JP2011207667A - Method for constructing concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for constructing a foundation concrete structure for buildings which has both a good constructing property and excellent hardened body characteristics and where the occurrence of initial cracks on the foundation concrete structure for the buildings is reduced and to provide the foundation concrete structure for buildings.SOLUTION: The method for constructing the foundation concrete structure for the buildings includes: a step to arrange a form to mold the foundation concrete structure for the buildings; a step to arrange reinforcing rods in the form; a step to mold a ground concrete part; and a step to pour and harden hydraulic mortar prepared by kneading a self-leveling hydraulic composition including a main component consisting of portland cement, a fine aggregate, an admixture and an expanding material, aluminum sulfate, a shrinkage reducing agent, a limestone fine powder and a thickening agent containing two kinds of cellulose-based water-soluble polymers having different viscosity with water.

Description

  The present invention relates to a construction method of a foundation concrete structure for buildings using a self-leveling hydraulic composition and a foundation concrete structure for buildings obtained by the construction method.

  Patent Document 1 discloses a low-shrinkage self-leveling material having excellent fluidity, good workability, no material separation, excellent surface hardness after curing (Shore hardness) and good surface accuracy. Disclosed is a self-leveling cement composition characterized by comprising 0.1 to 0.45% by weight of aluminum sulfate as a main component and aluminum sulfate based on the total amount of cement and aggregate. ing.

In Patent Document 2, as a high-strength self-leveling cement composition that is excellent in fluidity and self-smoothness, particularly extremely high in compressive strength after curing and adhesive strength with a base, a Blaine specific surface area is 7000 compared to Portland cement. A high-strength self-leveling cement composition comprising 5 to 30% by weight of one or more inorganic finely pulverized powders selected from the group consisting of -30000 cm ² / g limestone powder, fly ash, and granulated blast furnace slag Is disclosed.

  Patent Document 3 discloses a self-leveling hydraulic composition comprising a main component composed of Portland cement, fine aggregate, admixture and expansion material, and aluminum sulfate, shrinkage reducing agent, limestone fine powder, thickener and water retention agent. A self-leveling hydraulic composition is disclosed, wherein the thickener is a thickener of a cellulose-based water-soluble polymer, and the water-retaining agent is a water-retaining agent of a polyether-based water-soluble polymer. Yes.

  Patent Document 4 describes a construction method for a foundation concrete structure for buildings, which includes pouring and curing a hydraulic mortar prepared by kneading a self-leveling hydraulic composition and water. . Moreover, in the construction method described in Patent Document 4, the self-leveling hydraulic composition is composed of a main component composed of Portland cement, fine aggregate, admixture, and expansion material, aluminum sulfate, shrinkage reducing agent, limestone fine powder, It includes a thickener and a water retention agent, the thickener is a thickener of a cellulose water-soluble polymer, and the water retention agent is a water retention agent of a polyether water-soluble polymer.

JP-A-8-333150 JP-A-8-208285 JP 2008-247666 A JP 2008-248554 A

  When bolts are arranged at the place where the self-leveling hydraulic composition is applied, cracks (such as the part around the bolt and the part along the mold) at the initial stage when the self-leveling hydraulic composition is cured. There is a problem that cracks occur. When an initial crack is generated in a foundation concrete structure for buildings, not only does it look bad, but there is also a concern about strength reduction, so repair is necessary.

  Therefore, the present invention provides a construction method for a foundation concrete structure for a building and a building that has both good workability and excellent hardened body characteristics and can reduce the occurrence of initial cracks in the foundation concrete structure for a building. It aims at providing the foundation concrete structure for goods.

  In order to solve the above problems, the present inventors have conducted intensive research and completed the present invention.

  That is, the present invention includes a step of providing a formwork for forming a foundation concrete structure for a building, a step of arranging reinforcing bars in the formwork, and placing concrete in the formwork. A step of forming a base concrete portion by the above, and a step of pouring and curing a hydraulic mortar prepared by kneading a self-leveling hydraulic composition and water on the upper surface of the base concrete portion It is the construction method of the foundation concrete structure for buildings, Comprising: It is a construction method of the foundation concrete structure for buildings in which the self-leveling hydraulic composition contains a predetermined component. The self-leveling hydraulic composition containing predetermined components includes main components composed of Portland cement, fine aggregate, admixture and expansion material, and aluminum sulfate, shrinkage reducing agent, limestone fine powder and thickener. The self-leveling hydraulic composition is a self-leveling hydraulic composition, which is a thickening agent containing two types of cellulose-based water-soluble polymers having different viscosities. By the construction method of the present invention, the construction method of a foundation concrete structure for buildings that has both good workability and excellent hardened body characteristics and can reduce the occurrence of initial cracks in the foundation concrete structure for buildings. And the foundation concrete structure for buildings can be obtained.

The preferable aspect of the construction method of the foundation concrete structure for buildings of this invention is shown below. In the present invention, these embodiments can be appropriately combined.
(1) The main component of the self-leveling hydraulic composition is composed of 100 parts by weight of Portland cement, 100 to 400 parts by weight of fine aggregate, 5 to 150 parts by weight of admixture, and 3 to 30 parts by weight of intumescent material, and thickened. A high-viscosity cellulose-based water-soluble polymer having a viscosity of 20,000 to 50,000 mPa · s, more preferably 20,000 to 40,000 mPa · s, and a 2% aqueous solution. In a self-leveling hydraulic composition comprising a low-viscosity cellulose-based water-soluble polymer having a viscosity at 20 ° C. of 50 to 6,000 mPa · s, more preferably 100 to 2,000 mPa · s. The content of aluminum sulfate is 0.1 to 0.7 parts by mass and the content of fine limestone powder is 1 with respect to 100 parts by mass in total of fine aggregates. 1-35 parts by mass, high-viscosity type cellulose water-soluble polymer content is 0.005-0.2 parts by mass and low-viscosity type cellulose water-soluble polymer content is 0.04-0.2 mass Part. When the content of the high-viscosity type and the low-viscosity type cellulose-based water-soluble polymer is in the above range, the initial crack can be reliably reduced.
(2) The content of the shrinkage reducing agent in the self-leveling hydraulic composition is 0.1 to 3 parts by mass with respect to 100 parts by mass of the total of the main components. By mix | blending a shrinkage reducing agent, generation | occurrence | production of the crack at the time of hardening can be suppressed and durability can be improved.
(3) The self-leveling hydraulic composition further includes fibers, and the fiber content is 0.01 to 5 parts by mass with respect to 100 parts by mass in total of the main components. By containing the fiber, a cured product having excellent bending strength and hardly or hardly causing cracks can be stably obtained.
(4) The self-leveling hydraulic composition further includes a fluidizing agent and an antifoaming agent, and the content of the fluidizing agent is 0.01 to 3 parts by mass with respect to a total of 100 parts by mass of the main component, Content of an antifoamer is 0.01-3 mass parts with respect to a total of 100 mass parts of a main component. When the fluidizing agent and the antifoaming agent are in the above ranges, an effect that is economically commensurate with the content can be achieved.
(5) The self-leveling hydraulic composition further contains another setting modifier other than aluminum sulfate. By including a setting regulator, the pot life of the self-leveling hydraulic composition can be adjusted.
(6) The process of pouring and hardening hydraulic mortar places the concrete for forming the base concrete part, and after pouring the concrete's breathing water (floating water), pours and builds the hydraulic mortar. Including that. Since the hydraulic mortar is poured before the concrete is hardened, the base concrete portion and the hardened mortar body are integrated to prevent peeling.
(7) The step of forming the base concrete part is to form a base concrete part having a primer hardened body layer by applying a primer to the upper surface of the hardened concrete and drying it to form a primer hardened body layer. Including. By disposing the cured primer layer between the ground concrete and the hydraulic mortar layer of the self-leveling hydraulic composition, peeling at the interface between the two layers can be prevented.
(8) The foundation concrete structure for buildings is for a one-story to three-story house. By the construction method of the present invention, it is possible to obtain a foundation concrete structure for a building having a one-story to three-story house.

