Method for Controlling Strength of Hardened Body

Abstract

To provide a strength control method that can reduce a strength difference of a hardened body of a hydraulic composition without suppressing the occurrence of bleeding.SOLUTION: When a hardened body is manufactured from a hydraulic composition containing water and a hydraulic powder, the hardened body is cured by co-existing (A) amine oxide-type surfactant in the hydraulic composition to reduce the difference in strength of the hardened body in the direction of gravity applied to the hydraulic composition during curing.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for controlling the strength of a cured body.

Background Art

[0002] Hydraulic compositions such as concrete and mortar are used in various fields such as civil engineering and construction. For example, hydraulic compositions are used in the production of underground water cutoff walls, underground piles, and the like. In general, various chemical admixtures such as AE agents, water reducing agents, AE water reducing agents, high performance water reducing agents, high performance AE water reducing agents, fluidizing agents, and setting retarders are used in hydraulic compositions to adjust their workability, fluidity, strength, setting time, hardening time, and the like.

[0003] Patent Document 1 discloses that when constructing an underground continuous wall concrete by placing concrete containing cement, fine aggregate, coarse aggregate, and an admixture underground, at least an AE water reducing agent or a high performance AE water reducing agent and a thickening agent are used as the admixture, and the thickening agent is an aromatic compound having a sulfone group represented by the following compound (α) and / or a salt thereof and an alkyltrimethylammonium salt represented by compound (β), and a method for constructing an underground continuous wall concrete in which concrete having a slump flow of 350 mm or more is placed underground is disclosed. And in the examples of Patent Document 1, whether or not the bleeding amount is measured by pressurized bleeding measurement is used as an index of the strength difference between the upper and lower parts of the concrete.

[0004] Patent Document 2 discloses a rheology modifier containing two or more specific amine oxides having different structures.

[0005] Patent Document 3 discloses a self-compacting concrete composition in which a concrete composition containing an alkylamine oxide having an alkyl group with 8 to 22 carbon atoms and a high performance water reducing agent has a slump flow value (spread measured by JIS-A 1101) of 50 cm or more.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] It is desired that the hardened body of the hydraulic composition has appropriate strength according to the application. However, not only the magnitude of the strength but also the uniformity of the strength, that is, the absence of a difference in strength depending on the part of the hardened body is important. For example, when placing a longitudinally shaped hardened body such as a ground anchor for ground improvement, a strength difference may occur between the upper part (the part close to the ground surface) and the lower part (the part far from the ground surface) of the anchor due to the influence of gravity during hardening. If such a strength difference is significant, it will also affect the strength of the entire hardened body. In addition, in order to suppress the decrease in the strength of the hardened body of the hydraulic composition, it is generally recognized that suppressing the occurrence of bleeding is important (for example, Patent Document 1).

[0008] The present invention provides a strength control method capable of reducing the strength difference of the hardened body of the hydraulic composition without suppressing the occurrence of bleeding.

Means for Solving the Problems

[0009] When producing a hardened body from a hydraulic composition containing water and hydraulic powder, by coexisting (A) an amine oxide type surfactant [hereinafter referred to as component (A)] in the hydraulic composition and curing it, the strength difference of the hardened body is reduced in the direction of the gravity applied to the hydraulic composition during curing. It relates to a method for controlling the strength of a hardened body.

Effects of the Invention

[0010] According to the present invention, there is provided a strength control method capable of reducing the strength difference of a hardened body of a hydraulic composition without suppressing the occurrence of bleeding. Hereinafter, unless otherwise specified, the strength difference of the hardened body means the strength difference of the hardened body in the direction of gravity applied to the hydraulic composition during hardening.

Embodiments for Carrying Out the Invention

[0011] In the present invention, by coexisting an amine oxide type surfactant in the hydraulic composition, the uniformity of the strength in the hardened body produced from the hydraulic composition is remarkably improved. It is considered that a general thickener thickens the hydraulic composition by cross-linking and aggregating hydraulic powders or aggregating with opposite charges to aggregate the hydraulic powders. Although material separation can be suppressed by increasing the viscosity of the system by this method, the hydraulic powders become coarser and are more likely to settle from a microscopic viewpoint. On the other hand, the amine oxide type surfactant used in the present invention forms string-like micelles in water in the hydraulic composition to form a three-dimensional network structure, and it is considered that the hydraulic powders can be entangled and retained in place by being entangled with this. Therefore, it is presumed that the hydraulic powders are distributed in the hydraulic composition in a state where they are almost uniformly dispersed and harden in a state where they are hardly affected by gravity during hardening. In particular, since the amine oxide type surfactant has a very low critical micelle concentration compared to other surfactants, for example, cationic surfactants, it is considered to form a very strong three-dimensional network structure. Thus, in the present invention, it is presumed that the strength difference of the hardened body can be reduced in the direction of gravity applied to the hydraulic composition during hardening without particularly controlling the occurrence of bleeding. Note that the mechanism of the manifestation of the effects of the present invention is not limited to this.

[0012] First, the hydraulic composition according to the present invention will be described. Tap water, river water, lake water, etc. can be used as the water.

