JP2009161388A - High flow light weight mortar composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high flow lightweight mortar composition lightweight to have ≤1.85 kg/L mass per unit volume after kneading without adding vitreous foamed particles produced by foaming waste glass as a raw material, provided with excellent flowability and having high compressive strength of ≥30N mm<SP>2</SP>in the age of 28 days after hardening. <P>SOLUTION: The purpose is achieved by incorporating lightweight aggregate having specific mass per unit volume and specific volume change modulus, that is, the high flow lightweight mortar composition contains the lightweight aggregate having <0.3 kg/L mass per unit volume, ≥60% and <100% 1 kN volume change modulus and cement and ≤pH8. The lightweight aggregate is suitably inorganic lightweight aggregate. The lightweight aggregate suitably occupies 95-100 volume% in the incorporated lightweight aggregate. The lightweight aggregate is suitably incorporated by 1-12 pts.mass in cement of 100 pts.mass. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a high-flowing lightweight mortar composition, and more particularly, to a kneaded mortar having a high unit compressive strength and a high-flowing lightweight mortar composition having a unit volume mass of 1.85 kg / L or less.

  In civil engineering work or construction work, mortar with high fluidity such as non-shrink grout (mortar) is often used. Non-shrink grout (mortar) is used for bridge support and machine fixing. In addition, it is often used as a filler between the original bridge pier and the steel plate in the reinforcement method by rolling the steel plate of the pier. However, since a general non-shrink grout has a unit volume mass exceeding 2.0 kg / L, it is used for the reinforcement method by rolling up the steel pier of the bridge pier. There was a problem that the steel plate sometimes swelled to such an extent that it could be confirmed. Therefore, a mortar having a relatively small unit volume mass and high fluidity has been proposed. As a mortar having a relatively small unit volume mass and high fluidity, there is one using a bubble mortar in which bubbles are mixed (see, for example, Patent Document 1). However, although bubble mortar is lightweight, its strength is considerably smaller than concrete. In addition, there is a material to which a lightweight aggregate such as pearlite or expanded polystyrene is added (for example, see Patent Document 2 and Patent Document 3). However, the strength is also considerably smaller than concrete. In addition, there is also one that adds vitreous foam particles produced by foaming waste glass as a raw material (see, for example, Patent Document 4). Since general glass changes or reacts in the long term in the alkaline region, adding glassy foam granules produced by foaming waste glass as a raw material is uneasy from the viewpoint of long-term stability. .

Therefore, without adding heated foam granules made from waste glass, the unit volume mass after kneading is lightweight at 1.85 kg / L or less, with excellent fluidity, and compression strength after curing is common. A high flow lightweight mortar composition as high as concrete has been demanded.
JP 2004-2200 A Japanese Patent Laid-Open No. 2001-19528 JP 2002-308660 A Japanese Patent Laid-Open No. 11-343157

The present invention is light weight with a unit volume mass after kneading of 1.85 kg / L or less without adding heated foam granules made from waste glass, and has excellent fluidity, and has a compressive strength after curing. The object is to provide a high flow and light weight mortar composition as high as 30 N / mm ² or more at the age of 28 days as in general concrete.

The inventor of the present application has found that the compressive strength of the mortar increases as the lightweight aggregate used is more fragile and the 1 kN bulk volume change rate is relatively larger, thus completing the present invention. That is, this invention solved the said subject by including the lightweight aggregate of a specific unit volume mass and a specific bulk volume change rate. That is, the present invention is a high flow lightweight mortar composition represented by the following (1) to (4).
(1) A high-flowing lightweight mortar composition containing lightweight aggregate and cement having a unit volume mass of less than 0.3 kg / L and a 1 kN bulk volume change rate of 60% or more and less than 100% and a pH of 8 or less.
(2) The high fluidity lightweight mortar composition as described in said (1) whose said lightweight aggregate is an inorganic lightweight aggregate.
(3) The high fluidity lightweight mortar composition as described in said (1) or (2) whose ratio of the said lightweight aggregate in the lightweight aggregate contained is 95-100 volume%.
(4) The high-flowing lightweight mortar composition described in any one of (1) to (3) above, containing 1 to 12 parts by weight of lightweight aggregate with respect to 100 parts by weight of cement.

