JP2014169200A - Self-flowable hydraulic composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-flowable hydraulic composition which is excellent in workability, surface smoothness and surface horizontality while keeping a long pot life and allows a hardened product thereof to have such an excellent surface state that a rugged portion, a powdered deposit (efflorescence) or the like is not produced on the surface thereof due to material separation, water floating or the like.SOLUTION: The self-flowable hydraulic composition contains a hydraulic component, inorganic powder, fine aggregate, fluidizer, a setting modifier and a methylcellulose-based thickening agent. The inorganic powder is at least one selected from blast furnace slag fine powder, limestone fine powder and fly ash. A 2% aqueous solution of the methylcellulose-based thickening agent has 10-2,000 mPa-s viscosity at 20°C and the methylcellulose-based thickening agent has the substitution degree equal to or higher than 1.0 and lower than 1.6.

Description

  The present invention relates to a self-flowing hydraulic composition used for construction of a structure such as a concrete floor structure.

  The self-fluid slurry obtained by kneading the self-fluid hydraulic composition and water has excellent workability, surface smoothness, and surface horizontality. It is required to have good surface properties that do not occur, etc. Further, the construction area is large at the construction site, the supply amount of self-fluid slurry is small per unit time, etc. Under the conditions required, there is a need for a self-flowing hydraulic composition having a small change in flowability of the self-flowing slurry, that is, having a long pot life.

  In order to cope with these, Patent Document 1 discloses a hydraulic composition containing a setting accelerator, a water-soluble cellulose ether selected from one or both of a water-soluble alkyl cellulose and a water-soluble hydroxyalkyl cellulose, and water. In addition, a self-leveling material having a small change in fluidity with time and a quick setting time is shown because the substitution degree of the alkyl group of the water-soluble cellulose ether is 1.6 to 2.5.

  In Patent Document 2, (A) a cellulose derivative, (B) a polymer, and (C) anhydrous gypsum are contained, and the solid content mass ratio ((A) / (B)) between components (A) and (B) is 0.00. 1 to 1.4, and the total amount of components (A) and (B) at the time of blending with mortar is 0.3 to 9.0 parts by mass with respect to 100 parts by mass of cement. High flow mortar that is difficult to generate is shown.

  Moreover, in patent document 3, it is a self-flowing hydraulic composition containing a hydraulic component, a fine aggregate, a fluidizing agent, and a thickener, and the thickener is from a high viscosity thickener and a low viscosity thickener. The viscosity in a 2% by weight aqueous solution measured at 20 ° C. using a B-type viscosity form is 15,000 to 300,000 mPa · s for a high viscosity thickener, and 25 to 400 mPa · s for a low viscosity thickener. A cured product that is excellent in horizontal level and surface flatness because the mass ratio of the thickener to the low-viscosity thickener is high-viscosity thickener: low-viscosity thickener = 20: 80 to 80:20. A self-leveling hydraulic composition is obtained.

JP 2008-201612 A JP 2010-83710 A JP 2011-201748 A

  However, the longer the pot life is, the higher the possibility of adversely affecting the surface properties after curing due to material separation and the like. If more importance is attached to the surface properties after curing, it is necessary to accelerate the hydration reaction as much as possible. There is a tendency for pot life to be shortened. Therefore, it has excellent workability, surface smoothness, surface horizontality while having a long pot life, and has excellent surface properties that do not cause unevenness or powdering (white flower) on the surface after curing. There is a need for a self-flowing hydraulic composition that has a balanced and even better effect.

  Therefore, the present invention has excellent workability, surface smoothness, and surface horizontality while having a long pot life, and despite the long pot life, due to material separation, surface water floating, etc. It is an object of the present invention to provide a self-flowing hydraulic composition having excellent surface properties in which unevenness and powdering (white flower) do not occur on the surface after curing.

  As a result of intensive studies to achieve the above object, the present inventors have aimed to include a methyl cellulose thickener having a hydraulic component, a fine aggregate, a fluidizing agent, a setting modifier, a specific viscosity and the like. It was found that a self-flowing hydraulic composition was obtained, and the present invention was completed.

  That is, the present invention is a self-flowing composition containing a hydraulic component, an inorganic powder, a fine aggregate, a fluidizing agent, a setting modifier, and a methylcellulose-based thickener. One or two or more kinds selected from powder, fly ash and fine limestone powder. The methylcellulose thickener has a 2% aqueous solution viscosity at 20 ° C. of 10 to 2000 mPa · s and a substitution degree of methoxyl group of 1. Provided is a self-flowing hydraulic composition that is greater than or equal to 0 and less than 1.6.