[0013] Hydraulic powder is powder that hardens when mixed with water. Examples include ordinary Portland cement, early-strength Portland cement, ultra-early-strength Portland cement, sulfate-resistant Portland cement, low-heat Portland cement, white Portland cement, and eco-cement (such as JIS R5214, etc.). Among these, from the perspective of shortening the time until the required strength of the hydraulic composition is reached, cement selected from early-strength Portland cement, ordinary Portland cement, sulfate-resistant Portland cement, and white Portland cement is preferred, and cement selected from early-strength Portland cement and ordinary Portland cement is more preferred.

[0014] In addition, the hydraulic powder may contain blast furnace slag, fly ash, silica fume, anhydrous gypsum, etc., and may also contain non-hydraulic fine limestone powder, etc. As the hydraulic powder, blast furnace cement, fly ash cement, or silica fume cement in which cement is mixed with blast furnace slag, fly ash, silica fume, etc. may be used. Also, clay such as bentonite may be contained within a range that does not impair the effects of the present invention.

[0015] In the present invention, blast furnace slag cement may be used as the hydraulic powder. As the blast furnace slag cement, type A blast furnace cement, type B blast furnace cement, and type C blast furnace cement defined in JIS R 5211 can be used.

[0016] The amine oxide type surfactant of component (A) may be a surfactant having an amine oxide group. Examples of the amine oxide type surfactant include amine oxides having one hydrocarbon group with 8 or more, further 14 or more, and 22 or less carbon atoms. Examples of component (A) include compounds represented by the following general formula (1).

[0017]

Chemical formula

[0018] 〔In the formula, X is R1a or R 1b -[CONH-CH2CH2CH2] n -represents a group represented by R 1a is an alkyl group having 14 to 22 carbon atoms or an alkenyl group having 14 to 22 carbon atoms. R 1b is an alkyl group having 13 to 21 carbon atoms or an alkenyl group having 13 to 21 carbon atoms. n is an integer of 1 or more and 3 or less. R 2 and R 3 each independently represents an alkyl group having 1 to 4 carbon atoms or -(C2H4O) p a group represented by H. p is the average number of moles added, and R 2 and R 3 is a number of 0 or more and 5 or less in total is. ]

[0019] In the present invention, the component (A) is two or more kinds of compounds represented by the general formula (1) [hereinafter also referred to as compound (1)], in the two or more kinds of compounds, X in the general formula (1) is different, among the two or more kinds of compounds, at least one is R of X in the general formula (1) 1a or R 1b is a compound in which is an alkenyl group, which is preferable. Hereinafter, this aspect will be described.

[0020] Regarding the compound (1), when X in the general formula (1) is different, considering the case where there are two kinds of the compound (1) as an example, for example, the following aspects can be mentioned. In the following aspects, among the two kinds of the compound (1), R of at least one of the two kinds of the compound (1) 1a or R 1b is an alkenyl group. (i) One of R 1a or R 1b is an alkyl group, and the other R 1a or R 1b is an alkenyl group. (ii) One of R 1aor R 1b The carbon number of one of them and the other R 1a or R 1b have different carbon numbers. (iii) One of the Xs is R 1a and the other X is R 1b -[CONH-CH2CH2CH2] n . (iv) Both Xs are R 1b -[CONH-CH2CH2CH2] n - and one n and the other n are different. (v) Combinations of the above (i) to (iv).

[0021] In the general formula (1), X is a group represented by R 1a or R 1b -[CONH-CH2CH2CH2] n . R 1a is an alkyl group having 14 to 22 carbon atoms or an alkenyl group having 14 to 22 carbon atoms. When R 1a is an alkenyl group, the carbon number is preferably 18 or more, and preferably 22 or less. When R 1a is an alkyl group, the carbon number is preferably 16 or more, and preferably 22 or less. R 1b is an alkyl group having 13 to 21 carbon atoms or an alkenyl group having 13 to 21 carbon atoms. When R 1b is an alkenyl group, the carbon number is preferably 17 or more, and preferably 21 or less. When R 1b is an alkyl group, the carbon number is preferably 15 or more, and preferably 21 or less. n is an integer of 1 or more and 3 or less. Preferably, n is 0 or 1. R 2 and R 3 are each independently preferably an alkyl group having 1 to 2 carbon atoms or a group represented by (C2H4O) p H. p is preferably a number of 0 or more and 3 or less.

[0022] In the present invention, two or more, preferably five or less, more preferably two compounds (1) in which X in the general formula (1) is different are used. And, among the two or more compounds (1) used in the present invention, at least one is R of X in the general formula (1) 1a or R 1b is a compound having an alkenyl group having 14 to 22 carbon atoms, that is, R in X in the general formula (1) 1a is an alkenyl group having 14 to 22 carbon atoms or R 1b is a compound containing an alkenyl group having 13 to 21 carbon atoms.

[0023] In the present invention, there are two compounds (1). Among the two compounds (1) including the above (i) to (v), it is preferable that one of them is a compound in which X in the general formula (1) is R 1a and has an alkenyl group having 14 to 22 carbon atoms. That is, the component (A) is two compounds represented by the general formula (1), and the two compounds have different X in the general formula (1). Among the two compounds, one is such that X in the general formula (1) is R 1a and R 1a is preferably a compound having an alkenyl group.