  Moreover, this invention is the foundation concrete structure for buildings obtained by the construction method of the foundation concrete structure for buildings mentioned above. The foundation concrete structure for building of the present invention has good workability and excellent hardened body characteristics, and can reduce the occurrence of initial cracks in the foundation concrete structure for building. Is the body.

  In the construction method of the foundation concrete structure for buildings of the present invention, by using a predetermined self-leveling hydraulic composition, the construction foundation concrete structure has both good workability and excellent cured body characteristics. The construction method of the foundation concrete structure for buildings which can reduce generation | occurrence | production of the initial crack of this, and the foundation concrete structure for buildings can be obtained.

  Furthermore, in the construction method of the foundation concrete structure for a building of the present invention, the homogeneity of the joining location of the hydraulic mortar constructed from a plurality of locations as shown in FIG. A mortar cured body of hydraulic mortar having the above characteristics can be obtained.

  In addition, the high mortar flow rate and the rapid strength development properties, which are the above characteristics, can achieve high construction efficiency and good construction workability, and have a horizontal level property on the surface of the mortar cured body, which is good. It is possible to efficiently and stably form a building foundation concrete structure having a surface finish and a mortar hardened body having a high compressive strength as a surface layer.

It is a schematic diagram which shows the outline | summary of a construction procedure about the construction method of the foundation concrete structure for buildings of this invention. It is a perspective view which shows typically the confluence | merging location of the hydraulic mortar at the time of pouring construction of hydraulic mortar. It is a plane schematic diagram of an example of the mortar hardening body which has a corner | angular part obtained by pouring and constructing hydraulic mortar. It is a figure which shows the outline of self-leveling property evaluation using SL measuring device. It is a plane schematic diagram which shows the construction method of the top end of the foundation concrete structure for buildings, and shows the state before pouring hydraulic mortar. It is a plane schematic diagram which shows the construction method of the top edge of the foundation concrete structure for buildings, and shows a state where hydraulic mortar was poured into the ceiling edge construction part A. It is a plane schematic diagram which shows the construction method of the top edge of the foundation concrete structure for buildings, and shows a state where the casting of hydraulic mortar into the ceiling edge construction part B is started.

  This invention is the construction method of the foundation concrete structure for buildings using a predetermined self-leveling hydraulic composition. An example of an embodiment will be described with reference to the drawings shown in FIGS. 1a to 1e for a foundation concrete structure for buildings obtained by the construction method of the present invention.

  FIG. 1 a schematically shows a partial cross section of the ground 11 on which a foundation concrete structure for a building is constructed. The ground 11 where the building foundation concrete structure is formed excavates the earth and sand using a backhoe and then lays a crushed stone (consolidated layer) 12 and rolls it using a plate compactor or the like.

  FIG. 1 b shows a state in which a formwork 13 of a foundation concrete structure for a building is provided on the upper surface of the ground 11 and a reinforcing bar 14 is arranged (reinforced) in the formwork. Anchor bolts 15 are firmly fixed to the reinforcing bars 14 in the mold 13 after confirming the installation location.

  In FIG. 1c, foundation concrete 16 is poured and cast into a formwork 13 in which reinforcing bars 14 and anchor bolts 15 are installed, and is compacted by using a vibrator. The state which formed the part 21 is shown. The concrete concrete 16 for foundation to be used is not particularly limited, and the concrete 16 for foundation having a general architectural composition can be appropriately selected and used.

  FIG. 1d shows a state in which the hydraulic mortar 24 of the self-leveling hydraulic composition is poured so as to adjust the height of the top to a predetermined height. The timing for constructing the hydraulic mortar 24 of the self-leveling hydraulic composition is preferably after several hours after placing the concrete in the mold 13 and after the breathing water (floating water) on the concrete surface is drawn, When the breathing water (floating water) on the concrete surface is drawn, the hydraulic mortar 24 can be poured. When the hydraulic mortar 24 is poured before the concrete is hardened after the breathing water is drawn, the base concrete portion and the mortar hardened body are integrated without applying a primer and forming a primer hardened body layer. Peeling can be prevented.

  In addition, when concrete 16 is placed in the mold 13 due to circumstances such as a construction schedule and the hydraulic mortar 24 cannot be poured on that day, the concrete 16 in the mold 13 is cured after the concrete 16 is cured. After removing the latency on the top surface (white paste), oil, dust, etc., applying and drying the primer, the hydraulic mortar 24 can be poured.

  FIG. 1 e shows a state where the mold 13 is removed after the hydraulic mortar 24 of the self-leveling hydraulic composition applied to the surface 22 of the foundation concrete portion is cured. A mortar hardened body 17 adjusted to a predetermined height using a self-leveling hydraulic composition is formed on the base concrete part surface 22.

  In the construction method of the foundation concrete structure for building of the present invention, it is preferable to select and use a self-leveling hydraulic composition that has a high mortar flow rate while having excellent material separation resistance. When the mortar flow rate is large, not only the work efficiency at the time of construction is improved, but also the homogenization of the hydraulic mortar 24 at the junction 25 of the hydraulic mortar 24 constructed from a plurality of places as shown in FIGS. In addition to improving the finish of the surface of the mortar cured body 17, it has the effect of greatly improving the variation in construction thickness and cured body strength.

  Next, an example of a procedure for pouring hydraulic mortar into the ground concrete surface 22 will be described.

  In FIG. 5, the plane schematic diagram before pouring hydraulic mortar into the surface concrete part surface 22 is shown. The planar shape of the foundation concrete structure for buildings can take various shapes depending on the shape of the building. Therefore, in the foundation concrete structure for buildings, a plurality of top end construction portions (in the case of FIGS. 5 to 7, the top end construction portion A32 and the top end construction portion B34) may include many parts to be connected. is there. A weir 40 is provided in a portion to which the top end construction portion is connected, and hydraulic mortar can be poured into different top end construction portions sequentially. In the schematic plan view shown in FIG. 6, the hydraulic mortar 24 is poured into the top end construction portion A <b> 32 using a bucket 50 or the like.

