen phosphate. Examples of the third alkali metal phosphate include trisodium phosphate, tripotassium phosphate, and trilithium phosphate. Examples of the second alkaline earth metal phosphate include calcium hydrogen phosphate and magnesium hydrogen phosphate, and examples of the third alkaline earth metal phosphate include calcium phosphate and magnesium phosphate. These (a) gel time regulators are preferably used in an amount of 0.1% in terms of solids per m ^{3 of} total grout.
01-5 kg is used.

(B) The non-hydraulic inorganic fine particles have a primary particle diameter of 5 to 300 μm. For example, in the case of powder, fine particles of silicon oxide such as white carbon or aerosil, calcium carbonate powder, magnesium carbonate powder , Titanium white powder, zinc hydroxide powder, aluminum hydroxide powder, magnesium hydroxide powder and the like. These can be obtained as a powder or a suspension, and any of them can be used. Further, a commercially available aqueous colloidal silica solution or the like can be used. (B) the grout total amount 1m ³ per 20-25
0 kg can be contained.

In particular, the use of an aqueous colloidal silica solution as (b) is preferable because the viscosity is low and the uniform stability of the system in a standing state is remarkably improved. As the aqueous colloidal silica solution, a product obtained by a known method may be used. Generally, an alkali component in an alkali water glass solution is removed with an ion exchange resin, so that 10 to 30 parts are contained in the solution.
After generating silica particles of ultra-micro size of mμ size, a product obtained by a method such as securing a long-term storage stability by adding a trace amount of an alkali component such as caustic soda or potassium caustic again is generally preferable. Can be used. More specifically, 5 to 5 in terms of solid content of the active ingredient represented by SiO ₂
A 0% by weight solution may be used. Its use amount is 20 to 250 kg in terms of solid content, more preferably SiO ₂
100 to 200 kg of a 20 to 30% by weight aqueous solution of the active ingredient represented by the following formula is used.

As is evident from many documents, colloidal silica itself is amorphous like a general alkali water glass component, and basically has an ability to gel by contact mixing with a known curing agent. Therefore, even when used as a part of the grout agent component of the present invention, there is no adverse effect on the grout workability and the physical properties of the compact. Rather, it is one of the necessary and sufficient additives to ensure the stable workability of the grout agent composition for a long time until gelation.

(C) As the water reducing agent for cement, a known water reducing agent for cement can be used, and there is no particular limitation. For example, melamine-based, naphthalene-based, lignin-based,
Examples thereof include polycarboxylic acid-based and cross-linked polycarboxylic acid-based water reducing agents for cement, and the like may be used as appropriate. Preferably, a relatively inexpensive melamine-based or naphthalene-based water reducing agent for cement is used, or a mixture thereof.
The amount of cement water reducing agent, grout total 1 m ³ per 1
50 kg, preferably 1-30 kg, more preferably 1
１５15 kg.

(D) Examples of the setting retarder for cement include known setting retarders for cement, and are not particularly limited. Examples thereof include monosaccharides such as sucrose, fructose and glucose, disaccharides, polysaccharides, and the like. Further, for example, organic acid compounds such as lactic acid, malic acid, glycolic acid, itaconic acid, maleic acid, and succinic acid, and clathrate forming agents represented by, for example, urea, cyclodextrin, and the like can be mentioned. The amount used is less than 50 kg per 1 m ^{3 of} total grout, and preferably 0.1 to ³⁰ kg in a commercially available form.

(E) Examples of the surfactant include various known cationic soaps, anionic soaps, amphoteric soaps, and nonionic soaps. Further, aqueous silicon compounds, polyvalent water-soluble glycols such as ethylene glycol and glycerin, and 3,6-dimethyl-4-octyne-3,6-diol and 3,5-dimethyl-1-hexyn-3-ol. An acetylene alcohol-based antifoaming agent is also a preferred example. The amount is less than the total amount grout 1m ³ per 5kg,
Preferably, it is in the range of 0.1 to 3 kg in a commercially available form.