[0024] As the component (A), a combination of a compound (1a) in which X in the general formula (1) is R 1a or R 1b -[CONH-CH2CH2CH2] n - (wherein R 1a is an alkenyl group having 14 to 22 carbon atoms, and R 1b is an alkenyl group having 13 to 21 carbon atoms) and a compound (1b) in which X in the general formula (1) is different from that of the compound (1a) can be mentioned. Specifically, as the component (A), a combination of a compound (1a) represented by the following general formula (1a) and a compound (1b) represented by the following general formula (1b) can be mentioned.

[0025]

Chemical formula

[0026] 〔In the formula, n1 and n2 are each independently an integer of 0 or more and 3 or less. R 11a is an alkenyl group having 14 to 22 carbon atoms when n1 is 0, and an alkenyl group having 13 to 21 carbon atoms when n1 is 1 to 3. R 11b is an alkyl group having 14 to 22 carbon atoms or an alkenyl group having 14 to 22 carbon atoms when n2 is 0, and an alkyl group having 13 to 21 carbon atoms or an alkenyl group having 13 to 21 carbon atoms when n2 is 1 to 3. However, when n1 and n2 are the same number, the alkenyl group of R 11b is a different alkenyl group from R 11a . R 2 and R 3 are each independently an alkyl group having 1 to 4 carbon atoms or a group represented by -(C2H4O) p H. p is the average number of moles added, and the total of R 2 and R 3 is a number of 0 or more and 5 or less .〕

[0027] In general formula (1a), the number of carbon atoms of R 11a is preferably 17 or more, and preferably 22 or less. In general formula (1a), n1 is preferably 0 or 1, more preferably 0.

[0028] In general formula (1b), when n2 is 0 and R 11b is an alkyl group, the number of carbon atoms of R 11b is preferably 16 or more, and preferably 22 or less. In general formula (1b), when n2 is 0 and R 11b is an alkenyl group, the number of carbon atoms of R 11b is preferably 18 or more, and preferably 22 or less. In general formula (1b), when n2 is 1 to 3 and R11b When R is an alkyl group, 11b the number of carbon atoms is preferably 15 or more, and preferably 21 or less. In the general formula (1b), when n2 is 1 to 3 and R 11b is an alkenyl group, 11b the number of carbon atoms is preferably 17 or more, and preferably 21 or less. In the general formula (1b), R 11b is preferably an alkyl group. In the general formula (1b), n2 is preferably 0 or 1.

[0029] In the general formula (1a) or (1b), R 2 and R 3 are each independently preferably an alkyl group having 1 or 2 carbon atoms or a group represented by -(C2H4O) p H, and more preferably an alkyl group having 1 or 2 carbon atoms. In the general formula (1a) or (1b), p is preferably a number of 0 or more and 3 or less. When n1 and n2 are the same number, the alkenyl group of R 11b is an alkenyl group different from R 11a .

[0030] Examples of the component (A) of the present invention include a combination of a compound (11a) represented by the following general formula (11a) and a compound (1b) represented by the following general formula (1b).

[0031]

Chemical formula

[0032] 〔In the formula, n2 is an integer of 0 or more and 3 or less. R 11a is an alkenyl group having 14 or more and 22 or less carbon atoms. R 11bWhen n2 is 0, it is an alkyl group having 14 to 22 carbon atoms or an alkenyl group having 14 to 22 carbon atoms, and when n2 is 1 to 3, it is an alkyl group having 13 to 21 carbon atoms or an alkenyl group having 13 to 21 carbon atoms. However, when n2 is 0, R 11b The alkenyl group of is an alkenyl group different from R 11a R 2 And R 3 Are each independently an alkyl group having 1 to 4 carbon atoms or a group represented by -(C2H4O) p H. p is the average number of moles added, and R 2 And R 3 Is a number from 0 to 5 in total .

[0033] The compound (11a) represented by the general formula (11a) corresponds to the compound in which n1 is 0 in the general formula (1a). The preferred embodiments of R 11a , R 2 And R 3 Are the same as those of the general formula (1a). Also in this combination, the preferred embodiment of the compound (1b) is the same as described above.

[0034] In the present invention, when producing a cured body having a predetermined shape from a hydraulic composition containing water and hydraulic powder, the strength difference of the cured body is reduced in the direction of the gravity applied to the hydraulic composition during curing by allowing (A) an amine oxide type surfactant to coexist in the hydraulic composition and curing it.

[0035] In the present invention, when producing a cured body having a predetermined shape from a hydraulic composition containing water and hydraulic powder, the strength difference of the cured body is reduced in the direction of the gravity applied to the hydraulic composition during curing by allowing (A) an amine oxide type surfactant to coexist in the hydraulic composition and curing it.