  Next, as shown in FIG. 7, the weir 40 is removed, and the hydraulic mortar 24 is poured into the top end construction part B34 using a bucket 50 or the like. The hydraulic mortar 62 of the top end construction portion A32 and the hydraulic mortar 64 of the top end construction portion B34 merge at the place where the weir 40 is present. At this time, it is necessary for the hydraulic mortars 62 and 64 to be familiar. By using the hydraulic mortars 62 and 64 of the predetermined self-leveling hydraulic composition, it is possible to improve the familiarity when the hydraulic mortars 62 and 64 merge at the place where the weir 40 is present. By moving the bucket 50 containing the hydraulic mortar 24 and moving the pouring position of the hydraulic mortar 24 in the direction away from the place where the weir 40 was, as shown by the arrows in FIG. The hydraulic mortar 64 can be poured into the whole end construction part B34.

  In addition, when the concrete cast for forming the base concrete portion 21 is hardened, a primer is applied to the upper surface of the hardened concrete (the base concrete portion surface 22) and dried before pouring the hydraulic mortar 24. The cured primer layer can also be formed. By disposing the cured primer layer between the base concrete portion 21 and the hydraulic mortar 24 layer of the self-leveling hydraulic composition, peeling at the interface between the two layers can be prevented. Therefore, it is effective to form a hardened primer layer when concrete 16 is placed in the mold 23 due to circumstances such as a construction schedule and hydraulic mortar cannot be poured on that day.

  By the construction method as described above, a basic concrete structure for building having a horizontal level property on the surface of the mortar cured body, a good surface finish, and a mortar cured body with high compressive strength on the surface layer is obtained. be able to.

  Next, the self-leveling hydraulic composition used for the construction method of the foundation concrete structure for buildings of the present invention will be described. Since the predetermined self-leveling hydraulic composition described below is used in the construction method of the present invention, the occurrence of initial cracks in the foundation concrete structure for buildings can be reduced.

  The self-leveling hydraulic composition used in the construction method of the present invention contains main components composed of Portland cement, fine aggregate, admixture and expansion material, and further contains aluminum sulfate, shrinkage reducing agent, limestone fine powder and thickening agent. Contains agents. The self-leveling hydraulic composition used in the construction method of the present invention is characterized in that the thickener is a thickener containing two types of water-soluble cellulose-based polymers having different viscosities. If the hydraulic mortar of the self-leveling hydraulic composition used in the construction method of the present invention is used, initial cracks of the mortar cured body (cracks generated within one day after casting of the hydraulic mortar), particularly around the bolt and the mold Initial cracks in the portion along the frame can be reduced. Hereinafter, the self-leveling hydraulic composition used in the construction method of the present invention will be described.

  The main components of the self-leveling hydraulic composition used in the construction method of the present invention are Portland cement, fine aggregate, admixture and expansion material.

  Portland cement, which is one of the main components and is a hydraulic component, includes ordinary Portland cement, early-strength Portland cement, ultra-high-strength Portland cement, medium-heated Portland cement, sulfate-resistant Portland cement, low-heat Portland cement that conforms to JIS. And white Portland cement and combinations thereof. Further, instead of Portland cement, mixed cement such as blast furnace cement, fly ash cement and silica cement can be used.

  The self-leveling hydraulic composition used in the construction method of the present invention contains fine aggregate as one of the main components. Fine aggregates include silica sand, river sand, sea sand, mountain sand and crushed sand, alumina clinker, silica powder, clay mineral, waste FCC catalyst and inorganic materials such as limestone, urethane crushed, EVA foam and foaming resin It can select suitably from resin pulverized materials etc., such as. In particular, as the fine aggregate, one or a mixture of two or more selected from sands such as quartz sand, river sand, sea sand, mountain sand, crushed sand, waste FCC catalyst, quartz powder and alumina clinker is preferably used. it can.

  The particle size of the fine aggregate is preferably 2 mm or less, more preferably 1 mm or less, more preferably 0.7 mm or less, particularly preferably 0.6 mm or less. Those having a particle size of can be suitably used. The particle size of the fine aggregate is measured using several sieves having different nominal dimensions defined in JIS / Z-8801.

  The content of fine aggregate in the self-leveling hydraulic composition used in the construction method of the present invention is preferably 100 to 400 parts by weight, more preferably 120 to 350 parts by weight, with respect to 100 parts by weight of Portland cement. More preferably, it is 140-320 mass parts, Most preferably, it is the range of 150-300 mass parts. When the content of the fine aggregate in the self-leveling hydraulic composition used in the construction method of the present invention is within the above range, a mortar slurry excellent in fluidity and material separation resistance can be obtained, It is preferable because a cured product having an excellent surface state and high strength can be obtained.

  Examples of the admixture that is one of the main components include slag powder such as fly ash and blast furnace slag fine powder, and these can be used alone or in combination of two or more. In particular, bending and compressive strength can be increased by including blast furnace slag fine powder. Therefore, the admixture preferably contains blast furnace slag fine powder.

An admixture having a fineness (Brain specific surface area) of 3,000 to 5,000 cm ² / g can be preferably used. If the Blaine specific surface area of the admixture is less than 3,000 cm ² / g, the effect of increasing the material separation resistance of the mortar slurry will be poor, and the hydration reactivity of the admixture will be poor. On the other hand, when the Blaine specific surface area of the admixture exceeds 5,000 cm ² / g, the tendency of the viscosity of the mortar slurry to increase becomes remarkable, and the fluidity may be inhibited.

  The content of the admixture in the self-leveling hydraulic composition used in the construction method of the present invention is preferably 5 to 150 parts by mass, more preferably 10 to 120 parts by mass with respect to 100 parts by mass of Portland cement. The range is preferably 15 to 90 parts by mass, particularly preferably 20 to 80 parts by mass. When the admixture has a content in the above range, a mortar cured product having excellent surface properties and compressive strength can be obtained.

  Examples of the expansion material that is one of the main components include expansion materials mainly composed of ettringite-based calcium sulfoaluminate, expansion materials mainly composed of calcium oxide, aluminum oxide and sulfur trioxide, and lime-based materials such as quick lime. Examples of the expansion material and gypsum-based expansion material such as gypsum, and the like can be used as one or a mixture of two or more of these expansion materials. As the expansion material, it is preferable to use a gypsum-based expansion material, particularly an expansion material containing gypsum or gypsum.

  The content of the expansion material in the self-leveling hydraulic composition used in the construction method of the present invention is preferably 3 to 30 parts by mass, more preferably 5 to 25 parts by mass, with respect to 100 parts by mass of Portland cement. Preferably it is 8-20 mass parts, Most preferably, it can be the range of 10-18 mass parts. It is preferable for the inflatable material to be in the above-mentioned content range because appropriate expansibility can be expressed and the change in the length of the mortar cured body can be suppressed, and at the same time, generation of cracks due to excessive expansion action can be prevented.

  Gypsum that is particularly preferably used as the expansion material is gypsum such as anhydrous and semi-water. Regardless of the type of gypsum such as anhydrous and semi-water, the expansion material can be used as one kind or a mixture of two or more kinds thereof.

