JPH10259042A - Cement-based injection material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide good injectability and filling property from low water injection material ratio to high water injection material ratio, and to excel in cracking and ground injection of concrete structure. To provide an injection material that exhibits SOLUTION: Portland cement clinker fine powder (a), blast furnace slag, which is used as a slurry containing up to 3.0% by weight of a high-performance water reducing agent in terms of solid content at a water amount of 40 to 1000% by weight based on an injection material. A cement-based injecting material obtained by spheroidizing a mixture of the fine powder (b) and the gypsum fine powder (c), and a Portland cement clinker fine powder obtained by previously spheroidizing by mechanical or heat melting ( a '), (b) and (c) a cement-based injection material (a (a'), b and c
Is a (a ') 30 to 75 parts by weight: (b) 70 to
25 parts by weight: (c) 0 to 10 parts by weight (a (a ') to
(The total of (c) is 100 parts by weight.)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can secure good injectability and fillability from a low water injection material ratio to a high water injection material ratio, and is particularly suitable for cracking and ground injection of concrete structures. The present invention relates to a cement-based injection material exhibiting excellent performance. More specifically, the raw material particles are subjected to a spheroidizing treatment to improve the flowability of the grout, and the fine particles are adhered and fixed to the surface of a large particle, thereby reducing the amount of the fine particles and dispersing the particles in the grout. The present invention relates to a cement-based injection material applicable to cracking and ground injection of a concrete structure, which has improved injectability and suppresses generation of agglomerated coarse particles, thereby maintaining excellent injectability.

[0002]

2. Description of the Related Art A cement-based ultrafine particle injection material having a maximum particle size of about 10 μm is already known (Japanese Patent Publication No. 2-44269). In addition to dam foundation treatment, urban civil engineering, injection for crack repair of concrete structures. It has been put to practical use as a material, and has achieved considerable results. Although these ultrafine particle injection materials have a difference in particle size distribution, the constituent material is a mixture with ordinary Portland cement mainly composed of blast furnace slag fine powder.

[0003] The basic injection performance of the ultra-fine particle injection material is that it has made it possible to infiltrate into fine sand ground, which was impossible with the conventional cement-based injection material. This performance is based on Toyoura standard sand according to JIS R5201. (Particle size: 0.1 to 0.3 mm) is evaluated as a tentative indication that an injectable material milk (hereinafter, simply referred to as milk) permeates.

[0004] The grout used for dam foundation treatment is as follows:
The ratio of water to the injection material (water injection material ratio) is 200 to 1000
Used as milk in the range of weight percent. In urban civil engineering, gel time is sometimes set in grout for the purpose of limiting the injection range, and milk having a water ratio of 100 to 400% by weight is used in combination with water glass or silica sol. For repairing a crack in a concrete structure, it is necessary to have the same strength and water stopping property as concrete.
It is injected with a slurry of about% by weight.

[0005]

As a characteristic of the cement-based injection material, generally, the finer the particle size, the better the injection performance. However, if the finer than necessary, the lower the injection performance. Normally Portland cement alone fine particle injection material,
Aggregation rate in water is extremely fast due to high hydration activity,
Since agglomerated coarse particles are immediately formed, they cannot be practically used as a permeable grout. For this reason, blast furnace slag fine particles having relatively low activity are blended in a large amount to reduce agglomeration and used as a permeable grout.

Portland cement is composed of clinker minerals alite, belite, aluminate phase and ferrite phase, and these minerals have different grindability. In the pulverization process, small pieces of the aluminate phase or alite having good pulverizability tend to segregate on the fine powder side. Since they are fine, the surface energy of the particles is high, and upon contact with water, they agglomerate immediately to form coarse secondary particles. In addition, since it has a high activity as a component, it easily forms a hydrated product in water and gels.

On the other hand, on the coarse powder side, there are many relatively large particles having an angular and irregular surface shape generated from alite or belite having a large crystal form. These also have high surface activity in water due to their large surface area and exposed fracture surfaces of the particles, and release Ca ²⁺ ions to increase the viscosity of the grout. The agglomerated coarse particles in the grout block the injection cavities, sediment the suspended particles and cause separation, and the high viscosity of the grout
This will increase the injection resistance and therefore lower the injection properties.

