JPH06330037A - Grouting agent - Google Patents

Abstract

PURPOSE:To provide a grouting agent containing a specific alkali metal polysilicate, giving a ground having high water-resistance and strength (aging stability) without causing the soil-pollution and useful for the improvement of ground of gravelly soil, sandy soil, etc. CONSTITUTION:The grouting agent contains an alkali metal polysilicate containing SiO2 and a metal oxide of formula M2O (M is alkali metal) at a molar ratio of 4.5-10. The gelling time is easily adjusted by the addition of a curing agent. An instantly setting grouting agent exhibiting high initial strength by the gelling of <=10 see can easily be produced by this process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a water-soluble silicate type ground injection agent. The ground pouring agent of the present invention hardly contaminates the soil around the ground into which it is poured, and imparts its durability to the ground improved by the ground pouring agent.

[0002]

2. Description of the Related Art Conventionally, as a ground injection agent, it is 3 to 3.3.
A chemical solution consisting of JIS No. 3 water glass having a SiO ₂ / Na ₂ O molar ratio of and a hardening agent thereof is generally used, and in special cases, instead of this water glass, SiO ₂ / Na ₂ O of 1.6 to 2.5 is used. Low molar ratio water glasses called JIS No. 1 and No. 2 water glasses having a molar ratio were also used.

[0003] Examples of improved ground injection agents include:
Japanese Patent Application Laid-Open No. 54-73407, a chemical solution consisting of silica sol in which most of the alkali content in water glass is removed by cation exchange and a curing agent therefor, disclosed in Japanese Patent Application Laid-Open No. 3-210385, 3.7-4.5. Chemical solution comprising a high molar ratio sodium silicate aqueous solution having a SiO ₂ / Na ₂ O molar ratio and a curing agent thereof,
A chemical solution comprising a mixture of a high molar ratio sodium silicate aqueous solution and silica sol and a curing agent thereof disclosed in Japanese Patent Publication No. 5-70776 has been proposed.

[0004]

The above-mentioned conventional water-glass-based ground injecting agent has the advantages that the setting time is short and the setting strength is large, but in some cases, after the injection agent is injected, There is a problem that a large amount of sodium salt and acid used as a hardening agent elutes into the surrounding soil from the ground of No. 1 and contaminates the soil, and the ground once strengthened by this becomes loose again with the passage of time. Many.

On the other hand, the silica sol-based ground injecting agent obtained by removing the alkali content in the water glass by cation exchange does not cause soil contamination in the water glass, but It does not give high initial strength to the ground injected with the injectable agent, and cannot be applied as a quick-setting type ground injectable agent which usually shows a setting time within 10 seconds. In addition, 3.7 above
The high molar ratio sodium silicate aqueous solution ground injecting agent having a SiO ₂ / Na ₂ O molar ratio of 4.5 slightly lowers the ground strength and increases the permeability coefficient as compared with the case where water glass having a molar ratio of about 3 is used. It has the property of suppressing, but does not give the ground long-term durability.

Even if a curing agent is added to the mixed solution of silica sol and high molar ratio sodium silicate disclosed in JP-A-5-70776, a quick-setting type ground injection agent is not obtained, and the mixed solution Since it exhibits self-hardening property, it is difficult to provide it as a stable industrial product, and it is necessary to mix and prepare these components at the construction site. The present invention, the gelling time is easily adjusted by the addition of a curing agent, especially a quick-setting type ground injecting agent that expresses a high initial strength by gelling within 10 seconds can be easily obtained, and the soil around the ground It is an object of the present invention to provide a ground injecting agent that does not cause pollution to the ground and provides an improved ground having durability.

[0007]

The ground injection material according to the present invention is
It is characterized by containing an alkali metal polysilicate having a SiO ₂ / M ₂ O (M represents an alkali metal atom) molar ratio of 4.5 to 10. This alkali metal polysilicate is an alkali metal salt of a low polymer of silicic acid,
Not an alkali-stabilized particle of colloidal silica grown larger than millimicrons. This alkali metal polysilicate is usually prepared as an aqueous solution thereof. The preferred aqueous alkali metal polysilicate solution is 5 to 20% by weight.
It has a SiO ₂ concentration and a SiO ₂ / M ₂ O molar ratio of 4.5 to 10. Particularly preferred aqueous alkali metal polysilicate solutions are Na, K
Alternatively, two or more kinds of alkali metals of Li are contained in the above molar ratio of 4.5 to 10.

