JP2003138261A - Injection material for soil stabilization - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection material for soil stabilization which has actions of continuing the hindrance of a hydration reaction with a cement at a period immediately after the water addition on the one hand and of activating considerably the hydration thereafter on the other hand and which is capable of reducing the flash setting or stiffening of a fast-hardening/quick setting mate rial and of prolonging a gel time of the cement slurry for more than 60 min without decreasing in the homogel strength. SOLUTION: The injection material for soil stabilization contains one or more kinds of manganese oxides selected from MnO2 , Mn2 O3 and MnO in an amount of 2-20 wt.% relative to the total sum amount of the said manganese oxides, CaO and Al2 O3 , and contains a cement quick setting/quick hardening base material having a vitrification ratio of 50 wt.% or more, and furthermore comprises 95 vol.% or more of particles with 50 μm or less.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cement-based ground improvement injection material used in the field of civil engineering and construction.

[0002]

2. Description of the Related Art Conventionally, calcium aluminates have been known to accelerate the setting speed of cement (quick setting and rapid hardening), and this property is utilized to shorten the setting time of cement, mortar or concrete and to reduce the initial setting time. It has been used extensively to improve strength. Among them, amorphous calcium aluminate is excellent in quick setting and quick hardening, and therefore, it is used in combination with cement as a quick hardening material, a quick-setting material for spraying, a waterproof material, and the like. Hydration reaction between cement and quick-setting / quick-hardening material is the reaction process such as elution of Al ³⁺ ions into liquid phase, formation of aluminum gel, formation of calcium aluminate hydrate, formation of ettringite and monosulfate hydrate. Through the
It is considered that the reaction rate of each reaction, the morphology and the amount of hydrates have a great influence on the quick-setting performance and the gel time of the cement slurry.

On the other hand, the main materials used for the ground improvement injection material are roughly classified into water glass type, polymer type and cement type. Among the cement type injection materials, in particular, molten calcium aluminum is used. A rapid-hardening injection material has been used in which a cement rapid-hardening material slurry containing a nate or the like and a cement slurry are combined and mixed to significantly accelerate the gel time and hardening of the mixed solution. In addition, C that promoted curing
_{aO-Na 2 O-Al 2} O 3 based fired product (JP 9-869
No. 87) is also known, and it is possible to adjust the gel time from an extremely short gel time of 1 minute or less to about 15 minutes. It is known that the gel time can be arbitrarily adjusted from 1 minute or less to about 15 to 60 minutes by adding a coagulation modifier such as oxycarboxylic acid (Japanese Patent Laid-Open No. 9-
No. 100471).

[0004] On the other hand, recently, injecting materials which can maintain a stable injection property for a longer time of 60 to 120 minutes have been demanded because it is desired to inject a larger amount in a wider area in a construction site. Came.
Regarding the extension of gel time, it is possible to adjust the gel time as long as 60 to 120 minutes by increasing the addition amount of the coagulation modifier. However, in general, the longer the gel time is adjusted to 60 minutes or more, that is, the more the setting retarder is added, the homogel strength is significantly decreased or the hardening does not occur, and the sufficient performance as a ground improvement injection material is exhibited. There was a problem not to do.

[0005]

DISCLOSURE OF THE INVENTION The present invention is intended for improving a quick-hardening ground for which a long gel time of 60 to 120 minutes or more can be set with the addition of a smaller amount of a set retarder and the homogel strength does not decrease. The purpose is to provide an injection material.

[0006]

SUMMARY OF THE INVENTION The present inventors have studied various cement quick setting and quick hardening compositions in view of the above circumstances, and selected from MnO ₂ , Mn ₂ O ₃ and MnO. When one or more manganese oxides are added to the calcium aluminates, the hydration reaction is suppressed for a period immediately after the addition of water, while the subsequent hydration is significantly activated,
Instant setting and stiffness can be reduced, the gel time in cement slurry can be extended for 60 minutes or more without lowering the homogel strength, and at the same time, the melting temperature of the quick setting and rapid hardening base material can be lowered and the amorphization during cooling can be achieved. It was found that productivity can be improved by the promotion, and the present invention has been completed.

