JPH01122952A - Material for solidification - Google Patents

Abstract

PURPOSE:To obtain a solidification material having high strength and long-term solidification strength and high permeability, by using an alkali metal silicate and fumed silica as silica components and adding a polyvalent metal compound or a cement as a solidifying material. CONSTITUTION:The objective solidification material contains an alkali metal silicate and fumed silica as essential silica components and a polyvalent metal compound or a cement as a solidifying material. The alkali metal silicate is a liquid or powdery water-glass such as water-glass #3, sodium orthosilicate or sodium metasilicate especially having a low molar ratio of SiO2/Me2O, i.e., <=2.5. The water-glass may be produced by using a water-glass having high SiO2/Me2O molar ratio and adding an alkali to the high-molar ratio water-glass to lower the ratio to <=2.5. The polyvalent metal compound used as a solidifying material is polyvalent salt, base, oxide, etc., of Ca, Al, Fe, Mg, etc., especially preferably lime.

Description

[Detailed description of the invention] [Industrial application field] The present invention contains amorphous ultrafine particle silica (silica fume) in addition to an alkali metal salt of silicic acid as the silica component, and is mainly used as straw material for ground injection. Concerning consolidation materials, they not only exhibit particularly high strength, but also have high long-term consolidation strength, excellent permeability, and easy adjustment of gelation time. Concerning consolidation materials that can be adjusted to obtain high strength.

[Conventional technology]

Conventionally, cement grout or water glass grout has been used as straw material for ground injection, and injection materials containing non-colloidal silica alkaline solutions, calcium salts, etc. have been known. Furthermore, injection materials containing salt and ultrafine silica particles obtained by removing alkali metals from water glass using an ion exchange resin have also been used.

[Problem that the invention seeks to solve]

However, since cement grout has large particles, it can penetrate into fine-grained soil, and the cement content in the grout and mixed water separate in the ground, and this mixed water itself does not solidify, so it can be used as a stopper in sandy ground. The water effect was insufficient.

In addition, although the entire mixed liquid of water glass grout is sold, the strength of the gel itself is low, the strength decreases over time, and the shrinkage is large, resulting in insufficient long-term durability.

In addition, injection materials containing an alkaline solution of non-colloidal silica and calcium salts not only have an insufficient reaction of the material, but also have an unclear gelation time and tend to leak out of the injection target, and the alkaline content Easy to elute.

Furthermore, the above-mentioned injection material containing ultrafine silica and salt cannot increase the concentration of silica, making it difficult to obtain high strength. If too much salt (or base) is used, gelation will occur immediately, making it impossible to obtain high strength over a long gelation time, and furthermore, since an ion exchange resin is used, it will be economically expensive.

Therefore, the purpose of the present invention is to not only exhibit high strength, but also to have high long-term consolidation strength (in addition, it is possible to obtain high strength by adjusting the gelation time for a long time, and also to have excellent permeability, as described above). The object of the present invention is to provide a consolidation material mainly used as a ground injection material, which overcomes the drawbacks of the known technology.

[Means for solving problems]

In order to achieve the above object, the present invention is characterized in that the silica component contains an alkali metal salt of silicic acid and silica fume as essential components, and further contains a polyvalent metal compound or cement as a solidifying agent. do.

The alkali metal salt of silicic acid mentioned above is liquid or powdered water glass such as No. 3 water glass, sodium orthosilicate, sodium metasilicate, etc., and particularly has a molar ratio (SiOz/Mete) of 2.
It has a low molar ratio of 5 or less.

However, it is also possible to add an alkali to water glass having a high molar ratio and adjust the molar ratio to a low molar ratio of 2.5 or less.

In addition, silica fume is a byproduct that floats in the exhaust gas generated when silicon alloys such as silicon metal and ferrosilicon are manufactured in an electric furnace, and has a particle size of 0.1 μm.
It is extremely small and has a Blaine specific surface area of 20 to 2.
It is extremely large at 3rd/g and has a purity of 87~
It is extremely high at 94%, and this component composition (%) is 5i
(h: 87-94, A1 go!: 0.6-1.4
, FeJ3: 0.5-2.0, C: 0.8
~2.0.

