JP5964345B2 - High flow lightweight mortar composition and high flow lightweight mortar using the same - Google Patents

Description

  The present invention mainly relates to a high-flowing lightweight mortar composition and a high-flowing lightweight mortar using the same, which are used in the civil engineering and construction fields.

  Cement-based mortar grout materials used in civil engineering and construction work include PC grout, pre-packed concrete grout, tunnel and shield-back grout, precast grout, structural repair and reinforcement injection grout, bridge support grout In addition, there are grouts under orbit, seismic steel frame brace peripheral frame grouts, additional wall reverse grouts, steel sheet winding grouts, and nuclear power plant containment grouts.

The performance required for the grout material includes no material separation and bleeding, and good fluidity during construction.
In particular, in the steel pier winding method for bridge piers, a steel plate is wound around RC piers, and a grout material is generally filled in a gap of 30 to 50 mm. Since the volume mass was 2 t / m ³ or more, the steel sheet sometimes swelled when the casting speed was increased.

Therefore, a mortar having a small unit volume mass and excellent fluidity has been proposed. For example, a method of introducing bubbles into a mortar and a method of adding a lightweight aggregate are known. (Patent Documents 1, 2, and 3)
However, the compressive strength of lightweight mortar decreases linearly with weight reduction, and the use of foaming agents and lightweight aggregates increases costs.

In addition, although the increase in the amount of kneading water does not directly increase the cost, bleeding may occur or the separation resistance may decrease, and the addition of a thickener has also been proposed to improve the separation resistance. (Patent Documents 4 and 5).
However, the addition of a large amount of thickening agent has a problem that the setting delay occurs and the strength development is suppressed.

Japanese Patent Laid-Open No. 9-268043 JP 2009-161388 A JP 2010-155755 A Japanese Patent Laid-Open No. 7-258634 JP 2008-297140 A

  The present invention is lightweight, excellent in fluidity, has no bleeding and material separation, does not swell after construction as a filler for a steel sheet winding method, has good workability and exhibits sufficient strength, and a high fluidity lightweight mortar composition and A high flow lightweight mortar using the same is provided.

The present invention includes (1) cement, blast furnace slag fine powder having a brain specific surface area exceeding 6000 cm ² / g, an expander, a lightweight aggregate having a density of 0.1 to 0.7 kg / l, water-soluble and also contains a cellulosic thickener and an acrylic thickener, cement and blast furnace slag and a binder in 100 parts by mass consisting of expandable material, cement 20-70 parts by weight, ground granulated blast furnace slag is 25 75 parts by weight, the expansion material is 2 to 10 parts by weight, high flow lightweight mortar composition characterized by containing no water reducing agent, (2) cement and blast furnace slag to consist expanding material binder ( 1 ) High flow lightweight mortar with 0.05 to 0.8 parts by mass of water-soluble cellulose thickener and 0.01 to 0.5 parts by mass of acrylic thickener with respect to 100 parts by mass Composition, ( 3 ) polyoxyethylene alkyl (1) or (2) high-flowing light weight mortar composition, ( 4 ) cement, blast furnace slag fine powder having a Blaine specific surface area exceeding 6000 cm ² / g, and expansion A high fluidity characterized in that it contains a material, a lightweight aggregate having a density of 0.1 to 0.7 kg / l, a water-soluble cellulose thickener and an acrylic thickener, and no water reducing agent. A lightweight mortar composition, or a highly fluid lightweight mortar obtained by kneading at a water ratio of 50 to 100% by mass with respect to any of the highly fluid lightweight mortar compositions of (1) to ( 3 ).

  The high flow lightweight mortar composition of the present invention and the high flow lightweight mortar using the composition are lightweight and excellent in fluidity, have no bleeding and material separation, exhibit sufficient strength, and are applied as a filler for steel sheet winding method Swelling does not occur, and effects such as excellent workability are achieved.

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 used in the present invention is not particularly limited, and normal, early strength, very early strength, low heat, and moderate heat Portland cement, and these portland cements include blast furnace slag, fly ash, or silica. Various mixed cements, eco-cement, white cement, ultrafast cement, filler cement mixed with fine limestone powder, and the like can be mentioned, but considering strength development at short-term age, early-strength Portland cement is preferable.

The amount of the cement used is preferably 20 to 70 parts, more preferably 25 to 65 parts, in 100 parts of the binder composed of cement, blast furnace slag fine powder, and expansion material. If it is 20 parts or less, the initial strength of the cured body may be insufficient, and if it exceeds 70 parts, long-term strength may not be ensured sufficiently.

