JP4718969B2 - Foaming agent, non-shrink grout composition, and non-shrink grout material using the same - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a foaming agent, a non-shrinkable grout composition used in the civil engineering / building industry, and a non-shrinkable grout material using the same, and more particularly to a foaming agent and a non-shrinkable grout composition that maintain fluidity for a long time. And a non-shrink grout material using the same.

  Conventionally, grout materials generally include a cement with a water-reducing agent, and further include calcium sulfoaluminate-based expansion materials or lime-based expansion materials, aluminum powder mechanically pulverized with a mill, etc. A foaming agent is added to obtain non-shrinkable grout materials, and aggregates are blended in these materials, and they are widely used in civil engineering and construction work as pastes and mortars (see Patent Document 1).

  Non-shrink grout materials include PC grouts, prepacked concrete grouts, tunnel and shield backfill grouts, precast grouts, structural repair and reinforcement infusion grouts, reinforced joint grouts, bridge bearing grouts, undertrack grouts It is used in a wide variety of fields, such as grouts around the frame of seismic steel braces, wall grouts for extension walls, grouts for the steel sheet winding method, and grouts under the containment vessel of nuclear power plants.

The performance required for a non-shrink grout material includes no shrinkage, good fluidity, no bleeding and no material separation.
Moreover, in the seismic retrofit design guidelines for existing reinforced concrete buildings, the compressive strength of the seismic reinforcement press-fit grout is 30 N / mm ² or more at the age of 28 days (see Non-Patent Document 1).

  In recent years, the performance required for non-shrink grout materials used for civil engineering and building structures has been advanced, and improvement in fluidity retention performance has been demanded. Not only can the construction time be extended by improving the fluidity retention performance, but also the non-shrink grout material that was previously kneaded at the construction site is kneaded at the raw plant and delivered by agitator car for several hours. Over-pumping is possible. Further, the raw plant kneading prevents the dust from being scattered to the surroundings during the kneading, and has an effect of reducing the environmental load.

  However, if the fluidity is maintained for a long time exceeding 2 hours after kneading, the aggregate in the mortar settles, and not only material separation occurs, but also the foaming of the aluminum powder of the foaming agent is completed, In some cases, the cast grout could not have no shrinkage.

  In addition, aluminum powder mechanically pulverized with a mill has a scaly shape, large specific surface area, high reactivity, large foaming volume, and is mainly used for the production of non-shrinkable grout materials and lightweight cellular concrete. It has been.

  On the other hand, the aluminum powder produced by the atomizing method is used for brake lining, catalyst, fireworks, etc., but no examples of using it as a foaming agent for non-shrink grout materials are found.

Japanese Patent Publication No. 48-009331 Revised version 2001 Guidelines for seismic retrofit design of existing reinforced concrete buildings, published by Japan Building Disaster Prevention Association, February 2005, page 194

  As a result of various studies to solve the above problems, the present inventor has obtained the knowledge that the above problems can be solved by adopting a specific non-shrink grout composition, and has completed the present invention. .

That is, the present invention, cement, expansive, average particle diameter blowing agent consisting of aluminum powder produced by an atomization method is 6～50Myuemu, and water reducing agent, further, Ri Do from a formulation comprising a thickener , A non-shrink grout composition having 0.001 to 0.01 part of foaming agent, 0.05 to 1 part of water reducing agent, and 0.05 to 0.5 part of thickening agent with respect to 100 parts of a binder composed of cement and an expanding material , A non-shrink grout material comprising a non-shrink grout composition, a fine aggregate, and water.

  By using the non-shrinkable grout composition of the present invention, it is possible to provide a grout material that can maintain fluidity for a long time, does not cause material separation, and has non-shrinkage.

Hereinafter, the present invention will be described in detail.
Unless otherwise specified, the parts and% used in the present invention are shown on a mass basis.
In the present invention, the grout material refers to grout mortar and grout paste.

  In the present invention, a foaming agent made of an aluminum powder having an average particle size of 50 μm or less manufactured by an atomizing method is used, and the foaming agent, cement, expansion material, and water reducing agent are further added to a thickener. A non-shrinking grout composition containing a non-shrinking grout material is prepared by further blending fine aggregate as necessary and kneading with water.

  In this invention, the aluminum powder manufactured by the atomizing method is used as a foaming agent used for a non-shrink grout composition.

