JPWO2019142775A1 - High-strength grout material composition and high-strength grout mortar using it - Google Patents

Abstract

Contains cement, pozzolan fine powder, water-soluble calcium salt, water reducing agent, foaming agent, defoaming agent, and fine aggregate having a particle content of 5 μm or less of 5% by mass or less and a median diameter of 15 μm or more. It is a high-strength grout material composition.

Description

The present invention mainly relates to a high-strength grout material composition used in the fields of civil engineering and construction, and a high-strength grout mortar using the same.

Conventionally, as a grout of cement mortar used in the fields of civil engineering and construction, a cement to which a water reducing agent is added is generally used. Further, a calcium sulfate-based expansion material or a lime-based expansion material or a foaming agent such as aluminum powder is added to the non-shrinkage material, and river sand, silica sand, etc. are mixed with these to make fine voids in the concrete structure. It is widely used for filling voids in the reverse striking method, repairing and reinforcing points of structures, under the base plate of mechanical devices, under the track floor plate, etc.

Generally, cement mortar that is filled in civil engineering and construction work is called grout. Grout includes PC grout, prepacked concrete grout, tunnel and shield backfill grout, precast grout, structure repair / reinforcement grout, reinforced joint grout, bridge support grout, paving slab grout, under-track grout. There are grouts and grouts under the storage container of nuclear power plants.

In recent years, the quality of concrete used for civil engineering and building structures has improved, and the performance required for cement mortar used as grout is also required to be high flow and high strength depending on the application.
In order to obtain high fluidity and high strength development, cement, calcium aluminoferrite-based expansion material, siliceous fine powder with silicon dioxide (SiO ₂ ) content of 90% or more and hydrogen ion concentration in the acidic region, polycarboxylic acid It is known to use a high-strength grout mortar containing an acid-based water reducing agent and a fine aggregate (see Patent Document 1).

It is also known to use a high-strength grout mortar that imparts high fluidity by using a water-soluble calcium salt in combination without using an expansion material in order to obtain further high fluidity and high strength development. (See Patent Document 2).
However, these high strength grout mortar, compressive strength not only not expressed 180 N / mm ² approximately at a maximum, high strength grout mortar expressing 200 N / mm ² or more intensity did not exist.

Even if the water / cement ratio of high-strength grout mortar is reduced to improve the strength development, it is necessary to use a large amount of water reducing agent to ensure the fluidity of the mortar, which not only increases the economic burden but also increases the economic burden. In some cases, many bubbles were generated and the fine aggregate settled, and conversely, the strength development was inhibited.

On the other hand, for the purpose of reducing cracks in high-strength concrete, it has been proposed to use coarse-grained cement having a brain specific surface area of 1000 to 2400 cm ² / g (Patent Document 3). However, the cement pulverized so as to have a small brain specific surface area does not cut fine particles, and the water / cement ratio could not be reduced when preparing concrete.

For the purpose of preparing high-strength concrete, a hydraulic composition containing a binder containing coarse-grained cement, β-1,3 glucan, and a high-performance water reducing agent has been proposed (Patent Document 4). For this hydraulic composition, coarse-grained cement in the range of 40 μm to 100 μm is applied, but because the particle size composition of the cement is distorted, the particles are not densely packed, and high-strength concrete exceeding 100 N / mm ² is prepared. There was a problem that it was difficult. In addition, there is also a problem that material separation is likely to occur and durability is impaired.

Japanese Unexamined Patent Publication No. 2008-094675 Japanese Unexamined Patent Publication No. 2010-150072 Japanese Unexamined Patent Publication No. 2006-117439 Japanese Unexamined Patent Publication No. 06-263506

From the above, the present invention provides a high-strength grout material composition capable of ensuring fluidity even when kneaded at a low water / cement ratio and providing a high-strength grout mortar exhibiting a compressive strength of, for example, 200 N / mm ² or more. The purpose is to do.