As the blast furnace slag fine powder used in the present invention, those stipulated in JIS A 6206 and those obtained by further pulverizing and pulverizing the blast furnace slag powder can be used, and the fineness exceeds 6000 cm ² / g. . If it is 6000 cm ² / g or less, the long-term strength development may be insufficient, the mortar separation resistance may be insufficient, and the aggregate may settle. Moreover, even if the blast furnace slag fine powder exceeding 12000 cm < ² > / g is used, a grinding energy cost increases and it is uneconomical.
The amount of blast furnace slag fine powder used is preferably 25 to 75 parts, more preferably 30 to 70 parts, in 100 parts of a binder composed of cement, blast furnace slag fine powder and an expansion material. If it is less than 25 parts, the 28-day strength may be insufficient, and if it exceeds 75 parts, the short-term strength may be insufficient.
The 28-day compressive strength required for the filler for steel sheet winding method is 5 N / mm ^{2 in} the “East Japan Railway Company's“ Civil Engineering Standard Specification ”, and the 28-day strength is 10 N / in consideration of quality variations. mm ² or more is preferable. There is no target value for short-term strength, but higher values are preferred.

The expansion material used in the present invention is used for reducing dry cracking of mortar, and is not particularly limited, but examples thereof include Auin-based, calcium aluminoferrite-based, and lime-based materials.
Fineness of expanding material is preferably 4000 cm ² / g or more in specific surface area, 6000 cm ² / g is more preferable. If it is less than 4000 cm ² / g, the effect of preventing bleeding may not be sufficient.
The amount of the expansion material used is preferably 2 to 10 parts, more preferably 3 to 8 parts, in 100 parts of a binder composed of cement, blast furnace slag fine powder and expansion material. If it is less than 2 parts, the effect of preventing cracking and bleeding of the mortar may not be sufficient, and if it exceeds 10 parts, abnormal expansion may occur.

The usage-amount of the binder in 100 parts of high flow lightweight mortar compositions of this invention is 95-50 parts. When the amount is less than 50 parts, the deformation strain at the time of breaking the cured body is reduced, and the deformation followability may be reduced. When it mixes exceeding 95 parts, a lightweight aggregate cannot be mix | blended and it may become impossible to reduce a mortar density.

In the present invention, a thickener is used. By blending a thickener, it is possible to blend a lightweight aggregate with no material separation and a small unit volume mass, and further increase the amount of mixing water without causing bleeding. These make it possible to reduce the weight of the mortar composition.
Examples of the thickener include water-soluble celluloses such as hydroxymethylcellulose and hydroxypropylmethylcellulose, acrylics such as polyacrylic acid and polyacrylamide, polysaccharides such as alginic acid, β-1,3 glucan, pullulan and welan gum, polyvinyl Examples thereof include polyvinyl compounds such as alcohol.
In the present invention, it is preferable to use a water-soluble cellulose thickener and an acrylic thickener in combination.

Water-soluble cellulose has a large viscosity and a small plastic viscosity, and works effectively for preventing material separation and bleeding from occurring in a small amount.
However, when viscosity is given only with water-soluble cellulose, the spread of the mortar (flow value) is large, and when filled, if there is a gap between the steel plates, leakage or side pressure on the steel plate will increase. As a result, the steel plate may swell.
On the other hand, acrylic thickeners can increase the plastic viscosity, although the increase in viscosity is small. It is preferable that polyacrylamide contains dextrin because dispersibility in water is improved.
In the present invention, by using a water-soluble cellulose thickener and an acrylic thickener in combination, the material separation resistance is improved, bleeding is suppressed, and excessive spread (flow value) of mortar with a high water ratio is suppressed. It is possible to improve resistance to leakage from the gap of the mold and to reduce the side pressure of the mortar filled in the steel plate.

Moreover, it is preferable not to contain a water reducing agent in the present invention. For example, when a naphthalene water reducing agent is used, fluidity may not be ensured. In addition, when a melamine water reducing agent or a polycarboxylic acid water reducing agent is used, the fluidity is excessively increased, which may cause bleeding or material separation.

