JPH08109378A - Ground solidifying material - Google Patents

Abstract

PURPOSE: To obtain a ground solidifying material consisting essentially of a specific silica sol, fine particle slag having a specified specific surface and fine-particle cement, capable of prolonging gelling time, excellent in permeability, increasing solidifying strength and hardly causing alkali leaching. CONSTITUTION: This ground solidifying material consists essentially of (A) silica sol obtained by removing most of alkali of water glass with an ion exchange resin and (B) fine-particle slag, fine-particle cement, combination of fine-particle slag and fine-particle cement or a mixture of fine-particle slag with fine-particle cement, and the component B has >=9000cm<2> /g Blaine's specific surface. Furthermore, preferably, the component B has 0.9-2.0 hydraulic modulus and 1.9-2.9 basicity and the ground solidifying material contains a gelling controller such as a (hydrogen)carbonate or an (acidic) phosphate of an alkali (alkaline earth) metal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a slag / cement-based ground consolidating material, specifically, neutral to weak obtained by removing most of alkali in water glass with an ion exchange resin. By using alkaline silica sol (hereinafter referred to as neutral silica sol), fine particle slag and fine particle cement in a specific condition range, high consolidation strength can be obtained and gelation time is long and gelation time is long. The present invention relates to a slag / cement-based ground consolidation material that is easy to adjust, has excellent permeability as a suspension-type ground consolidation material, and has less alkali leaching than ordinary water glass-based suspension consolidation materials.

[0002]

2. Description of the Related Art Various grouts for ground injection for solidifying the ground are known. For example, as a slag-based water glass grout, it is known to use water glass having a small molar ratio and a high alkalinity. This grout has a high consolidation strength, but alkali leaching is a concern. Further, in the case of grout consisting of an acidic silica sol obtained by mixing water glass and an acid and a cement system, gelation time is short and floc-like precipitation is likely to occur, resulting in poor permeability. Ordinary slag (Blaine specific surface area
At 3500 to 4400 cm ² / g), it acts as a neutralizing agent for the above acidic silica sol and can act as a promoter for the gelation time, but it has little effect on the strength, and it has no effect on the neutral silica sol. Shows almost no reactivity and no strength development.
A method is also known in which neutral silica sol and Portland cement are combined and injected at 1.5 shots. However, this grout has a short gelling time of at most 1 minute and has poor permeability. In addition, the grout obtained by adding a polyvalent metal salt or an alkali metal salt to the neutral silica sol has a drawback of low strength. In order to solve this strength problem, the neutral silica sol has been recently made up of 75 to 90 parts by weight of blast furnace slag powder and 25 to 10 parts by weight of Portland cement clinker powder and has a Blaine specific surface area within the range of 7000 to 8500 cm ² / g. An injection material added with a slurry of a certain mixed blast furnace slag powder is also disclosed (JP-A-6-145662). However, this grout has the drawbacks that it has poor penetration into fine-grained soil, causing clogging between soil particles, and that the gelling time is difficult to adjust with a long gelling time.

Thus, the water glass-slag system, silica sol-cement or slag system and neutral silica sol-cement or slag system used as suspension type ground injection materials have their respective drawbacks. Therefore, an object of the present invention is to adjust the gelation time to be excellent in permeability, to increase the consolidation strength, and to reduce alkali leaching silica sol-fine particle slag / fine particle cement-based suspension type ground consolidation. Is to provide wood.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that neutral silica sol, fine particle slag, and ground consolidation material containing fine particle cement as a main component,
Alternatively, the inventors have found a ground consolidation material further containing a gelling agent, and completed the present invention. That is, the present invention is a ground consolidating material mainly composed of a neutral silica sol, a fine particle slag or a fine particle cement, or a combination of fine particle slag and a fine particle cement, or a mixture of a fine particle slag and a fine particle cement, wherein the fine particles are Ground consolidation material characterized by having a Blaine specific surface area of at least about 9,000 cm ² / g or more of cement, fine particle slag, or a mixture of both, and a ground formed by further compounding a gelation modifier therewith. It provides a solidifying material.