As a result of various studies to solve the above problems, the present inventors have combined cement from which fine powder has been removed by classifying cement with a specific raw material to flow even if the water / cement ratio is significantly reduced. It has been found that a high-strength grout mortar capable of ensuring properties and exhibiting a strength of 200 N / mm ² or more at a compressive strength can be obtained, and the present invention has been completed.

That is, in the present invention, (1) cement, pozzolan fine powder, water-soluble calcium salt, water reducing agent, foaming agent, defoaming agent having a particle content of 5 μm or less of 5% by mass or less and a median diameter of 15 μm or more. A high-strength grout composition containing an agent and a fine aggregate.
(2) A high-strength grout material composition in which the content of particles of 5 μm to 40 μm of the cement is 75% by mass or more.
(3) The pozzolan fine powder is a high-strength grout material composition which is a siliceous fine powder having a SiO ₂ content of 90% by mass or more, containing zirconium oxide, and having a hydrogen ion concentration in an acidic region.
(4) The pozzolan fine powder is a high-strength grout material composition in which 20 to 30 parts by mass out of a total of 100 parts by mass of cement and pozzolan fine powder.
(5) The water-soluble calcium salt is a high-strength grout material composition in which the amount is 0.2 to 1 part by mass with respect to 100 parts by mass in total of cement and pozzolan fine powder.
(6) The fine aggregate is a high-strength grout material composition which is a heavy aggregate having a density of 3 g / cm ³ or more.
(7) The fine aggregate is a high-strength grout material composition having 60 to 100 parts by mass with respect to 100 parts by mass in total of cement and pozzolan fine powder.
(8) A high-strength grout mortar obtained by kneading the high-strength grout material composition with water.
(9) A method for producing a high-strength grout mortar, in which 15 to 18 parts by mass of water is added and kneaded with respect to 100 parts by mass of the high-strength grout material composition.

By using the high-strength grout material composition of the present invention, it is possible to secure fluidity even when kneaded at a low water / cement ratio, and to provide, for example, a high-strength grout mortar exhibiting a compressive strength of 200 N / mm ² or more. Can be done.

Hereinafter, the present invention will be described in detail.
Parts and% used in the present invention are based on mass unless otherwise specified.

The cement of the present invention includes various Portland cements such as ordinary, early-strength, ultra-fast-strength, low-heat, and moderate-heat, various mixed cements obtained by mixing these cements with blast furnace slag, fly ash, or silica, limestone powder, and blast furnace Xu. Examples include filler cement mixed with cold slag fine powder and environment-friendly cement (eco-cement) manufactured from city waste incineration ash and sewage sludge incineration ash as raw materials.

The cement of the present invention has a particle content of 5 μm or less of 5% by mass or less and a median diameter of 15 μm or more. Further, the content of the particles of 5 μm to 40 μm is preferably 75% by mass or more. If the content of particles of 5 μm or less exceeds 5% by mass, the water / cement ratio cannot be reduced, and the viscosity at the time of kneading the mortar becomes high, resulting in a large load. If the content of the particles of 5 μm to 40 μm is less than 75% by mass, the initial strength development is deteriorated and bleeding is likely to occur.
The content of particles having a diameter of 5 μm or less and the content of particles having a median diameter of 5 μm to 40 μm can be measured by the method described in Examples.

And the content of particles of 5μm is 5 mass% or less, cement median diameter of 15μm or more, usually, _{C 3} S solid solution 50 to 70 parts by mass, _{C 2} S solid solution of 10 to 30 parts by mass, _{C 3} A is composed of 5 to 20 parts by mass, C ₄ AF is composed of 2 to 20 parts by mass, and cement is composed of 0.1 to 5 parts by mass.
Blaine specific surface area is ^preferably in the range of 1500cm ² / g~3500cm 2 / ^g, and more preferably in the range of 1600cm ² / g~3000cm 2 / g.