  Examples of limes preferably used as the expansion material include quick lime, slaked lime, calcined dolomite, and the like, and can be used as one kind or a mixture of two or more kinds thereof.

  The self-leveling hydraulic composition used in the construction method of the present invention is composed of aluminum sulfate, shrinkage reducing agent, fine limestone powder and cellulose-based water-soluble polymer, together with main components comprising Portland cement, fine aggregate, admixture and expansion material. Contains a thickener.

  Aluminum sulfate contained in the self-leveling hydraulic composition used in the construction method of the present invention has a function as a setting accelerator. The content of aluminum sulfate is preferably 0.1 to 0.7 parts by mass, more preferably 0.15 to 0.6 parts by mass with respect to the total amount (100 parts by mass) of Portland cement and fine aggregate. More preferably, the range is 0.2 to 0.5 parts by mass, and particularly preferably 0.25 to 0.45 parts by mass. By making the content of aluminum sulfate in the above range, it is possible to obtain a good strength enhancement effect, and it is possible to obtain a good effect of reducing shrinkage of the cured product due to this early strength development. When there is too little content of aluminum sulfate, the expression of the shrinkage reduction effect will be insufficient. In addition, the shrinkage reduction effect increases as the content of aluminum sulfate increases, but if added excessively, the setting effect of cement becomes prominent and fluidity of the mortar slurry decreases, and fine cracks appear in the hardened body. May occur. Therefore, the content of aluminum sulfate is preferably in the above range.

  The self-leveling hydraulic composition used in the construction method of the present invention contains a shrinkage reducing agent. For the self-leveling hydraulic composition used in the construction method of the present invention, by adding a shrinkage reducing agent within a range that does not impair the characteristics, the occurrence of cracks during curing is suppressed and the compressive strength is improved. Can do.

  A known shrinkage reducing agent can be used as the shrinkage reducing agent. As the shrinkage reducing agent, in particular, those having an alkylene oxide polymer represented by the following chemical formula (1) in the skeleton of the chemical structure can be suitably used.

（但し式（１）中、Ｒ^１及びＲ^２は、互いに独立してアルキル基、フェニル基、シクロアルキル基、水素基などであり、Ａは炭素数２〜３の１種のアルキレン基（エチレン基、プロピレン基）又はランダム若しくはブロック重合させた２種のアルキレン基であり、ｎは２〜２０の整数である。）

(In the formula (1), R ¹ and R ² are each independently an alkyl group, a phenyl group, a cycloalkyl group, a hydrogen group, etc., and A is an alkylene group having 2 to 3 carbon atoms (ethylene Group, propylene group) or two kinds of random or block polymerized alkylene groups, and n is an integer of 2 to 20.)

  As the shrinkage reducing agent, for example, polyalkylene glycols such as polypropylene glycol and poly (propylene / ethylene) glycol and generally known ones such as alkoxy poly (propylene / ethylene) glycol having 1 to 6 carbon atoms are appropriately selected and used. be able to.

  The content of the shrinkage reducing agent relative to the self-leveling hydraulic composition can be appropriately selected according to the content of the main component and subcomponent used. For example, the content of the shrinkage reducing agent is preferably 0.1 to 3 parts by mass, more preferably 0.15 to 2 parts by mass, and more preferably 0.18 to 1 part by mass with respect to 100 parts by mass of the main component. More preferably, the content is 0.2 to 0.8 parts by mass.

  The self-leveling hydraulic composition used in the construction method of the present invention contains limestone fine powder. The self-leveling hydraulic composition used in the construction method of the present invention contains fine limestone powder, thereby providing excellent fluidity to hydraulic mortar, in particular, excellent flow rate and improving material separation resistance. Further, a mortar cured body having a high compressive strength can be obtained.

  As content of the limestone fine powder with respect to a self-leveling hydraulic composition, Preferably it is 11-35 mass parts with respect to the total amount (100 mass parts) of Portland cement and a fine aggregate, More preferably, it is 12-33 masses. Parts, more preferably 13 to 31 parts by mass, particularly preferably 14 to 30 parts by mass. By using the limestone fine powder in the above content range, a hydraulic mortar slurry having good fluidity and excellent material separation resistance can be obtained. Further, by using the hydraulic mortar slurry, a mortar cured body having a good surface state and excellent compressive strength can be obtained.

  If the content of fine limestone powder with respect to the self-leveling hydraulic composition is too small, it becomes difficult to obtain good material separation resistance, and the effect of improving the strength of the cured product becomes insufficient. Conversely, if the addition of fine limestone powder to the self-leveling hydraulic composition is excessive, the viscosity of the hydraulic mortar / slurry tends to increase and the fluidity is lowered. For this reason, it is preferable that content of limestone fine powder is the said range.

As the fineness (brane specific surface area) of the fine limestone powder, a powder having a fine particle size of 3,000 to 5,000 cm ² / g can be suitably used. When the specific surface area of the brane is less than 3,000 cm ² / g, the effect of increasing the material separation resistance of the mortar slurry becomes poor. On the other hand, if the Blaine specific surface area exceeds 5,000 cm ² / g, the tendency of the viscosity of the mortar slurry to increase becomes remarkable and flowability may be impaired.

  In the self-leveling hydraulic composition used in the construction method of the present invention, the self-leveling property of the hydraulic mortar and the material separation resistance are balanced at a high level, and further, the hydraulic property in the initial stage in which the hydraulic mortar is cured. In order to suppress the drying of the mortar surface and avoid the occurrence of cracks, a thickener containing two types of water-soluble cellulose-based polymers having different viscosities is used.

  The thickener contained in the self-leveling hydraulic composition used in the construction method of the present invention has a 2% aqueous solution viscosity at 20 ° C. of 20,000 to 50,000 mPa · s, preferably 20,000 to 40,000 mPa A high-viscosity cellulose-based water-soluble polymer that is s, and a low-viscosity cellulose-based polymer whose 2% aqueous solution has a viscosity at 20 ° C. of 50 to 6,000 mPa · s, more preferably 100 to 2,000 mPa · s It consists of a water-soluble polymer. In this specification, the viscosity means a 2% aqueous solution of a cellulose-based water-soluble polymer at a rotational speed of 12 rpm and 20 ° C. using a B-type viscometer (digital viscometer DVL-B type manufactured by Toki Sangyo Co., Ltd.). The measured value.

  Specific examples of thickeners include water-soluble polymers such as cellulose derivatives such as methylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, hydroxyethylmethylcellulose, glyoxal-added hydroxypropylmethylcellulose and carboxymethylcellulose. 1 type, or 2 or more types of mixtures selected from these can be used.

  The viscosity of the cellulose-based water-soluble polymer contained in the thickener can be adjusted by selecting one having a predetermined viscosity from commercially available thickeners. As a thickener containing a cellulose-based water-soluble polymer, various types having different viscosities are commercially available.