The “1 kN bulk volume change rate” in the present invention refers to the bulk volume change rate measured and determined by the following method.
How to obtain 1 kN bulk volume change rate: Light weight aggregate is put into a compression molding form consisting of a metal cylinder with an inner diameter of 15.4 mm and a lower plunger inscribed in the inner wall of the cylinder, and the form is being tapped. After leveling the lightweight aggregate, a top plunger inscribed in the inner wall of the mold was placed and placed on the top of the top plunger at a speed of about 3 mm / min up to 1000 N. The bulk volume of the lightweight aggregate is obtained, and the bulk volume change rate expressed as a percentage is obtained by dividing the change amount of the bulk volume by the bulk volume before loading. At this time, there may be a gap of about 0.2 mm between the inner wall of the cylinder and each plunger.

According to the present invention, the unit volume mass after kneading is light weight of 1.85 kg / L or less without adding glassy foam granules produced by heating and foaming waste glass as a raw material, and JIS R 5201 “cement” 11. Physical test method of The flow value (hereinafter referred to as “static flow value”) that can be left standing without using the flow cone defined in the flow test is 200 mm or more and has excellent fluidity, and compression after curing. A high-fluidity lightweight mortar composition having a strength as high as 30 N / mm ² or more at the age of 28 days as in general concrete can be obtained and used as a grout material. The high-flowing lightweight mortar kneaded with the high-flowing lightweight mortar composition of the present invention is lightweight with a unit volume mass of 1.85 kg / L or less and has excellent fluidity. . Moreover, since the member using this high fluidity lightweight mortar is lightweight, the member which supports it can also be made small. In addition, when the high-fluidity lightweight mortar composition of the present invention is used as a filler in a reinforcing method by winding a steel pier of a bridge pier, the risk of the steel swell expanding to such an extent that the steel slag can be visually confirmed is reduced. The height that can be driven in can be increased.

  In addition, the high-flowing lightweight mortar kneaded with the high-flowing lightweight mortar composition of the present invention can reduce the capacity (power consumption) of the machine used during the manufacture and use of mixers and pumps used for mixing. It is.

  The lightweight aggregate used in the present invention is a lightweight aggregate having a unit volume mass of less than 0.3 kg / L, a 1 kN bulk volume change rate of 60% or more and less than 100%, and a pH of 8 or less. It is preferable that the lightweight aggregate is an inorganic lightweight aggregate because adhesion with cement hydrate is excellent.

  Here, the unit volume mass is obtained by filling a lightweight aggregate in a container whose internal volume is known up to the upper end of the container, and measuring the mass of the lightweight aggregate in the container at this time. This mass is obtained by dividing by the internal volume of the container. When the unit volume mass of the lightweight aggregate is 0.3 kg / L or more, there is a high possibility that the unit volume mass when the high-flowing lightweight mortar is kneaded exceeds 1.85 kg / L, or the unit volume mass is 1.85 kg. If the amount of lightweight aggregate is less than / L, there is a high possibility that the compressive strength will be insufficient. A preferable unit volume mass value of the lightweight aggregate to be used is 0.05 to 0.25 kg / L.

The 1 kN bulk volume change rate indicates the strength of the lightweight aggregate, and the smaller the value, the more difficult the lightweight aggregate is broken, and the larger the value, the easier the lightweight aggregate is broken. The 1 kN bulk volume change rate of the lightweight aggregate used in the present invention is 60% or more and less than 100%, preferably 60 to 90%. If it is less than 60%, the compressive strength at the age of 28 days does not reach 30 N / mm ² .