The above-mentioned auxiliary additives (a) to (e) need to be used after confirming in advance that there is no adverse effect on the basic performance of the grout composition of the present invention. Together within a range that does not interfere with In addition to the above, an organic so-called cement particle sedimentation / separation reducing agent may be used in combination in the grout composition of the present invention, and examples thereof include methylcellulose, hydroxycellulose, soluble starch, and polyvinyl alcohol.

The grout composition of the present invention may be in the form of one liquid or two liquids, or may be three or more liquids. The handling form can be arbitrarily selected and is not particularly limited. Among them, a grouting agent consisting of one or two liquids is preferable. When the curing time of the grout agent composition of the present invention is as short as, for example, about 20 minutes, it is basically preferable to use two liquids. A preparation and injection method for forming a product is preferred.

The form of the two liquids is not particularly limited, but is generally a water suspension of granulated slag powder as a main liquid and an aqueous solution containing an alkali metal pyrophosphate as the other alkali stimulant liquid. It is most common. The additives (a) to (e), which can be added as needed, are appropriately contained in one or both of the liquids. Further, as another embodiment of the two liquids, for example, as the main liquid, a suspension composed of granulated slag, water and a very small amount of alkali metal pyrophosphate, and the other alkali stimulant liquid as the remaining liquid And an aqueous solution containing an alkali metal pyrophosphate.

The curing time of the grout composition of the present invention is
For example, if the time is as long as 30 minutes to 1 hour, basically 1
A method in which the grout composition is made into a liquid and the grout agent composition is press-fitted and discharged from a single injection tube can be preferably employed. There are no particular restrictions on the mixing procedure, adjustment method and the like of the one-pack type. For example, granulated slag powder, alkali metal pyrophosphate powder and, if necessary, an appropriate amount of an auxiliary additive are charged in advance, and then dispersed and dissolved in a predetermined amount of water to form one liquid, or vice versa. First, water is charged, and then granulated slag powder is charged and dispersed and dissolved.
It may be a liquid. Also, as described above, granulated slag, alkali metal pyrophosphate and, if necessary, an appropriate amount of a solid additive aid are dry blended, packed in one pack, stored and transported.
After the supplied product is opened at the injection site and then dispersed and dissolved in a predetermined amount of water, there is a one-liquid-mixing method. This is a more preferable on-site preparation method.

The ground improvement method of the present invention is the following method. That is, this is a ground or rock improvement method in which the grout agent composition of the present invention is press-fitted into an unstable ground or rock crack gap in the ground with one liquid via a grout injection pipe and solidified. The grout agent composition of the present invention adjusted to one solution is applied through a plurality of grout injection pipes usually buried deep in the ground while applying a pressure of approximately 1 to 50 kg / cm ² as a gauge pressure to the area around the grout pipe embedding. This is a method of stabilizing the unstable ground as a whole by injecting it into unstable ground and consolidating it. Injection consolidation at the top and bottom of the injection range can be achieved by continuing to press-in the chemical solution while gradually pulling out the grout injection tube. In addition, when injecting a rock crack gap, the grouting agent of the present invention is prepared by liquefying it into one liquid, and is pressed into an underground unstable ground or a rock crack gap through a grout injection pipe and solidified, thereby solidifying the ground or the rock. It is preferable to use a method of strengthening and stabilizing the injection work because the injection operation is simple.

Next, as a method of constructing a continuous underground pile or a continuous underground wall using the grout composition of the present invention, as an example, a continuous gap in the ground formed by discharging water at an extremely high pressure is described. There is a method of constructing a continuous underground pile or a continuous underground wall by using it as an injection agent for a so-called jet grouting method, which is press-fitted and consolidated through a grout injection pipe. Further, a powder obtained by suspending or dry-blending the grout agent composition of the present invention through an injection mixing pipe lowered into the ground and through a discharge hole provided near the tip of the injection mixing pipe. By discharging the mixture in a body shape and pulling up or down the mixing tube while mixing with the surrounding earth and sand and continuing or repeating the same operation, the earth and sand around the injection tube and the grout agent composition of the present invention are integrally mixed. And a method of constructing a continuous underground pile or a continuous underground wall by a so-called deep mixing treatment method. Regarding the improved sectional shape,
Taking into account the construction conditions, a pile type, a lattice type, a wall type, a block type, etc. can be applied.