[0008] For this reason, it is difficult to ensure good injectability in a wide range of water injectable material ratio only by adjusting the blending amount of the blast furnace slag fine powder. Also, if the slag particles themselves are too finely pulverized, the fine powder portion increases, the activity increases, and the injectability deteriorates. Therefore, an object of the present invention is to provide a cement-based injection material having a good injection property in a wide range of water injection material ratio, that is,
Improved cement grouting with improved grout flowability, improved particle dispersibility in the grout, and excellent groutability over a wide range of water grout ratios, especially suitable for cracking and ground grouting of concrete structures To provide materials.

[0009]

Means for Solving the Problems In view of the above problems, the present inventors have conducted intensive studies on the particle size, shape, and hydration characteristics of the injection material particles. Excellent by improving the flowability of fine particles, and by adhering and immobilizing fine particles on the surface of large particles, reducing the amount of fine particles, improving the dispersibility of particles in grout, and suppressing the generation of aggregated coarse particles. We have developed a cement-based injection material applicable to cracks and ground injection of concrete structures that maintain injection properties.

That is, the present invention provides: 1) Portland cement clinker fine powder (a) 3
0 to 75 parts by weight, blast furnace slag fine powder (b) 70 to 25 parts by weight, and gypsum fine powder (c) 0 to 10 parts by weight ((a) to
The sum of the components (c) is 100 parts by weight. ), A cement-based injectable material obtained by subjecting the particle surface to spheroidizing treatment with mechanical energy; 2) reducing the amount of fine particles by adhering and fixing fine particles to large particle surfaces by mechanical energy Wherein the maximum particle diameter of the particles is in the range of 8 to 16 μm, 3) Portland cement obtained by subjecting the particle surface to spheroidizing treatment by mechanical energy or heat melting. 30 to 75 parts by weight of clinker fine powder (a '), 70 to 25 parts by weight of blast furnace slag fine powder (b), and gypsum fine powder (c) 0 to 0
A cement-based injectable material comprising a mixture of 10 parts by weight (the total of the components (a ') to (c) is 100 parts by weight); 4) the maximum particle diameter of the particles is in the range of 8 to 16 µm. And 5) used as a slurry containing 40 to 1000% by weight of water with respect to the amount of the injected material and containing up to 3.0% by weight of a high-performance water reducing agent in terms of solid content. It is intended to provide the cement-based injection material according to any one of the above items 1 to 4, which is used for repairing a concrete structure or for injecting a ground.

Hereinafter, the present invention will be described in detail. A technology for improving various properties of concrete by subjecting cement particles to spheroidizing treatment is conventionally known (JP-A-2-92439).
issue). This is due to the effect of improving the workability by the ball bearing action of cement particles by spheroidization, reducing the water-cement ratio, or densifying the hardened matrix by increasing the particle filling property by improving the shape, etc. It improves strength and durability.

In these, the water-cement ratio is 30 to
Concrete is composed of coarse aggregates, fine aggregates, admixtures, cement particles and materials having a wide range of particle sizes. Therefore, the effect of the spheroidization is largely controlled by the properties as a plastic fluid due to the interaction between the cement particles forming the hydration layer, or the aggregate and the admixture.

On the other hand, in the present invention, the water injection material ratio is 4
The range is from 0 to 1000% by weight, and the particle size is 16 μm or less. Therefore, the injection material particles are dispersed in water, and the injection characteristics and rheological characteristics of the grout are greatly affected by the interaction between water and the particles as a dispersion medium. That is, move,
Physical, such as dispersion and aggregation, acting on individual particles,
Chemical properties and mechanochemical properties of the particle surface become more problematic.

The injectable material according to the present invention may be produced by mixing a predetermined amount of Portland cement clinker, blast furnace slag and gypsum and mixing and pulverizing them. May be mixed. In the pulverization, after pulverizing to a certain particle size, it may be classified by an air classifier to collect the fine powder portion, or may be pulverized to a predetermined particle size by a high-performance pulverizer.

The spheroidizing treatment of the injection material particles is to modify the particles into a shape close to a sphere, and the finely divided powder is physically and physically applied to the surface of the particles using a high-speed air impact method or the like.
This is performed by applying mechanical energy. The high-speed airflow impact method uses a hybridization system (Co., Ltd.)
Nara Machinery Co., Ltd.) is used to grind the surface of the particles by collision between powders in a high-speed air stream and impact from a rotor to make them spherical.