The neutral silica sol used in the present invention treats water glass with an ion exchange resin to almost separate and remove alkalis such as Na ⁺ ions, and is neutral to weakly alkaline, preferably having a weak pH of 8.0 to 10.5. Adjusted to alkaline and has a specific gravity
1.16 to 1.24, approximately 10 to 60 wt% SiO _{2 and} 0 to ₂ Na ₂ O.
It is in the range of 01 to 4% by weight. Therefore, it can be expected that the leaching of alkali will be much less than that of the solidified material using ordinary strong alkaline water glass.

In the present invention, the fine particle slag, the fine particle cement and the combination or mixture of the fine particle slag, the fine particle cement and the mixture of the fine particle slag, the fine particle cement and the mixture of the fine slag and the fine particle slag mixed with the neutral silica sol have a Blaine specific surface area of about 9000 cm ² / It is necessary that the amount be g or more, but if the powder is extremely pulverized, reaggregation may occur in the suspension, so that such an effect cannot be expected, and the crushing cost becomes expensive. Considering these points, the Blaine specific surface area is preferably in the range of about 9,000 to 20,000 cm ² / g. When using fine particle slag, a combination of fine particle slag / fine particle cement, or a mixture of fine particle slag / fine particle cement, it is often desirable that the hydraulic modulus of these is 0.9 to 2.0 and the basicity is in the range of 1.9 to 2.9. . Here, the hydraulic modulus of fine particle slag and fine particle cement
CaO / (SiO ₂ + Al ₂ O ₃ + Fe ₂ O ₃ ), What is basicity? (CaO + MgO +
Represents Al ₂ O ₃ ) / SiO ₂ (note that CaO, SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , M
gO indicates the content percentage of each in cement and slag).

In this system of neutral silica sol-fine particle slag and fine particle cement, the gelation time is generally short (several seconds to 2 seconds).
Therefore, the gelling time can be delayed by a gelling agent to improve the permeability. In this case, although the Blaine specific surface area of the fine particle slag and fine particle cement is about 9000 cm ² / g as a boundary, a retarding effect is shown below this, but the addition amount of the gelling regulator is increased to about 10 minutes at most. On the other hand, when the particles are made into ultra-fine particles of about 9000 cm ² / g or more, the delay effect of the gelling agent becomes remarkable, and the gelling time can be delayed to about 60 minutes. It was also found that the increase in viscosity was small. Moreover, it has been found that the strength of the ground consolidation material increases without deterioration.

Examples of the gelling agent used in the present invention include alkali metal and alkaline earth metal bicarbonates, carbonates, phosphates, acid phosphates, pyrophosphates, and the like. Those that are easily soluble are preferred. These gelling modifiers are mixed and dissolved in water in advance, and then the fine particle slag, fine particle cement or neutral silica sol can be added, or the fine particle slag and the fine particle cement can be added to water at the same time, but the effect is obtained. To get the most out,
It is preferably dissolved in water in advance.

The fine particle cement used in the present invention may be Portland cement, blast furnace cement, crushed products of these clinker, or fine particles of cement in which gypsum or the like is mixed. Furthermore, even if the mixture of these and fine particle slag is pulverized to have a Blaine specific surface area of about 9000 cm ² / g or more before mixing, the pulverized material is mixed to some extent, and the Blaine specific surface area is further increased. about
It may be crushed to a size of 9000 cm ² / g or more. Further, fine particles in a suspension form may be classified and used as a fine particle suspension.

In the ground consolidation material of the present invention, the content of the neutral silica sol is 50 per 1000 g of the ground consolidation material (grout).
Approximately 300 g is preferable, and when the amount is more than 300 g, the gel has elasticity similar to that of a solution type grout homogel, and almost no increase in strength is observed. Also, the mixing amount of fine particle slag, fine particle cement or a mixture thereof is grout 1000.
20 to 400 g per g is preferable, and if it is less than this, the strength of the solidifying material is low, and if it is more than this, the viscosity of the liquid becomes high and the solidification time cannot be lengthened. Further, in the ground consolidation material of the present invention, when a gelling regulator is blended, the blending amount is difficult to unconditionally be specified by the type of gelling regulator, other component composition, etc. It is preferably 10% by weight or less in the total liquid mixture.