Examples of the pozzolan fine powder of the present invention include one or more selected from blast furnace slag fine powder, fly ash, and silica fume.
In the present invention, for the purpose of ensuring good fluidity at a low water / cement ratio, use of zirconia-derived silica fume having a SiO ₂ content of 90% by mass or more, containing zirconium oxide, and having an acidic hydrogen ion concentration is used. Is preferable.
The hydrogen ion concentration referred to here is a value obtained by putting 20 g of silica fume in 100 g of pure water, stirring for 5 minutes with a magnetic stirrer, and then measuring the hydrogen ion concentration (PH) of the suspension with a pH meter.

As specified in JIS A 6207, silica fume is spherical ultrafine particles containing amorphous silicon dioxide as the main component, and is captured from the exhaust gas generated when metallic silicon and ferrosilicon are manufactured in an arc furnace. Gathered. In addition, in the method of oxidizing metallic silicon fine powder in a flame and the method of melting a siliceous raw material fine powder in a high-temperature flame, the heat treatment conditions of the raw material are adjusted and the collection temperature is set to 550 ° C. or higher. Can be manufactured. There is also a so-called zirconia-derived silica fume, which is produced by collecting zircon sand with a cyclone or the like and classifying it when the zircon sand is melted in an electric furnace.

In the present invention, it is preferable to use silica fume of zirconia origin. Zirconia origin silica fume, refractories, grinding-polishing materials, electronic materials, and the invention is by-produced in the manufacture of fused zirconia used (zirconium oxide ZrO ₂₎ in ceramic pigment, zircon sand (ZrSiO ₄ ), For example, is a collection of exhaust gas generated when electric fusion is performed at 2,200 ° C.
Its average particle size is about 1 μm, which is larger than silica fume having an average particle size of 0.1 to 0.3 μm collected from exhaust gas generated when metallic silicon or ferrosilicon is produced in an arc furnace.

The amount of pozzolan fine powder used is preferably 20 to 30 parts out of a total of 100 parts of cement and pozzolan fine powder. If it is less than 20 parts, the strength development may be insufficient or the load at the time of kneading may be large, while if it exceeds 30 parts, the load at the time of kneading will be large and fluidity will be obtained with a predetermined amount of water. It may not be possible.

The water-soluble calcium salt of the present invention is used to obtain excellent fluidity. Generally, examples of the water-soluble calcium salt include calcium acetate, calcium formate, calcium nitrate and the like, but the use of calcium acetate is preferable in the present invention.

To obtain excellent fluidity at a low water / cement ratio, use silica fume with a SiO ₂ content of 90% or more, zirconium oxide, and a hydrogen ion concentration in the acidic region, and a polycarboxylic acid-based water reducing agent. This is also possible, but depending on the type of cement, it may be necessary to add a large amount of water reducing agent. Since the addition of a large amount of water reducing agent adversely affects the initial strength development, a water-soluble calcium salt is used in combination in order to keep the addition amount of the water reducing agent within a certain range.

The amount of the water-soluble calcium salt used is preferably 0.2 to 1 part, more preferably 0.4 to 0.6 part, based on 100 parts in total of the cement and the pozzolan fine powder. If it is less than 0.2 parts, the fluidity may be insufficient, while if it exceeds 1 part, the fluidity may decrease.

The water reducing agent of the present invention is a general term for those having a dispersing action and an air entraining action on cement to improve fluidity and strength, and generally, a naphthalene sulfonic acid-based water reducing agent and a melamine sulfonic acid-based. Examples thereof include water reducing agents, lignin sulfonic acid-based water reducing agents, and polycarboxylic acid-based water reducing agents.
The water reducing agent can be used in either powder or liquid, but powder is preferable when used as a premix product.

The amount of the water reducing agent used is preferably 0.2 to 1 part, more preferably 0.4 to 0.6 part, based on 100 parts in total of cement and pozzolan fine powder. If it is less than 0.2 parts, the fluidity may be insufficient, while if it exceeds 1 part, bubbles may be generated and the strength development may be insufficient, or a significant delay in condensation may occur.