The amount of the water-soluble cellulose thickener used is preferably 0.05 to 0.8 part, preferably 0.1 to 0.5 part with respect to 100 parts of the binder composed of cement, blast furnace slag fine powder, and expansion material. More preferred. If the amount of water-soluble cellulose thickener used is less than 0.05 parts, bleeding may occur, and if it exceeds 0.8 parts, the viscosity increases so much that the fluidity necessary for filling cannot be obtained, It may cause a setting delay.
The amount of the acrylic thickener used is preferably 0.01 to 0.5 part, more preferably 0.1 to 0.3 part with respect to 100 parts of the binder composed of cement, blast furnace slag fine powder, and expansion material. preferable. If the amount of acrylic thickener used is less than 0.01 parts, material separation will not occur, and the spread of mortar will not be reduced, improving resistance to leakage from the gaps in the formwork and filling the inside of the steel plate The lateral pressure of the mortar cannot be reduced, and if it exceeds 0.5 parts, the plastic viscosity is excessively increased and the fluidity necessary for filling may not be obtained.

  The lightweight aggregate used in the present invention may be a lightweight aggregate that can be used in a cement composition. For example, pearlite, shirasu balloon, etc. obtained by pulverizing igneous rocks such as obsidian, shirasu, or pearlite, and fly ash balloons. The density of the lightweight aggregate is 0.1 to 0.7 kg / l. When the density of the lightweight aggregate exceeds 0.7 kg / l, the density of the mortar increases. When used as a filler for the steel sheet winding method, the steel sheet may swell, and if it is below 0.1 kg / l , And other components may not be sufficiently blended, resulting in insufficient compressive strength.

The amount of the lightweight aggregate is preferably 80 to 400 liters in 1000 liters of high fluidity lightweight mortar in which water and a highly fluid lightweight mortar composition are mixed. If it is 80 liters or less, the density of the mortar cannot be reduced, and there may be a case where the mortar is filled when filling the gap between the steel plates. Moreover, when it exceeds 400 liters, sufficient compressive strength may not be obtained.
The maximum particle size of the lightweight aggregate is preferably 1.2 mm or less. When the thickness exceeds 1.2 mm, the number of aggregate particles per unit volume decreases, and when premix (dry) mortar is produced, segregation may occur due to a large density difference from each component.

In this invention, it mixes with the water ratio of 50-100% with respect to a high flow lightweight mortar composition, More preferably, 60-80%. If it is less than 50%, the mortar density cannot be made sufficiently small. Conversely, if it exceeds 100%, the compression strength may not be sufficient.

In the present invention, a polyoxyethylene alkyl ether-based powder foaming agent can be blended. The weight reduction of the mortar density can be adjusted by a foaming agent, and further, separation resistance can be improved by introducing fine air into the mortar composition.
The amount of the polyoxyethylene alkyl ether-based powder foaming agent used is preferably 0.05 to 0.50 part, more preferably 0.10 to 0.20 part with respect to 100 parts of the high-flowing lightweight mortar composition. If it is less than 0.05 part, the effect of reducing the mortar density by adding the foaming agent is small, and even if it exceeds 0.5 part, the amount of air introduced may reach a peak and the weight may not be further reduced.

In this invention, it can be set as the premix type which dry-blended the high flow lightweight mortar composition. By using a premix type, quality can be stabilized, and in the construction site, it is easy and preferable because only water is prepared and mixed.

In the present invention, a water reducing agent generally used in mortar concrete is not used. If a water reducing agent is used, the amount of mixing water for obtaining a predetermined fluidity decreases, and the amount of mixing water necessary for reducing the density of the mortar cannot be increased.

In the present invention, a gas foaming material can be used to integrate with a structure or to prevent the mortar that has not yet solidified from sinking or shrinking.
Examples of gas foaming substances include flaky aluminum powder surface-treated with stearic acid, aluminum powder produced by an atomizing method, substances that foam nitrogen gas in an alkaline atmosphere, such as azo compounds, nitroso compounds, and hydrazine derivatives. Percarbonate such as sodium percarbonate, potassium percarbonate and ammonium percarbonate, perborate such as sodium perborate and potassium perborate, permanganate such as sodium permanganate and potassium permanganate In addition, peroxide substances such as hydrogen peroxide can be used.
The amount of gas foaming material used is 0.0005 to 0.003 part for aluminum powder, 0.01 to 0.5 part for nitrogen gas foaming material, and 0.01 to 0 for peroxide material with respect to 100 parts of binder. .1 part is preferred.

