JPH10102058A - Grout - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a grout baving an excellent hardening and durability for organic acid-containing soft grounds containing humus soil without generating a bleeding phenomenon. SOLUTION: This grout contains colloidal silica and a cement-based solidifying agent. When the grout further contains a gel time-adjusting agent as an additional component, the colloidal silica, the cement-based solidifying agent and the gel time-adjusting agent are contained in a weight ratio of 1:(2.5-25):(0.12-1.2). The cement-based solidifying material has a specific surface area of >=2700cm<2> /g and a chemical composition having a SiO2 :Al2 O3 :CaO:SO3 weight ratio of (15-25):>=3.5:(40-70):>=4.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to strengthening of soft ground,
The present invention relates to a ground injection material applied for stopping water, and particularly to a ground injection material suitable for a ground having a high natural water content, a soft ground containing humus, and the like.

[0002]

2. Description of the Related Art Conventionally, ground injection materials have been playing a role as temporary materials in auxiliary construction methods for civil works for the purpose of strengthening the ground and stopping water. However, in recent years, the ground reinforcement and liquefaction of existing structures have been performed. Particular attention has been paid as a means of prevention.

[0003] As an existing ground injection material, a cement slurry represented by JIS standards and a cement-based solidifying material slurry have been mainly used. However, these materials have a problem that a solid-liquid separation phenomenon, so-called breathing, occurs in the ground. When the breathing occurs, the position of the solidified material of the injected material may be lower than the planned position after consolidation of the injected material injected into the ground, or the ground at the upper end of the consolidated material may collapse after the escape of breathing water, etc. There was a problem.

[0004] As one of effective methods for preventing breathing, it has been considered to shorten the solidification time of the injected material, and for this purpose, a ground injection material containing water glass as a main component has been frequently used. As a curing agent for water glass, for example, Portland cement, slaked lime, calcium salts such as steel slag, sodium hydrogen sulfate, magnesium sulfate, acids such as phosphoric acid, glyoxal, organic acids such as ethylene carbonate, or specific esters. Has been used.

[0005] However, a ground injection material containing water glass as a main component has problems such as durability and pollution as already pointed out in many documents.

On the other hand, as a ground injection material mainly containing water glass, some materials mainly containing colloidal silica have been proposed. As a curing agent for colloidal silica as a main agent, for example, a method using slaked lime or cement (JP-A-59-66482), a method using an alkaline earth metal salt such as magnesium sulfamate (JP-A-63-168485). Gazette), a method using an alkali metal salt such as sodium chloride or sodium hydrogen sulfate (JP-A-59-152985), and a method using a trivalent metal salt such as an aluminum salt (JP-A-59-1529).
No. 84).

[0007] Examples of other ground injection materials include:
Japanese Patent Publication No. Sho 62-17636 proposes a ground injection material composed of a Portland cement slurry and silica sol compliant with JIS standards.

[0008] However, although these conventional soil injection materials can be expected to have a certain effect on breathing, organic acids such as humus soil, especially in humus soil, are found in the ground of harbors, coastal facilities, river facilities, roads and railway facilities. (Humic acid such as humic acid), the hardening ability of the ground decreases. In the case of ground containing organic acids, the main agent, colloidal silica, does not react with the organic acids and causes no problem.On the other hand, the alkaline hardener such as cement usually reacts with the organic acids, so the hydration reaction occurs. Is impaired, the curing ability is reduced, and durability cannot be obtained. The component composition of the ground injection material that can be effectively applied to the ground containing such an organic acid has not been proposed yet.

[0009]

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a ground injection material that is effective for soft ground. In particular, an object of the present invention is to provide a ground injection material capable of obtaining excellent hardening ability and durability without causing bleeding on soft ground containing humus, that is, containing organic acid.

[0010]

Means for Solving the Problems In order to achieve the above object, a ground injection material according to the present invention contains colloidal silica and a cement-based solidifying material as components.

Further, another embodiment of the ground injection material according to the present invention contains a gel time regulator as an additional component in addition to the above components.