When the above-mentioned silica fume is mixed with an aqueous water glass solution at room temperature, it easily becomes a homogeneous viscous mixture, and this mixture does not precipitate even if left as it is for a long time and remains in a suspended state. The reason for this is unclear, but as mentioned above, silica fuum has a very large specific surface area and has excellent surface activity, and molecules of dissolved water glass are adsorbed around the silica fume particles, creating a hydrophilic state and making it stable for a long time. It is presumed that this is to maintain a colloidal suspended state.

In addition, the polyvalent metal compounds used as the solidifying material mentioned above are Ca, A
Examples include polyvalent metal salts such as I, Fe, and Mg, bases, and oxides, with lime (Ca(OH)*) being particularly preferred.

The consolidation material of the present invention contains the above-mentioned alkali metal silicate salt (water glass) and silica fume as essential components as the silica component, and includes consolidation agents such as polyvalent metal salts, bases, oxides, and cement. Consolidated by adding etc.
Mainly used as ground injection material. The content of silica fume is desirably 1 g or more in 100 cc of the total consolidation material.

Further, as the silica component, other arbitrary materials (for example, fly ash, diatoms, etc.) may be used in combination.

In addition to being poured into the ground, the above-mentioned consolidation material of the present invention can be mixed with soil, sand, etc., stirred, or sprayed onto the soil, and used for constructing earth structures or the structures themselves.

[Effect]

As mentioned above, the silica fume used in the present invention consists of extremely fine particles and remains suspended in a water glass solution for a long time.

This is proven by the following experiment.

〔experiment〕

Silica fume and water glass or caustic soda were mixed and stirred at the mixing ratio shown in Table 1.

Slag, fly ash, and diatomaceous earth were used instead of silica fuyume as targets.

Table 1 In Table 1, samples N11l and 2 had a uniform mixed state and were viscous, did not separate into two layers even when they stood still, and this state was maintained for a long time.

On the other hand, sample magnets 3 to 5 were stirred to be sufficiently uniform, but as soon as they came to rest, they separated into upper and lower layers, with the upper layer being liquid-like and the lower layer being mud-like.

The slag used in the above experiment is made up of gangue or non-woven fabric that is combined with melted material and separated when ore is wired in a furnace, and contains calcium silicate as its main component, and diatomaceous earth is composed of the remains of diatomite. A siliceous deposit, fly ash consists of fine ash particles in flue gases.

Therefore, the consolidated material of the present invention hardly causes material separation even when injected into the ground, and therefore has excellent permeability.

In addition, in the present invention, since an alkali metal salt of silicic acid (water glass) and silica fuyum are used as the silica content, the silica concentration becomes high due to the silica content of the silica fuyume in addition to the water glass, and the silica content of the silica fuyume is Q
Since it is in a QQ state, it does not react immediately, so even if the concentration of the consolidation agent is increased, the gelation time will not be shortened, and high strength and long-term consolidation strength can be obtained while maintaining a long gelation time. .

Moreover, silica fuyume is activated as the alkaline content increases, especially when the molar ratio of the water glass solution is SiO, /
If the value of Meyo0 is less than 2.5, or if water glass with a high molar ratio is adjusted to a low molar ratio by adding alkali, it is possible to maintain a long gelation time while maintaining high strength and oral properties. Increased mechanical strength (durability) can be easily obtained.

〔Example〕

Hereinafter, the present invention will be specifically explained in detail with reference to Examples.

Prepare each of the liquid mixtures shown in Table 2 as liquids A and B,
The gelation time and the daily axial compressive strength (kg/cd) of the consolidated sand were measured for the mixed solution of these A and B solutions,
The results are shown in Table-3.