  The content of the high-viscosity cellulosic water-soluble polymer contained in the thickener is 0.005 to 0.2 parts by mass, preferably with respect to the total amount (100 parts by mass) of Portland cement and fine aggregate. Is preferably 0.008 to 0.1 parts by mass, more preferably 0.01 to 0.07 parts by mass. The content of the low-viscosity cellulose-based water-soluble polymer contained in the thickener is 0.04 to 0.2 parts by mass with respect to the total amount (100 parts by mass) of Portland cement and fine aggregate. , Preferably 0.05 to 0.17 parts by mass, more preferably 0.06 to 0.14 parts by mass. When the content of the high-viscosity type and low-viscosity type cellulosic water-soluble polymers is in the above range, the effect of the present invention can be ensured. In addition, when the content of the thickener is reduced, the effect of the thickener is reduced, and when the content of the thickener is increased, the fluidity may be lowered. The ratio of the high-viscosity cellulose-based water-soluble polymer in the total thickener is not particularly limited, but is 40% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more, and particularly Preferably it is 70 mass% or more.

  By adding a predetermined thickener to the self-leveling hydraulic composition used in the construction method of the present invention, the effect of increasing the material separation resistance of a hydraulic mortar having particularly excellent fluidity is remarkable. Material separation can be avoided and suppressed without substantially impairing the fluidity of the material. Therefore, it is possible to prevent the occurrence of cracks by suppressing the drying of the surface of the hydraulic mortar in the initial stage of hardening of the hydraulic mortar, and in particular, the initial crack around the bolt of the hydraulic mortar, specifically the crack The width and length, especially the crack length, can be reduced. Specifically, if the self-leveling hydraulic composition used in the construction method of the present invention having a predetermined thickener is used, the crack width is 0.25 mm or less in the initial crack around the bolt of the hydraulic mortar. , Preferably less than 0.15 mm, and the crack length can be less than 10 mm. If the thickener is a high-viscosity cellulose-based water-soluble polymer alone, initial cracks around the bolt cannot be sufficiently suppressed, and the low-viscosity-type cellulose-based water-soluble polymer alone can cause problems such as material separation and whitening. This is not preferable.

  The self-leveling hydraulic composition contains one or more of a setting adjuster (setting retarder and setting accelerator), a fluidizing agent (water reducing agent), an antifoaming agent, a resin powder, and a fiber as necessary. be able to.

  The self-leveling hydraulic composition used in the construction method of the present invention can contain a setting modifier other than aluminum sulfate, if necessary. As the setting regulator, a setting retarding agent that is a component that delays the setting and a setting accelerator that is a component that accelerates the setting can be used alone or in combination.

  In the self-leveling hydraulic composition used in the construction method of the present invention, the fluidity, pot life, curing properties, etc. are selected by appropriately selecting the components, content and mixing ratio of the setting retarder and / or setting accelerator. Can be adjusted. Specifically, by appropriately performing the above selection, at 20 ° C., the pot life of the self-leveling hydraulic composition can be adjusted to an arbitrary time from about several minutes to about 1 hour.

  As the setting accelerator, a known setting accelerator can be used. Examples of setting accelerators include lithium salts, specifically, lithium carbonate, lithium chloride, lithium sulfate, lithium nitrate, lithium hydroxide and other inorganic lithium salts, lithium acetate, lithium tartrate, lithium malate, lithium citrate, etc. One or more selected from organic lithium salts and metal sulfates other than aluminum sulfate can be preferably used. In particular, by using aluminum sulfate and potassium sulfate in combination, a stable setting promoting effect can be obtained. Moreover, it is preferable to use aluminum sulfate and potassium sulfate as a setting accelerator from the point of availability and low cost.

  When using potassium sulfate as a setting accelerator, the amount used (content) is preferably 0.1 to 0.9 parts by mass with respect to the total amount (100 parts by mass) of Portland cement and fine aggregate. More preferably, it is 0.15-0.8 mass part, More preferably, it is 0.2-0.75 mass part, Especially preferably, it is preferable that it is the range of 0.25-0.7 mass part. When the content of potassium sulfate is in the above range, it is possible to obtain a good strength enhancement effect for hydraulic mortar.

  As the particle size of the setting accelerator, it is preferable to use a particle which does not interfere with the characteristics of the self-leveling hydraulic composition used in the construction method of the present invention. Specifically, the particle size of the setting accelerator is preferably 50 μm or less.

  As the setting retarder, a known setting retarder can be used. Examples of setting retarders include sodium salts, specifically selected from inorganic sodium salts such as sodium sulfate and sodium bicarbonate, and organic sodium salts such as sodium tartrate, sodium malate, sodium citrate and sodium gluconate. The above can be used.

  The content of the setting retarder in the self-leveling hydraulic composition used in the construction method of the present invention is preferably 0.01 to 1 with respect to the total amount (100 parts by mass) of Portland cement and fine aggregate. It is 0.0 mass part, More preferably, it is 0.02-0.85 mass part, More preferably, it is 0.025-0.8 mass part, Most preferably, it is the range of 0.03-0.75 mass part. When the content of the setting retarder is in the above range, preferable workability can be obtained.

  As a fluidizing agent, naphthalene sulfonate formalin condensate, olefin unsaturated carboxylic acid copolymer salt, lignin sulfonate, casein, casein calcium, polyether-based and polycarboxylic acid-based fluidizing agents are commercially available. A thing can be used as those 1 type, or 2 or more types of mixtures irrespective of the kind. The fluidizing agent can also have a water reducing effect.

  A fluidizing agent (water reducing agent) can be added as long as the characteristics of the present invention are not impaired. The content of the fluidizing agent (water reducing agent) in the self-leveling hydraulic composition used in the construction method of the present invention is preferably 0.01 to 3 parts by mass, more preferably 0 to 100 parts by mass of the main component. 0.02 to 2 parts by mass, more preferably 0.04 to 1 part by mass, and particularly preferably 0.06 to 0.5 part by mass. If the content of the fluidizing agent (water reducing agent) is too small, sufficient effects are not exhibited. Moreover, even if the content of the fluidizing agent (water reducing agent) is too much, an effect commensurate with the content cannot be expected and not only is uneconomical, but the amount of kneading water to obtain the required fluidity increases, At the same time, the viscosity increases and the filling property may deteriorate.

  In the self-leveling hydraulic composition used in the construction method of the present invention, it is preferable to use an antifoaming agent in combination with the above thickener. When the self-leveling hydraulic composition used in the construction method of the present invention contains an antifoaming agent, it is preferable for suppressing the separation of fine aggregates contained in the main component, suppressing the generation of bubbles and improving the surface of the mortar hardened body. And the properties as a self-leveling material can be improved.

  Anti-foaming agents contained in the self-leveling hydraulic composition used in the construction method of the present invention include synthetic materials such as silicon-based, alcohol-based and polyether-based materials, mineral oils derived from petroleum refining, and natural materials derived from plants For example, one or more known ones can be selected and used.