[0036] ​The hydraulic composition according to the present invention may have a water / hydraulic powder ratio (hereinafter sometimes referred to as W / P) of, for example, 50% by mass or more, further 60% by mass or more, further 65% by mass or more, further 70% by mass or more, and 200% by mass or less, further 150% by mass or less, further 100% by mass or less. Here, the water / hydraulic powder ratio is the mass percentage (% by mass) of water and hydraulic powder in the hydraulic composition, and is calculated by water / hydraulic powder × 100. The water / hydraulic powder ratio is calculated based on the amount of powder having physical properties that harden by a hydration reaction. When the hydraulic powder includes, in addition to powder having physical properties that harden by a hydration reaction such as cement, powder having a pozzolanic action, powder having latent hydraulicity, and stone powder (calcium carbonate powder), in the present invention, the amounts thereof are also included in the amount of the hydraulic powder. Further, when the powder having physical properties that harden by a hydration reaction contains a high-strength admixture, the amount of the high-strength admixture is also included in the amount of the hydraulic powder. This is the same for other mass percentages etc. related to the mass of the hydraulic powder.

[0037] (A) component can be used in a proportion of, for example, 0.001% by mass or more, further 0.005% by mass or more, further 0.01% by mass or more with respect to the water of the hydraulic composition from the viewpoint of reducing the strength difference of the hardened body, and 10% by mass or less, further 8% by mass or less, further 5% by mass or less, further 3% by mass or less, further 2% by mass or less, further 1.5% by mass or less, further 1.0% by mass or less from the viewpoint of economy.

[0038] When compound (1) is used as the (A) component, compound (1) is preferably used in a total amount of 0.001% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more with respect to the water of the hydraulic composition, and preferably 20% by mass or less, more preferably 15% by mass or less, still more preferably 10% by mass or less, even more preferably 8% by mass or less, even more preferably 5% by mass or less.

[0039] When using compound (1a) and compound (1b) as component (A), the compound (1a) is preferably used in an amount of 0.00095% by mass or more, more preferably 0.0075% by mass or more, still more preferably 0.035% by mass or more, even more preferably 0.06% by mass or more, and preferably 3.75% by mass or less, more preferably 3% by mass or less, still more preferably 2.8% by mass or less, even more preferably 2% by mass or less, even more preferably 1% by mass or less, based on the water of the hydraulic composition. Also, when using compound (1a) and compound (1b) as component (A), the compound (1b) is preferably used in an amount of 0.00005% by mass or more, more preferably 0.0025% by mass or more, still more preferably 0.015% by mass or more, even more preferably 0.04% by mass or more, and preferably 19% by mass or less, more preferably 11.25% by mass or less, still more preferably 7% by mass or less, even more preferably 5.2% by mass or less, even more preferably 3% by mass or less, based on the water of the hydraulic composition.

[0040] When using compound (1a) and compound (1b) as component (A), the mass ratio of compound (1b) / compound (1a) is preferably 5 / 95 or more, more preferably 25 / 75 or more, still more preferably 40 / 60 or more, and preferably 95 / 5 or less, more preferably 75 / 25 or less, still more preferably 60 / 40 or less.

[0041] The hydraulic composition according to the present invention may optionally contain water, hydraulic powder, and components other than component (A).

[0042] The hydraulic composition according to the present invention preferably contains a defoaming agent [(B) hereinafter referred to as component (B)]. Component (B) is preferably one or more compounds selected from polysiloxane, polyoxyethylene polyoxypropylene, polypropylene oxide and its derivatives (such as polyoxypropylene, polyoxypropylene glyceryl ether, etc.), acetylene glycol and its derivatives (such as acetylene glycol, alkylene oxide adducts of acetylene glycol, etc.), polyoxyalkylene fatty acid esters, polyoxyalkylene alkyl ethers, polyoxyalkylene alkyl amides, trialkyl phosphates, and alcohols. More preferably, these compounds are water-insoluble compounds.

[0043] Examples of polysiloxane include polysiloxane, dimethylpolysiloxane, polyhydroxymethylsiloxane, etc.

[0044] Examples of polyoxyethylene polyoxypropylene include polyoxyethylene polyoxypropylene random polymers, polypropylene oxide-polyethylene oxide-polypropylene oxide block polymers, etc. From the viewpoint of defoaming property, the weight average molecular weight of these is preferably 2,000 or more and 100,000 or less.

[0045] Examples of polypropylene oxide and its derivatives include polyoxypropylene glyceryl ether, polyoxypropylene, etc. From the viewpoint of defoaming property, the weight average molecular weight of the polypropylene oxide portion of these is preferably 2,000 or more and 100,000 or less.

[0046] Examples of acetylene glycol and its derivatives include commercially available products such as acetylenol E00, acetylenol E13 (both from Kawaken Fine Chemicals Co., Ltd.), DYNOL® 604, SURFYNOL® 440, SURFYNOL® 104, SURFYNOL® 2502, SURFYNOL® 420, and SURFYNOL® DF-75 (all from Air Products and Chemicals, Inc.). Examples of derivatives of acetylene glycol include alkylene oxide adducts of acetylene glycol. From the perspective of defoaming properties, the average number of moles of alkylene oxide added is preferably 1 or more and 100 or less. Propylene oxide is preferred as the alkylene oxide.