[0012] Further, in the above embodiment containing the gel time controlling agent, the colloidal silica, the cement-based solidifying material, and the gel time controlling agent are in a weight ratio of 1: 1:
It is characterized by being contained at a ratio of 2.5 to 25: 0.12 to 1.2.

Further, in another aspect of the ground injection material according to the present invention, in any one of the above-described embodiments, the specific surface area of the cement-based solidified material is 2700 cm ² / g or more, and In composition, SiO ₂
, Al ₂ O ₃ , CaO, and SO ₃ are contained in a weight ratio of 15 to 25: 3.5 or more: 40 to 70: 4.0 or more.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The ground injection material according to the present invention basically contains at least colloidal silica and a cement-based solidification material as components. To date, no ground injection material using a combination of colloidal silica and a cement-based solidification material has been known.

The colloidal silica used in the present invention is obtained by using water glass as a raw material, an ion exchange method, a deflocculation method, an acid neutralization method,
It is manufactured by an electrodialysis method or the like. Examples of this production method include JP-A-52-33899 and JP-A-1-31711.
5, U.S. Pat. Nos. 2,577,484 and 3,711,141.
No. 9, No. 25725578, and No. 3668088
There is a disclosure in each gazette of the issue.

Other methods for producing colloidal silica include JP-B-46-7367 and US Patent No. 3650.
There is a method by oxidation of metallic silicon described in each publication of No. 977, etc., or a method of dispersing fine silica powder in water described in each publication of JP-A-62-212716 and U.S. Pat. Colloidal silica obtained by the production method can also be used in the present invention.

As the characteristics of colloidal silica, those having a large particle diameter have a low gel strength, so that the average particle diameter is 3%.
Those having a mean particle size of 50 nm or less, particularly 20 nm or less, are practically suitable. In particular, colloidal silica of a small particle grade having an average particle diameter of 3 to 15 nm has a particularly high gel strength and is optimal. Incidentally, colloidal silica of a grade having an average particle diameter of less than 3 nm has a high alkali stabilizer content like water glass, and is not suitable for the purpose of the present invention.

The colloidal silica usually contains a small amount of alkali ions (or hydrogen ions) for stabilizing the colloid, but the alkali content of the colloidal silica used in the present invention is SiO ₂ / M ₂ O (M is an alkali metal) in a molar ratio of 5 to 500 is preferable.

In the present invention, it is particularly important to use a cement-based solidifying material together with the above-mentioned colloidal silica. The cement-based solidifying material is of a type different from Portland cement and mixed cement of the JIS standard. Usually, cement is made of Portland cement and JIS standard cement in which admixtures such as blast furnace slag and fly ash are mixed at a predetermined ratio, based on Portland cement as a base, and special cements other than JIS standard such as colloid cement and ultra-rapid hardening cement. It is roughly divided. Cement-based solidification material belongs to special cement in this,
An active ingredient is added in accordance with the purpose such as reinforcement of specific components of the standard, adjustment of particle size or soil properties.

The cement-based solidification material used in the present invention may be added as an effective ingredient to bozolan materials such as slag and fly ash, strength-enhancing materials such as alumina cement and jet cement, or hydration materials such as gypsum and sodium sulfate. Contains stimulants. Further, the specific surface area is 2700 cm ² / g or more, and the weight ratio of each composition is SiO ₂ : Al ₂ O ₃ : C
aO: SO ₃ = 15 to 25: 3.5 or more: 40 to 70:
It has a chemical composition of 4.0 or more. As for CaO, the ratio to the total amount of cement-based solidified material is 5% by weight.
8～60Wt%, about SO _3, like 9~13w
Those containing t% are particularly preferred.