Preferred examples of the polysilicate aqueous solution containing two kinds of alkali metals include sodium potassium polysilicate aqueous solution having a K / Na molar ratio of 0.05 to 1.5 and sodium lithium having a Li / Na molar ratio of 0.05 to 1.5. Examples thereof include a polysilicate aqueous solution and a potassium lithium polysilicate aqueous solution having a Li / K molar ratio of 0.05 to 1.5. A preferable example of the polysilicate aqueous solution containing three kinds of alkali metals is a molar ratio of Na: K: Li.
1.00: 0.05-1.5: 0.05-1.5 sodium potassium lithium lithium polysilicate aqueous solution.

These polysilicate aqueous solutions can be produced by known methods. As a preferable example thereof, an aqueous solution of activated silicic acid and an aqueous solution of an alkali metal hydroxide or an alkali metal silicate are added to 4.5-10 SiO ₂ / M ₂ O.
(M represents an alkali metal atom.) A method of mixing at a molar ratio and heating at room temperature to 100 ° C., preferably 50 to 80 ° C. for about several hours can be mentioned. The aqueous solution of this active silicic acid is obtained by, for example, treating an aqueous solution of sodium water glass having a SiO ₂ concentration of about 1 to 6% by weight, which is obtained by diluting ordinary sodium water glass with water, with a cation exchange resin. Can be easily obtained by. The aqueous solution of lithium polysilicate can also be produced by the method disclosed in Japanese Patent Publication No. 50-2162. The polysilicate aqueous solution containing two or more kinds of alkali metals can also be obtained by mixing two or more kinds of polysilicate aqueous solutions containing a single alkali metal.

When the above-mentioned alkali metal polysilicate aqueous solution is poured into the ground, a mixed solution of this aqueous solution and its curing agent is usually used. Any curing agent may be used as long as the object of the present invention can be achieved, and examples thereof include curing agents used in conventional water glass-based ground injecting agents. Specific examples of the curing agent include hydraulic materials such as Portland cement, blast furnace cement and gypsum; inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid and sulfamic acid; formic acid,
Organic acids such as acetic acid and citric acid; acidic salts such as sodium acid sulfate, sodium bicarbonate and sodium monophosphate; ammonium salts such as ammonium sulfate and ammonium bicarbonate; sodium chloride, calcium chloride, magnesium sulfate, aluminum sulfate, sodium aluminate Metal salts such as; organic reaction agents such as glyoxal, ethylene carbonate, γ-butyrolactone, ethylene glycol diacetate, and the like, and these are used alone or as a mixture. In particular, a curing agent that gels the above alkali metal polysilicate aqueous solution in the vicinity of neutrality is preferable.

The ground injecting agent of the present invention may contain any component in addition to the alkali metal polysilicate aqueous solution as long as the object of the present invention is achieved.

[0012]

The above-mentioned alkali metal polysilicate aqueous solution itself has sufficient stability. However, when the above-mentioned curing agent is added to this solution, this aqueous solution is transformed into a uniform and high initial strength gel within 10 seconds. Moreover, it was found that the gelation time can be extended to 10 minutes or more by adjusting the addition amount of the curing agent.

[0013] In particular, it is surprising that the use of a ground injection agent composed of an aqueous polysilicate solution containing two or more kinds of alkali metals results in the formation of improved ground having long-term water resistance. Perhaps this effect is due to hydrated sodium ions, hydrated potassium ions, hydrated lithium ions, etc. with different hydrated ionic radii in the network structure of silica produced when the alkali metal polysilicate gels with the curing agent. It is considered that this is due to the interaction of the hydrated ions with the network structure of silica and the formation of a gel body in which these hydrated ions do not easily migrate to the outside of the network structure of silica.

However, using an aqueous alkali metal polysilicate solution having a SiO ₂ / M ₂ O molar ratio of 4.5 or less,
The water resistance of the cured product is not sufficient, so that the strength of the solidified ground does not last for a long time. When an aqueous solution of an alkali metal polysilicate having a SiO ₂ / M ₂ O molar ratio of 10 or more is used, the stability of the aqueous solution itself is not sufficient and it is not practical. Further, the aqueous solution of alkali metal polysilicate having an SiO ₂ / M ₂ O molar ratio increased to nearly 20 is not only unstable and easy to proceed with the polymerization of the polysilicate after its preparation, but also due to the progress of this polymerization. The generated silica colloidal particles work, and when an aqueous solution containing such silica colloidal particles is used, a gel body having high initial strength cannot be obtained.