The production methods of aluminum powder are broadly divided into two methods: a method in which aluminum is mechanically pulverized with a stamp mill or a ball mill, and a method in which aluminum is melted from a metal and a jet stream of air, water, or inert gas is applied to the molten metal. The atomization method can be divided into atomizing methods in which the molten metal is pulverized by spraying and solidified as droplets or dropped onto a disk rotating at high speed and sheared in the tangential direction to crush and form fine powder.
The mechanically pulverized aluminum powder is scaly, and the aluminum powder produced by the atomization method is granular.
The aluminum powder used in the present invention is an aluminum powder produced by an atomizing method (hereinafter referred to as atomized aluminum powder), and the average particle size is preferably 50 μm or less, more preferably 10 to 25 μm. If it exceeds 50 μm, no shrinkage may be exhibited.
In the present invention, in addition to atomized aluminum powder, mechanically pulverized aluminum powder can be used in combination as long as the object of the present invention is not substantially impaired.

  The amount of the foaming agent made of atomized aluminum powder is preferably 0.001 to 0.01 part with respect to 100 parts of the binder made of cement and expansion material. If it is less than 0.001 part, no shrinkage may be obtained, and if it exceeds 0.01 part, the amount of expansion may be large and the strength may be lowered.

  As the cement used in the present invention, various portland cements such as ordinary, early strong, moderately hot, and low heat, various mixed cements obtained by mixing blast furnace slag, silica, fly ash, fine limestone powder, and the like with these portland cements, and Ordinary eco-cement.

Examples of the expanded material used in the present invention include calcium sulfoaluminate-based expanded material, calcium aluminoferrite-based expanded material, quicklime-based expanded material, and gypsum-based expanded material, and one or more of these are used. Among these, from the viewpoint of fluidity retention performance, calcium aluminoferrite-based expansion materials, quicklime-based expansion materials, and gypsum-based expansion materials are preferable.
Fineness of expansion material, Blaine specific surface area value (hereinafter, referred to as Blaine value) is preferably 2,000~10,000cm ² / g in, 3,000~5,000cm ² / g is more preferable. If it is less than 2,000 cm ² / g, bleeding may occur easily, and if it exceeds 10,000 cm ² / g, fluidity may deteriorate.
The amount of the expansion material used is preferably 3 to 20 parts in 100 parts of the binder. If it is less than 3 parts, it may be difficult to obtain an expandable property, and if it exceeds 20 parts, the amount of expansion becomes large, which may lead to destruction of the cemented body.

The water reducing agent used in the present invention is a general term for those having a dispersing action and air entrainment property on cement and improving fluidity and strength, specifically naphthalene sulfonic acid-based water reducing agent, melamine sulfonic acid-based water reducing agent, Water reducing agents such as a lignin sulfonic acid water reducing agent and a polycarboxylic acid water reducing agent can be mentioned, and one or more of these can be used. Of these, polycarboxylic acid-based water reducing agents are more preferred because of fluidity retention.
The amount of water reducing agent used is preferably 0.05 to 1 part, more preferably 0.2 to 0.5 part, based on 100 parts of the binder. If it is less than 0.05 part, fluidity retention performance may be poor, and if it exceeds 1 part, material separation may occur.

In the present invention, a thickener can be used.
Examples of the thickener include polyvinyl alcohol thickeners, acrylic thickeners, and water-soluble cellulose thickeners. Among these, the water-soluble cellulose thickener has a small temperature dependency. preferable.
The amount of the thickener used is preferably 0.05 to 0.5 part, more preferably 0.1 to 0.3 part with respect to 100 parts of the binder. If the amount is less than 0.05 part, the material separation resistance may not be sufficient.

  Moreover, in this invention, it is possible to use together oxycarboxylic acid or its salt, saccharides, such as dextrin and sucrose, and what has delay, such as inorganic salt.

  As the fine aggregate in the present invention, commonly used silica sand, river sand, sea sand, crushed sand, and the like can be used, and 80 to 250 parts are preferable with respect to 100 parts of the binder. If it is less than 80 parts, the crack resistance may be deteriorated, and if it exceeds 250 parts, the strength development may be deteriorated or the separation resistance may be lowered.

  Although the amount of kneading water used in the present invention is not particularly limited, it is usually preferably 30 to 60%, more preferably 35 to 55% in terms of water / binder ratio. Outside this range, fluidity may be greatly reduced, material separation resistance may be reduced, and strength may be reduced.

  Further, in the present invention, fiber materials such as limestone fine powder, blast furnace slag fine powder, silica fume, fly ash, antifoaming agent, rust inhibitor, antifreeze agent, shrinkage reducing agent, vinylon fiber, carbon fiber, and wollastonite fiber It is possible to use one or two or more of polymer emulsions and clay minerals such as bentonite as long as the object of the present invention is not substantially inhibited.