The foaming agent of the present invention generates gas when mixed with water in order to make the mortar non-shrinkable, and obtains initial expansion.
The foaming agent is not particularly limited, and examples thereof include metal powder and peroxide. Of these, aluminum powder is preferable from the viewpoint of the amount of addition and the effect. Since the surface of the aluminum powder is easily oxidized and the reactivity is lowered when it is covered with an oxide film, it is more preferable to use the aluminum powder surface-treated with vegetable oil, mineral oil, stearic acid or the like.

The amount of the foaming agent used is preferably 0.0003 to 0.002 parts, more preferably 0.0005 to 0.0009 parts, based on 100 parts in total of the cement and pozzolan fine powder. If it is less than 0.0003 parts, the foaming effect may be insufficient, while if it exceeds 0.002 parts, the foaming may be too large and the strength may be lowered.

The defoaming agent of the present invention plays a role of reducing the amount of air entrained during mortar kneading and improving the strength development.
The defoaming agent is not particularly limited, and examples thereof include a polyoxyethylene alkyl ether-based defoaming agent and a pluronic compound defoaming agent.

The amount of the defoaming agent used is preferably 0.02 to 0.2 parts, more preferably 0.04 to 0.15 parts, based on 100 parts in total of the cement and pozzolan fine powder. If it is less than 0.02 parts, the defoaming effect is insufficient and may adversely affect the strength development, while if it exceeds 0.2 parts, the effect may reach a plateau and the economic burden may increase.

As the fine aggregate used in the present invention, it is preferable to use a heavy aggregate.
The heavy aggregate is not particularly limited as long as it has fluidity retention performance, strength development, etc., has a density of 3 g / cm ³ or more, and is crushed sand. For example, crushed sand such as magnetite, hematite, peridotite, ferrochrome slag, ferronickel slag, copper slag, and electric furnace oxide slag can be mentioned. In the present invention, one or more of these can be used in combination. When used as a premix product, it is preferable to use dry sand.

The amount of fine aggregate used is preferably 60 to 100 parts, more preferably 70 to 90 parts, based on 100 parts in total of cement and pozzolan fine powder. If it is less than 60 parts, the amount of self-shrinkage and drying shrinkage of the mortar becomes large, and cracks may easily occur. On the other hand, if it exceeds 100 parts, the fluidity and strength development may decrease.

The high-strength grout mortar of the present invention is obtained by kneading the above-mentioned high-strength grout material composition of the present invention with water. The high-strength grout mortar is produced, for example, by adding 15 to 18 parts by mass of water to 100 parts by mass of the high-strength grout material composition of the present invention and kneading.

The amount of kneading water of the present invention is preferably 15 to 18 parts with respect to 100 parts of the high-strength grout material composition. Outside this range, fluidity may be significantly reduced or strength may be reduced.
In the present invention, the method of kneading the high-strength grout material composition and water is not particularly limited, but a hand mixer having a rotation speed of 900 rpm or more, a normal high-speed grout mixer, or a biaxial forced mixer is used. It is preferable to use it.

For kneading with a hand mixer or a high-speed grout mixer, for example, a container such as a pail can or a mixer is filled with predetermined water in advance, and then the high-strength grout material composition is added while rotating the mixer, and the mixture is kneaded for 3 minutes or more. Is preferable. Further, for kneading with the forced mixer, for example, it is preferable to put the high-strength grout material composition into the mixer in advance, add predetermined water while rotating the mixer, and knead for at least 4 minutes or more. If the kneading time is less than a predetermined time, appropriate high-strength grout mortar fluidity may not be obtained due to insufficient kneading.
The kneaded high-strength grout mortar is usually pumped to the construction site by a manual injection gun, a diaphragm type hand pump, or a squeeze type mortar pump, and filled.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

(Experimental Example 1)
High-strength gout material compositions were prepared using cements (A) to (H). The composition is 20 parts of pozzolan fine powder (a) in a total of 100 parts of cement and pozzolan fine powder, and 0.5 part of water-soluble calcium salt and water reducing agent for a total of 100 parts of cement and pozzolan fine powder. 0.5 parts, 0.0007 parts of foaming agent, 0.09 parts of antifoaming agent, and 80 parts of fine aggregate (I). To 100 parts of this high-strength grout material composition, 16 parts of water was added and kneaded to prepare a high-strength grout mortar, and the fluidity and compressive strength were measured. A hand mixer was used for kneading, and the mixture was kneaded in a laboratory at a temperature of 20 ° C. and a humidity of 60% for 5 minutes. The results are shown in Table 1.