  According to the self-flowing hydraulic composition of the present invention, since there is little change in fluidity with time, it has excellent workability, surface smoothness, and surface horizontality while having a long pot life. Obtaining a self-flowing hydraulic composition having excellent surface properties that does not cause unevenness or powdering (white flower) on the surface after curing due to material separation or surface water floatation despite a long pot life be able to. Thus, in the self-flowing hydraulic composition of the present invention, it has excellent workability, surface smoothness, and surface horizontality while having a long pot life, and in particular, unevenness on the surface after curing. The reason for providing an excellent surface property that does not cause powdering (white flower) or the like is not necessarily clear, but as one of the reasons, the present inventors interacted with each component contained in the self-flowing composition. At the same time, it is considered that the action caused by the combination with a specific methylcellulose thickener contributes to the improvement of the excellent surface properties.

  Preferred embodiments of the self-flowing hydraulic composition of the present invention are shown below. In the present invention, it is more preferable to appropriately combine the following aspects.

  The hydraulic component is preferably contained in 75 to 99 mass% of Portland cement and 1 to 25 mass% of gypsum in 100 mass% of the hydraulic component. Thereby, while having favorable fluidity | liquidity and pot life, the length change at the time of hardening is moderately small, and the outstanding hardening characteristic (hydration rate) can be obtained.

  The inorganic component is preferably 10 to 300 parts by mass and fine aggregate 85 to 325 parts by mass with respect to 100 parts by mass of the hydraulic component. Thereby, more excellent fluidity, surface properties, strength development and dimensional stability can be obtained.

  The fine aggregate preferably has a coarse particle ratio in the range of 0.60 to 1.80 and a water absorption of 2.0% or less. Thereby, more excellent fluidity and surface properties can be obtained.

  A methylcellulose type | system | group thickener is a hydroxypropyl methylcellulose thickener, and it is preferable that it is 0.10-2.00 mass parts of methylcellulose type | system | group thickeners with respect to 100 mass parts of hydraulic components. Thereby, it is possible to obtain more excellent fluidity retention, long pot life and excellent surface properties.

  According to the self-flowing hydraulic composition of the present invention, the material has excellent workability, surface smoothness, surface horizontality, and a long pot life while having a long pot life. It is possible to provide a self-flowing composition having an excellent surface property in which unevenness or powdering (white flower) does not occur on the surface after curing due to separation or surface water floating.

It is a perspective view of SL measuring device used for self-leveling property evaluation. (A) It is sectional drawing which shows the state which filled the SL measuring device with the slurry, and the state which pulled up the (b) weir board and the slurry flowed.

  A preferred embodiment of the self-flowing hydraulic composition of the present invention will be described below. The self-fluid hydraulic composition of the present embodiment is a self-fluid hydraulic composition containing a hydraulic component, inorganic powder, fine aggregate, fluidizer, setting modifier, and methylcellulose thickener.

  Hereinafter, each component contained in the self-flowing hydraulic composition of the present embodiment will be described in detail.

  As the hydraulic component, it is preferable to use a hydraulic component including Portland cement and gypsum. Thereby, while having good fluidity and pot life, the change in length during curing is moderately small, and excellent curing characteristics (hydration rate) can be obtained. In order to further improve the dimensional stability, alumina cement may be added to such an extent that the pot life is not lost. Several types of alumina cements with different mineral compositions are known and commercially available, but the main component is monocalcium aluminate, and commercially available products can be suitably added regardless of the type.

  Portland cement is a common hydraulic material, and any commercially available product can be used. Among these, it is preferable to use Portland cement specified by JIS R 5210: 2009 “Portland cement”.

  Examples of the gypsum include dihydrate gypsum, hemihydrate gypsum, and anhydrous gypsum. Any gypsum produced as a by-product in flue gas desulfurization or hydrofluoric acid production process, or gypsum produced in nature can be used. . From the viewpoint of workability (high fluidity, long pot life), it is preferable to use anhydrous gypsum.

  The hydraulic component preferably contains 75 to 99% by mass of Portland cement and 1 to 25% by mass of gypsum, more preferably 85 to 99% by mass of Portland cement and 1 to 15% by mass of gypsum, in 100% by mass of the hydraulic component. %, More preferably 90 to 99% by mass of Portland cement and 1 to 10% by mass of gypsum. Thereby, while having favorable fluidity | liquidity and pot life, the length change at the time of hardening is moderately small, and the outstanding hardening characteristic (hydration rate) can be obtained.

  As the inorganic powder, blast furnace slag fine powder defined by JIS A 6206: 1997 “Blast Furnace Slag Fine Powder for Concrete”, fly ash and fine limestone powder defined by JIS A 6201: 1999 “Fly Ash for Concrete” are used. One or a combination of two or more selected from these can be used. By using these, fluidity, surface properties, strength development and dimensional stability can be further improved.