  An antifoamer can be added in the range which does not impair the characteristic of the self-leveling hydraulic composition used for the construction method of this invention. The content of the antifoaming agent in the self-leveling hydraulic composition used in the construction method of the present invention is preferably 0.01 to 3 parts by mass, more preferably 0.02 to 100 parts by mass of the main component. It is 1.5 mass parts, More preferably, it is 0.03-1 mass part, Most preferably, it is 0.04-0.5 mass part. When the content of the antifoaming agent is within the above range, a good antifoaming effect is recognized, and the fluidity of the hydraulic mortar slurry and the finish of the surface of the mortar cured body can be preferably adjusted.

  The self-leveling hydraulic composition used in the construction method of the present invention can contain fibers. Fibers include polyethylene, ethylene / vinyl acetate copolymer (EVA), polyolefins such as polypropylene, organic fibers composed of resin components such as polyester, polyamide, polyvinyl alcohol, and polyvinyl chloride, and metal systems such as stainless steel fibers and aluminum fibers. A fiber etc. can be used and it can use as a 1 type, or 2 or more types of mixture of these.

  The fiber contained in the self-leveling hydraulic composition used in the construction method of the present invention is preferably an organic fiber because of its low cost and easy handling. The fiber length of the organic fiber is preferably about 0.5 to 15 mm.

  The fiber content of the self-leveling hydraulic composition used in the construction method of the present invention is preferably 0.01 to 5 parts by mass, more preferably 0.02 to 2 parts by mass, with respect to 100 parts by mass of the main component. More preferably, it is 0.03-1 mass part, Most preferably, it is 0.05-0.2 mass part. By containing the fiber of the above-mentioned content with respect to the self-leveling hydraulic composition of the present invention, it is possible to stably obtain a cured product that is excellent in bending strength and hardly or does not generate cracks.

  The self-leveling hydraulic composition used in the construction method of the present invention can contain a resin powder. As the resin powder, polymer particles (such as re-emulsified resin particles) obtained by removing a liquid component from a known polymer emulsion for construction or building materials can be used. For example, polymer resin particles obtained by removing a liquid component of a polymer emulsion obtained by emulsion polymerization of an α, β-ethylenically unsaturated monomer can be used as the resin powder.

  The content of the resin powder with respect to the self-leveling hydraulic composition used for the construction method of the present invention is preferably 0.001 to 10 parts by mass, more preferably 0.005 to 8 parts by mass with respect to 100 parts by mass of the main component. More preferably, the content can be 0.01 to 5 parts by mass, and particularly preferably 0.05 to 2 parts by mass.

Examples of the α, β-ethylenically unsaturated monomer that can be used as the resin powder include known α, β-ethylenically unsaturated monomers. Examples of the α, β-ethylenically unsaturated monomer include acrylic acid and derivatives thereof such as esters, methacrylic acid and derivatives such as esters, α-olefins such as ethylene and propylene, aromatics such as vinyl acetate and styrene. Tertiary fatty acid vinyl esters having 9 to 11 carbon atoms (R—COO—CH═CH ₂ , R is a tertiary carbon having 9 to 11 carbon atoms, such as vinyls, vinyl chloride, and versatic acid vinyl esters. ) And the like.

  A hydraulic mortar can be produced by blending and kneading the self-leveling hydraulic composition used in the construction method of the present invention and water. Moreover, since the mortar flow (flow value) of hydraulic mortar can be adjusted by selecting the compounding quantity of water suitably, the hydraulic mortar suitable for a use can be manufactured.

  In the self-leveling hydraulic composition used in the construction method of the present invention, the amount of water is preferably 10 to 70 parts by mass, more preferably 20 to 50 parts by mass, and still more preferably 100 parts by mass of the main component. It is preferable to set it as 23-40 mass parts.

  The self-leveling hydraulic composition used in the construction method of the present invention has a flow value of a hydraulic mortar prepared by mixing with water (measured according to the test method described in JASS 15M-103), preferably 180. It is preferable to be adjusted to ˜270 mm, more preferably 200 to 260 mm, and even more preferably 210 to 250 mm. Due to the flow value being in the above range, hydraulic mortar has ease of construction and excellent fluidity, in particular, stably exhibits excellent mortar flow rate, has high horizontal level accuracy, The conformability of the confluence of the slurry is excellent.

The self-leveling hydraulic composition used in the construction method of the present invention is a cured product of hydraulic mortar prepared by mixing with water, and the compressive strength at 28 days of age can obtain a value of 27 N / mm ² or more. As a result, it has sufficient strength as a foundation concrete structure for buildings.

  The self-leveling hydraulic composition used in the construction method of the present invention has an SL flow rate (L0) (second / 200 mm) using a hydraulic mortar SL meter (FIG. 4) prepared by mixing with water. It is preferably adjusted in the range of 2 to 9 seconds, more preferably in the range of 2.5 to 8 seconds. Due to the SL flow rate (L0) being in the above range, the hydraulic mortar stably demonstrates the ease of construction and the excellent mortar flow rate, and the horizontal level accuracy is high. Excellent adaptability.

  Moreover, the hydraulic mortar of the self-leveling hydraulic composition used in the construction method of the present invention does not need to be shielded from sunlight and wind using a curing sheet after construction, and the construction is easy. .

  The self-leveling hydraulic composition used in the construction method of the present invention can be used as a mortar for pouring, troweling and spraying in applications such as plastering materials, roofing materials, flooring materials and waterproofing materials. . Furthermore, the self-leveling hydraulic composition used in the construction method of the present invention can be used in the civil engineering, construction, and construction fields as a cross-sectional restoration material, a grout material, etc. used for repairing and reinforcing civil engineering structures.

  In particular, the self-leveling hydraulic composition used in the construction method of the present invention is a surface finish of concrete and a top finish (level adjustment) of the top end of a foundation concrete structure for buildings (foundation concrete structure for buildings), etc. Excellent performance. The example of the construction method in the case of using the hydraulic mortar using the self-leveling hydraulic composition used for the construction method of this invention for FIG. 2 and FIGS. If the self-leveling hydraulic composition used in the construction method of the present invention is used, it is possible to improve the construction efficiency and the horizontal level accuracy, and by forming a high strength mortar hardened body, a highly reliable building foundation. A concrete structure can be provided.

  Hereinafter, the present invention will be described in more detail based on examples. However, the present invention is not limited by the following examples.

(Flow evaluation of hydraulic mortar)
The flow value is measured according to the test method described in JASS 15M-103. A pipe made of vinyl chloride (internal volume: 100 ml) having an inner diameter of 50 mm and a height of 51 mm is placed on a glass sheet having a thickness of 5 mm, filled with kneaded hydraulic mortar, and then the pipe is pulled up. After the spread has stopped, the diameters in two perpendicular directions are measured, and the average value is taken as the flow value.

(SL evaluation of hydraulic mortar)
Using a SL (self-leveling) measuring instrument shown in FIG. 4, a weir plate is provided on a rail 30 mm wide × 30 mm high × 750 mm long, 150 mm long from the tip, and hydraulic mortar immediately after kneading is used. A predetermined amount is filled and molded. Immediately after molding, the weir plate is pulled up, and after stopping the flow of hydraulic mortar, measure the distance from the gage (installed portion of the weir plate) to the shortest portion of the flow of hydraulic mortar, and the value (SL value) Let L0. Further, the time required for hydraulic mortar to flow 200 mm from the weir plate is measured, and the measurement time is defined as SL flow rate (L0) (second / 200 mm).