Moreover, you may use the fine aggregate normally used for the high flow lightweight mortar composition of this invention. River sand, crushed sand and the like can be used as fine aggregates, and dry sand is preferred when premixed mortar.
In addition, one or more of various additives (agents), foaming agents, bentonite and other clay minerals, siliceous fine powder, and calcium carbonate are used within a range that does not substantially impair the object of the present invention. Is possible.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

"Experiment 1"
As shown in Table 1, the cement, various blast furnace slag (blast furnace granulated slag) fine powder, and 100 parts of the binder composed of 5 parts of the expanded material, 10 parts of lightweight aggregate A, 25 parts of fine aggregate, thickener A0. .3 parts and 0.2 part of thickener B are uniformly mixed in a V-type blender, and 65 parts of water is added to 100 parts of the high-flowing light weight mortar composition in a room at 20 ° C. and kneaded with a mixer. a high flow lightweight mortar was measured compressive strength and fluidity (J ₁₄ funnel value). The results are also shown in Table 1.

(Materials used)
Cement: Hayashi Portland cement, commercial blast furnace slag fine powder A: Blaine specific surface area 3980 cm ² / g (product name: ESMENT 4000 Blaine, manufactured by Nippon Steel & Sumikin Mining Co., Ltd.)
Blast furnace slag fine powder B: Blaine specific surface area 6180 cm ² / g (trade name: ESMENT SUPER 6000 Blaine manufactured by Nippon Steel & Sumikin Mining Co., Ltd.)
Blast furnace slag fine powder C: Blaine specific surface area 7860 cm ² / g (trade name: Sment Super 8000 Blaine manufactured by Nippon Steel & Sumikin Mining Co., Ltd.)
Blast furnace slag fine powder D: Blaine specific surface area 10500 cm ² / g (trade name: Sment Super 10000 Blaine manufactured by Nippon Steel & Sumikin Mining Co., Ltd.)
Blast furnace slag fine powder E: Blaine specific surface area 11820 cm ² / g (Esment Super 10000 Blaine manufactured by Nippon Steel & Sumikin Mining Co., Ltd.)
Expanding material: Auin, specific surface area 6110 cm ² / g (CSA # 20 manufactured by Denki Kagaku Kogyo Co., Ltd.)
Lightweight aggregate A: Pearlite lightweight aggregate 1.2mm, density 0.26g / l (commercially available)
Thickener A: Water-soluble cellulose thickener, commercial product, 2% aqueous solution of hydroxypropylmethylcellulose, viscosity 32000 mPa · s
Thickener B: acrylic thickener, commercial product, polyacrylamide 80%, dextrin 6%, sodium sulfate 14%, average molecular weight 300,000 fine aggregate: limestone ground product 0.6mm

According to Table 1, it can be seen that the short-term strength and the long-term strength are excellent within the scope of the examples of the present invention.

(Measuring method)
Liquidity: measure _{J 14} funnel value in accordance with JSCE-F541.
Compressive strength: Measured according to JSCE-G505.

"Experimental example 2"
Cement shown in Table 2, an expansion member, except for the use of blast furnace slag powder D50 parts is carried out in the same manner as in Experimental Example 1, the fluidity (J ₁₄ funnel value) was measured bleeding, the presence or absence of abnormality expansion. The results are also shown in Table 2.

(Measuring method)
Bleeding: Measured according to JSCE-F533. The case where no bleeding occurred was indicated as ◯, and the case where the bleeding occurred was indicated as ×.
Abnormal expansion: A mortar having a diameter of 100 mm and a thickness of 10 mm was prepared on a glass plate, and inflatable cracks were measured according to the stability test method of JIS R5201. The case where mortar cracks did not occur was marked with ○, and the case where cracks occurred was marked with ×.

According to Table 2, it can be seen that there is no bleeding and no abnormal expansion within the scope of the examples of the present invention.

"Experiment 3"
The type and amount of the thickener are changed as shown in Table 3, and water shown in Table 3 is added to 100 parts of the high-flowing lightweight mortar composition in a room at 20 ° C. The test was conducted in the same manner as in Experimental Example 1 except that. In addition to fluidity and bleeding (similar to Experimental Example 2), static flow values, presence / absence of material separation, and mortar density were measured. Moreover, the kind and quantity of water reducing agents shown in Table 3 were added to 100 parts of the high-flowing light weight mortar composition and tested in the same manner. The results are also shown in Table 3.

(Materials used)
Water reducing agent A: Naphthalene "Mighty 100" (manufactured by Kao Corporation)
Water reducing agent B: Melamine-based “Melment F10M” (manufactured by BASF Japan)
Water reducing agent C: Polycarboxylic acid type “Melflux 2651F” (manufactured by BASF Japan)

(Measuring method)
Static flow value: Flow value that does not cause 15 drop motions in the flow test of JISR5202.
Material separation: Visual observation of floating paste layer and fine aggregate sedimentation. The case where no material separation occurred was marked with ◯, and the case where material separation occurred was marked with ×.
Mortar density: Measured according to JIS A 1171.