Inorganic powder, JIS R 5201: Blaine specific surface area measured in accordance with 1997 "Physical testing methods for cement" is, preferably 1500~10000cm ² / g, more preferably 2000~8000cm ² / g, further Preferably it is 2500-6000 cm < ² > / g, Most preferably, it is 3000-5000 cm < ² > / g. When the Blaine specific surface area is in the above range, more excellent fluidity, surface properties, strength development and dimensional stability can be obtained.

  The inorganic powder used in the self-flowing composition of the present embodiment is preferably 10 to 300 parts by mass, more preferably 20 to 200 parts by mass, and still more preferably with respect to 100 parts by mass of the hydraulic component. Is 25 to 150 parts by mass, particularly preferably 30 to 100 parts by mass. By setting the content of the inorganic powder in the self-flowing hydraulic composition in the above range, more excellent fluidity, surface properties, strength development and dimensional stability can be obtained.

  The fine aggregate has a maximum particle diameter of 850 μm or less, and preferably contains less than 5 mass% of coarse particles having a particle diameter of 600 μm or more in 100 mass% of the fine aggregate. As such fine aggregates, sands such as quartz sand, river sand, land sand, sea sand, crushed sand, slag fine aggregates, regenerated fine aggregates and alumina clinker can be appropriately selected and used. In particular, as the fine aggregate, those selected from sands such as quartz sand, river sand, land sand, sea sand and crushed sand can be suitably used.

  The particle diameter of the fine aggregate can be measured by using several sieves having different nominal dimensions as defined in JIS Z 8801: 2006. In the present invention, the term “coarse particles having a particle diameter of 600 μm or more” refers to the mass ratio of particles on the sieve residue when a 600 μm sieve is used.

  When the coarse aggregate having a particle diameter of 600 μm or more is contained in 5% by mass or more in 100% by mass of the fine aggregate, the fluidity of the self-flowing composition tends to be lowered. The lower limit of the coarse particles is not particularly limited, and may be 0% by mass. In order to obtain excellent self-fluidity, the coarse fraction having a particle diameter of 600 μm or more in 100% by mass of fine aggregate is more preferably 0 to 3% by mass, and further preferably 0 to 1.0% by mass. It is particularly preferably 0 to 0.5% by mass.

  In the self-flowing composition of the present embodiment, it is preferable that the fine aggregate has a coarse particle ratio in the range of 0.60 to 1.80 and a water absorption of 2.0% or less. Thereby, more excellent fluidity and surface properties can be obtained.

  Here, the “rough grain ratio” refers to the coarse grain ratio of the aggregate as defined in JIS A 1102: 2006. Further, the “water absorption rate” refers to a value measured according to the method for measuring the water absorption rate (unit:%) of an aggregate defined in JIS A 1109: 2006.

  The coarse particle ratio of the fine aggregate is more preferably 0.75 to 1.78, further preferably 0.82 to 1.75, and particularly preferably 0.91 to 1.68. Further, the lower limit value of the water absorption rate is not particularly limited, and may be 0%. The water absorption rate of the fine bone agent is more preferably 1.75% or less, still more preferably 1.70% or less, and particularly preferably 1.65% or less.

  The fine aggregate used in the self-flowing hydraulic composition of the present embodiment is preferably 85 to 325 parts by mass, more preferably 120 to 285 parts by mass with respect to 100 parts by mass of the hydraulic component. More preferably, it is 155-245 mass parts, Most preferably, it is 175-220 mass parts. By setting the content of the fine aggregate in the self-flowing hydraulic composition within the above range, more excellent fluidity, surface properties, strength development and dimensional stability can be obtained.

  The self-flowing hydraulic composition of the present embodiment is usually used with a small amount of mixing water in order to obtain a high-strength cured body while suppressing material separation. Accordingly, in the self-fluid hydraulic composition of the present invention, a fluidizing agent having a water reducing effect is an essential component in order to ensure high fluidity even if the water / hydraulic component ratio is small.

  As the fluidizing agent, commercially available fluidizing agents such as formaldehyde condensate of melamine sulfonic acid, casein, casein calcium, polycarboxylic acid, polyether and polyether polycarboxylic acid, which have a water reducing effect, are included. It can be used regardless of the type, and it is particularly preferable to use a commercially available fluidizing agent such as polyether-based and polyether polycarboxylic acid.

  The fluidizing agent used in the self-flowing hydraulic composition of the present embodiment is preferably 0.01 to 3.00 parts by mass, more preferably 0.02 to 100 parts by mass of the hydraulic component. It is 2.00 mass parts, More preferably, it is 0.05-1.00 mass part, Most preferably, it is 0.10-0.50 mass part. If the content of the fluidizing agent in the self-flowing hydraulic composition is too small, suitable effects (excellent fluidity and high cured body strength) will not be exhibited, and even if the content is too large, the content will be commensurate with the content. In addition to being uneconomical, there are cases where the viscosity is increased and the amount of kneading water for obtaining the required fluidity increases to deteriorate the strength properties.