[0011]

The present invention uses fine particle slag and fine particle cement having a Blaine specific surface area of about 9000 cm ² / g or more, so that it has good permeability into the soil, activates the hardening reaction, and exhibits excellent strength of the solidified product. , High strength. It is also considered that the reactivity with the gelling regulator is activated, and the original function as the gelling regulator, that is, the effect of delaying the gelling time is remarkably exhibited. Further, in the present invention, since a neutral to weakly alkaline colloidal silica prepared by removing most of alkali such as Na ⁺ ions from water glass and heat-polymerizing is used as the silica sol, the curing time is long, and the floc is high. It seems that homogenization is further promoted without formation of a precipitate and the penetration is further promoted. Generally, hard components or gypsum components that easily release in cement impair the dispersibility of the suspension in the solution, and even if the particles are made into fine particles, they are electrically aggregated in the suspension to increase the viscosity and penetrate. However, the use of a gelling agent having a Blaine specific surface area of about 9000 cm ² / g or more hinders the properties of these components and improves the permeability.

[0012]

EXAMPLES The present invention will be specifically described below with reference to examples, but these examples are merely examples of the present invention, and the present invention is not limited to these examples. The neutral silica sol, slag, cement, slag-cement mixture, and gelling agent used in the following Examples and Comparative Examples are summarized below.

(1) Neutral silica sol A neutral silica sol having a composition shown in Table 1 obtained by treating water glass with a cation exchange resin to remove most of the alkali was used.

[0014]

[Table 1]

(2) Slag Two types of slag shown in Table 2 were used with different pulverization degrees.

[0016]

[Table 2]

(3) Cement Portland cement and blast furnace cement having different pulverization degrees shown in Table 3 were used.

[0018]

[Table 3]

(4) Slag-Cement Mixture A mixture shown in Table 4 in which the slag of Table 2 and the cement of Table 3 were premixed was used for compounding the grout.

[0020]

[Table 4]

(5) Gelation conditioner Sodium hydrogen carbonate (first-grade reagent: NaHCO ₃ ) was used as a typical gelation conditioner. Although other gelation regulators have a gelling retarding effect although the addition amount is different, the alkali metal salt of bicarbonate or the alkali metal salt of carbonic acid obtained a particularly excellent effect. The alkali metal salt of bicarbonate and the alkali metal salt of carbonic acid showed almost the same effect.

Examples 1 to 6 and Comparative Examples 1 to 4 (Neutral silica sol-slag system) Aqueous solution of neutral silica sol in Table 1 was used as solution A, and as solution B, water suspension of slag in table 2 and sodium hydrogen carbonate was used. Using the suspension, the solutions A and B were mixed at the ratios shown in Table 5 to prepare various ground consolidation materials. The gelation time of the obtained ground consolidation material was measured by the cup upside-down method, and the uniaxial compressive strength was measured by the standard of Japan Society of Geotechnical Engineering "Soil uniaxial compression test method". The results are shown in Table 5.

[0023]

[Table 5]

In Table 5, the slags of Comparative Example 1 and Examples 1 and 2 have a low basicity of 1.78 and a hydraulic modulus of 0.82, and have extremely long gelling times and weak consolidation strength, but the slag branes Examples 1 and 2 having a specific surface area within the scope of the present invention
In comparison with Comparative Example 1, the gelation time is shorter and the consolidation strength is higher. Both the basicity and hydraulic modulus of the slags of Comparative Example 2 and Examples 3 to 4 are in the above preferred ranges, of which Comparative Example 2 is a particle having a Blaine specific surface area outside the range of the present invention. Compared with Nos. 4 and 4, the gelation time was faster and the strength was clearly inferior. In Examples 4 to 6 and Comparative Examples 2 to 4, the effect of the added amount of sodium hydrogencarbonate as a gelling modifier was tested. Examples 5, 4 and 6 are examples in which the addition amount of sodium hydrogen carbonate was changed in the fine particle slag of the present invention. On the other hand, Comparative Examples 3, 2 and 4 use slags of particles having a Blaine specific surface area outside the range of the present invention, and obviously, in Examples 5, 4 and 6, the addition amount of the gelling modifier increases. Accordingly, the effect of delaying the gelling time is remarkable, and on the contrary, in Comparative Examples 3, 2 and 4, the effect of delaying the gelling time is not remarkable even when the amount of the gelling modifier added is large. Further, in Examples 5, 4, and 6, the strength is obviously improved as the addition amount of the gelling modifier is increased.