In the ground injection material, the SiO ₂ concentration is preferably 1 to 20% by weight. When the ground injection agent having a SiO ₂ concentration of 1% by weight or less is used, the strength of the cured product is low and the ground cannot be sufficiently improved. An alkali metal polysilicate aqueous solution having a SiO ₂ concentration of 20% by weight or more has poor stability and is difficult to be practically used as a ground injection agent.

[0016]

Example A JIS No. 3 sodium water glass having a SiO ₂ concentration of 30 wt% and a SiO ₂ / Na ₂ O molar ratio of 3.0 was diluted with water to prepare a dilute sodium silicate aqueous solution having a SiO ₂ concentration of 4 wt%. Prepared. The aqueous solution of sodium silicate was passed through a cation exchange resin column to obtain an aqueous solution of active silicic acid containing no sodium.

Then, the above JIS No. 3 sodium water glass was added little by little to this aqueous solution of activated silicic acid with stirring, and the mixture was heated at 50 ° C. for 6 hours to give 4.8 SiO ₂ / Na.
An aqueous sodium polysilicate solution (A ₁ ) having a molar ratio of ₂ O and a SiO ₂ concentration of 12% by weight was obtained. Similarly, for 6.0
An aqueous sodium polysilicate solution (A ₂ ) having a SiO ₂ / Na ₂ O molar ratio and a SiO ₂ concentration of 12% by weight was obtained.

Further, the above-mentioned aqueous solution of activated silicic acid is stirred with stirring.
3. Add potassium water glass having a SiO ₂ / K ₂ O molar ratio of 3 and a SiO ₂ concentration of 28 wt% little by little,
An aqueous potassium polysilicate solution (A ₃ ) having a SiO ₂ / K ₂ O molar ratio of 4.8 and a SiO ₂ concentration of 12% by weight was obtained. Furthermore, lithium water glass having a SiO ₂ / Li ₂ O molar ratio of 3.5 and a SiO ₂ concentration of 20% by weight was added little by little to the above aqueous solution of active silicic acid under stirring, and 4.8 of SiO ₂ / An aqueous lithium polysilicate solution (A ₄ ) having a Li ₂ O molar ratio and a SiO ₂ concentration of 12 wt% was obtained.

In the comparative example, 12% by weight of S obtained by diluting the above JIS No. 3 sodium water glass with water was used.
an aqueous solution of sodium silicate (A ₅ ) having an iO ₂ concentration of 60
An aqueous silica sol (A ₆ ) having a SiO ₂ / Na ₂ O molar ratio and a SiO ₂ concentration of 12% by weight was prepared. As a curing agent, 75
A wt% sulfuric acid aqueous solution (B ₁ ) and a 25 wt% magnesium sulfate aqueous solution (B ₂ ) were prepared.

Example 1 Four kinds of (G ₁ ) to (G ₄ ) shown in Table 1 were prepared by mixing an aqueous solution of an alkali metal polysilicate as solution A and an aqueous solution of a curing agent as solution B in equal volumes. The ground injection material was prepared. Only (A ₁ ) was used as solution A for the preparation of (G ₁ ) and (G ₂ ), and only (A ₂ ) was used as solution A for the preparation of (G ₃ ) and (G ₄ ). . Solution B was prepared by adding the above curing agent to water so that the composition of solution B shown in Table 1 was obtained.

Next, the pH and gelation time of the four types of ground injectants (G ₁ ) to (G ₄ ) were measured, and the results shown in Table 1 were obtained. Separately, the above-mentioned (G ₁ ) to (G ₄ ) injectable solution for each plate was gelled in a mold having a diameter of 5 cm and a height of 10 cm to prepare a test gel body. Immediately after this preparation and after curing for 1 day in humid air, the volume of this gel body was measured to obtain the volume change rate. Further, the uniaxial compressive strength was measured for the gel body preserved and cured for one day.