  The self-flowing hydraulic composition of the present embodiment contains a setting regulator as an essential component in order to adjust the pot life (flow retention) and fast curing. The setting modifier includes a setting accelerator that accelerates the hydration reaction of the hydraulic component and a setting retarder that delays the hydration reaction of the hydraulic component. Depending on the combination of the hydraulic component used, The addition amount is appropriately selected.

  As the setting accelerator, a known component for promoting setting can be used. For example, chlorides, nitrites, nitrates, sulfates, carbonates, organic acid salts and the like having a setting acceleration effect can be suitably used, and these can be used alone or in combination.

  Examples of sulfates include calcium sulfate, sodium sulfate, potassium sulfate, and lithium sulfate. Examples of carbonates include calcium carbonate, sodium carbonate, potassium carbonate, and lithium carbonate. Examples of the organic acid salt include calcium formate, calcium acetate, and calcium acrylate.

  The setting accelerator used in the self-flowing hydraulic composition of the present embodiment is preferably 0.01 to 1.50 parts by mass, more preferably 0.02 to 100 parts by mass of the hydraulic component. It is 1.00 mass part, More preferably, it is 0.05-0.80 mass part, Most preferably, it is 0.10-0.50 mass part. By setting the content of the setting accelerator in the self-flowing hydraulic composition within the above range, it has better fluidity and secures a good pot life, and then expresses a suitable fast-curing property. Can do.

  A well-known thing can be used as a setting retarder. For example, organic acids such as oxycarboxylic acids, sugars such as glucose, maltose, dextrin, sodium bicarbonate, sodium phosphate, etc. may be used alone or in combination of two or more components. it can.

  Oxycarboxylic acids include oxycarboxylic acids and their salts. Examples of oxycarboxylic acid include citric acid, gluconic acid, tartaric acid, glycolic acid, lactic acid, hydroacrylic acid, α-oxybutyric acid, glyceric acid, tartronic acid, malic acid and other aliphatic oxyacids, salicylic acid, m-oxy Mention may be made of aromatic oxyacids such as benzoic acid, p-oxybenzoic acid, gallic acid, mandelic acid and tropic acid.

  Examples of the salt of oxycarboxylic acid include alkali metal salts (specifically sodium salt and potassium salt) and alkaline earth metal salts (specifically calcium salt, barium salt and magnesium salt). it can.

  The viscosity of a 2% aqueous solution at 20 ° C. measured with a B-type viscometer is 10 to 2000 mPa · s. Thereby, surface smoothness (flatness) and surface levelness can be obtained while having excellent workability due to high fluidity. In particular, excellent surface characteristics can be obtained in which the change in fluidity with time is small and the pot life is long, and surface pulverization and surface unevenness due to material separation and surface water floating do not occur.

  Examples of the methylcellulose thickener include hydroxyethyl methylcellulose thickener, hydroxypropylmethylcellulose thickener, methylcellulose thickener and the like. Of these, the use of a hydroxypropyl methylcellulose thickener is preferred.

  The viscosity of a 2% aqueous solution of a methylcellulose thickener at 20 ° C. is preferably 20 to 1500 mPa · s, more preferably 100 to 1000 mPa · s, still more preferably 150 to 800 mPa · s, and particularly preferably. Is 200 to 600 mPa · s.

The methylcellulose thickener is obtained by substituting a part of three hydroxyl groups on 1,4-bonded D-glucopyranose with a methoxyl group, a hydroxypropoxyl group and / or a hydroxyethoxyl group. The average number of hydroxyl groups substituted with a methoxyl group per D-glucopyranose unit is defined as the substitution degree DS of the methoxyl group, and the hydroxypropoxyl group and / or hydroxy substituted per D-glucopyranose unit. When the average number of moles added of the ethoxyl group is defined as the molar substitution degree MS,
The substitution degree DS of the methoxyl group is 1.0 or more and less than 1.6. Further, the molar substitution degree MS is preferably 0.05 to 1.00. Thereby, surface smoothness (flatness) and surface levelness can be obtained while having excellent workability due to high fluidity. In particular, while having a long pot life, it is possible to obtain excellent surface characteristics that do not cause surface pulverization or surface irregularities due to material separation or surface water floating.

  The substitution degree DS of the methoxyl group is preferably 1.10 to 1.59, more preferably 1.30 to 1.57, and still more preferably 1.45 to 1.54. Further, the molar substitution MS is more preferably 0.10 to 0.50, further preferably 0.11 to 0.30, and particularly preferably 0.12 to 0.20.

  The degree of substitution DS and the degree of molar substitution MS are described in J. G. Gobler, E .; P. Samsel and G.M. H. It can be measured according to Zeisel-GC described in Beaver, Talanta, 9, 474 (1962).