  The lightweight aggregate used in the present invention has a pH of 8 or less. Lightweight aggregates exceeding pH 8 such as vitreous foam granules produced by heating and foaming waste glass as a raw material are not preferred because they are likely to be altered or reacted in mortar over the long term. The lightweight aggregate used in the present invention does not include vitreous foam granules produced by heating and foaming waste glass as a raw material. Examples of the material of the lightweight aggregate used in the present invention include pearlite and shirasu balloons obtained by crushing and heating igneous rocks such as obsidian, shirasu, or pearlite, and fly ash balloons.

  Although the present invention can include light-weight aggregates other than the light-weight aggregates described above, the ratio of the light-weight aggregates in the light-weight aggregates included is preferably 95 to 100% by volume, more preferably 98. ˜100% by volume. Most preferably, a lightweight aggregate other than the above-mentioned lightweight aggregate is not used. If it is less than 95% by volume, there is a high possibility that the compressive strength at 28 days of age will be insufficient or the unit volume mass after kneading will exceed 1.85 kg / L. As lightweight aggregates other than the above-mentioned lightweight aggregates, inorganic lightweight aggregates having a unit volume mass of 0.3 kg / L or more, inorganic lightweight aggregates having a kN bulk volume change rate of less than 60%, and unit volume mass of 0 Organic lightweight aggregates such as expanded polystyrene having a rate of change of 3 kg / L or more or 1 kN bulk volume of less than 60%.

The amount of the lightweight aggregate used in the present invention is 1 to 12 parts by mass of the lightweight aggregate with respect to 100 parts by mass of cement, and the unit volume mass of the mortar is 1.85 kg / L or less and the compression is 28 days old. It is preferable because the strength can be 30 N / mm ² or more. If the light aggregate is 3 to 8 parts by mass with respect to 100 parts by mass of cement, the unit volume mass of the mortar can be 1.75 kg / L or less and the compressive strength at 28 days of age can be 38 N / mm ² or more. More preferred.

  The cement used in the present invention may be a hydraulic cement, for example, various portland cements such as normal, early strength, super early strength, low heat and moderate heat, ecocement, and these portland cement or ecocement, Various cements mixed with fly ash, blast furnace slag, silica fume or limestone fine powder, etc., "Jet cement" (trade name) manufactured by Taiheiyo Cement Co., Ltd. and "Jet cement" (trade name) manufactured by Sumitomo Osaka Cement Co., Ltd. , Alumina cement, and the like. These may be used alone or in combination of two or more. Since the compressive strength of mortar is high, it is preferable to use early-strength Portland cement as cement.

The cement content in the high flow lightweight mortar composition of the present invention is preferably 85% by mass to 99% by mass. If it is less than 85% by mass, the compressive strength is low, and if it exceeds 99% by mass, the unit volume mass of the mortar is likely to exceed 1.85 kg / L. A more preferable cement content is 89 mass% to 96.5 mass% because the unit volume mass of the mortar can be 1.85 kg / L or less and the compressive strength at the age of 28 days is 33 N / mm ² or more. It is.

  In the high flow lightweight mortar composition of the present invention, in addition to cement and lightweight aggregate, one or more admixtures other than those described above can be used in combination as long as the effects of the present invention are not substantially impaired. Examples of the admixture include water reducing agents, AE water reducing agents, high performance water reducing agents, high performance AE water reducing agents, cement dispersing agents such as fluidizing agents, thickeners, aggregates other than lightweight aggregates, polymers for cement, Foaming agent, foaming agent, waterproofing agent, rust preventive agent, shrinkage reducing agent, water retention agent, pigment, fiber, water repellent agent, white flower preventing agent, expansion material (agent), quick setting agent (material), rapid hardening agent (Material), antifoaming agent, blast furnace slag fine powder, stone powder, silica fume, volcanic ash, water repellent, surface hardener, water retention agent and the like.