The ground improvement application using the grout composition of the present invention is, in addition to the above-mentioned applications, a ground improvement application mainly for water stoppage, and a gel time of 10 seconds or less among known general-purpose grout agents. The use of a so-called flash-setting agent exhibiting the instantaneous gelation behavior is selected and used, and the ground improvement application by double-phase injection performed by combining the drug with the long-curing type agent of the present invention for about 30 minutes to 1 hour. Can be

[0039]

EXAMPLES Examples and comparative examples of the present invention are shown below.
The present invention is not limited by the examples. Further,% and parts in the examples mean weight% and part by weight, respectively, unless otherwise specified, and L and mL mean liter and milliliter, respectively.

[Materials Used] Granulated slag Commercial blast furnace granulated slag (trade name: Fine Cementment)
It was used. However, the Blaine value is a measured Blaine value obtained by the cell ventilation method specified by the Concrete Association. Table 1 shows the results of slag types and brane values.

[0041]

[Table 1]

2. Alkali stimulants Sodium pyrophosphate, potassium pyrophosphate and sodium acid pyrophosphate were each used as reagents. In the aqueous solution containing the alkali metal pyrophosphate, the active ingredient content is 10 to 40.
% (No. 1 to No. 5). The composition is shown in Table 2 below.

[0043]

[Table 2]

3. Disodium hydrogen phosphate (reagent product) was used as an additive (a). 4. A commercially available aqueous colloidal silica solution (trade name: Cataloid) was used as the additive aid (b). The solution is S
The active ingredient concentration of iO ₂ is 30%, the pH value is 9.5, and the primary silica gel particle size is 20 mμ. 5. Melamine type water reducing agent which is a water reducing agent for cement as additive aid (c) (Mitsui Toatsu Chemicals product: Melflow 40)
It was used. 6. As the additive aid (d), citric acid (reagent product) in the form of solid powder, which is a kind of setting retarder for cement, was used.

Example 1 500 parts of the alkali stimulant No. 1 in a ratio shown in Table 3 was placed in a 5 L mixing vessel, and 500 parts of No. 2 slag was added under vigorous stirring. Tap water was added to make 1 L, and the mixture was stirred and mixed for 1 minute. The suspension-like grouting agent of Example 1 thus obtained was evaluated by the following method.

The gel time was measured as follows. Based on the time when the addition of the slag to the alkali stimulant was completed, the elapsed time from when the prepared liquid mixture lost its fluidity when it was tilted from the standing state was measured, and this was defined as the gel time. -4.

The permeability was measured as follows. Using 500 mL of the liquid immediately after completion of the stirring, a transparent acrylic cylindrical container (50 mm in diameter, 1 m in length) is filled in advance with a height of 5 mm.
From the upper part of the Toyoura standard sand layer laminated to be 0 cm,
Penetration was carried out under a constant pressurized state at an osmotic pressure of 1 kg / cm ² through a porous shielding guide plate having a hole diameter of about 1 mm.
When permeation into the gaps between the standard sand particles by visual observation from the outside, the permeation layer gradually becomes opaque due to the cloudy suspension color of the slag itself toward the bottom. Was determined, and the case where the entire area filled with the standard sand layer was visually observed in the above state was judged to be good permeability (pass). The results are shown in Table-4.

The syneresis water, the uniaxial compressive strength and the self-disintegration were evaluated as follows. Immediately after the completion of the stirring, the mixture was filled into a mold (50 mmφ × 100 mm), and the mold was removed one day later. The amount of syneresis water generated at this time was measured, and the volume ratio to the cured product was calculated and evaluated in four steps. The presence or absence of self-disintegration was determined by immersing the homogel removed from the mold in tap water for 1 hour, wiping off the surface moisture, and then leaving it in the air for 1 hour. This operation was repeated five times, and visual observation was performed, and a sample in which no crack was observed was judged to have no self-disintegration (pass). Regarding the uniaxial compressive strength, the obtained homogel was cured for 7 days in water and then subjected to measurement. The crosshead speed at this time was 1 mm / min. The results are shown in Table-4.