  The methylcellulose thickener used in the self-flowing hydraulic composition of the present embodiment is preferably 0.01 to 2.00 parts by mass, more preferably 0.0. 1 to 2.00 parts by mass, more preferably 0.15 to 1.50 parts by mass, and particularly preferably 0.20 to 1.00 parts by mass. By setting the content of the setting accelerator in the self-flowing hydraulic composition within the above range, the surface has a higher flowability and less change in flowability over time, and has excellent workability and a long pot life. Smoothness (flatness) and surface levelness can be obtained. In particular, excellent surface characteristics can be obtained in which the change in fluidity with time is small and the pot life is long, and surface pulverization and surface unevenness due to material separation and surface water floating do not occur.

  Here, the “viscosity” of the methylcellulose-based thickener means that a 2% aqueous solution of the thickener is obtained from a rotor No. using a B-type viscometer. 4. A value measured at a rotational speed of 12 rpm and 20 ° C.

  In addition to the essential components described above, the self-flowing composition of the present embodiment can be appropriately added with a re-emulsifying resin powder, an antifoaming agent, or the like as long as the characteristics of the present invention are not impaired.

  There are no particular restrictions on the type of re-emulsified resin powder, such as the method of pulverizing the resin, and those manufactured by known production methods can be used. What has adhered the agent mainly on the surface of the re-emulsification type resin powder can be used. The re-emulsified resin powder may be a re-emulsified resin powder obtained by removing the solvent from the aqueous polymer dispersion by a method such as spraying or freeze drying.

As the re-emulsifying resin powder, 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. . Examples of the α, β-ethylenically unsaturated monomer include known α, β-ethylenically unsaturated monomers such as acrylic acid and acrylate derivatives, methacrylic acid and methacrylic acid esters. Derivatives such as α-olefins such as ethylene and propylene, aromatic vinyls such as vinyl acetate and styrene, vinyl chloride and versatile acid vinyl esters such as tertiary fatty acid vinyl esters (R-COO) having 9 to 11 carbon atoms -CH = _CH 2, R may be mentioned tertiary carbon) of 9 to 11 carbon atoms.

  The re-emulsifying resin powder can be appropriately added within a range that does not impair the characteristics of the self-flowing hydraulic composition of the present embodiment. The addition amount of the re-emulsified resin powder is preferably 0.10 to 3.00 parts by mass, more preferably 0.25 to 2.00 parts by mass, with respect to 100 parts by mass of the hydraulic component. Preferably it is 0.50-1.50 mass part, Most preferably, it is 0.70-1.30 mass part.

  Examples of the antifoaming agent include known substances such as synthetic substances such as silicone-based, alcohol-based and / or polyether-based substances and / or plant-derived natural substances. Among these, polyether antifoaming agents are preferable from the viewpoints of price and availability. By using an antifoaming agent, it can be expected that the antifoaming effect of the self-flowing hydraulic composition is improved.

  The self-flowing hydraulic composition of the present embodiment has excellent workability due to high fluidity, surface smoothness, surface horizontality, quick hardening, etc., and in particular, while having high fluidity, Since it has excellent surface properties that do not cause surface pulverization or surface irregularities due to surface water floating, it can be used as a floor base material for buildings such as schools, condominiums, convenience stores, and hospitals.

  A slurry can be produced by mixing and stirring the self-flowing hydraulic composition of the present embodiment with a predetermined amount of water. Further, the flow value of the self-flowing hydraulic slurry can be used as an index of the fluidity of the slurry. Here, the flow value is a value (unit: mm) measured in accordance with the test method described in JASS 15M-103 “The Architectural Institute of Japan: Quality standards for self-leveling materials”.

  The slurry preferably has a mass ratio (W / S) of water (W) to the self-flowing hydraulic composition (S) of 0.22 to 0.30, more preferably 0.23 to 0.00. 29, more preferably 0.24 to 0.28, and particularly preferably 0.25 to 0.27.

  From the viewpoint of the fluidity of the slurry, the flow value of the slurry is preferably 190 mm to 260 mm, more preferably 195 mm to 255 mm, still more preferably 198 to 230 mm, and particularly preferably 199 to 225 mm. When the flow value is in the above range, the fluidity is suitable, and it tends to be easy to obtain a cured body surface with high smoothness and horizontality (flatness).

  Further, the self-fluidity and pot life of the slurry can be evaluated using the SL measuring device shown in FIG.

  FIG. 1 is a perspective view schematically showing an SL measuring instrument used for self-fluidity evaluation of a slurry. The SL measuring instrument 10 is made of steel and has an inner dimension of 30 mm wide × 30 mm high × 750 mm long. Only one end is an open end. The SL measuring instrument 10 includes a filling portion 11 for filling the closed end side with slurry, and a synthetic resin dam plate 12 adjacent to the filling portion 11 for blocking the filled slurry. The filling portion 11 has a capacity with an internal dimension of 30 mm width × 30 mm height × 150 mm length.