  The high flow lightweight mortar composition of the present invention preferably contains a cement dispersant. When a cement dispersant is used, the compressive strength is easily increased. The type of the cement dispersant used in the present invention is not particularly limited, but a high performance water reducing agent or a high performance AE water reducing agent is preferable because high strength can be obtained. Moreover, it is preferable that it is a powdery cement dispersant since the high fluidity lightweight mortar composition of this invention can be preserve | saved after manufacture. When the cement dispersant is contained in the high flow lightweight mortar composition of the present invention, the amount is preferably 0.5 to 3 parts by mass with respect to 100 parts by mass of cement. If it is less than 0.5 part by mass, the effect of containing a cement dispersant is low, and if it exceeds 3 parts by mass, the initial strength may be lowered. More preferably, it is 1.5-2.5 mass parts with respect to 100 mass parts of cement.

  The high flow lightweight mortar composition of the present invention preferably contains a thickener. When a thickener is used, there is an advantage that even if a lightweight aggregate having a small unit volume mass is used, material separation, that is, in this case, the lightweight aggregate can be prevented from floating and being separated from other materials. Examples of the thickener used in the present invention include water-soluble celluloses such as hydroxymethyl cellulose and hydroxypropyl cellulose; polysaccharides such as alginic acid, β-1,3 glucan, pullulan and welan gum; polyvinyl such as acrylic resin and polyvinyl alcohol; It is possible to use one or more of these, but since it is easy to obtain the effect of adding the above thickener in a small amount that does not have much influence of setting delay, water-soluble cellulose is preferable. When the thickener is contained in the high-flowing lightweight mortar composition of the present invention, it is preferably 0.01 to 0.1 parts by mass with respect to 100 parts by mass of cement. If the amount is less than 0.01 parts by mass, the effect of containing a thickener is low. If the amount exceeds 0.1 parts by mass, the initial strength may be lowered. The amount added is more preferably 0.02% by mass to 0%. 0.05% by mass.

  Furthermore, when making the high flow lightweight mortar composition of this invention into a non-shrinkable high flow lightweight mortar composition, it is preferable to contain an expansion | swelling material, a foaming agent, and an antifoamer.

  The method for producing the high-flowing lightweight mortar composition of the present invention is not particularly limited. For example, a mixer such as a gravity concrete mixer, a Henschel mixer, a Nauter mixer, a Ladige mixer, a V-type mixer, or a ribbon mixer is used. It can manufacture by mixing each material of the fixed quantity high flow lightweight mortar composition of this invention. The mixer used at this time may be a continuous mixer or a batch mixer. The order in which each material is charged into the mixer is not particularly limited. The high-fluidity and lightweight mortar composition of the present invention can be added one by one, or a part or all of it can be added simultaneously. It can also be manufactured.

  The high flow lightweight mortar composition of the present invention uses water for kneading. The method of kneading is not particularly limited, for example, a method of adding and kneading all the high flow lightweight mortar composition of the present invention to water, a method of adding and kneading the high fluid lightweight mortar composition of the present invention to water while mixing, A method for adding and kneading all the water to the high flow lightweight mortar composition of the invention, a method for adding water to the high flow lightweight mortar composition of the present invention while kneading and further kneading, water and a high flow lightweight mortar composition of the present invention There is a method in which a part of each is divided into two or more and kneaded, and the kneaded ones are further kneaded. Moreover, although the apparatus and kneading apparatus used for kneading are not particularly limited, it is preferable to use a mixer because a large amount can be kneaded. The mixer that can be used may be a continuous mixer or a batch mixer, such as a pan concrete mixer, a pug mill concrete mixer, a gravity concrete mixer, a grout mixer, a hand mixer, and a plaster mixer.

The water to be used is not particularly limited. You may use the water contained in an admixture. The amount of water used at this time is 35 parts by mass to 45 parts by mass with respect to 100 parts by mass of the high flow lightweight mortar composition of the present invention, and the stationary flow value of the high flow lightweight mortar after kneading is 200 mm or more. It is preferable from the viewpoint of excellent fluidity and compressive strength after curing as high as 30 N / mm ² or more at the age of 28 days as in general concrete, and more preferably 37 parts by mass to 42 parts by mass.

