JP2007045657A - Plastic grout material and grouting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic injection (grout) material in which a liquid material or liquid mixture to be used does not harden and its fluidity does not fall off in a brief span of time, and to provide a method of solidifying the grout material at the point of time needing strength expression by injecting a stimulant into the grout material. <P>SOLUTION: This plastic grout material is obtained by mixing a milk (liquid A) which is prepared by kneading a gypsum with water and another milk (liquid B) in which a latent hydraulic material, plasticizer and water are kneaded, and agitating to gelate. The grout material further contains a retarder for keeping its unhardened state until hardening is required. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a grouting material and a grouting method that can be used for cavity filling of civil engineering structures, lightweight embankment, and landfilling, and more particularly to a plastic grouting material and a grouting method using a latent hydraulic material.

For grout materials that use cavities and gaps in the ground and civil engineering structures for filling, etc., in order to ensure efficient and reliable injection into the target cavity filling part and to prevent leakage into surrounding gaps, etc. In order to prevent the material from being diluted with ground water or running water, it is often desirable that the injected material has properties as a gel-like aggregate. And such an injection material needs to maintain fluidity | liquidity sufficient for pumping with a pump, and needs to harden | cure reliably in a filling part, in order to exhibit the performance as a grout material.
A plastic injection material (plastic grout material) having such properties and functions has been proposed and put into practical use.
For example, a plastic injection material for cavity filling, lightweight embankment, and landfill obtained by mixing and stirring cement milk and bentonite milk has been proposed (see Patent Document 1), and montmorillonite clay mineral is added to a flowable mortar. It has been proposed to obtain a non-flowable plastic grout material by adding a mixed fluid swelling liquid (see Patent Document 2).

However, in these plastic injection materials, cement milk or fluid mortar is used as a curing aid, so that the cement milk itself itself is reduced in fluidity or cured after a predetermined time. It becomes.
For this reason, conventionally, in order to delay the curing of the plastic grout material, a retarder used in concrete or the like is used, and in order to obtain a predetermined delay effect, the amount of the retarder has been adjusted. In this case, the predetermined delay effect can be exhibited in the laboratory test, but the effect of the retarder cannot be exhibited as planned depending on the situation at the site (temperature, underwater / air curing conditions, presence / absence of load pressure). In the case of plastic grout materials using clay agglomeration, clay adsorbs the retarder, so adjustment of the curing time with the retarder is extremely complicated because it must be added in a larger amount than the usual addition amount. It is. In addition, there may be cases where the effect of the retarder cannot be expected, such as when injection is interrupted for several hours to several days due to problems such as the completion of daily construction or a manufacturing plant, and it is necessary to clean the inside of the hose and take out cement milk each time. There is. In addition, it is necessary to process the washed waste water, which is troublesome.

In Patent Document 3, cement hydrate is used as a delay type plastic injection material in which a liquid material to be used does not harden in a short time or does not cause a decrease in fluidity without adding a retarder or the like. It is formed by stirring and mixing an alkaline liquid material (stimulating liquid) mixed with a curing aid such as a liquid material (hardening liquid) containing a latent hydraulic substance such as blast furnace slag and a plasticizing material such as bentonite. Plastic injection materials have been proposed.
In this plastic injection material, a hardening liquid in which a latent hydraulic material such as blast furnace slag and a plasticizing material such as bentonite are mixed comes into contact with the stimulating liquid and begins to develop strength. However, in various application situations and application environments of the grout method, the mixed solution of these two solutions is not always constant in terms of temporal and physical properties, and is difficult to adjust. There were many cases that could not be secured.

Japanese Patent No. 3378501 Japanese Patent Laid-Open No. 11-124574 Japanese Patent No. 3366617

  In view of such a situation, the present invention is a plastic injection material (plastic grout material) in which the liquid material and the mixed liquid to be used are not cured within a short period of time, or the decrease in fluidity does not occur. It is an object of the present invention to provide a method for injecting an irritant into a plastic grout material and solidifying it when necessary.

  As a result of intensive studies, the inventors mixed and stirred milk (liquid A) in which gypsum and water were kneaded, and milk (liquid B) in which a latent hydraulic material, a plasticizer and water were kneaded. A plasticized grout material that has been gelled, injecting a plastic grout material containing a retarder so as to maintain an uncured state until the curing is required, and a stimulant that elutes Ca ions when the curing is necessary. The present invention has been completed by finding that a grout method for curing a grout material can solve the above-mentioned problems.