The evaluation of the durability was carried out by the following method.
The results are summarized in Table-5. The compounded liquid prepared according to Table-3 and Toyoura standard sand were mixed at a weight ratio of 1: 4,
A sand gel obtained by filling a mold (50 mmφ × 100 mm) and demolding after 1 day is cured for 7 days, 1 month, 3 months, 6 months and 12 months in water, and then measured for uniaxial compressive strength for durability. Was evaluated.

Further, after the mold was released from the mold, X-ray diffraction measurement was performed on the homogel cured in water for 7 days and a cured ordinary cement (mixed and cured ordinary Portland cement and city water). The obtained chart is shown in FIG. The main peaks (circles) of the two charts in FIG. 1 completely coincide with each other, and it is clear that the calcium silicate hydrate crystal has a lattice spacing of 3.03 Å.

Examples 2 to 19 According to the formulations shown in Table 3, a mixture was prepared in the same manner as in Example 1, and the physical properties were evaluated using the same evaluation method as in Example 1. In Examples 13 and below, the auxiliary additive was added after the alkali stimulant and water, and finally slag was added to obtain a predetermined mixed liquid. The results are summarized in Table 4. Regarding the evaluation of the durability, Examples 5, 9, 14, and 15 were performed in the same manner as in Example 1. The results are summarized in Table-5.

Examples 20 and 21 A dry mix pack was prepared using slag and an alkali stimulant so as to have the same amount of active ingredient as in Examples 1 and 2 (using an aluminum-polyethylene laminate bag; sealing by heat sealing) ) And after storage for 3 months, required amount of tap water was added and stirred, and physical property evaluation and durability evaluation were performed in the same manner as in Example 1. As a result, the results were completely equivalent to those of Examples 1 and 2.

Reference Examples 1 and 2 and Comparative Examples 1 to 9 According to the formulations shown in Table 3, a mixture was prepared in the same manner as in Example 1, and the physical properties were evaluated using the same evaluation method as in Example 1. The results are summarized in Table 4.

Comparative Examples 10 and 11 In accordance with the composition shown in Table 3, a liquid mixture composed of water glass and slag was prepared, and the physical properties were evaluated in the same manner as in Example 1. The results are summarized in Table 4.

Working Example 1 Using the compositions of Examples 1 and 10, a working test (grout suitability) was carried out on a model ground. The model ground was filled into a pool of 3m square and 1m depth with sand having an average particle size of about 200μm equivalent to the standard sand in a wet state.
It was made to stand for 0 days. Using a pump, the mixed liquid was injected at a pressure of 0.5 kgf / cm ² through a 2 cm diameter pipe penetrated into the center of the model ground, and the pipe was gradually pulled out, and the diameter was generally 20 cm and the depth was 50 cm. In a cylindrical area. After digging out 7 days later and observing each part, a uniform infiltrated solid was formed at any part. No cracks or significant volume shrinkage were observed,
The pH of the pore water outside the permeation range hardly changed compared to before the permeation.

Construction Example 2 Using the compositions of Examples 1 and 10, a construction test (suitability for jet grout) was performed on the model ground. A model ground was prepared in the same manner as in Construction Example 1, and the ground was cut by injecting water with air at a high pressure (20 kgf / cm ² ) while rotating the injection pipe using an experimental jet grout apparatus. The mud drainage is discharged out of the ground, and at the same time, the mixed liquid is filled. Thereafter, the injection pipe is gradually pulled out to obtain a columnar shape having a diameter of approximately 20 cm and a depth of 50 cm. Put this operation on a horizontal straight line 15cm
Repeated 5 times at intervals. When the surrounding area was dug up seven days later, a continuous wall was built over the entire press-fitting area. No cracks or significant volume shrinkage were observed in each part,
The pH of the pore water outside the injection range hardly changed compared to before the injection.

Working Example 3 Using the compositions of Reference Examples 1 and 2, a working test (suitability for jet grout) was carried out on the model ground in the same manner as in Working Example 2. Although slag (No. 1), which is not very suitable for infiltration, was used, jet grout suitability was good, and there was no difference from the case of Construction Example 2, and a continuous wall was constructed over the entire press-fitting range. No cracks or remarkable volume shrinkage were observed in each part, and the pH of the pore water outside the injection range hardly changed as compared to before the injection.