Commercially available cement-based solidifying materials usable in the present invention include, for example, Asano Clean Set (manufactured by Nippon Cement), Chichibu Soil Fix (manufactured by Chichibu / Onoda Cement), Ube UKC (manufactured by Ube Industries), and Stabilite (Mitsubishi Materials), Toughlock (Sumitomo / Osaka Cement), Cement-based Chemico (Chichibu / Onoda Cement), Nittetsu Earth Tight (Nittetsu Cement), Neo Cement Series (Daiichi Cement), Aso Solid Ace (Made by Aso Cement), High Hard (made by Hitachi Cement),
Solstar (manufactured by Nippon Steel Chemical), Denka Soil Pack (manufactured by Denki Kagaku Kogyo), hard keep (manufactured by Tokuyama Soda) and the like.

The soil injection material according to the present invention is basically composed of the above-mentioned components. If necessary, a known cement dispersant, synthetic silica or synthetic zeolite having an average particle diameter of 1 μm or less may be used. Such an inorganic fine powder may be blended. In particular, when inorganic fine powder is blended, the gel strength of the ground injection material is further improved, so that the range of application is expanded, which is preferable.

Next, the operation and effect of using the cement-based solidifying material as a component of the soil injection material according to the present invention will be described in comparison with the case where JIS standard ordinary Portland cement is used. When a ground injection material containing JIS standard Portland cement is applied to a ground containing an organic acid, calcium hydroxide generated by the initial hydration reaction of the cement and the organic acid combine to precipitate on cement particles, Inhibits subsequent hydration reactions. As a result, no strength is observed.

On the other hand, when the ground injection material containing the cement-based solidification material according to the present invention is applied to the ground containing an organic acid, the above-mentioned inhibition of the hydration reaction does not occur. The cement-based solidification material is characterized by containing a large amount of sulfur trioxide (SO ₃ ). This sulfur trioxide is used in hemihydrate gypsum (CaS
O ₄ .0.5H ₂ O) or gypsum (CaSO ₄ .2H)
₂ O). This gypsum component takes up the products of the initial hydration reaction of the cement and ettringite
By producing a large amount of (3CaO.Al ₂ O ₃ .3CaSO ₄ .32H ₂ O), a reaction with an organic acid can be avoided.
Therefore, an increase in strength is achieved without inhibiting the hydration reaction. In addition, the effect of increasing the strength can be obtained also by the fact that ettringite takes in a large amount of water as bound water and the formation of calcium silicate.

Further, when a gel time regulator is used,
The alkali metal salt also acts as a hydration accelerator for the cement-based solidifying agent, and increases the gel strength.

Hereinafter, some examples of the present invention will be described, and test results relating to the characteristics of these examples will be shown.
It should be noted that the illustrated embodiments do not limit the invention.

[0027]

[Table 1]-Formulation of each example of the present invention---------------------------| Liquid A (200 ml) | Liquid B (200 ml) | Colloidal Kertime water | Cement-based water | Silica (ml) Modifier (g) (ml) | Solidified material (g) (ml) --------- −−−−−−−−−−−−−−−−−−−−−−−−−−−− Example 1 | 20 6 180 | 148 148 Example 2 | 20 4 180 | 70 176 Example 3 | 20 2 180 | 40 188 Example 4 | 30 6 170 | 148 148 Example 5 | 30 4 170 | 70 176 Example 6 | 30 2 170 | 40 188 Example 7 | 40 6 160 | 148 148 Example 8 | 404 160 | 70 176 Example 9 | 40 2 160 | 40 188 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− −−−

Table 1 shows the amounts of Examples 1 to 9 used in the test. The main agent (Solution A) contains colloidal silica (Silica Doll 30; manufactured by Nippon Kagaku Kogyo) slurry and sodium bicarbonate as a gel time regulator. Also a curing agent
(Liquid B) is a cement-based solidifying material (Stabilite M-15;
(Mitsubishi Materials) Includes slurry. These A liquid and B
The liquids were mixed in the amounts shown in Table 1, and the properties thereof were tested by measuring (1) gel time at 20 ° C., (2) compressive strength of sand gel, and (3) breathing rate. Each measurement method is described below.