[0016] Agitation force is generated between particles by stirring and mixing in a high-speed air flow, and fine particles adhere to the surface of large particles,
Strongly fixed by mechanical energy. It is said that the ratio of the particle size of the large particles to the fine particles is suitably 10: 1 or less. The spheroidizing method can also be performed by using other devices that apply mechanical energy, such as Angmil (produced by Hosokawa Micron Corp.) or Kryptron (produced by Kawasaki Heavy Industries, Ltd.).

When the grouted injection material is kneaded with water and used as a grout, the particles become nearly spherical and have small anisotropy, which reduces steric hindrance. Even with the same particle average diameter, it is possible to penetrate into finer voids and the injection properties are improved.

The spheroidized particles have a reduced surface activity because the fracture surface and cleavage plane of the particle surface are worn away and are covered with fine particles. In addition, even if the powder weight is the same, the overall surface area is smaller than that of the powder not subjected to the spheroidizing treatment. Therefore, the degree of increasing the viscosity of the grout, which is observed in the case of particles having a large surface area and immediately eluted with water when kneaded with water, is reduced. In addition, when the particles are spherical, it is one of the factors that do not increase the viscosity because the migration resistance in water is small and the shear resistance at the time of stirring the grout is small.

Since the fine particles are adhered and fixed on the surface of the large particles, their apparent abundance is reduced. For this reason, the probability of generation of coarse secondary particles formed by agglomeration of fine particles due to interparticle force in grout is significantly reduced. Coarse secondary particles have a high sedimentation velocity, so they settle first during grout injection to close the injection gap, and impede the penetration of subsequent particles. Can be removed by the spheroidizing treatment, and the injection property can be improved.

The Portland cement clinker used in the present invention is a clinker for high-strength Portland cement, ordinary Portland cement, moderately heated Portland cement or low-heat Portland cement. It is preferred to use a clinker for medium heat Portland cement or low heat Portland cement.

In the present invention, blast furnace slag (b) is used.
When the cement clinker fine powder alone is used, the hydration activity is too high when kneaded with water, viscosity increases and gelation occurs, and a grout having good injection properties cannot be obtained. Use of blast furnace slag (b) is to dilute fine cement clinker powder to reduce hydration activity, to improve fluidity and to extend pot life, and to ensure the strength and durability of the cured product. The purpose is to increase the gender.

The blast furnace slag (b) is quenched slag specified in JIS A 6206, and preferably has a basicity of 1.8 and a vitrification ratio of 90% or more. The blending ratio of the blast furnace slag is preferably in the range of 25 to 70 parts by weight, more preferably 40 to 70 parts by weight, per 100 parts by weight of the total amount with the clinker.

If the blending ratio of the blast furnace slag is less than 25 parts by weight, the injection property is lowered because the amount of dilution of the clinker mineral is reduced. On the other hand, if it exceeds 70 parts by weight, it is considered that the shape of the slag particles influences, the injectability at a low water ratio is reduced, and the development of strength is not preferable, and there is a problem in applying the injection material for repairing cracks in concrete structures. There is.

The injection material of the present invention has a maximum particle size of 8.0 even if fine particles are adhered and fixed to large particles.
It is preferably in the range of 116.0 μm. Maximum particle size is 1
If it is larger than 6.0 μm, the injectability decreases due to coarse particles. When the maximum particle size is smaller than 8.0 μm, the amount of fine particles having a size of 1 μm or less inevitably increases in the ordinary pulverization and classification method, and large particles cannot completely adhere and fix. Therefore, the cohesive secondary particles increase and the injectability decreases.

The fine powder of cement clinker (a) has a remarkably high hydration reactivity as compared with the fine powder of blast furnace slag, and tends to directly cause the formation of coagulated coarse particles. In the present invention,
In order to improve the injectability, it is also possible to subject the clinker particles alone to spheroidizing treatment (the spheroidized clinker particles are referred to as a ') and then mix them with the blast furnace slag fine powder (b). If the spheroidizing treatment is performed in advance in this way, there is no danger that the activity of devitrification due to the heating of the blast furnace slag will be reduced. It is also possible to do.

The injection material of the present invention contains a small amount of gypsum (c) of up to 10% by weight in order to alleviate the rapid setting of 3CaO.Al ₂ O _{3 in} the cement clinker and to promote the strength development of blast furnace slag. ) Can also be blended. As gypsum (c), dihydrate or insoluble anhydrous gypsum can be used, and its amount is preferably 2% by weight or less in terms of SO ₃ .