  The usage method of the high flow lightweight mortar manufactured by kneading the high flow lightweight mortar composition of this invention is not specifically limited. For example, the manufactured high flow lightweight mortar is pumped to a mortar pump or a concrete pump and filled into a gap between the original pier and the steel rod wound around it. In this case, it is preferable to insert the tip of the tremy tube or the pumping hose into the high-flowing lightweight mortar that has been filled first, and filling the high-flowing lightweight mortar so as not to fall in the air.

[Example 1]
An inorganic lightweight aggregate was used as the lightweight aggregate. As the inorganic lightweight aggregate, nacreous pearlite having unit volume mass, maximum particle size, pH and 1 kN bulk volume change rate shown in Table 1 was used. The unit volume mass and the 1 kN bulk volume change rate were determined by the following methods.
<How to obtain 1 kN bulk volume change rate>
FIG. 1 shows a schematic diagram of a metal cylinder, a lower plunger, and an upper plunger used for obtaining the 1 kN bulk volume change rate. An inorganic lightweight aggregate is placed in a compression molding mold consisting of a metal cylinder 1 having an inner diameter of 15.4 mm and a metal lower plunger 2 inscribed in the inner wall of the cylinder, and the inorganic lightweight bone being tapped on the mold After leveling the material, a metal upper plunger 5 inscribed in the inner wall of the formwork was placed and placed on top of the upper plunger 5 at a speed of about 3 mm / min up to 1000 N, before and after the loading. The bulk volume of the inorganic lightweight aggregate was determined, and the bulk volume change rate expressed as a percentage was determined by dividing the bulk volume change amount by the bulk volume before loading. At this time, the metallic cylinder 1 used had a cylindrical shape with an inner diameter of 15.4 mm and an outer diameter of 47.9 mm. The lower plunger 2 includes a disc-shaped washer portion 3 having a diameter of 47.9 mm and a thickness of 15.0 mm, and a cylindrical portion 4 (diameter: 15.0 mm, height: 60 mm) standing vertically at the center of the washer portion 3. 0.0 mm). The upper plunger 5 includes a disc-shaped head 6 having a diameter of 47.9 mm and a thickness of 15.0 mm, and a cylindrical portion 7 (diameter 15.0 mm, height 40.0 mm) that hangs perpendicularly to the center of the head 6. It consists of. There was a gap of 0.2 mm between the inner wall of the metal cylinder 1 and the column portion of each plunger fitted to the cylinder.
<How to find unit volume mass>
Gently put the inorganic lightweight aggregate in a metal container with an internal volume of 0.5000L until it protrudes from the container, scrape the protruding part with a ruler, and fill it to the top of the container. The mass of the inorganic lightweight aggregate in the container at this time Was measured. It calculated | required by remove | dividing the mass of the inorganic lightweight aggregate in a container by the internal volume of a container.

。

.

The mixing ratio shown in Table 2 was mixed for 3 minutes in a metal container using a Redige mixer (FM130D) to prepare 50 kg of primary mixed materials. The materials used at this time are shown below.
<Materials used>
Cement: Early strong Portland cement (manufactured by Taiheiyo Cement)
Foaming agent: Aluminum powder (commercially available)
Cement dispersant A: polycarboxylic acid-based high-performance water reducing agent (trade name “Core Flow NF-100”, manufactured by Taiheiyo Materials Co., Ltd.)
Cement dispersant B: Polycarboxylic acid-based high-performance water reducing agent (trade name “Core Flow NF-200”, manufactured by Taiheiyo Materials Co., Ltd.)
Thickener: Water-soluble cellulose thickener (trade name "Metroze", manufactured by Shin-Etsu Chemical Co., Ltd.)