That is, according to the present invention, MnO ₂ , Mn ₂ O ₃
And 1 to 2 or more manganese oxides selected from MnO and ₂ to 20% by weight based on the total amount of the manganese oxide, CaO and Al ₂ O ₃ , and having a vitrification rate of 50.
Including a cement quick setting / quick setting base material with a weight percentage of 9 or more, 9
It is intended to provide an injection material for ground improvement, characterized in that 5% by volume or more is composed of particles of 50 μm or less.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The cement-based ground improvement injection material of the present invention is selected from MnO ₂ , Mn ₂ O ₃ and MnO.
A manganese oxide, or two or more manganese oxides,
It contains 2 to 20% by weight of the total amount of CaO and Al ₂ O ₃ , and contains a quick-setting cement-hardening base material having a vitrification rate of 50% by weight or more. The cement quick setting / hardening base material of the present invention contains CaO and Al ₂ O ₃ as main components, and contains one or more manganese oxides selected from MnO ₂ , Mn ₂ O ₃ and MnO. Therefore, the vitrification rate is 50% by weight or more.

The content of manganese oxide is manganese oxide,
It is 2 to 20% by weight, preferably 3 to 10% by weight, based on the total amount of CaO and Al ₂ O ₃ . When the content of manganese oxide is less than 2% by weight with respect to the total amount of manganese oxide, CaO and Al ₂ O ₃ , the instantaneous setting and stiffness are reduced, the gel time is prolonged for 60 minutes or more, and the rapid setting and rapid hardening are achieved. The improvement is insufficient, and when it exceeds 20% by weight, the content of CaO and Al ₂ O _{3 in} the quick-setting and quick-hardening base material is small and the homogel strength is lowered.

The contents of CaO and Al ₂ O ₃ contained in the cement quick-setting and quick-hardening base material of the present invention are 10 to 78% by weight of CaO and 20 to 20% of Al ₂ O ₃ from the viewpoint of strength development. 60
It is preferable that the content is wt%.

The cement quick setting / quick setting base material and cement of the present invention
Hydration reaction with the ³⁺Ion elution,
Lumigel formation, calcium aluminate hydrate raw
And ettringite and monosulfate hydrate formation
The reaction rate, hydrate form, etc.
It is considered that the production amount and the production amount affect the gel time and homogel strength.
available. And by adding manganese oxide
While the hydration reaction immediately after addition of fresh water is suppressed for a certain period,
Subsequent hydration is remarkably activated, and in fast hardening and quick setting materials
Instant binding and stiffness are reduced without reducing homogel strength
Extend the gel time in cement slurry to more than 60 minutes
Can be postponed.

Further, the rapid setting and rapid hardening of the cement-hardening base material of the present invention becomes higher as the vitrification rate increases, so that the vitrification rate is preferably 50% by weight or more. More preferably, the vitrification rate is 80% by weight or more.

Further, the cement quick setting / quick setting base material of the present invention
From industrial raw materials to the extent that it does not affect its performance.
Na which is an inevitable ingredient₂O, K₂O, MgO, S
iO ₂, Fe₂O₃, TiO₂Etc. may be included.

The ground improvement pouring material of the present invention is composed of particles whose 95% by volume or more is 50 μm or less. As a result, the distribution composed of particles having a size that hinders the injection is reduced, so that an injection amount as large as the injection material can be secured.

In the ground improvement injection material of the present invention, the addition of gypsum further enhances the rapid hardening property due to activation after the hydration reaction is suppressed for a certain period of time, and an alkali metal carbonate is further added to the mixture of gypsum. As a result, the expression of the initial strength also increases. Also, by adding a small amount of setting regulator,
The gel time can be adjusted, a long gel time of 60 to 120 minutes or more can be set, and the homogel strength does not decrease.

[0016] Gypsum enhances the production of ettringite and monosulfate hydrate when hydration is activated after manganese oxide suppresses the hydration reaction for a certain period. Anhydrous gypsum and dihydrate gypsum. Although any of hemihydrate gypsum can be used, anhydrous gypsum is the most preferable from the viewpoint of improving strength development.