The amount of water to be kneaded into the injecting material is, when the crack is injected for the purpose of repairing a concrete structure,
Compared to injection into sandy ground, the area of the opening is large and the voids are large, so that injection and filling can be performed with a small water injection material ratio. It is desirable that the hardening strength of the grout is close to the strength of the existing concrete, and therefore, it is better that the ratio of the water injection material is small. The amount of water is preferably from 40 to 300% by weight, more preferably from 50 to 150% by weight, based on the amount of the injected material.

When the injection material is used for injecting into the sand layer ground, it is necessary to infiltrate the sand layer with low-concentration milk in order to enhance the injectability. By increasing the injection amount, the grout material is concentrated in the gaps in the sand layer by dehydration due to the filtering action of the sand layer, thereby developing strength. Therefore, the amount of water relative to the filling material of milk is preferably 200 to 1000% by weight.

Assuming that the injection material is applied to both crack repair and ground injection of concrete structures, the amount of water is in the range of 40 to 1000% by weight based on the injection material. In order to more effectively prevent agglomeration of the filler particles and improve the dispersibility of the particles to enhance the injectability and permeability of milk and grout, it is necessary to add a high-performance water reducing agent. As the high-performance water reducing agent, those which are usually used, for example, polycarboxylic acid type, naphthalene type, melamine type, aminosulfonic acid type and the like can be used. If the amount of the high-performance water reducing agent is too large, separation of the injection material and water occurs in the grout when the stirring is stopped. Further, since the curing of the grout is also significantly delayed, a defect is easily generated in the cured product. Therefore, the amount of the high-performance water reducing agent is appropriately 0 to 3.0% by weight in terms of solid content.

[0030]

Hereinafter, the present invention will be described with reference to examples.
The present invention is not limited by the following examples. Table 1
The ordinary Portland cement clinker, dried blast furnace slag and gypsum of the chemical composition shown in the following are supplied to a tube mill at a weight percentage ratio of 39.2: 58.8: 2.0 and pulverized to produce a mixed powder having a Blaine specific surface area of 3200 cm ² / g. did.

[0031]

[Table 1]

This was prepared using a tower mill (Nihon Tower Mill Co., Ltd.)
KD-100), diethylene glycol was added as a grinding aid in an amount of 0.1% based on the total weight, and the mixture was finely pulverized to produce ground injection material samples A and B shown in Table 2.

[0033]

[Table 2]

Spherification treatment These were treated with the Nara hybridization system NHS-
It was put into a type 1 (manufactured by Nara Machinery Co., Ltd.) and subjected to spheroidizing treatment by a high-speed airflow impact method. By changing the treatment time, six types of spheroidized treatment injection materials H-A1 to H-B3 shown in Table 3 were obtained. Table 3 also shows the number of rotations of the turntable and the charged amount.

[0035]

[Table 3]

Table 2 shows a laser particle size analyzer (SK LASER M)
2 shows the particle size distribution of an original sample and a spheroidized injection material measured by ICRON SIZERPRO-7000S (manufactured by Seishin Enterprise Co., Ltd.). Table 4 shows the percent particle size and the Blaine specific surface area when the porosity is 0.544.

[0037]

[Table 4]

From the results shown in Table 2, by performing the spheroidizing treatment on both of the original samples A and B, the amount of particles less than 1.0 μm was reduced, and the amount of particles near 3 μm was reduced.
The amount of particles of 8 to 12 μm is increasing. This tendency becomes more remarkable by increasing the processing time. The results in Table 4 show that the longer the treatment time, the smaller the Blaine specific surface area. Although not attached, according to the results of electron microscopic observation, when spheroidization is performed, the shape of the particles is rounded and rounded, aggregates of aggregated particles are dissociated, and particles of 1 μm or less adhere to large particles. It was recognized that it was.

Penetration test 1% by weight of a naphthalene-based high-performance water reducing agent (Mighty 150 manufactured by Kao Corporation) with respect to 115 g of each of the above injection materials.
And 460 g of water were added, and the mixture was stirred for 2 minutes at 300 rpm with a multipurpose digital stirrer (produced by Inuchi Seieido) to produce milk.