[0047] Examples of polyoxyalkylene fatty acid esters include alkylene oxide adducts of fatty acids having 4 to 22 carbon atoms. From the perspective of defoaming properties, the average number of moles of alkylene oxide added is preferably 1 or more and 100 or less. Also, from the same perspective, the alkylene oxide preferably contains propylene oxide.

[0048] Examples of polyoxyalkylene alkyl ethers include alkylene oxide adducts of alcohols having 4 to 22 carbon atoms. From the perspective of defoaming properties, the average number of moles of alkylene oxide added is preferably 1 or more and 100 or less. Also, from the same perspective, propylene oxide is preferred as the alkylene oxide. Specifically, polypropylene glycol lauryl ether, polypropylene glycol myristyl ether, and mixtures thereof can be mentioned.

[0049] Examples of polyoxyalkylene alkylamides include alkylene oxide adducts of amides of fatty acids having 8 to 22 carbon atoms and amines such as monoethanolamine and diethanolamine. From the perspective of defoaming properties, the average number of moles of alkylene oxide added is preferably 1 or more and 100 or less. Also, from the same perspective, propylene oxide is preferred as the alkylene oxide.

[0050] Examples of the trialkyl phosphate include tributyl phosphate and triisobutyl phosphate. From the viewpoint of defoaming properties, the number of carbon atoms in the alkyl group is preferably 1 or more and 5 or less.

[0051] Examples of the alcohol include alcohols having 4 to 22 carbon atoms, preferably monohydric alcohols having 4 to 22 carbon atoms. From the viewpoint of defoaming properties, the number of carbon atoms in the alcohol is preferably 6 or more and 18 or less.

[0052] Suitable examples of the defoamer include, as the polysiloxane, SAG (trademark) 672, SAGTEX (trademark) DSA (both Momentive Performance Materials Inc.), as the polyoxyalkylene fatty acid ester, polyoxyalkylene alkyl ether, or polyoxyalkylene alkylamide, polypropylene glycol lauryl ether, polypropylene glycol myristyl ether and mixtures thereof, propylene oxide - ethylene oxide adduct of oleic acid, SN Deformer 260 (trademark), SN Deformer 265 (trademark), SN Deformer 466 (trademark) (all San Nopco Ltd.), Defoamer NO. 21 (trademark), Defoamer NO. 8 (trademark) (both Kao Corporation), as the acetylene glycol, DYNOL (trademark) 604, SURFYNOL (registered trademark) 440, as the trialkyl phosphate, tributyl phosphate, triisobutyl phosphate, as the alcohol, 2 - ethylhexanol, as the polyoxyethylene polyoxypropylene, Newpol PE - 61 (trademark), Newpol PE - 71 (trademark) (both Sanyo Chemical Industries, Ltd.), and as the polyoxypropylene, polypropylene glycol having a molecular weight of 2,000 or more and 100,000 or less.

[0053] Also, from the perspective of economy, the antifoaming agent is preferably a polysiloxane, such as DK Q1-1183 (trademark), and a polyoxyalkylene fatty acid ester, polyoxyalkylene alkyl ether, or polyoxyalkylene alkylamide, such as SN Deformer 260 (trademark), SN Deformer 265 (trademark), SN Deformer 466 (trademark), Antifoaming Agent NO. 21 (trademark), Antifoaming Agent NO. 8 (trademark), a trialkyl phosphate, such as tributyl phosphate and triisobutyl phosphate, an alcohol, such as 2-ethylhexanol, a polyoxyethylene polyoxypropylene, such as Newpol PE-61 (trademark) and Newpol PE-71 (trademark), and a polyoxypropylene, such as a polypropylene glycol having a molecular weight of 2,000 or more and 100,000 or less.

[0054] When the hydraulic composition according to the present invention contains the component (B), the composition preferably contains the component (B) in a proportion of 0.001% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.1% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, and still more preferably 5% by mass or less, based on the component (A).

[0055] The hydraulic composition according to the present invention can contain (C) an anionic aromatic compound. Examples of the component (C) include one or more compounds selected from sulfonic acids having an aromatic ring, carboxylic acids having an aromatic ring, phosphonic acids having an aromatic ring, or salts thereof. The anionic aromatic compound is preferably an acid-type compound having a total carbon number of 6 or more and 12 or less. Specific examples of the anionic aromatic compound include salicylic acid, p-toluenesulfonic acid, sulfosalicylic acid, benzoic acid, m-sulfobenzoic acid, p-sulfobenzoic acid, 4-sulfophthalic acid, 5-sulfoisophthalic acid, p-phenolsulfonic acid, m-xylene-4-sulfonic acid, cumenesulfonic acid, methyl salicylic acid, styrenesulfonic acid, chlorobenzoic acid, and the like. These may form salts. Two or more anionic aromatic compounds may be used. The anionic aromatic compound is preferably one or more compounds selected from sulfonic acids having an aromatic ring, carboxylic acids having an aromatic ring, or salts thereof.

[0056] When using the component (C), the mass ratio of the component (A) / the component (C), and further the mass ratio of the compound (1) / the component (C) are preferably 50 / 50 or more, more preferably 70 / 30 or more, still more preferably 80 / 20 or more, and preferably 99.9 / 0.1 or less, more preferably 95 / 5 or less.