Examples 7 to 10 and Comparative Examples 5 to 8 (Neutral silica sol-cement system) Aqueous solution of neutral silica sol in Table 1 was used as liquid A, and as liquid B, the cement of Table 3 and aqueous suspension of sodium hydrogen carbonate were suspended. Using the solution, the solutions A and B were mixed at the ratios shown in Table 6 to prepare various ground consolidation materials. The gelation time and the uniaxial compressive strength of the obtained ground consolidation material were measured in the same manner as in Example 1. The results are shown in Table 6.

[0026]

[Table 6]

In Table 6, the consolidation strength is generally higher than that of the slag in Table 5. On the contrary, gelling times appear to be generally fast and viscously high. However, Examples 7 and 8 in which the Blaine specific surface area is within the scope of the present invention.
Has a relatively long gelation time and excellent consolidation strength. Sodium hydrogencarbonate is effective in delaying gelation time and strengthening, as in the case of slag. That is, Examples 9, 7 and 10 are examples in which fine grain cement having a Blaine specific surface area within the range of the present invention was used, and Comparative Examples 7, 5 and 8 were cements with particles having a Blaine specific surface area outside the range of the present invention. In the example of use, it can be seen that the former is clearly superior in both the effect of delaying gelation time and the enhancement of strength.

Examples 11 to 18 and Comparative Examples 9 to 10 (neutral silica sol-slag / cement combination system) Aqueous solution of neutral silica sol in Table 1 was used as solution A, and slag of table 2 and cement of table 3 were used as solution B. Was used in combination with each other, and an aqueous suspension prepared by further adding sodium hydrogencarbonate was used to mix solutions A and B at the ratios shown in Table 7 to prepare various ground consolidation materials. The gelation time and the uniaxial compressive strength of the obtained ground consolidation material were measured in the same manner as in Example 1. The results are shown in Table 7.

[0029]

[Table 7]

In Table 7, Comparative Examples 9 and 10 are slags,
This is an example in which particles having a Blaine specific surface area outside the range of the present invention are used together with cement, and the viscosity is relatively high and the strength is also poor. In Examples 11 to 14, only one of slag or cement is fine particles having a Blaine specific surface area within the range of the present invention, but Examples 11 and 13 are basicity of slag / cement combination, and water hardness is preferable of the present invention. Example out of range
No. 11 has a weak caking strength, and the gelation time is too fast in Example 13. Gelling time in Examples 12 and 14 in which the Blaine specific surface area of only one of slag or cement is within the scope of the present invention, particularly in Examples 15 and 16 in which the slag and the cement Blaine specific surface area are within the scope of the present invention. It has a long consolidation time and excellent consolidation strength. Examples 17, 16 and 18 are cases in which the addition amount of sodium hydrogen carbonate was changed in a formulation having a Blaine specific surface area within the range of the present invention, and the gelling time was obviously delayed as the addition amount increased, and the solidification Strength is increasing.

Examples 19 to 24 and Comparative Examples 11 to 12 (neutral silica sol-slag / cement mixture system) An aqueous solution of the neutral silica sol in Table 1 was used as solution A and solution B was used as the slag-cement mixture in table 4. Liquids A and B were mixed at a ratio shown in Table 8 using an aqueous suspension of sodium hydrogen carbonate to prepare various ground consolidation materials. The gelation time and the uniaxial compressive strength of the obtained ground consolidation material were measured in the same manner as in Example 1. Table 8 shows the results.

[0032]

[Table 8]

Regarding the ratio of the slag / cement mixture in Table 8, Comparative Examples 9 to 10 and Examples 11 to 16 in Table 7 are completely suitable for Comparative Examples 11 to 12 and Examples 19 to 24 in Table 8. .
The results almost corresponded to those in Table 7, and the slag,
It shows that there is no great difference between the cements used in combination, or the mixture prepared in advance as a mixture.
However, when observed in detail, the strength after 30 days did not change within the error range, but in Table 8, the strength after 7 days seems to be slightly higher than in the case of Table 7, and the gelation time seems to be relatively shortened. is there.