(Material used)
Cement (A): Ordinary Portland cement, commercially available product manufactured by Denka Co., Ltd., brain specific surface area 3,200 cm ² / g, particle content of 5 μm or less 28%, median diameter 12 μm, particle content of 5-40 μm 61%
Cement (B): Classified cement A, brain specific surface area 2,400 cm ² / g, particle content 5% with 5 μm or less, median diameter 15 μm, particle content 75% with 5-40 μm
Cement (C): Classified cement A, brain specific surface area 1,700 cm ² / g, particle content of 5 μm or less 3%, median diameter 19 μm, particle content of 5-40 μm 82%
Cement (D): Ordinary Portland cement prepared by using the same cement clinker as cement A and adding the same amount of gypsum. Brain specific surface area 1,700 cm ² / g, particle content of 5 μm or less 6%, median diameter 14 μm, particle content of 5-40 μm 70%
Cement (E): Early-strength Portland cement, commercially available product manufactured by Denka Co., Ltd., brain specific surface area 4,500 cm ² / g. Particle content of 5 μm or less 37%, median diameter 7 μm, particle content of 5-40 μm 61%
Cement (F): Classified cement E, brain specific surface area 2,300 cm ² / g, particle content of 5 μm or less 4%, median diameter 15 μm, particle content of 5-40 μm 85%
Cement (G): Blast furnace cement type B, commercially available product manufactured by Denka Co., Ltd., brain specific surface area 3,800 cm ² / g, particle content of 5 μm or less 30%, median diameter 8 μm, particle content of 5 to 40 μm 78%
Cement (H): Classified cement G, brain specific surface area 2,300 cm ² / g, particle content of 5 μm or less 4%, median diameter 17 μm, particle content of 5-40 μm 84%
Pozzolan fine powder (a): silica fume, SiO ₂ content 95.2%, pH (hydrogen ion concentration) = 2.90, zirconium oxide content, commercial product

Water-soluble calcium salt: Calcium acetate Water reducing agent: Polycarboxylic acid-based water reducing agent, commercially available product (manufactured by BASF, trade name: Melflux AP101F)
Foaming agent: Aluminum powder, commercial product (100 mesh pass product)
Defoamer: Polyoxyethylene alkyl ether-based defoamer, commercially available product (manufactured by ADEKA, trade name: Adecanate B115F)
Fine aggregate (I): Ferronickel slag, density 3.15 g / cm ³ , 1.5 mm vulgar, commercially available water: tap water

(Test method)
Particle size distribution measurement: Using a laser diffractometer (HELOS & RODOS manufactured by Sympatec), the sample was dry-dispersed and the particle size distribution was measured. As a result, the content of particles having a size of 5 μm or less and the content of particles having a median diameter of 5 μm to 40 μm were determined. The median diameter is a particle diameter at which the cumulative frequency is 50%.
Fluidity: The static flow was measured in accordance with JIS R 5201 "Physical test method for cement" of the Japanese Standards Association.
Compressive strength: Measured according to JSCE-G 505, "Compressive strength test method for mortar or cement paste using cylindrical specimen". After demolding at the age of 1 day, the mixture was cured in water at 20 ° C. and measured at the ages of 28 and 56 days.

(Experimental Example 2)
Using cement (F), the same procedure as in Experimental Example 1 was carried out except that the type and amount of pozzolan fine powder added were changed for a total of 100 parts of cement and pozzolan fine powder. The results are shown in Table 2.