Working Example 4 Using the compositions of Examples 1 and 10, a working test (suitability for deep mixing treatment) was carried out on the model ground. Construction example 1
A model ground is prepared in the same manner as described above, and the mixed liquid is sprayed at a pressure of ² kgf / cm ² from the injection port immediately below the stirring blade while rotating the stirring blade (mixing radius 10 cm) by the experimental mixing processing device. By gradually pulling out the stirring blade, a cylindrical shape having a diameter of approximately 20 cm and a depth of 50 cm is obtained. This operation was repeated five times at a 15 cm interval on a straight line in the horizontal direction. After excavation of the surroundings after 7 days, a continuous wall had been constructed over the entire mixed treatment area. No cracks or remarkable volume shrinkage were observed in each part, and the pH of the pore water outside the mixing treatment range hardly changed as compared to before the injection.

[0059]

[Table 3]

[0060]

[Table 4] -In each case, water is added to the above mixture to make 1 L.

[0061]

[Table 5]

[0062]

[Table 6] (Explanation of symbols in Table 2) [Permeability] ：: Permeable to standard sand [Synthetic water] ：: 0.1% or less ×: Impossible to standard sand ○: 0.1 to 1% [Self-disintegration] ：: not visible to the naked eye Δ: 1 to 5% ×: visible to the naked eye ×: 5% or more

[0063]

[Table 7]

[0064]

According to the results of the evaluation of physical properties (Table 4), in Examples 1 to 21, the gel time was about 20 to 12.
The result that the uniaxial compressive strength was 20 kgf / cm ² or more for 0 minute was obtained. Both have no problem in permeability. Example 1
From the results of Nos. To 12, the grouting agent having good properties can be obtained by combining only the slag and the alkali metal pyrophosphate if the materials and the mixing ratio are within the range of the present invention.

Of these, Examples 1-4 show that good properties can be maintained when the alkali metal pyrophosphate within the scope of the present invention is used. , The same is shown for a combination with a slag having a larger specific surface area. Further, if the amount of the slag in Examples 7 to 10 and the amount of the alkali metal pyrophosphate in Examples 11 and 12 are within the range of the present invention, a grout agent having good properties can be obtained. Is shown.

On the other hand, Examples 13 to 19 show that the use of several kinds of chemicals as additives has the effects of adjusting the setting time and increasing the strength without impairing the effects of the present invention. Of these, in Examples 13 and 17,
By adding disodium hydrogen phosphate, the gel time can be extended, and the same effects as described above can be observed in the systems to which citric acid is added as in Examples 16 and 18. Example 1
4, 17 to 19, the addition of colloidal silica did not cause a decrease in strength or the like, and showed an effect of improving stability.

Further, as shown in Example 15, a water reducing agent could be added. Further, in Examples 20 and 21, it is shown that even when a necessary ingredient is made into a dry pack and suspended in water to prepare a grout, the same result as that obtained when the grout is prepared by an ordinary method is obtained.

Compared with the above example, when non-particulate slag is used as in Reference Examples 1 and 2, the slag hardens, but the permeability is not sufficient assuming the permeation injection. Applicable only to construction methods that do not require the penetration of construction methods. When an alkali stimulant outside the scope of the present invention is used as in Comparative Examples 1, 2, and 9, no curing is observed within at least 24 hours. Comparative Examples 3 and 4
When the amount of the alkali stimulant is less than the lower limit as described above, or when the amount of the slag is less than the lower limit as in Comparative Examples 5 and 6, no curing is similarly observed within at least 24 hours. On the other hand, when the amount of slag is excessive with respect to the amount of water as in Comparative Examples 7 and 8, the slag becomes paste from the initial stage of mixing, and the permeability is extremely poor. Furthermore, as in Comparative Examples 10 and 11, in the conventional slag-based grouting agent using water glass, the uniaxial compressive strength is not as high as that of Examples, and a self-disintegration phenomenon is also observed, which is not preferable as a permanent grout. .

On the other hand, from the results of the above evaluation of the durability (Table 5), the change with the lapse of time in any of the formulations is in the direction of increasing the strength. This is presumed to be due to the complete hydration and coagulation of the unhydrated particles, but no self-disintegration phenomenon was observed and permanent strength retention was observed.