The amount of gypsum added is preferably 10 to 100 parts by weight with respect to 100 parts by weight of the cement quick setting and rapid hardening base material. If it is less than 10 parts by weight, ettringite and monosulfate are insufficiently produced, and higher homogel strength may not be obtained. On the other hand, when it exceeds 100 parts by weight, when the injection material is added to the cement suspension, the amount of the cement quick-setting / rapid-hardening base material becomes small, and hydration is suppressed for a certain period of time. The rising becomes unclear, curing progresses very slowly, and after curing, expansion continues and the strength decreases. The fineness of gypsum is preferably 2000 cm ² / g or more in terms of Blaine specific surface area, 3000 cm
² / g to 9000 cm ² / g is particularly preferable because the reaction activity is enhanced.

The alkali metal carbonate acts on the cement quick-setting and quick-hardening base material and promotes the elution of Al ³⁺ ions into the liquid phase during the period when the hydration reaction is suppressed by the contained manganese oxide, and ettringite Acts to accelerate the rate of formation of, and enhances initial strength. Examples of the alkali metal carbonate include sodium carbonate, potassium carbonate, lithium carbonate and the like, and a highly water-soluble alkali metal carbonate is preferable. The blending amount of the alkali metal carbonate is 10 parts by weight or less based on 100 parts by weight of the cement quick-setting and quick-hardening base material,
Particularly, 8 parts by weight or less is preferable. If it exceeds 10 parts by weight,
It is not preferable because the gel property due to the formation of ettringite becomes poor and the elongation of strength after curing also deteriorates.

The setting regulator has a function of adjusting the pot life and gel time of the ground improvement pouring material of the present invention, and the gel time can be arbitrarily adjusted by adding a setting retarder. Such setting retarders include, for example, citric acid, gluconic acid, malic acid, tartaric acid, glucoheptonic acid, hydroxycarboxylic acids such as galactonic acid and salts thereof, sugars such as glucose, saccharose and dextrin, phosphoric acid, boric acid and salts thereof. Inorganic acids (salts) such as citric acid and tartaric acid are particularly preferable because the gel time can be adjusted almost linearly by the addition amount. Also,
These setting retarders can be used alone or in combination of two or more kinds.

The ground improvement injection material of the present invention is used in combination with cement, and examples of such cement include ordinary cement, early strength cement, moderate heat cement, blast furnace cement, fly ash cement, silica cement and fine particles. Known cements such as cement and ultrafine particle cement can be used. The use ratio of the ground improvement injection material and the cement of the present invention is not particularly limited and can be appropriately determined depending on the purpose of use, but 100 to 2000 parts by weight of cement is preferable to 100 parts by weight of the ground improvement injection material.

The method of using the ground improvement casting material of the present invention is as follows:
(1) A one-shot method in which a suspension obtained by simultaneously kneading the ground improvement injection material of the present invention and cement is pumped through one injection pipe and injected into the ground, (2) ground improvement of the present invention The suspensions prepared by kneading the injection material and cement separately are separately pumped through the two injection pipes, joined and mixed immediately before being injected into the ground, and then injected into the ground.
5-shot method, (3) Suspensions prepared by separately kneading the ground improvement injection material of the present invention and cement are separately fed under pressure through two injection pipes to be merged and mixed in the ground 2 Any of the shot methods can be selected according to the gel time. Among these, the method of mixing the ground improvement injecting agent slurry and the cement slurry immediately before construction is preferably used.

In order to improve the fluidity of the ground improvement injection material and / or cement of the present invention or the mixing water thereof, a water reducing agent, an AE water reducing agent, a high performance water reducing agent, a high performance AE water reducing agent, A fluidizing agent or the like may be added, and aluminum sulfate, aluminum hydroxide, aluminate, alum, calcined alum, lime, glycerin, triethanolamine, water glass, or the like may be added in order to enhance rapid hardening.

[0023]

EXAMPLES Next, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto. Examples 1 to 16 and Comparative Examples 1 to 4 (1) Manganese is contained in an amount shown in Table 1 in terms of oxide MnO based on 51.0 parts by weight of calcium oxide and 49.0 parts by weight of aluminum oxide. Mix the temperature in the furnace 1
After completely melting in an electric furnace at 600 ° C., the melt was rapidly cooled by air cooling to obtain a clinker as an amorphous quick-setting / quick-hardening base material. Further, a clinker of a quick-setting / hard-hardening base material having a low vitrification rate was obtained by slowing the cooling rate from the same melt. Each of the obtained clinker was pulverized with a mill to obtain a quick-setting / quick-hardening base material having a Blaine specific surface area of 5000 cm ² / g. The materials used are shown below. The vitrification ratio was measured by the powder X-ray diffraction method from the height of the diffraction peak.