  Similarly, after 30 minutes after molding, the weir plate is pulled up, and after stopping the flow of hydraulic mortar, the distance from the gauge point (the installation portion of the weir plate) to the shortest portion of the flow of hydraulic mortar is measured, and the value ( SL value) is set to L30. Moreover, the time required for hydraulic mortar to flow 200 mm from the weir plate is measured, and the measurement time is defined as SL flow rate (L30) (second / 200 mm).

(Evaluation of material separation resistance of hydraulic mortar)
Using a SL measuring device shown in FIG. 4, a rail is provided on a rail having a width of 30 mm × a height of 30 mm × a length of 750 mm, and a length of 150 mm from the tip, and a predetermined amount of slurry immediately after kneading is filled and molded. Immediately after molding, the weir plate is pulled up, and after the flow of the hydraulic mortar is stopped, the material separation state of the fine aggregate and the paste is evaluated by palpation at the head of the flow of the hydraulic mortar.

(Evaluation of surface condition after curing)
As shown in FIG. 2, the foundation concrete is placed, and after watering, a hydraulic mortar is poured onto the ground concrete portion and exposed to the outside air, and the surface of the obtained cured product is visually observed and evaluated. Evaluation was made on five items: surface whitening, initial cracks (cracks generated within one day after casting of hydraulic mortar), irregularities, bubble traces and floats.
・ Evaluation of whitening: (O: No whitening, Δ: Some whitening was observed, ×: Whitening was recognized.)
・ Evaluation of initial cracks: The presence or absence of cracks was evaluated on the boundary between the daily allowance and shade, around the bolts, and other parts. When there was a crack, the width and length were measured.
・ Evaluation of surface irregularities: (O: performed in three stages: irregularities were 0, Δ: about 1 to 5 irregularities, and x: many irregularities were observed.)
・ Evaluation of bubble marks: (○: No bubble marks, ×: Bubble marks)
-Evaluation of float: The ratio of the float 7 days after construction was measured.

(1) Materials used: The following materials were used. The viscosity of thickeners A and B was determined by using a B-type viscometer (digital viscometer DVL-B type manufactured by Toki Sangyo Co., Ltd.) with a 2% aqueous solution of a cellulose-based water-soluble polymer. Measured at ° C. The B-type viscometer is a viscometer that measures the viscous resistance torque of the liquid acting on the rotor when the cylindrical rotor is rotated in the liquid. In the B type viscometer, it is necessary to select the type of rotor according to the viscosity to be measured. To measure the viscosity of thickener A, rotor No. for DVL-B type manufactured by Toki Sangyo Co., Ltd. 4 for measuring the viscosity of thickener B. 1 was used.
Portland cement: Hayashi Cement, manufactured by Ube Mitsubishi Cement, Blaine specific surface area of 4,500 cm ² / g.
-Fine aggregate A: quartz sand, Takano No. 6 (Takano Shoji).
-Fine aggregate B: Silica sand, N70 (Ashiya).
Admixture: Blast furnace slag, manufactured by Kawasaki Steel Corporation, liberment, Blaine specific surface area 4,400 cm ² / g.
Expansion material: gypsum, manufactured by Asahi Glass Co., Ltd., hydrofluoric acid anhydrous gypsum, Blaine specific surface area 3,300 cm ² / g
-Setting accelerator A: Potassium sulfate, manufactured by Ueno Pharmaceutical Co., Ltd.
-Setting accelerator B: Aluminum sulfate, manufactured by Daimei Chemical Co., Ltd., S150.
-Limestone fine powder: Calcium carbonate fine powder, manufactured by Yuesu Mining Co., Ltd., TM-1, No. Blaine surface area 4,830 cm ² / g.
Thickener A: MX30000 (high viscosity type cellulose water-soluble polymer), Matsumoto Yushi Seiyaku Co., Ltd., viscosity 30000 mPa · s.
Thickener B: MP400 (low viscosity type cellulose water-soluble polymer), manufactured by Matsumoto Yushi Seiyaku Co., Ltd., viscosity 400 mPa · s.
・ Shrinkage reducing agent: Hibidan, manufactured by Takemoto Yushi Co., Ltd.
・ Fluidizing agent: Polycarboxylic acid-based water reducing agent (commercial product, for building materials).
-Antifoaming agent B: ADEKA company make, Adecanate B115F.
-Setting retarder: Sodium gluconate, manufactured by Tomita Pharmaceutical.
Resin powder: Nippon Synthetic Chemical Co., Ltd., Movinyl Powder DM200.
-Fiber: Polyester fiber, manufactured by Kyoto Textile Materials Co., Ltd., fiber length: 2 mm.

(Comparative Examples 1-3, Examples 1-3)
The components listed in Table 1 were mixed to produce a self-leveling hydraulic composition. Table 2 shows the content ratio of components such as a setting accelerator among the components shown in Table 1 when the total of Portland cement and aggregate is 100 parts by mass. Table 3 shows the content of components such as a shrinkage reducing agent among the components shown in Table 1 when the total of the main components (Portland cement, aggregate, admixture and expansion material) is 100 parts by mass. Indicates the percentage. Next, while stirring the inside of a polyethylene beaker (2.0 liters) containing water (0.26 kg) with a mixer, the self-leveling hydraulic composition is 0.26 so that the water / self-leveling hydraulic composition ratio is 0.26. A product (1 kg) was added and kneaded for 3 minutes to obtain a hydraulic mortar. The flow value, SL value and flow rate of the obtained hydraulic mortar were measured, and the tendency of material separation was evaluated. The results are shown in Table 4.

  About the mortar hardened | cured body of hydraulic mortar, evaluation of the surface state after 1 day of material age and evaluation of the float after 7 days of material age were performed. The results are shown in Table 5.

In the description of Table 5, the width and length of each part of the initial crack mean the following value range. In addition, as shown in FIG. 3, a “corner part” means a part that becomes a corner when the mortar cured body is shown in a schematic plan view.
Crack width; Thick: greater than 0.35 mm, Medium: 0.35-0.25 mm, Fine: 0.25-0.15 mm, Ultrafine: less than 0.15 mm, None: No crack.
Length of crack; length: more than 30 mm, medium: 30 to 10 mm, short: less than 10 mm, no: no crack.

  In Examples 1 to 3, hydraulic mortars were produced using a self-leveling hydraulic composition using a thickener containing a high-viscosity and low-viscosity type cellulosic water-soluble polymer. In the hydraulic mortars of Examples 1 to 3, it was possible to reduce initial cracks, particularly initial cracks around the bolts. Specifically, in Examples 1 and 3, the width of the initial crack around the bolt is less than 0.15 mm, the width of the initial crack in Example 2 is 0.25 to 0.15 mm, and the length is less than 10 mm. Met. Moreover, initial cracks did not occur at the daily allowance / shade boundary and other parts. That is, the hydraulic mortars obtained using the self-leveling hydraulic compositions of Examples 1 to 3 have excellent fluidity (flow value and SL flow rate) and material separation resistance while maintaining initial cracking. The occurrence of was solved.