(1) Gel time The ground injection material mixed in a predetermined formulation is put into a beaker,
If the stirring is continued with a magnetic stirrer, the viscosity gradually increases and gels. In this process, the time from the point when the ground injection material was put into the beaker to the time when it gelled to lose the fluidity and did not flow down even when the beaker was tilted at 90 degrees was measured as the gel time.

(2) Compressive strength (sand gel) 400 ml of a solution of ground injection material mixed as described above
And 1000ml of Toyoura standard sand are uniformly mixed.
The sample is put in a cylindrical mold having a diameter of 50 mm and a length of 100 mm, and after 1 hour to several hours, the specimen removed from the mold is immersed in water. And
After a lapse of a predetermined number of days, the specimen was taken out, and the uniaxial compressive strength was measured with a compressive strength tester.

(3) Breathing rate 1000 ml of ground injection material solution mixed as described above
Into a measuring cylinder, leave it for a predetermined time,
The time and the amount of the supernatant liquid after 2 hours were measured and determined as a percentage of the total volume.

As Comparative Example 1, a ground injection material mixed with 148 g of bolt land cement, 1 g of a condensate of a dispersant naphthalenesulfonic acid and modified lignin, and 348 ml of water was used. Examples 1 to 9 and Comparative Example 1 above
Table 2 shows the test results.

[0033]

[Table 2]-Test results for Examples of the present invention---------------------------- Gel time Sand gel compressive strength Breathing rate (minutes: seconds) (kgf / cm ² ) (%) 1 day 7 days 28 days 0.5h 1h 2h ---------------------- −−−−−−−−−−−−−−−−−− Example 1 2:22 3.1 11.0 11.0 0 0 Example 2 4:16 1.2 3.5 4.6 0 0 0 Example 3 2:50 1.0 2.0 2.9 0 0 0 Example 4 2:17 4.5 12.1 14.8 0 0 0 Example 5 2:31 2.3 4.9 6.4 0 0 0 Example 6 4:30 2.3 3.7 3.8 0 0 0 Example 7 3:42 6.2 12.9 13.9 0 0 0 Example 8 3:44 3.1 6.9 9.3 0 00 Example 9 9 2:10 4.0 6.4 7.2 0 0 0 ------------------------------------------------------ −−−−−−−−−−− Comparative Example 1 −1.0 5.8 14.5 8 17 28 −−−−−−−−−−−−−− -----------------------

From the results in Table 2, in Comparative Example 1, the breathing rate of 28% was measured after 2 hours, whereas the soil injection material containing colloidal silica and cement-based solidified material according to the present invention as basic components was not used. It can be seen that no breathing occurred. The gel time regulator used was of a fast type, but a stable gel time was obtained in all Examples. Good results were obtained especially from Examples 1, 4, and 7 from the sand gel compressive strength test. In each of these examples, the mixing ratio of the cement-based solidification material is relatively large.

Next, the results of evaluating the durability of the soil injection material according to the present invention against humus are shown. Table 1
Examples 1, 5 and 9 were used from the examples of the soil injection material of the present invention, and the ground injection material having the following composition was used as Comparative Example 2.・ Comparative Example 2 Liquid A: JIS sodium silicate No. 3 100 ml, water 100 m
Liquid B: 80 g of bolt land cement, 174 ml of water

The above sample and Comparative Example 2 were placed in a mold and placed in a mold.
After 4 hours, the mold was released to prepare a cured specimen for measuring compressive strength. The size of the cured specimen and the composition of the sand are the same as those used in the above-mentioned compressive strength test. Thereafter, the test specimens were divided into two groups, one of which was 3 watts of peat moss.
The other group was dipped in tap water and the other group was dipped in tap water. The immersion magnification is such that the volume ratio of the immersion liquid solution / test sample is 4. In addition, all were performed at 20 degreeC. Peat moss was used as a humus in the test, and its components are as follows.