[0057] The hydraulic composition according to the present invention can optionally contain components such as a dispersant, an AE agent, a retarder, a foaming agent, a thickener, a foaming agent, a waterproof agent, and a fluidizing agent, etc. within a range that does not affect the effects of the present invention.

[0058] In addition, optional components such as the component (B) and the component (C) can be added when adding the component (A) or after adding the component (A), in addition to being premixed in the hydraulic composition. Also, it can be used as a composition containing the component (A) and an optional component, for example, the component (C).

[0059] The hydraulic composition according to the present invention may contain aggregates. Examples of the aggregates include fine aggregates and coarse aggregates. The fine aggregates are preferably mountain sand, land sand, river sand, and crushed sand, and the coarse aggregates are preferably mountain gravel, land gravel, river gravel, and crushed stone. Depending on the application, lightweight aggregates may be used. The term "aggregate" is based on "Concrete Compendium" (published by Technical Bookstore on June 10, 1998).

[0060] In the present invention, since it is not particularly necessary to suppress the occurrence of bleeding of the hydraulic composition to be used, a hydraulic composition in which bleeding occurs can also be used. For example, in the present invention, a hydraulic composition having a bleeding rate of preferably 20% or less, more preferably 15% or less, still more preferably 12% or less can be used. This range is preferable also from the viewpoint of, for example, constructing the hydraulic composition. However, in the present invention, even if bleeding occurs up to such a wide range, the strength difference of the hardened body can be reduced. On the other hand, if the component (A) is not used, as shown in the comparative examples described later, it is not possible to expand to such a bleeding rate and reduce the strength difference of the hardened body. The lower limit value of the bleeding rate is preferably 0% or more, more preferably 1.0% or more, still more preferably 2.0% or more, and even more preferably 3.0% or more. That is, in the present invention, a hydraulic composition having a bleeding rate of preferably 0% or more, more preferably 1.0% or more, still more preferably 2.0% or more, and even more preferably 3.0% or more, and preferably 20% or less, more preferably 15% or less, still more preferably 12% or less can be used. Here, the bleeding rate of the hydraulic composition is the bleeding rate 3 hours after the preparation of the hydraulic composition containing the component (A), measured using the bleeding rate and expansion rate test method (polyethylene bag method) of the injected mortar of JSCE-F 522-2007 prepacked concrete. In the present invention, it is possible to reduce the strength difference of the hardened body for a hydraulic composition prepared with a composition in which the bleeding rate 3 hours after preparation according to JSCE-F 522-2007 is within the above range. As an example of the method of the present invention, when producing a hardened body from a hydraulic composition containing water and hydraulic powder, the component (A) is allowed to coexist in the hydraulic composition, and the composition of the hydraulic composition having a bleeding rate of 0% or more and 20% or less 3 hours after preparation according to JSCE-F 522-2007 is determined, and the hardened body is obtained by curing the hydraulic composition having that composition. A method for controlling the strength of a hardened body can be mentioned, which reduces the strength difference of the hardened body in the direction of the gravity applied to the hydraulic composition during curing.

[0061] The cured body of the hydraulic composition targeted by the present invention is a cured body of a predetermined shape. Although the shape of the cured body is not limited, a cured body having a longitudinal shape often has a large disadvantage due to the strength difference, so it is suitable as the shape of the cured body targeted by the present invention. The present invention may be, for example, a method of curing the hydraulic composition according to the present invention in a longitudinal shape in the gravitational direction and reducing the strength difference in the longitudinal direction of the obtained cured body. Further, the present invention may be, for example, a method of curing the hydraulic composition according to the present invention in a shape having a portion of 30 cm or more in length in the gravitational direction and reducing the strength difference in the portion of the obtained cured body having a length of 30 cm or more. Here, a plurality of the portions of 30 cm or more may exist in the cured body. For example, in a cured body having a longitudinal shape in the gravitational direction, the thickness (length) in the longitudinal direction and the thickness in the lateral direction may each be 30 cm or more. Further, when the cured body has a portion having a length of 30 cm or more in the gravitational direction and a portion having a length of less than 30 cm in the gravitational direction, the present invention may reduce the strength difference in both portions.

[0062] As an example of the cured body targeted by the present invention, there are mentioned fillers such as piles, pile peripheral fixing liquids, root fixing liquids, backfill materials, buried backfill materials for pipe channels, buried backfill materials after pile extraction, and diaphragm walls. Examples of piles include ground improvement piles.

[0063] The present invention can be applied, for example, when using a hydraulic composition for ground improvement for the purpose of improving the foundation ground of a house or the like, such as ground improvement such as a columnar ground reinforcement method (also referred to as a soil cement column method). It can also be used in a method for preventing ground collapse and stabilizing the ground mass and rock mass after excavation. By applying the present invention to a hydraulic composition for ground injection to a columnar ground reinforcement method, for example, a ground improvement body with a small strength difference can be constructed.

[0064] In the present invention, the fact that the strength difference of the cured body is reduced can be confirmed, for example, by extracting the core of the object, measuring its strength, and the difference in the strength being within 5%. Core extraction and the measurement of its strength can be measured according to JIS A 1107 or JIS A 1216.