A 75 μm sieve (6) was fixed on a 5 mm sieve (7) at the bottom of the transparent acrylic pipe (4) shown in FIG. 1, and Toyoura standard sand according to JIS R5201 (particle size: 0.1 to 0.3mm) (5) and pour the sand layer 15c
m and a void ratio n = 45%, and filled with water to such an extent that the surface was immersed in the sand layer. The funnel (2) is placed on top of it, and the milk (1) is poured gently while being dispersed through the perforated plate (3). The cock (8) at the bottom is opened to allow the milk to flow naturally, and The penetration length and the time until the penetration of the milk stopped and the time until the milk reached the bottom were measured. Table 5 shows the results.

[0041]

[Table 5]

None of the infusate milks of the original Sample A series, Sample Nos. 1-4, spontaneously penetrated to the bottom of the 15 cm sand layer. However, the spheroidized product has an increased permeation length and an increased permeation duration. The long permeation continuation time is an index indicating that the injectability is good because the injectable material particles in the milk have a long time to close the infusion gap in the sand layer. On the other hand, all the grouts of the series of the original sample B of the sample numbers 5 to 8 reached the bottom of the sand layer 15 cm. The short time to reach the bottom means that the flow rate of the milk flowing through the sand layer is high, which is a measure of the injectability as well as the length of the permeation duration. From these results, it can be seen that the spheroidizing treatment of the injection material greatly improves the injection properties.

100 g of water was added to 100 g of each of the injection materials in Table 2 of the funnel flow test .
300 r.p. with a multipurpose digital stirrer (manufactured by Iuchi Seieido)
m. Stir for 2 minutes to make milk. Upper end inner diameter 72m
86 ml of the above milk flowed into a vinyl chloride funnel having an outlet pipe with an inner diameter of 9 mm and a length of 60 mm with an inner diameter of 9 mm and a length of 60 mm at a lower end of 10 mm, a height of a funnel of 60 mm, and a grout when the bottom of the outflow pipe was opened. The time was measured. Table 6 shows the results.

[0044]

[Table 6]

This test was conducted assuming repair injection of a concrete structure having a low water injection material ratio of 100% by weight. The time was reduced and approached the water shown in the comparative example, indicating that the viscosity of the grout was reduced and the flowability was improved.

[0046]

According to the present invention, the injected material subjected to the spheroidizing treatment of the particles by the mechanical energy according to the present invention has a particle size distribution in which the amount of fine particles is reduced, and the particle shape is rounded and rounded. The ability of the milk to be injected into the sand layer is significantly improved due to the suppression of clogging of the infiltration voids by the injection material particles and the reduced viscosity of the milk. Also, the fluidity is improved even when the water injection material ratio is as high as 100% by weight.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an apparatus for performing a permeability test of a cement-based injection material.

[Explanation of symbols]

 Reference Signs List 1 milk to be infiltrated 2 funnel 3 perforated plate 4 transparent acrylic pipe 5 Toyoura standard sand 6 75 μm sieve 7 5 mm sieve 8 cook

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09K 17/10 C09K 17/10 P E04G 23/02 E04G 23/02 B // (C04B 28/08 22:14) 111: 72 C09K 103: 00

Claims (5)

[Claims] 1. Portland cement clinker fine powder (a) 30 to 75 parts by weight, blast furnace slag fine powder (b) 70
To 25 parts by weight and gypsum fine powder (c) 0 to 10 parts by weight (the total of the components (a) to (c) is 100 parts by weight).
A cement-based injection material, which is a mixture comprising: and a particle surface spheroidized by mechanical energy. 2. The method according to claim 1, wherein the fine particles are adhered and fixed on the surface of the large particles by mechanical energy to reduce the amount of the fine particles, and the maximum particle size of the particles is in the range of 8 to 16 μm. The cement-based injection material as described in the above. 3. A Portland cement clinker fine powder (a ') of 30 to 75 parts by weight, a blast furnace slag fine powder (b) of 70 to 25 parts by weight, and gypsum obtained by spheroidizing the particle surface by mechanical energy or heat melting. A cement-based injection material comprising a mixture of fine powder (c) 0 to 10 parts by weight (total of components (a ') to (c) is 100 parts by weight). 4. The cement-based injection material according to claim 3, wherein the maximum particle size of the particles is in the range of 8 to 16 μm. 5. The amount of water is 40 to 1000% by weight with respect to the injection material.
The cement according to any one of claims 1 to 4, wherein the cement is used for repairing a concrete structure used as a slurry containing a high-performance water reducing agent up to 3.0% by weight in terms of solid content, or for injecting into the ground. System injection material.