Peat moss component pH: 4.1 to 5.5 Base substitution capacity: 159 to 177 (me / 100 g) Organic matter: 90 to 98 wt% Ash: 2.0 to 10 wt% Nitrogen: 0.8 to 2.3 wt % Phosphoric acid: 0.11 to 0.49 wt% Potassium: 0.06 to 0.13 wt% Lime: 0.12 to 1.8 wt%

The material age (elapsed days) is 7 days, 28 days,
The durability was tested by measuring the uniaxial compressive strength of each specimen after 91 days. Table 3 shows the results.

[0039]

[Table 3]-Durability test results by peat moss immersion -------------------------------------------------------- Example 1 Example 5 Example 9 | Comparative Example 2 ------------------------------------------------------------------ 7 days | 1.0 1.0 1.0 | 0.728 days | 1.0 1.0 1.0 | 0.491 days | 1.2 0.9 0.9 | 0.5 --- −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− (Values in the table: Same samples of the same material age immersed in tap water Ratio of compressive strength to

In Table 3, for each material age (elapsed days),
Based on the value of compressive strength of the same sample immersed in tap water (1.
0) and the relative value of the compressive strength of the sample immersed in peat moss is shown. Regarding each embodiment of the ground injection material according to the present invention, even under peat moss immersion conditions, the strength 0.9 to approximately the same as in the case of tap water immersion.
1.2 has been obtained. On the other hand, in Comparative Example 2 which is a conventional ground injection material, the strength was significantly reduced under peat moss immersion conditions, with 0.7 after 7 days, 0.4 after 28 days, and 0.5 after 91 days. You can see that it is doing.
From these results, it was shown that the ground injection material according to the present invention can exert sufficient strength even on a humus containing an organic acid such as peat moss without inhibiting the hardening.

From the results of the above tests, the ground injection material according to the present invention shows that the colloidal silica, the cement-based solidification material, and the gel time modifier are in a weight ratio of 1: 2.
Those contained at a ratio of 5 to 25: 0.12 to 1.2 are preferable.

[0042]

The ground injection material according to the present invention has a novel composition containing colloidal silica and a cement-based solidifying material as basic components, and thus does not cause any bleeding as seen in the conventional ground injection material. Moreover, the gel time is stable.

Further, as a useful feature of the soil injection material according to the present invention, it has excellent hardening ability, that is, durability, even on humus soft ground containing an organic acid. In addition, the soil injection material according to the present invention has practically no concern about pollution problems and is highly practical.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Tadashi Onishi 1-112-38 Esaka-cho, Suita-shi, Osaka Toko Construction Co., Ltd. Osaka Branch (72) Inventor Hideaki Baba 9-15-1, Kameido, Koto-ku, Tokyo No. Nippon Kagaku Kogyo Co., Ltd. (72) Inventor Akira Sekine 9-15-1, Kameido, Koto-ku, Tokyo Nippon Kagaku Kogyo Co., Ltd. (72) Inventor Sadamori Sato 1-7, Kyomachibori, Nishi-ku, Osaka-shi No. 12 Inside Asano Kagaku Sangyo Co., Ltd. (72) Inventor Katsuya Morishita 1-7-12 Kyomachibori, Nishi-ku, Osaka City Inside Asano Kagaku Sangyo Co., Ltd.

Claims (4)

[Claims] 1. A ground injection material comprising colloidal silica and a cement-based solidifying material as components. 2. The soil injection material according to claim 1, further comprising a gel time regulator as an additional component. 3. The colloidal silica, the cement-based solidifying material, and the gel time modifier are contained in a weight ratio of 1: 2.5 to 25: 0.12 to 1.2. The ground injection material according to claim 2, characterized in that: 4. The cement-based solidifying material has a specific surface area of 27.
00 cm ² / g or more, and in the chemical composition of the cement-based solidifying material, SiO ₂ , Al ₂ O ₃ , CaO
When the SO ₃ is, by weight ratio, 15 to 25: 3.5 or more: 40 to 70: according to any one of claims 1 to 3, characterized in that contained in 4.0 above ratio of Ground injection material.