Further, as shown in Construction Examples 1, 2 and 4, the grouting agent of the present invention has a workability sufficient for construction with ordinary ground improvement equipment, and provides a good reinforced ground or continuous ground. An intermediate wall may be formed. Further, as shown in Construction Example 3, for applications other than infiltration injection, coarse particle slag (No. 1) that is not suitable for infiltration injection can also be used.

In summary of the above results, the use of the slag-based grouting agent of the present invention has remarkable effects in the following points. It shows a compressive strength of 1.50 kgf / cm ² or more, and is comparable to hardened cement. It has good durability, is stable against repeated wet and dry, and has no self-disintegration phenomenon. The crystal structure is the same as that of the hardened cement. 2. By limiting the particle size of the slag, the initial viscosity can be reduced and the permeability to the soil can be improved, and the method can be applied to the method of infiltration into almost all the ground. The jet grouting method, the deep mixing method and the like can be applied regardless of the slag particle size. Further, the injection pressure into the ground or the like can be set low, and high-speed injection can be performed. 3. Third, the reproducible gelation / consolidation time of several tens minutes to several hours can be arbitrarily and stably adjusted easily, and an appropriate gel time can be selected depending on the application example. 4. The powder of the alkali metal pyrophosphate can be dry-blended with the granulated slag powder, and the mixed powder composition is stable for a long period of time and can be supplied to the grouting site in one pack. Therefore, it is possible to easily establish a supply system in a form that completely conforms to the demands of any grouting manufacturer in advance, and there is no compounding mistake at the site. As a result, the setting reliability of the grouting agent of the present invention and the injection work Stability is ensured. 5. An environmentally friendly grouting agent that does not contain hazardous or harmful substances and has no pollution to groundwater or the like.

[Brief description of the drawings]

FIG. 1 shows the X of the cured product of Example 1 obtained from the grouting agent of the present invention (a) and a cured product of ordinary cement (mixed and cured of ordinary Portland cement and city water) (b)
FIG. 3 is a diagram illustrating a line diffraction chart (XRD chart).

Claims (9)

[Claims] 1. A granulated slag of 100 to 1,5 per m ³
00 kg, an alkali metal pyrophosphate of 20
A suspension-type grout composition comprising 〜250 kg and water. 2. The granulated slag has a Blaine value of 8,000 to 3
2. The grout composition according to claim 1, which is a granulated slag having a particle size of 000 cm ² / g. 3. The grouting composition according to claim 1, wherein the granulated slag is granulated blast furnace slag. 4. A gel time regulator further comprising 0.01 to 5 kg of a second or third alkali metal phosphate or a second or third alkaline earth metal phosphate in terms of solid content per 1 m ^{3 of} grout. The grout composition according to any one of claims 1 to 3. 5. A non-hydraulic fine particle having a primary particle diameter of 5 to 300 μm is added in an amount of 20 to 25 per m ^{3 of} total grout.
The grout composition according to any one of claims 1 to 4, comprising 0 kg. 6. The grout composition according to claim 1, further comprising 1 to 50 kg of a cement water reducing agent per 1 m ³ of grout. 7. The grout agent composition according to any one of claims 1 to 6 is press-fitted as a single solution into a ground crack or a crack in an unstable ground or a bedrock through a grout injection pipe. The ground or bedrock improvement method to be made. 8. The grout agent composition according to claim 1, which is press-fitted into a continuous gap in the ground formed by discharging water at an ultra-high pressure via a grout injection pipe and solidified. A method of constructing a continuous underground pile or a continuous underground wall, wherein the method is used as an injection agent for a so-called jet grouting method. 9. The grout composition according to any one of claims 1 to 6 is discharged from a discharge hole provided near an end of the injection mixing tube via an injection mixing tube lowered into the ground. By pulling up or pulling down the injection mixing tube while mixing with the surrounding earth and sand and continuing or repeating the same operation, the earth and sand around the injection tube and the grout agent composition are integrally mixed and consolidated. A method of constructing a continuous underground pile or continuous underground wall by the so-called deep mixing method.