Examples 25 to 30 and Comparative Examples 13 to 15 (penetration test) From the results of the above Examples 1 to 24 and Comparative Examples 1 to 12, in the system of neutral silica sol-fine particle slag / fine particle cement-gelling conditioner. It has been observed that if the conditions of the present invention are satisfied, a high consolidation strength and a relatively long gelation time can be obtained, and that the use of neutral silica sol is also generally lower in viscosity than the case of ordinary water glass. It is expected to have excellent permeability. Therefore, the following penetration test was conducted in order to actually confirm the permeability. The results are shown in Table 10.

<Penetration test> A layer of 90 cm Toyoura standard sand on a 5φ x 100 cm acrylic pipe (layer of fine sand 5 cm above and below)
Was prepared, and the mixed solutions of the above-mentioned representative examples and comparative examples were injected at an injection pressure of 0.5 kgf / cm ² , and the degree of permeation was measured. The filling of Toyoura standard sand was carried out by dividing a predetermined amount into several times, and the side of the pipe was hit with a hammer each time. The mixed solution was prepared by adding an aqueous solution of sodium hydrogencarbonate, slag and cement in a mixer and stirring for 30 seconds, and then adding an aqueous solution of neutral silica sol and stirring for 10 seconds. The permeability was evaluated by demolding one day after the injection of the solidifying material, measuring the length of the solidifying material, and evaluating it according to the criteria shown in Table 9.

[0036]

[Table 9]

[0037]

[Table 10]

In Table 10, Examples 25, 29 and 30 show excellent penetrability in examples using fine particle slag or fine particle slag and fine particle cement having all Blaine specific surface areas within the range of the present invention. It was Example 26 is an example of fine particle cement, and the permeability is somewhat inferior to that of Example 25 of fine particle slag. Examples 27 and 28, slag, cement is an example in which the Blaine specific surface area of either one is within the scope of the present invention is good permeability, but both are Blaine specific surface area within the scope of the present invention Example 29 and Somewhat inferior to 30. In the case of the slag of the particles whose Blaine specific surface area of Comparative Example 13 is not within the range of the present invention, the permeability is poor, but it is somewhat better than that of the cement of the Blaine specific surface area of Comparative Example 14 which is not within the range of the present invention. Is. A cement of particles having a Blaine specific surface area of Comparative Example 14 that is not within the scope of the present invention, Comparative Example 15
Almost no permeability was observed in the combined slag / cement system of particles having a Blaine specific surface area outside the range of the present invention. From the above, it was confirmed that the ground consolidation material having a Blaine specific surface area within the range of the present invention exhibits excellent permeability as a suspension type.

[0039]

EFFECTS OF THE INVENTION A suspension type ground consolidation material of the present invention containing a neutral silica sol, fine particle slag having the above-mentioned specific brane specific surface area and fine particle cement, and a ground solid matter of the present invention further containing a gelation modifier. The binder has the following effects. The gelation time can be adjusted for a relatively long time, and it exhibits extremely excellent permeability as a suspension type. High consolidation strength not seen in the solution type is obtained. Neutral silica sol does not show a high alkali like ordinary water glass, and therefore, it can be expected that alkali leaching is small.

Claims (3)

[Claims] 1. A silica sol obtained by removing most of the alkali of water glass with an ion exchange resin, and a combination of fine particle slag or fine particle cement or fine particle slag and fine particle cement, or a mixture of fine particle slag and fine particle cement. A ground consolidation material containing as a main component, at least one of the above-mentioned fine particle cement or fine particle slag or a mixture of the fine particle cement and the fine particle slag having a Blaine specific surface area of about 9,000.
A ground consolidation material characterized by being at least cm ² / g. 2. The ground consolidation material according to claim 1, which contains a gelling conditioner. 3. When using fine particle slag, a combination of fine particle slag / fine particle cement or a mixture of fine particle slag / fine particle cement, the hydraulic modulus of these is 0.9 to 2.0,
The ground consolidation material according to claim 1 or 2, which has a basicity of 1.9 to 2.9.