  The machine used for kneading the non-shrink grout material of the present invention is not particularly limited. For example, it is possible to use a mixer used in a hand mixer, a grout mixer, a simple batcher plant, and a green plant. .

  Hereinafter, although an example of an experiment is given and the present invention is explained concretely, the present invention is not limited to these examples of experiment.

Experimental example 1
For 95 parts of cement, 5 parts of expansion material, and 100 parts of binder composed of cement and expansion material, the foaming agent and thickener shown in Table 1, 0.3 part of water reducing agent, and 150 parts of fine aggregate were mixed. A grout composition was prepared, water was added so that the water / binder ratio was 46%, and a grout mortar was prepared using a high-speed hand mixer.
The fluidity, volume expansion coefficient, and compressive strength of the produced grout mortar were evaluated. The results are also shown in Table 1.

<Materials used>
Cement: Ordinary Portland cement, commercial product foaming agent A: aluminum powder, mechanical powder, 100 mesh pass, commercial product foaming agent B: atomized aluminum powder, average particle size 6 μm, commercial product foaming agent C: atomized aluminum powder, average Commercial size foaming agent D: atomized aluminum powder, average grain size 15 μm, commercial product foaming agent E: atomized aluminum powder, average grain size 25 μm, commercial product foaming agent F: atomized aluminum powder, average grain size 50 μm, commercially available Product expansion material: Calcium aluminoferrite-based expansion material, Blaine 3,000cm ² / g, Commercial product thickener: Cellulose-based thickener, Commercial product water reducing agent: Polycarboxylic acid-based, Commercial product fine aggregate: Limestone-based crushed sand, Density 2.62g / cm ² , 4mm

<Measurement method>
Fluidity: JIS R5201-1997 “Physical test method for cement” 11. Static flow without 15 drop motions in flow test, measured after 2 hours of kneading Volume expansion: JSCE-F 533-1999 “PC grout 4. Bleeding rate and expansion rate test method "4. Volume expansion rate for one day of age was measured by the expansion rate test method. However, the mold filling into the tester was filled with mortar after 2 hours of finishing and used as the base length.
Compressive strength: Measured at a material age of 28 days according to JSCE-G 505-1999 “Testing method for compressive strength of mortar or cement paste using cylindrical specimens”

Experimental example 2
Using 100 parts of the binder, 0.005 part of the foaming agent D, 0.15 part of the thickener, and the water reducing agent shown in Table 2, the fluidity immediately after kneading, the material separation resistance, the volume expansion coefficient, and The same procedure as in Experimental Example 1 was performed except that the compressive strength was evaluated. The results are also shown in Table 2.

<Measurement method>
Material separation resistance: Leave for 2 hours after kneading, and determine the degree of aggregate settling on the bottom of the container by tactile sensation. “Good” indicates no material separation, “Yes” indicates a minute material separation, but no problem in use. “No” indicates material separation.

Experimental example 3
The experiment was performed in the same manner as in Experimental Example 2, except that 0.3 parts of the water reducing agent and the thickener shown in Table 3 were used for the water / binding material ratio shown in Table 3 and 100 parts of the binding material. The results are also shown in Table 3.

By using the non-shrink grout composition of the present invention, there is provided a grout material having no shrinkage without material separation even in a mortar that has been kept fluid for a long time after mixing for 2 hours. I get out.
And the non-shrink grout of the present invention includes PC grout, prepacked concrete grout, tunnel and shield backfill grout, precast grout, structural repair and reinforcement grout, reinforced joint grout, under bridge grout, undertrack grout It can be widely used in civil engineering and construction applications, such as grouting around the earthquake-resistant steel brace, grout for expansion of the back wall, grout for the steel plate winding method, and grout under the containment vessel of nuclear power plant.

Claims (2)

Cement, expansive, average particle diameter of aluminum powder produced by an atomization method is 6~50μm foaming agent, and water reducing agent, further, Ri Do from a formulation containing a thickener, made of cement and expansive A non-shrink grout composition in which the foaming agent is 0.001 to 0.01 part by mass, the water reducing agent is 0.05 to 1 part by mass, and the thickener is 0.05 to 0.5 part by mass with respect to 100 parts by mass of the binder . A non-shrink grout material comprising the non-shrink grout composition according to claim 1 , a fine aggregate, and water.