In Table-2, A-1 and A-2 are the following water glasses.

A-1: Molar ratio (n) SiOx/NagO
O, 87 solid content (weight%) 21.5A
-2: Molar ratio (n) SiOt/NazO1,
81 Solid content (wt%) 17.1 Table-2 Table-3 Table-2) From Table-3, the water glass-silica fume-consolidation material system sample has easy gelation time adjustment and high strength. On the other hand, even if the silica fume-caustic soda caking material sample is finally solidified, the gelation time is extremely long, making it difficult to adjust.

Actual ff1 Liquid A was prepared as shown in Table 4 by changing the molar ratio SiO□/NazO of a water glass aqueous solution containing 15 g of solid content in 50 cc, and Liquid B was prepared as shown in Table 4. The gelation time and the oral strength qu (kg/ci) of the gel were measured for the mixture of solutions A and B, and the results are shown in Table 5.

Table 4 (Continued) Tables 4 and 5 show that the gelation time varies depending on the molar ratio of water glass, and that as the molar ratio becomes lower than around 2.5, the long-term strength increases and the gel strength also increases. I understand. This seems to be because silica fuyum is activated by alkali, and the bond between the activated silica fuyum and Ca ions becomes strong.

In addition, as a consolidation material, especially Ca(OH)z, the gelation time can be easily adjusted from a long time to a short time, and CaCβ
2 is suitable for adjusting the gelation time of instant setting, and overall it is a polyvalent metal compound such as Ca(OH)z, CaC1! Compounds that easily supply polyvalent metal ions into water, such as , or cement, are suitable.

Solution A was prepared using sodium metasilicate (molar ratio 1.0) and sodium orthosilicate (molar ratio 0.5) as the main water glass at the blending ratio shown in Table-6. Solution B was prepared at the blending ratio shown, and the gelation time of the mixed solution of A and B'a was measured, and the results are shown in Table 6.

From Table 6, samples according to the present invention! lh2.4.6.8
It can be seen that gelation occurs in both cases. This is thought to be because silica fuum is activated by the presence of water glass at a low molar ratio, and the activated silica fume reacts with Ca ions in slaked lime or Portland cement to cause gelation.

Although a Ca compound was used as the reactant in this example, similar results can be obtained even if bases, salts, and oxides of polyvalent metals other than Ca compounds, such as Mg, Al, and Fe, are used.

〔Effect of the invention〕

As described above, the consolidation material according to the present invention contains an alkali metal salt of silicic acid and silica fume as essential components as a silica component, and also contains a polyvalent metal compound or cement as a consolidation agent, thereby achieving high strength. Not only does it have a high long-term consolidation strength, it is also possible to obtain high strength by adjusting the gelation time for a long time, and it also has excellent permeability, so it can be used as a ground injection material, the construction of earth structures, or the structure itself. It is an extremely useful material for practical purposes.

Procedural amendment December 16, 1988 Director General of the Patent Office Kunio Ogawa 1. Indication of the case Patent Application No. 279370 of 1988 2) Title of the invention Consolidation of materials 3. Person making the amendment Related Patent Applicant Address Ochanomizu Building KS, 3-3-1 Hongo, Bunkyo-ku, Tokyo
Building name: Reinforced Earth Engineering Co., Ltd. 4, Agent: 6, Number of inventions increased by amendment: None 7, Subject of amendment: “Detailed description of the invention” column of the specification.

8. Contents of the amendment Table 2 on page 10-1 of the present specification is corrected as shown in the attached sheet.

Claims (3)

[Claims] (1) A consolidation material containing an alkali metal salt of silicic acid and silica fume as essential components as a silica component, and further containing a polyvalent metal compound or cement as a consolidation agent. (2) In the consolidation material according to claim 1, the alkali metal salt of silicic acid is contained in a molar ratio (n=SiO_
2/Na_2O) 2.5 or less water glass. (3) The consolidation material according to claim 1, wherein the polyvalent metal compound is lime.