Using the prepared primary mixed material and one or two kinds of inorganic lightweight aggregates of aggregates A to F, mortar compositions having the formulations shown in Tables 3 and 4 were prepared, and water in the amounts shown in Table 3 was used. Was added and kneaded in a metal container for 90 seconds with a hand mixer (1000 rpm, blade diameter 100 mm) to prepare a mortar. As a quality test for the mortar produced, as shown below, J ₁₄ funnel flow time, standing flow value, unit volume mass, the compressive strength was measured to confirm the separation resistance and fluidity. The test temperatures were all 20 ° C. Table 5 shows the results of the quality test.
<Quality test method>
· According _{J 14} funnel flow time of Civil Engineers reference JSCE-F 541 "Test Method of Flowability for Filling _Mortar", with _{J 14} funnel was measured sulfide time.
Static flow value JIS R 5201 “Cement physical test method” 11. According to the flow test, the static flow value was measured without performing the drop motion.
-Unit volume mass The mortar produced in the metal container of internal volume 0.5000L was filled to the upper end of the container, and the mass of the mortar in the container at this time was measured. It calculated | required by remove | dividing the mass of the mortar in a container by the internal volume of a container.
-Compressive strength test According to the Japan Society of Civil Engineers standard JSCE-G 541 "Compressive strength test method for filled mortar", the compressive strength at the age of 28 days was measured. The specimen at this time was demolded at the age of 1 day and then cured in water at 20 ° C.
-Separation resistance It was visually confirmed whether or not the material in the mortar was separated. X (weight separation resistance is poor) that can be confirmed that the lightweight aggregate has separated and floated on the cement paste in the mortar, ○ that the lightweight aggregate has not been confirmed to float It was determined that the separation resistance was good.
And liquidity standing flow value is more than 200 mm, J ₁₄ funnel flow time is determined to ○ what is good 4-10 seconds and separation resistance (fluidity good).

Formulation No. corresponding to the examples of the present invention. 1-No. The mortar composition of No. 8 is lightweight, with a unit volume mass of kneaded mortar of 1.85 kg / L or less, excellent flowability with a static flow value of 200 mm or more, and a compressive strength after curing of general concrete In addition, it had a high fluidity of 30 N / mm ² or more at an age of 28 days, and had excellent separation resistance. In particular, formulation no. 1 and no. 3-No. The mortar composition of No. 6 was lighter with a unit volume mass of the mortar after kneading of 1.75 kg / L or less. In addition, blending No. 1-No. The mortar compositions of No. 8 each had a static flow value of 200 mm or more after kneading, and had sufficient performance as a grout mortar composition.

Formulation No. corresponding to the comparative example. 9-No. In the mortar composition No. 10, the inorganic lightweight aggregate floated after kneading, that is, separated and had low separation resistance, and the compressive strength at 28 days of age was less than 30 N / mm ² .

  The high flow lightweight mortar composition of the present invention includes various fillers such as fillers in reinforcing methods by rolling steel piers at bridge piers, grout mortars used for bridge support and machine fixing, mortars filled with steel pipes and steel shells, etc. Etc. can be used suitably.

It is a schematic diagram which shows the metal cylinder, the lower plunger, and the upper plunger which were used when calculating | requiring 1kN bulk volume change rate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal cylinder 2 Lower plunger 3 Washer part 4 Cylindrical part 5 Upper plunger 6 Head 7 Cylindrical part

Claims (4)

A high-flowing lightweight mortar composition containing a lightweight aggregate and cement having a unit volume mass of less than 0.3 kg / L and a 1 kN bulk volume change rate of 60% to less than 100% and a pH of 8 or less. The high-flowing lightweight mortar composition according to claim 1, wherein the lightweight aggregate is an inorganic lightweight aggregate. The ratio of the said lightweight aggregate in the lightweight aggregate contained is 95-100 volume%, The high flow lightweight mortar composition of Claim 1 or Claim 2. The high-flowing lightweight mortar composition according to any one of claims 1 to 3, comprising 1 to 12 parts by mass of a lightweight aggregate with respect to 100 parts by mass of cement.

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