In order to measure the water resistance of another gel body produced in the same manner as above, after curing and curing for 1 day in wet air in the same manner as above, after further immersing this gel body in running water for 7 days The volume and uniaxial compressive strength of this gel body were measured. From these measurement results, the volume change rate before and after immersion in running water was also obtained. The results of these measurements are shown in Table 2.

Table 1 Example Injectant B liquid composition (% by weight) Gelation time pH No. Code H ₂ SO ₄ MgSO ₄ (sec) Example 1 G ₁ 4.32 2.36 6 7.5 G ₂ 5.18 1.89 270 6.4 G ₃ 4.21 2.36 6 8.2 G ₄ 7.31 2.41 620 4.8 Example 2 G ₅ 4.3 1.2 6 7.5 Example 3 G ₆ 3.8 1.2 6 7.6 Comparative Example 1 G ₇ 4.3 1.2 5 7.5 2 G ₈ 0.1 5.4 6 7.6 Table 2 Example Volume reduction rate of injectable gel (%) Strength (kg / cm ² ) No. code 1 day 7 days 1 day 7 days Example 1 G ₁ 8 12 0.30 0.23 G ₂ 8 12 0.26 0.21 G ₃ 6 10 0.24 0.19 G ₄ 6 10 0.24 0.19 Example 2 G ₅ 3 5 0.31 0.28 Example 3 G ₆ 2 3 0.27 0.26 Comparative Example 1 G ₇ 22 Disintegration 0.32 Not measurable 2 G ₈ 1 1 0.08 0.11 Example 2 Aqueous solution of alkali metal polysilicate A ground injection agent of (G ₅ ) was prepared by using the solution A as the solution A and the solution B as the solution B in equal volumes. For the preparation of this (G ₅ ), a mixed solution of 2 parts by weight of (A ₁ ) and 1 part by weight of (A ₃ ) was used as solution A. The composition of the B liquid is shown in Table 1.

Then, in the same manner as in Example 1, preparation of the ground injection, measurement of its pH and gelation time, preparation of the gel body, measurement of the volume of the gel body, volume change rate, and uniaxial compressive strength were measured. . The results of these measurements are shown in Tables 1 and 2. Example 3 A ground injection agent (G ₆ ) was prepared by mixing an aqueous solution of an alkali metal polysilicate as a solution A and an aqueous solution of a curing agent as a solution B in equal volumes. A liquid mixture of 2 parts by weight of (A ₂ ), 1 part by weight of (A ₃ ) and 1 part by weight of (A ₄ ) was used as solution A for the preparation of (G ₆ ). The composition of the B liquid is shown in Table 1.

Then, in the same manner as in Example 1, preparation of the ground injection, measurement of its pH and gelation time, preparation of the gel body, measurement of the volume of the gel body, volume change rate, and uniaxial compressive strength were measured. . The results of these measurements are shown in Tables 1 and 2. Comparative Examples 1 and 2 Instead of the alkali metal polysilicate aqueous solution as the liquid A, in Comparative Example 1, the aqueous solution of sodium water glass was used.
(A ₅ ) is used, and in Comparative Example 2, the aqueous silica sol (A 5
₆ ) was used. The composition of the B liquid is shown in Table 1.

Then, in the same manner as in Example 1, preparation of the ground injection, measurement of its pH and gelation time, preparation of gel body, measurement of volume of gel body, volume change rate, and uniaxial compressive strength were measured. . The results of these measurements are shown in Tables 1 and 2.

[0027]

The results shown in Tables 1 and 2 show that all the ground injecting agents according to the present invention have a small volume change rate and high water resistance and strength. In addition, it is possible to obtain a quick-setting type ground injecting agent having a gelation time of about 6 seconds in the vicinity of neutrality. In particular, as shown in Examples 2 and 3 using the polysilicate containing two or more kinds of alkali metals, the instantaneous setting type ground injecting agent according to the present invention can provide the improved ground having remarkably high water resistance. That is a significant improvement over the prior art.

The ground injecting agent of the present invention can be applied to the ground such as gravel soil and sandy soil, as well as to the general target soil. And according to this ground injecting agent, not only a stable improved ground is formed, but also the soil around the improved ground is contaminated with salts, acids, alkalis, etc. based on the low alkali content of this ground injecting agent. Never.

Claims (1)

[Claims] 1. A ground injection agent containing an alkali metal polysilicate having a SiO ₂ / M ₂ O (M represents an alkali metal atom) molar ratio of 4.5 to 10.