  On the other hand, in Comparative Examples 1-3, Comparative Examples 1-3 in which hydraulic mortars were manufactured using a self-leveling hydraulic composition using a thickener containing one type of cellulose-based water-soluble polymer. In this hydraulic mortar, initial cracks in the part around the bolt and other parts (parts along the formwork) occurred with such a size as to cause problems in construction. Specifically, in Comparative Example 1, a crack having a width of 0.25 to 0.15 mm and a length of more than 30 mm occurred around the bolt. In Comparative Example 2, cracks having a width of 0.25 to 0.15 mm and a length of 30 to 10 mm occurred at the corners. In Comparative Example 3, a crack having a width of 0.25 to 0.15 mm and a length of more than 30 mm occurred around the bolt.

  From the above, excellent slurry fluidity and material separation by using a hydraulic composition containing a thickener containing a high-viscosity and low-viscosity type cellulose water-soluble polymer as in Examples 1 to 3 It was revealed that a mortar cured body having a good surface state can be obtained while maintaining the resistance. In particular, when the flow rate of the slurry is large, it not only improves the efficiency at the time of construction, but also has a positive effect on the homogenization of the hydraulic mortar slurry at the location where the hydraulic mortar slurry constructed from multiple locations merges, It was revealed that the finished surface of the mortar cured body was improved. Therefore, by using the self-leveling hydraulic composition used in the present invention as in Examples 1 to 3 for level adjustment of the top end of a foundation concrete structure for a house (foundation concrete structure for a building). It is clear that it is possible to obtain excellent construction workability, high smoothness, and high-strength foundation concrete structures for buildings (foundation concrete structures for buildings) in a short construction period. It became.

  The self-leveling hydraulic composition used in the present invention is a self-comprising main component comprising Portland cement, fine aggregate, admixture and expansion material, and aluminum sulfate, shrinkage reducing agent, limestone fine powder and thickener. A leveling hydraulic composition, wherein the thickener is a thickener containing two types of water-soluble cellulose-based polymers having different viscosities, so that the resulting hydraulic mortar has excellent mortar flow rate and material separation resistance. The cured mortar has a good surface state while maintaining a high compressive strength. In particular, it not only improves the efficiency at the time of construction, but also has a positive effect on the homogenization of hydraulic mortar at the location where mortars constructed from multiple locations join as shown in Fig. 2, and the surface finish of the cured mortar is In addition to improving, there is an effect of greatly improving the variation in strength of the cured product.

  In the construction method of the foundation concrete structure for building of the present invention, by selecting and using the above self-leveling hydraulic composition, excellent construction workability can be obtained, smoothness is high, and high strength. It is possible to efficiently form a basic concrete structure for a building such as a house in a short construction period.

11: Ground 12: Crushed stone (consolidated layer)
13: Formwork 14: Reinforcing bar 15: Anchor bolt 16: Concrete for foundation 17: Hardened mortar of self-leveling hydraulic composition 18: Corner part 21: Base concrete part 22: Base concrete part surface 23: Formwork 24: Hydraulic mortar of self-leveling hydraulic composition 25: Merge point of hydraulic mortar 32: Top end construction part A
34: Top end construction part B
40: Weir 50: Bucket 62: Hydraulic mortar at top end construction part A 64: Hydraulic mortar at top end construction part B

Claims (10)

Providing a form for forming a foundation concrete structure for a building;
Placing the reinforcing bars in the formwork;
A process of forming a base concrete part by placing concrete in a formwork;
A method for constructing a foundation concrete structure for a building, including a step of pouring and curing a hydraulic mortar prepared by kneading a self-leveling hydraulic composition and water on the upper surface of an underlying concrete part. ,
A self-leveling hydraulic composition comprising a main component comprising Portland cement, fine aggregate, an admixture and an expansion material, and aluminum sulfate, a shrinkage reducing agent, limestone fine powder and a thickener. The construction method of the foundation concrete structure for buildings which is a self-leveling hydraulic composition which is a thing, Comprising: The thickener is a thickener containing two types of cellulosic water-soluble polymers with different viscosities. The main component of the self-leveling hydraulic composition consists of 100 parts by weight of Portland cement, 100 to 400 parts by weight of fine aggregate, 5 to 150 parts by weight of an admixture, and 3 to 30 parts by weight of an expansion material,
A thickener is a high-viscosity cellulose-based water-soluble polymer whose viscosity at 20 ° C. of a 2% aqueous solution is 20,000 to 50,000 mPa · s, and a viscosity at 20 ° C. of a 2% aqueous solution is 50 to 6,000 mPa A low-viscosity cellulose water-soluble polymer that is s,
In a self-leveling hydraulic composition, for a total of 100 parts by mass of Portland cement and fine aggregate,
0.1 to 0.7 parts by mass of aluminum sulfate content,
The content of fine limestone powder is 11 to 35 parts by mass,
The content of the high-viscosity type cellulose water-soluble polymer is 0.005 to 0.2 parts by mass, and the content of the low-viscosity type cellulose water-soluble polymer is 0.04 to 0.2 parts by mass. The construction method of the foundation concrete structure for buildings of 1.   The basic concrete structure for buildings according to claim 1 or 2, wherein the content of the shrinkage reducing agent in the self-leveling hydraulic composition is 0.1 to 3 parts by mass with respect to 100 parts by mass of the main components. Body construction method. The self-leveling hydraulic composition further comprises fibers,
The construction method of the foundation concrete structure for buildings according to any one of claims 1 to 3, wherein the fiber content is 0.01 to 5 parts by mass with respect to 100 parts by mass in total of the main components. The self-leveling hydraulic composition further comprises a fluidizing agent and an antifoaming agent,
The content of the fluidizing agent is 0.01 to 3 parts by mass with respect to 100 parts by mass in total of the main components,
The construction method of the foundation concrete structure for buildings according to any one of claims 1 to 4, wherein the content of the antifoaming agent is 0.01 to 3 parts by mass with respect to 100 parts by mass of the total of the main components. .   The construction method of the foundation concrete structure for buildings of any one of Claims 1-5 in which a self-leveling hydraulic composition contains the other setting regulator except aluminum sulfate further.   The step of pouring and hardening hydraulic mortar includes pouring concrete for forming the base concrete part, and pouring hydraulic mortar after drawing the breathing water on the concrete surface. The construction method of the foundation concrete structure for buildings of any one of -6.   The process of forming a foundation concrete part includes having a primer hardening body layer by apply | coating a primer on the upper surface of the hardened concrete, and drying and forming a primer hardening body layer. The construction method of the foundation concrete structure for buildings of Claim 1.   The construction method of the foundation concrete structure for buildings according to any one of claims 1 to 8, wherein the building foundation concrete structure is for a one-story to three-story house.   The foundation concrete structure for buildings obtained by the construction method of the foundation concrete structure for buildings according to any one of claims 1 to 9.

Images