  FIG. 2 is a cross-sectional view schematically showing a method for evaluating self-fluidity of a slurry using the above-described SL measuring device. First, as shown in FIG. 2A, the slurry immediately after kneading is poured so as to fill the filling portion 11. Then, immediately after the weir plate 12 is pulled up, the poured slurry flows toward the opening end side of the SL measuring instrument 10 as shown in FIG.

  The time required for the flowing slurry to flow a distance of 200 mm from the reference point 13 is the SL flow time (seconds) at L0, and the distance from the reference point 13 to the end point 14 at which the slurry flow stops is the SL value at L0 ( mm). By measuring the SL flow time and SL value, the self-fluidity of the slurry can be evaluated. The shorter the SL flow time is, the longer the SL value does not separate the slurry, and the longer the SL value, the self-fluidity becomes. Excellent, in other words, excellent workability.

  Further, the SL value (mm) that can be measured by pouring the slurry immediately after the kneading so as to fill the filling portion 11 and leaving it for 60 minutes and then pulling up the weir plate 12 is defined as the SL value at L60. And it can be said that it has long working life, so that the ratio (L60 / L0) of SL value in L0 and SL value in L60 mentioned above is near 1, and it is excellent in workability | operativity. As the SL value ratio (L60 / L0) is larger than 1, the slurry is separated from the material, and the hydration reaction is delayed. Further, the pot life is shortened as it becomes smaller than 0.5, and workability is lowered.

  The SL flow time at L0 of the slurry is preferably 3 to 35 seconds, more preferably 5 to 30 seconds, still more preferably 8 to 25 seconds, and particularly preferably 10 to 25 seconds in an environment at a temperature of 20 ° C. 20 seconds.

  The SL value at L0 of the slurry is preferably 300 to 500 mm, more preferably 300 to 450 mm, still more preferably 300 to 420 mm, and particularly preferably 300 to 400 mm in an environment at a temperature of 20 ° C. By making SL flow time and SL value in L0 into the above-mentioned range, it is excellent in self-fluidity, has surface smoothness and surface horizontality, and can suppress material separation and surface water floating.

  The ratio of SL value and SL value at L60 of the slurry (L60 / L0) is preferably 105 to 500 mm and 0.35 to 1.0, more preferably 120 to 450 mm and 0.4 in an environment of 20 ° C. It is -1.0, More preferably, it is 135-420 mm and 0.45-1.0, Most preferably, it is 150-400 mm and 0.5-1.0. By making the ratio of SL value and SL value (L60 / L0) in L60 to be in the above-mentioned range, since there is little change with time of self-fluidity, a long pot life is obtained, excellent workability, and , Material separation and surface water floating can be suppressed.

  When the slurry is placed, although it depends on the temperature and humidity conditions at the construction site, curing starts from 1 hour to 3 hours after the construction is completed, and the surface hardness of the cured body tends to increase as the curing progresses. It is in. As an index of the surface hardness of the cured body, hardness (Shore hardness) obtained using a spring type hardness tester type D type can be used.

  The Shore hardness of the surface of the cured body after 24 hours from the placement of the slurry is preferably 30 or more, more preferably 40 or more, even more preferably 45 or more, particularly in an environment of a temperature of 20 ° C. Preferably it is 50 or more.

  The upper limit of the Shore hardness is not particularly limited, but is about 100 which is the measurement limit value of the Shore hardness meter. If the Shore hardness of the surface of the cured body is in the above range, it will not hinder the work process after the next day after the slurry application is completed.

  When constructing a tension object on the upper surface of the surface of the cured body, the tension object is laid on the surface of the cured object or an adhesive tape, and then the tension object is laid and integrated. From this, it is preferable that there are no unevenness | corrugation on the surface of a hardening body, powdering (white flower), etc. which become an obstruction factor of integration. Here, the unevenness is a state in which fine unevenness is formed on the surface of the cured body and is not smooth, and pulverization is a state in which a thin powdery layer is formed on the surface of the cured body. It is thought that separation and water float on the surface of the slurry are caused.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  The contents of the present invention will be described in more detail with reference to the following experimental examples, but the present invention is not limited to the following experimental examples.

[Materials used]
(1) Hydraulic component Portland cement [PC] (early strength Portland cement, manufactured by Ube Mitsubishi Cement, Blaine specific surface area: 4580 cm ² / g)
Gypsum [GG] (natural anhydrous gypsum, Blaine specific surface area 4470 cm ² / g)

  The said sample was mix | blended in the ratio shown in Table 1, and the hydraulic component was prepared.