Example

[0065] [Components Used] (1) Water Tap water (2) Hydraulic powder Blast furnace B-type cement (Sumitomo Osaka Cement Co., Ltd.) (3) Component (A) Oleyl dimethylamine oxide Oleic acid amidopropyldimethylamine oxide (4) Component (B) Defoamer 1: Manufactured by Momentive Performance Materials Ink, SAG672 Defoamer 2: Manufactured by Kao Corporation, Antifoam E-20 (5) Component (C) Sodium m-xylene sulfonate Sodium p-toluenesulfonate

[0066] [Additives] Formulations 1 - 4: Additives obtained by combining Component (A) and Component (C) as shown in Table 1 (% in Table 1 is mass%) C16 - quaternary salt: Hexadecyltrimethylammonium chloride C18 - quaternary salt: Octadecyltrimethylammonium chloride Commercially available mixture: Asaclean, manufactured by Shin-Etsu Chemical Co., Ltd. Bentonite: TB - 250, manufactured by Tachibana Materials Co., Ltd. Basic magnesium carbonate: Manufactured by Kanto Chemical Co., Inc.

[0067]

Table 1

[0068] <Example 1 and Comparative Example 1> [Preparation of Hydraulic Composition] (1) Examples 1 - 1 to 1 - 6 In a 5-liter plastic container, 1200 g of water, 2000 g of hydraulic powder, and a predetermined amount of component (B) shown in Table 2 were added, and the mixture was stirred with a cooking hand mixer for 15 seconds. The unmixed hydraulic powder adhering to the bottom was scraped off and stirred for another 15 seconds to obtain Mixture 1. Also, Formulations 1 to 4 in Table 1 (% in Table 1 is mass %) were weighed into another container and added to 400 g of water taken, and dissolved well until uniform to obtain Mixture 2. The prepared Mixture 1 and Mixture 2 were mixed and stirred for 60 seconds to prepare a hydraulic composition of the sample.

[0069] (2) Comparative Examples 1-1 to 1-2 In a 5-liter plastic container, 1200 g of water, 2000 g of hydraulic powder, a predetermined amount of component (B) shown in Table 2, and a predetermined amount of component (C) (sodium p-toluenesulfonate) shown in Table 2 were added, and the mixture was stirred with a cooking hand mixer for 15 seconds. The unmixed hydraulic powder adhering to the bottom was scraped off and stirred for another 15 seconds to obtain Mixture 1. Also, a C16 quaternary salt and a C18 quaternary salt were used in combination at a mass ratio of C16 quaternary salt / C18 quaternary salt = 60 / 40, and added to 400 g of water taken in another container so as to be a predetermined amount shown in Table 2, and dissolved well until uniform to obtain Mixture 2. The prepared Mixture 1 and Mixture 2 were mixed and stirred for 60 seconds to prepare a hydraulic composition of the sample.

[0070] (3) Comparative Examples 1-3 to 1-5 A predetermined amount of the commercially available admixture shown in Table 2 was added to 400 g of water and stirred to prepare a slurry in a well-dispersed state. 1200 g of water and 2000 of hydraulic powder were added to a 5-liter plastic container and stirred with a cooking hand mixer for 15 seconds. The unmixed hydraulic powder adhering to the bottom was scraped off and stirred for another 15 seconds. Then, the entire amount of the slurry of the commercially available admixture was added and stirred for 60 seconds to prepare a hydraulic composition of the sample.

[0071] (4) Comparative Examples 1-6 to 1-7 1600 g of water was added with the predetermined amount of the bentonite shown in Table 2 and stirred to prepare a bentonite slurry in a well-dispersed state, which was sufficiently swollen over 24 hours. 2000 g of hydraulic powder and the total amount of the swollen bentonite slurry were added to a 5-liter plastic container, and the sample hydraulic composition was prepared by sufficiently stirring with a cooking hand mixer for 60 seconds or more.

[0072] (5) Comparative Examples 1-8 to 1-9 1600 g of water, 2000 g of hydraulic powder, and the predetermined amount of the basic magnesium carbonate shown in Table 2 were added to a 5-liter plastic container, stirred with a cooking hand mixer for 15 seconds, the un-mixed hydraulic powder adhering was scraped off, and further stirred for 45 seconds to prepare the sample hydraulic composition.

[0073] The water / hydraulic powder ratio of the hydraulic compositions of Example 1 and Comparative Example 1 was 80%. In addition, the addition amounts of the respective additives used in Example 1 and Comparative Example 1 were adjusted to an amount capable of suppressing the occurrence of bleeding (a large addition amount) or an amount that shortens the flow-down time (a small addition amount).

[0074] [Evaluation] (1) Flow-down time The flow-down time of the hydraulic composition immediately after preparation was measured using the fluidity test method (method using a P funnel) for the injection mortar of pre-packaged concrete in JSCE-F 521-1999.

[0075] (2) Bleeding rate The bleeding rate of the hydraulic composition 3 hours after preparation was calculated using the bleeding rate and expansion rate test method (polyethylene bag method) for the injection mortar of pre-packaged concrete in JSCE-F 522-2007.