That is, the present invention is a mixture of milk (liquid A) in which gypsum and water are kneaded and milk (liquid B) in which a latent hydraulic material, a plasticizer and water are kneaded, and gelled by stirring. The present invention provides a plastic grout material containing a retarder so as to maintain an uncured state until curing is necessary, and the mass ratio of the latent hydraulic material and gypsum is 95: 5 to 30:70. It is preferable to contain a retarder in a mass ratio of 0.4 to 2.0% with respect to the mass mixture of the latent hydraulic material and gypsum.
The plasticizer is preferably at least one selected from bentonite, attapulgite, and metakaolin, and anhydrous gypsum is most preferably used as the gypsum.
And this invention inject | pours the irritation | stimulation agent which elutes Ca ion in the plastic grout material matrix which is previously inject | poured into a construction location and is an unhardened state, The grout material matrix is hardened | cured, It is characterized by the above-mentioned I will provide a.

The liquid A of the present invention is uncured for several days to several weeks. Meanwhile, the grout material obtained by mixing the liquid A and the liquid B maintains a plastic state and is not cured. When strength is required, a stimulant is injected to harden the grout material and strength is developed.
In other words, the plastic grout material of the present invention can delay the curing until it needs to develop strength while maintaining the plastic state. For this reason, there is no deviation to cracks and the like, and limited injection is possible, and there is an advantage that planned construction management can be performed.
In addition, according to the present invention, since the liquid material (A liquid, B liquid) and the liquid mixture to be used do not harden in a short time or the fluidity does not deteriorate, During the interruption, it is not necessary to clean the mixer, hose, etc., which saves work and eliminates the problem of waste water treatment for the washing water.

Embodiments of the present invention will be described below.
The plastic grout material of the present invention is obtained by adding gypsum and water to blast furnace slag, which is a latent hydraulic substance.

  The latent hydraulic substance contains a mineral component that can be hardened by forming a hydrate by a hydration reaction, but it does not initiate a hydration reaction even when contacted with water under normal conditions. In the present invention, a slag powder such as blast furnace slag and / or fly ash (coal ash) is used.

Gypsum has the function of causing aggregation and plasticization of plasticized materials such as bentonite. Moreover, when there is much addition amount, there exists a tendency which accelerates | stimulates hardening of a plastic grout material, and since hardening of a plastic grout material is overdue when it is small, addition of a retarder can be decreased.
In the present invention, the gypsum can be any of anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum. Among these, anhydrous gypsum is most preferably used in that the strength of expression after hardening of the grout material is increased.

  In the plastic grout material, the mass ratio of slag and / or fly ash to gypsum is preferably 95: 5 to 30:70, more preferably 90:10 to 70:30.

The plastic grout material of the present invention contains a retarder so as to maintain an uncured state until it is necessary to cure. As the retarder, a retarder used in concrete or the like can be used, and examples thereof include lignin sulfonate, oxycarboxylate, and saccharide derivatives.
The retarder is preferably contained in a mass ratio of 0.4 to 2.0% with respect to the mixture of the latent hydraulic material and gypsum.

In the plastic grout material of the present invention, a plasticizer for plasticizing the grout material and water for dispersing the same are mixed.
Plasticizing materials such as bentonite in the plastic grout material swell in water and are charged with negative ions. When calcium ions neutralize negative charges on the surface of bentonite particles due to calcium ions in gypsum and the like, a rapid agglomeration reaction due to intermolecular attractive force of bentonite particles occurs, and plasticity is instantly generated.
As the plasticizer, clay minerals are preferably used, and among them, at least one selected from bentonite, attapulgite, and metakaolin is preferable.
Further, a water reducing agent as an admixture can be added to the plastic grout material in order to increase its fluidity. As such a water reducing agent, water reducing agents used in concrete such as naphthalene sulfonic acid, melamine sulfonic acid, and polycarboxylic acid can be used. The amount of water-reducing agent added varies depending on the type of water-reducing agent and the product, but is usually 0.5 to 2.0% by mass with respect to the plasticizer.

  The plastic grout material of the present invention exhibits plasticity with a cylinder flow value in the range of 80 to 150 mm.

The plastic grout material of the present invention is pre-injected into a construction site and can be kept in an uncured state until it is necessary to cure, and when strength development is required, a stimulant that elutes Ca ions is injected to the plastic grout material. A grout method for solidifying the material becomes possible. If uniformity is required after injection, high-pressure jet stirring or mechanical stirring may be performed.
Examples of the stimulant for eluting Ca ions include Portland cement, blast furnace cement, fly ash cement, silica cement, eco cement, cement-based solidified material, calcium hydroxide, and the like. The stimulant is usually used in a slurry state (concentration: 50 to 200% by weight) mixed with water, and the addition amount is preferably about 5 to 10% of the grout material volume as a slurry.