Materials used Calcium carbonate: manufactured by Wako Pure Chemical Industries, Ltd. Primary reagent calcium carbonate manganese oxide: manufactured by Kanto Kagaku Co., manganese dioxide (M
nO ₂ ) Aluminum oxide: First-class aluminum oxide manufactured by Kanto Chemical Co., Inc.

(2) The ground rapid-hardening quick-setting base material was mixed with anhydrous gypsum and sodium carbonate in the compounding ratio shown in the table to prepare a ground improvement injection material. (3) Measurement of gel time 54 g of water was weighed in a 300 mL cup, 40 g of ordinary cement was added, and the mixture was kneaded for 1 minute with a mixer (hereinafter referred to as liquid B). Further, 63 g of water was weighed in another 300 mL cup to dissolve citric acid, 9.4 g of the ground improvement injection material adjusted at each mixing ratio shown in the table was added, and the mixture was kneaded for 1 minute with a mixer (hereinafter, referred to as liquid A). That). Then, mix solution A and solution B quickly, then transfer the total amount of the mixture to a 200 mL cup, and set the time (gel time) until the mixture does not show fluidity (gelation) from cup to cup. The measurement was performed by observing while moving at intervals (cup upside down method).
The results are also shown in Table 1.

(4) Measurement of Strength 54 g of water was weighed in a 300 mL cup, 40 g of ordinary cement was added, and the mixture was kneaded with a mixer for 1 minute (hereinafter referred to as liquid B). Further, 63 g of water was weighed in another 300 mL cup to dissolve citric acid, 9.4 g of the ground improvement injection material prepared at each mixing ratio shown in the table was added, and the mixture was kneaded for 1 minute with a mixer (hereinafter, liquid A). That). Next, after mixing A liquid and B liquid quickly, pour into a mold and have a diameter of 35 mm and a length of 70 mm.
The cylindrical specimen of was prepared. The strength after 1 day of wet air curing was measured using a uniaxial compression tester. The results are also shown in Table 1.

[0027]

[Table 1]

[0028]

INDUSTRIAL APPLICABILITY The ground improvement injection material of the present invention has the effect of remarkably activating the subsequent hydration while continuing to suppress the hydration reaction with cement for a period immediately after the addition of water.
Therefore, it is possible to reduce the instantaneous setting and stiffness of the quick-hardening and quick-setting material, and it is possible to extend the gel time in the cement slurry for 60 minutes or more without lowering the homogel strength. In addition, the addition of manganese oxide promotes lowering of the melting temperature of the quick-setting / quick-hardening base material and amorphization during cooling, which also contributes to improvement in productivity.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C04B 28/02 C04B 28/02 C09K 17/02 C09K 17/02 P 17/06 17/06 P 17/08 17/08 P 17/14 17/14 P // C04B 103: 14 C04B 103: 14 111: 70 111: 70 C09K 103: 00 C09K 103: 00 (72) Inventor Ryozo Yoshida 2-chome Daisaku Sakura City, Chiba Prefecture 4-2 Taiheiyo Material Co., Ltd. Development Laboratory (72) Inventor Shigeru Matsuura 2-4-2 Daisaku Sakura, Chiba Prefecture Taiheiyo Cement Co., Ltd. Central Research Laboratory F-term (reference) 4G012 MA00 MB06 MB23 PB03 PB05 PB08 PB11 PB17 PB39 PC06 PC11 PC12 PD01 PD03 PE04 4H026 CA04 CA06 CB02 CB08 CC06

Claims (4)

[Claims] 1. Containing 1 to 2 or more manganese oxide selected from MnO ₂ , Mn ₂ O ₃ and MnO in an amount of 2 to 20% by weight based on the total amount of the manganese oxide, CaO and Al ₂ O _3. In addition, including a cement quick setting / hardening base material having a vitrification rate of 50% by weight or more, 95% by volume or more is 50% by weight or more.
An injection material for ground improvement, which is composed of particles with a size of μm or less. 2. The injection material for ground improvement according to claim 1, which further contains gypsum or / and an alkali metal carbonate. 3. The ground improvement injection material according to claim 1, further comprising a setting retarder. 4. The ground improvement injection material according to claim 1, which is used as a mixture with a cement slurry.