[0076] (3) Strength The 11-day strength of the hydraulic composition was measured. A polyethylene bag used for measuring the bleeding rate was joined together so that its height was 100 cm or more, and the sample was filled to a predetermined height and left at 20°C. After 10 days, the hardened body was taken out of the bag, 5 cm from the upper and lower parts of the hardened body was cut off with a concrete cutter or a wire saw, and it was further cut off to a height of 10 cm, and two specimens with a diameter of 5 cm and a height of 10 cm were prepared. On the day after the preparation (24 hours later), the specimen was compressed at a speed of 0.2 N / mm per second, and the maximum stress was taken as the strength. The strength of the specimen was measured with the upstream as the upper part and the downstream as the lower part based on the direction of the gravity applied to the hydraulic composition during hardening (the same applies hereinafter). 2

[0077]

Table 2

[0078] Note that the addition rate in the table is the mass% with respect to water for water, the mass% with respect to the hydraulic powder for the powder, and the mass% with respect to the additive for the additive (the same applies hereinafter).

[0079] In Examples 1-1 to 1-6, the upper / lower strength ratio can reach 1.03 or less, while in Comparative Examples 1-1 to 1-9, the upper / lower strength ratio is 1.06 or more. Also, in Examples 1-1 to 1-6, it can be seen that the upper / lower strength ratio is within the range of 1.00 ± 0.04 when the bleeding rate is in the range of 0% to 10.5%. On the other hand, in Comparative Examples 1-1 to 1-9, it can be seen that in order to make the upper / lower strength ratio 1.09 or less, it is necessary to make the bleeding rate 0.8% or less. Comparing Example 1-6 with Comparative Examples 1-2 and 1-7 where the bleeding rate is 0.0%, it can be seen that Example 1-6 has a smaller strength difference and also has excellent fluidity considering the application time as the flow-down time is shorter.

[0080] <Examples 2 and Comparative Examples 2> A hydraulic composition was prepared in the same manner as in Example 1 and Comparative Example 1, and the same evaluation was performed. However, the water / hydraulic powder ratio (denoted as W / P in the table) of the hydraulic composition was as shown in Table 3. Also, when the water / hydraulic powder ratio was 2.0, the uniaxial compressive strength was measured according to JIS A 1216, and the maximum stress was taken as the strength. Also, as the additive containing components (A) and (C) which are additive components, formulation 4 in Table 1 was used, and the addition rate was as shown in Table 3. Also, the filling height of the hydraulic composition was as shown in Table 3. Also, the antifoaming agent of component (B) was not added. The results are shown in Table 3.

[0081]

Table 3

[0082] Comparing Example 2-1 with a W / P of 50% by mass and a filling height of 80 cm and Comparative Example 2-3, their flow-down time and bleeding rate of the hydraulic composition are almost the same, but Example 2-1 has an upper / lower strength ratio of 1.02, while Comparative Example 2-3 has an upper / lower strength ratio of 1.25. It can be seen that the strength difference between the upper and lower parts of Example 2-1 is smaller. Also, in Comparative Examples 2-1 to 2-3, as the filling height increases to 30 cm, 40 cm, and 80 cm, the upper / lower strength ratio increases. On the other hand, in Examples 2-2 and 2-3 with a filling height of 30 cm and 80 cm, Examples 2-4 and 2-5, and Examples 2-6 and 2-7, the values of the upper / lower strength ratio are all close to 1, and the fluctuation range is significantly smaller than that of the comparative examples. It can be seen that even when the hydraulic composition is cured in a shape that is easily affected by gravity, the strength difference can be reduced in the examples.

Claims

1. When producing a hardened body from a hydraulic composition containing water and hydraulic powder (excluding those containing a high-performance water-reducing agent), By coexisting (A) an amine oxide surfactant (hereinafter referred to as component (A)) with the hydraulic composition and curing it, the strength difference of the hardened body is reduced in the direction of the gravity acting on the hydraulic composition during curing. A method for controlling the strength of a hardened body, The hydraulic composition is cured in a shape having a portion with a length of 80 cm or more in the direction of gravity, and the strength difference in the portion of the obtained hardened body with a length of 80 cm or more is reduced. The hydraulic composition has a water / hydraulic powder ratio, which is the mass ratio of water to hydraulic powder, of 60% by mass or more. A method for controlling the strength of a hardened body, wherein the hardened body is a pile for ground improvement.

2. The method for controlling the strength of a hardened body according to claim 1, wherein the hydraulic composition is cured in a longitudinal shape in the direction of gravity, and the strength difference in the longitudinal direction of the obtained hardened body is reduced.

3. The method for controlling the strength of a hardened body according to claim 1 or 2, wherein the bleeding rate after 3 hours of preparation of the hydraulic composition is 20% or less.

4. The method for controlling the strength of a hardened body according to any one of claims 1 to 3, wherein two or more kinds of component (A) coexist.

5. The method for controlling the strength of a hardened body according to any one of claims 1 to 4, wherein the hydraulic composition contains (B) an antifoaming agent.

6. The method for controlling the strength of a hardened body according to any one of claims 1 to 5, wherein the hydraulic composition contains (C) an anionic aromatic compound.

Images