(Material used)
Pozzolan fine powder (b): blast furnace slag, density 2.92 g / cm ³ , specific surface area 11,090 cm ² / g, commercially available pozzolan fine powder (c): fly ash, density 2.27 g / cm ³ , specific surface area 3 , 526 cm ² / g, commercially available

(Experimental Example 3)
Using cement (F), the same procedure as in Experimental Example 1 was carried out except that the amount of water-soluble calcium salt added to a total of 100 parts of cement and pozzolan fine powder was changed. The results are shown in Table 3.

(Experimental Example 4)
Using cement (F), the same procedure as in Experimental Example 1 was carried out except that the amount of the water reducing agent added to a total of 100 parts of cement and pozzolan fine powder was changed. The results are shown in Table 4.

(Experimental Example 5)
Using cement (F), the expansion and contraction rate was measured by changing the amount of foaming agent added to a total of 100 parts of cement and pozzolan fine powder, as in Experimental Example 1. The results are shown in Table 5.

(Test method)
Expansion and contraction rate: Measured according to JSCE-F 533 "Test method for bleeding rate and compressive strength of PC grout" of the Japan Society of Civil Engineers. Measured value for one day of age.

(Experimental Example 6)
Using cement (F), the same procedure as in Experimental Example 1 was carried out except that the amount of antifoaming agent added to a total of 100 parts of cement and pozzolan fine powder was changed. The results are shown in Table 6.

(Experimental Example 7)
Using cement (F), the amount and type of fine aggregate added to a total of 100 parts of cement and pozzolan fine powder were changed, and the length change was measured in the same manner as in Experimental Example 1. The results are shown in Table 7.

(Material used)
Fine aggregate (II): silica sand, density 2.60 g / cm ³ , 1.5 mm vulgar, commercially available

(Test method)
Length change: Measured according to JIS A 1129-3 "Mortar and concrete length change test method-Part 3: Dial gauge method". The material was cured under the conditions of a temperature of 20 ° C. and a humidity of 60% until the age of the material was 28 days, and the change in length was measured.

(Experimental Example 8)
The same procedure as in Experimental Example 1 was carried out except that a high-strength grout mortar was prepared by changing the amount of water added to 100 parts of the high-strength grout material composition of Experimental Example 1-6. The results are shown in Table 8.

By using the high-strength grout material composition of the present invention, fluidity can be ensured even when kneaded at a low water / cement ratio, and a high-strength grout mortar exhibiting a compressive strength of 200 N / mm ² or more can be obtained.

Claims (9)

Contains cement, pozzolan fine powder, water-soluble calcium salt, water reducing agent, foaming agent, defoaming agent, and fine aggregate having a particle content of 5 μm or less of 5% by mass or less and a median diameter of 15 μm or more. High-strength grout material composition. The high-strength grout material composition according to claim 1, wherein the content of particles of 5 μm to 40 μm of the cement is 75% by mass or more. The high-strength grout according to claim 1 or 2, wherein the pozzolan fine powder is a siliceous fine powder having a SiO ₂ content of 90% by mass or more, containing zirconium oxide, and having a hydrogen ion concentration in an acidic region. Material composition. The high-strength grout material composition according to any one of claims 1 to 3, wherein the pozzolan fine powder is 20 to 30 parts by mass in a total of 100 parts by mass of the cement and the pozzolan fine powder. The high-strength grout material according to any one of claims 1 to 4, wherein the water-soluble calcium salt is 0.2 to 1 part by mass with respect to a total of 100 parts by mass of the cement and pozzolan fine powder. Composition. The high-strength grout composition according to any one of claims 1 to 5, wherein the fine aggregate is a heavy aggregate having a density of 3 g / cm ³ or more. The high-strength grout material composition according to any one of claims 1 to 6, wherein the fine aggregate is 60 to 100 parts by mass with respect to a total of 100 parts by mass of the cement and pozzolan fine powder. A high-strength grout mortar obtained by kneading the high-strength grout material composition according to any one of claims 1 to 7 with water. A method for producing a high-strength grout mortar, wherein 15 to 18 parts by mass of water is added and kneaded with respect to 100 parts by mass of the high-strength grout material composition according to any one of claims 1 to 7.