The invention according to the present invention will be described in more detail with reference to the following examples. In addition, the test in an Example was performed as follows.
The plasticity evaluation was based on the cylinder method flow test, which is the Japan Highway Public Corporation standard test method. The flow value is preferably 80 to 150 mm, more preferably 80 to 120 mm. Those having a flow value of 150 mm or more are not suitable for limited injection or the like (since an 80 mm diameter cylinder is used, it is not less than 80 mm).
The compressive strength of the cured body was measured by the Geotechnical Society standard “uniaxial compression test (JIS A1216)”. It is sufficient that the compressive strength of the grout material cured body in the grout method is 0.5 N / mm ² or more.

Example 1
Blast furnace slag as slag (as defined in JIS R5211 “Blast furnace cement”), gypsum as anhydrous gypsum, retarder (admixture for JETMS-A liquid (polycarboxylic acid), manufactured by Sumitomo Osaka Cement Co., Ltd.) And water are kneaded with the composition shown in Table 1 to prepare solution A, and attapulgite (200 mesh sieve overall particle size) or bentonite (swelling degree 16; 200 mesh sieve all particles) as a plasticizer Diameter), a water reducing agent (admixture for JETMS-B solution (pyrophosphoric acid), manufactured by Sumitomo Osaka Cement Co., Ltd.) and water were kneaded with the composition shown in Table 1 to prepare solution B. The liquid A and liquid B had no material separation and had good pumpability. The two liquids were mixed and stirred to be plasticized (gelled).
The cylinder flow values (plasticity) immediately after mixing both liquids are shown in Table 1. Moreover, about the mixing | blending No. 1-2 of Table 1, 7 days after mixing both liquids, the plasticizer uncured grout material is added to a stimulant (cement milk with W / C ratio = 100%: normal Portland cement, Sumitomo Osaka cement (Made by Co., Ltd.) was injected at a volume ratio of 5%, mixed and stirred with a hand mixer, and strength development was confirmed. Table 3 shows the daily changes in the compressive strength of the grout after injection of the stimulant, as formulation Nos. 1 'to 2'. (In addition, Table 2 shows the solidification state after kneading both liquids of the grout material without injection of the stimulant and the change over time in the compression strength after solidification as formulation Nos. 1-2.)

From Table 1, it can be seen that the mixture Nos. 1 and 2 having the predetermined composition of the present invention show good plasticity of the mixed solution.
Also, from Tables 2 and 3, the plastic grout material of the present invention was in an uncured state for 7 days or more simply by mixing the liquid A and the liquid B, but strength was developed by injecting a stimulant. I can confirm that.

Claims (10)

  A plastic grout material which is obtained by mixing a latent hydraulic material, gypsum, a plasticizing material and water, stirring and gelling, and containing a retarder so as to maintain an uncured state until it is necessary to cure.   Milk mixed with gypsum and water (Liquid A), latent hydraulic material, plasticizer and milk mixed with water (Liquid B) are mixed, stirred and gelled, and need to be cured A plastic grout material containing a retarder so as to maintain an uncured state.   The plastic grout material according to claim 1 or 2, wherein a mass ratio of the latent hydraulic material and gypsum is 95: 5 to 30:70.   The plastic grout material according to claim 1 or 2, wherein the retarder is contained in a mass ratio of 0.4 to 2.0% based on the total amount of the latent hydraulic material and gypsum. The plastic grout material according to claim 1 or 2, wherein the latent hydraulic material is blast furnace slag and / or fly ash.   The plastic grout material according to claim 1 or 2, wherein the plasticizer is at least one selected from bentonite, attapulgite, and metakaolin.   The plastic grout material according to claim 1 or 2, wherein the gypsum is anhydrous gypsum.   The plastic grout material according to claim 1 or 2, wherein a water reducing agent is added in a mass ratio of 0.5 to 2.0% with respect to the plasticized material.   Injecting a stimulant that elutes Ca ions into the plastic grout material matrix according to any one of claims 1 to 8, wherein the grout material matrix is hardened by being injected into a construction site in advance and in an uncured state. A characteristic grout method.   The grout method according to claim 9, wherein the stimulant is at least one selected from Portland cement, blast furnace cement, fly ash cement, silica cement, eco cement, cement-based solidified material, and calcium hydroxide.