According to Table 3, by using the water-soluble cellulose thickener and acrylic thickener of the present invention in combination, the fluidity and the stationary flow value are well balanced, and both bleeding and material separation can be suppressed. I understand. In addition, it can be seen that when a water reducing agent is used in combination, fluidity is lowered, bleeding or material separation occurs.

"Experimental example 4"
The high flow lightweight mortar composition of Experiment No. 1-7 of Experimental Example 1 was tested in the same manner as Experimental Example 1 except that the lightweight aggregates and fine aggregates shown in Table 4 were used. In a room at 20 ° C., and its high fluidity weight 65 parts of water was added to the mortar composition 100 parts by kneading in a mixer high fluidity lightweight mortar fluidity (J ₁₄ funnel value), compressive strength, as in Experimental Example 3 Similarly, the density of the mortar and the swelling of the steel plate after filling the steel plate were measured. The results are also shown in Table 4.

(Materials used)
Lightweight Aggregate B: Pearlite lightweight aggregate 1.2mm, density 0.13kg / l (commercially available)
Lightweight aggregate C: 1.2mm of pearlite lightweight aggregate, density 0.48kg / l (commercially available)
Lightweight aggregate D: Pearlite lightweight aggregate 1.2mm, density 0.67kg / l (commercially available)

(Test method)
Steel bulge: □ 50 × 50cm × 2m high concrete column with a gap width of 40mm and t = 4.5mm steel rod is wound up, and the gap is continuously filled with mortar at a speed of 0.8m ³ / h did. After completion of filling, the displacement of the steel plate having a height of 1 m was confirmed. The amount of displacement was small when less than 5 mm, medium between 10 and 10 mm, and large when over 10 mm.

From Table 4, it can be seen that, within the scope of the present invention, the compressive strength is high and the bulge of the steel sheet is small.

“Experimental Example 5”
The amount of foaming agent shown in Table 5 is used for 100 parts of the high-flowing lightweight mortar composition, 65 parts of water is added to 100 parts of the high-flowing lightweight mortar composition, and the mixture is kneaded with a mixer. The test was conducted in the same manner as in Experimental Example 1 except that the fluidity, the mortar density (same as in Experimental Example 4), and the compressive strength were measured. The results are shown in Table 5.

(Materials used)
Foaming agent: Polyoxyethylene alkyl ether-based powder foaming agent (commercial product:
Fatty alcohol polyglycol ether based on cetearyl alcohol having an average of 50 ethylene oxide units in the molecule)

According to Table 5, it is possible to reduce the mortar density by adding a foaming agent, but even if added in excess of 0.5 part, the effect of reducing the weight is small.

  The high flow lightweight mortar composition of the present invention and the high flow lightweight mortar using the composition are lightweight and excellent in fluidity, have no bleeding and material separation, exhibit sufficient strength, and are applied as a filler for steel sheet winding method Since it does not swell and has an effect such as excellent workability, it can be widely used in the civil engineering and construction fields.

Claims (4)

Cement, fine powder of blast furnace slag with a Blaine specific surface area exceeding 6000 cm ² / g, an expander, a lightweight aggregate with a density of 0.1 to 0.7 kg / l, a water-soluble cellulose thickener and an acrylic and also contains a system thickener, binder in 100 parts by mass consisting of cement and blast furnace slag and expanding material, cement 20-70 parts by weight, ground granulated blast furnace slag is 25 to 75 parts by weight, the expansion member Is a high flow lightweight mortar composition characterized by not containing a water reducing agent. The water-soluble cellulose thickener is 0.05 to 0.8 parts by mass and the polyacrylamide type thickener is 0.01 to 0.100 parts by mass with respect to 100 parts by mass of the cement, blast furnace slag fine powder, and the expansion material. The high-flowing lightweight mortar composition according to claim 1 , which is 5 parts by mass. The high flow lightweight mortar composition according to claim 1 or 2 , comprising a polyoxyethylene alkyl ether-based powder foaming agent. Cement, fine powder of blast furnace slag with a Blaine specific surface area exceeding 6000 cm ² / g, an expander, a lightweight aggregate with a density of 0.1 to 0.7 kg / l, a water-soluble cellulose thickener and an acrylic A high-flowing lightweight mortar composition characterized by containing a system thickener and not containing a water reducing agent, or the high-fluidity lightweight mortar composition according to any one of claims 1 to 3 . , High fluidity lightweight mortar kneaded at a water ratio of 50 to 100% by mass.