（２）無機粉体
・高炉スラグ微粉末［ＢＦＳ］（ブレーン比表面積４７４０ｃｍ^２／ｇ）
・フライアッシュ［ＦＡ］（ブレーン比表面積３５６０ｃｍ^２／ｇ）

(2) Inorganic powder-Blast furnace slag fine powder [BFS] (Brain specific surface area 4740 cm ² / g)
・ Fly ash [FA] (Blaine specific surface area 3560 cm ² / g)

  The said sample was mix | blended in the ratio shown in Table 2, and inorganic powder was prepared.

(3) Fine aggregate ・ Silica sand (coarse fraction having a particle size of 600 μm or more 0.30 mass%, coarse grain ratio 1.54%, water absorption 1.62%)
(4) Fluidizer ・ Polycarboxylic acid based fluidizer (manufactured by Kao Corporation)
(5) Setting adjuster-Setting accelerator (potassium sulfate)
(6) Methylcellulose thickener ・ Hydroxypropylmethylcellulose thickener A to F (Matsumoto Yushi Co., Ltd.)

  Table 3 shows a list of the thickeners.

  The substitution degree DS of the methoxyl group and the molar substitution degree MS of the hydroxypropoxyl group of the thickener are described in J. G. Gobler, E .; P. Samsel and G.M. H. The measurement was performed according to Zeisel-GC described in Beber, Talanta, 9, 474 (1962).

  As for the viscosity of the thickener, a B-type viscometer was used. 4. Measurement was performed under the condition of a rotor rotational speed of 12 rpm. The viscosity of the thickener D could not be measured because it exceeded the upper limit value of 50000 mPa · s.

  Table 4 shows the blending ratio of the above materials for obtaining a self-flowing composition excluding the methylcellulose thickener.

[Preparation of mortar]
The above materials (total amount: 1.5 kg) were mixed based on the blending ratio shown in Table 3, and the thickener was mixed at the blending ratio shown in Table 4 to prepare a self-flowing hydraulic composition. Next, 390 g of water was added to the obtained self-flowing hydraulic composition and kneaded for 3 minutes using a chemistor to obtain a slurry. The slurry was prepared in a constant temperature room at a temperature of 20 ° C.

[Evaluation of slurry]
(1) Measuring method of flow value The flow value was measured in accordance with JASS 15M-103 “Architectural Institute of Japan: Quality standards for self-leveling materials”. The measurement was performed in a constant temperature room at a temperature of 20 ° C. Table 5 shows the measurement results.
(2) SL flow time and SL value Slurry immediately after kneading is poured into the filling part 11 of the SL measuring device 10 shown in FIG. 1, and immediately after that, the weir plate 12 is pulled up, and as shown in FIG. After the flow of the slurry that flowed out, the distance from the gauge point (dam plate installation portion) 13 to the end point 14 where the flow of the slurry stopped was measured as the SL value (mm) at L0. Further, the time required for the slurry to flow a distance of 200 mm from the gauge point 13 was measured as the SL flow time (second / 200 mm) at L0. Moreover, the slurry immediately after kneading | mixed was poured into the filling part 11, and after leaving still for 60 minutes, the weir board 12 was pulled up, and SL value (mm) in L60 was measured similarly to SL value in L0. Table 5 shows the measurement results.

[Evaluation of cured body surface]
(3) Surface hardness The slurry immediately after kneading is poured into a synthetic resin container having internal dimensions of width 130 × length 190 × height 17 mm so as to have a thickness of 15 mm. The hardness (Shore hardness) was measured using a spring type hardness tester type D type (manufactured by Ueshima Seisakusho Co., Ltd.). The surface hardness at any four locations was measured, and the average value of the readings of the spring type hardness tester type D gauge was taken as the Shore hardness. Table 5 shows the measurement results.
(4) Surface properties The slurry immediately after kneading is poured into a synthetic resin container having an inner dimension of width 130 × length 190 × height 17 mm to a thickness of 15 mm, and after 24 hours, touched with eyes and fingers Then, unevenness and powdering on the surface of the cured body were evaluated. Here, the “unevenness” is an unevenness present on the surface and having a width of about several hundred μm to several mm and a thickness of about several hundred μm. “Powdering” is a state in which white or nearly white powder is deposited on the surface, or a state in which the surface layer portion becomes powdery when lightly rubbed with a finger. The evaluation of unevenness is `` X '' when the presence of surface unevenness can be visually confirmed or is not sufficiently visible by visual contact with a finger, but is `` X '', and when it is slightly known by touching with a finger, `` △ '' The case where it was not known even if it was touched with a finger was indicated as “◯”. Evaluation of pulverization is “△” when the appearance of powder is visually observed or when the surface becomes powdery when rubbed with a finger, and “△” when the surface becomes powdery when rubbed with a finger. A case where the surface did not become powdery even when rubbed strongly with a finger was indicated as “◯”. The measurement was performed in an environment with a temperature of 20 ° C. and a humidity of 65%. The evaluation results are shown in Table 5.

  As shown in Table 5, the flow value of the slurry of Example 1 in which the thickener A was blended showed good fluidity of 218 mm, the SL flow time at L0 was 14 seconds, and the SL value was 363 mm. Showed good self-fluidity. From this, it was shown that it has excellent workability. The SL value at L60 was 245 mm, and the SL value ratio (L60 / L0) was 0.67, which was longer than that of other comparative examples. And it has good fluidity, self-fluidity, and long pot life, and it does not cause unevenness or pulverization on the surface of the cured product due to slurry material separation or water floating on the slurry surface. Met. From this, it was shown that it has the outstanding surface smoothness and surface levelness (surface flatness).

  In Comparative Example 1 in which the thickener B was blended, the flow value was close to that of Example 1, and the SL value at L0 was slightly higher than Example 1, but the SL value and SL value at L60 were low. The ratio was low and irregularities occurred. In Comparative Example 2 in which the blending ratio of the thickener B was increased, the SL flow time in L0 showed a value close to that of Example 1, and unevenness did not occur, but the flow value was lower than that in Comparative Example 1, and in L60. The ratio of SL value and SL value was low.

  In Comparative Example 3 in which the thickener C was blended, the flow value and the SL value at L0 were close to those of Example 1, but the ratio of the SL value and SL value at L60 was low, and unevenness and powdering occurred. did. In Comparative Example 4 in which the blending ratio of the thickener C was increased, the SL flow time at L0 showed a value close to that of Example 1, and the unevenness was slightly improved as compared with Comparative Example 3, but the flow was insufficient. The value was lower than that of Comparative Example 3, and the ratio of SL value and SL value at L60 was low.

  In Comparative Example 5 in which the thickener D is blended, the flow value and the SL value at L0 are lower than those in Example 1, but the SL flow time at L0 is short, the SL value at L60 is 0 mm, and unevenness and powdering are observed. Occurred.

  In Comparative Example 6 in which the thickener E was blended, the flow value, the SL flow time at L0, and the SL value at L0 were close to those of Example 1, but the ratio of the SL value and SL value at L60 was low. Powdering occurred.

  In Comparative Example 7 in which the thickener F was blended, although the viscosity was almost the same as the thickener A and the blending ratio was the same, the flow value and the SL value at L0 were slightly lower than those in Example 1. And the ratio of the SL value and the SL value at L60 was low and pulverization occurred.

  From the above, as in the examples, the hydraulic component, inorganic powder, fine aggregate, fluidizer, setting modifier, methylcellulose thickener, the inorganic powder is blast furnace slag fine powder, limestone One or two or more types selected from fine powder and fly ash, and the methylcellulose-based thickener has a viscosity of 2% aqueous solution at 20 ° C. of 10 to 2000 mPa · s, and a substitution degree of methoxyl group of 1.0 or more. In addition, the self-flowing composition of the present invention which is less than 1.6 has a long pot life, excellent workability, surface smoothness, surface horizontality (surface flatness), and a long potency. In spite of the usage time, it was confirmed that the surface after curing due to material separation or surface water floating has excellent surface properties that do not cause unevenness or powdering (white flower).

DESCRIPTION OF SYMBOLS 10 ... SL measuring device, 11 ... Filling part, 12 ... Dam plate, 13 ... Marking point, 14 ... End point.

Claims (5)

A self-flowing composition comprising a hydraulic component, an inorganic powder, a fine aggregate, a fluidizing agent, a setting modifier, a methylcellulose thickener,
The inorganic powder is one or more selected from blast furnace slag fine powder, limestone fine powder and fly ash,
The methylcellulose-based thickener has a viscosity of 2% aqueous solution at 20 ° C. of 10 to 2000 mPa · s, and a substitution degree of methoxyl group is 1.0 or more and less than 1.6.
Self-flowing hydraulic composition. The hydraulic component contains 75 to 99% by mass of Portland cement and 1 to 25% by mass of gypsum in 100% by mass of the hydraulic component.
The self-flowing hydraulic composition according to claim 1. The inorganic component is 10 to 300 parts by mass and the fine aggregate is 85 to 325 parts by mass with respect to 100 parts by mass of the hydraulic component.
The self-flowing hydraulic composition according to claim 1 or 2. The fine aggregate has a coarse particle ratio in the range of 0.60 to 1.80 and a water absorption of 2.0% or less.
The self-flowing hydraulic composition according to any one of claims 1 to 3. The methylcellulose-based thickener is a hydroxypropyl methylcellulose thickener, and is a methylcellulose-based thickener 0.10 to 2.00 parts by mass with respect to 100 parts by mass of the hydraulic component.
The self-flowing hydraulic composition according to any one of claims 1 to 4.

Images