Sulfuric acid-resistant grout composition, sulfuric acid-resistant mortar composition, sulfuric acid-resistant concrete composition, and methods for producing the same

Abstract

To provide a sulfuric acid-resistant grout composition, a sulfuric acid-resistant mortar composition, a sulfuric acid-resistant concrete composition, and methods for producing the same, characterized by excellent fluidity and suppressed post-expansion.SOLUTION: One aspect of the present invention relates to a sulfuric acid-resistant grout composition, a sulfuric acid-resistant mortar composition, or a sulfuric acid-resistant concrete composition, comprising (a) a first cement, (b) limestone fine powder, (c) a sulfuric acid resistance-imparting agent, (d1) a first admixture comprising 1 to 5 wt.% of hydroxypropyl methylcellulose having a viscosity of 1,000 mPa s or more and 18,000 mPa s or less in a 2 mass% aqueous solution at 20°C, and a second cement, and (e) water.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a sulfuric acid-resistant grout composition, a sulfuric acid-resistant mortar composition, a sulfuric acid-resistant concrete composition, and methods for producing the same. [Background technology]

[0002] Corrosion of hardened cement paste by sulfuric acid has been a problem in places exposed to sulfuric acid or sulfates, such as sewers, hot springs, etc. In recent years, corrosion by acid rain has become a problem not only in limited places such as sewers and hot springs, but also in all structures that use cement.

[0003] When hardened cement products (such as grout, mortar, and concrete) are exposed to sulfuric acid for extended periods, they form insoluble gypsum and produce silica gel and alumina gel. This effect of sulfuric acid on concrete naturally depends on the acid concentration. At pH levels above 2 (sulfuric acid concentrations below 0.1%), i.e., low acid concentrations, corrosion caused by carbon dioxide, low-concentration acids, or corrosive salts such as sulfates can be prevented by densifying the hardened cement product, for example, by using high-performance air-entraining water-reducing agents to reduce the water-cement ratio while maintaining workability, thereby improving corrosion resistance. However, at higher sulfuric acid concentrations, densification alone is not sufficient to prevent this. For example, at pH levels below 2, it is difficult to expect the cement material itself to be resistant to sulfuric acid.

[0004] Patent Document 1 discloses a grout composition that contains cement, a specific naphthalene sulfonate condensate, an expanding agent, a foaming agent, and a fine aggregate, and that can give a hardened body with improved sulfuric acid resistance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-234101 Summary of the Invention [Problem to be solved by the invention]

[0006] To further expand the options for sulfuric acid-resistant grout compositions, mortar compositions, and concrete compositions, the inventors conducted detailed studies on admixtures for use in these compositions. Patent Document 1 uses the acrylic compound TNS-100 as a separation-reducing agent in the examples. Instead, we investigated admixtures that can be used. However, when mortar compositions were mixed using various acrylic compounds known as cement admixtures, we found that the compositions did not flow (did not exhibit fluidity) and tended to aggregate into granular particles as they were mixed. Therefore, the present invention aims to provide sulfuric acid-resistant grout compositions, sulfuric acid-resistant mortar compositions, sulfuric acid-resistant concrete compositions, and the like that can suppress material separation during mixing, have good fluidity after mixing, exhibit little change in fluidity over time, and have excellent workability. [Means for solving the problem]

[0007] Preferred embodiments of the present invention are as follows.

[0008] 1. (a) First cement; (b) fine limestone powder, (c) sulfuric acid resistance imparting agent; (d1) A first admixture containing 1% by weight to 5% by weight of hydroxypropyl methylcellulose having a viscosity of 1,000 mPa·s or more and 18,000 mPa·s or less in a 2% by weight aqueous solution at 20 ° C., and a second cement; and (e) water 1. A sulfuric acid resistant grout composition comprising:

[0009] 2. Furthermore, (d2) A second admixture which is one or more selected from the group consisting of attapulgite, sepiolite, bentonite, talc, and silica fume. Item 1. The sulfuric acid resistant grout composition according to item 1, comprising:

[0010] 3. The sulfuric acid-resistant grout composition according to item 1 or 2, wherein the hydroxypropyl methylcellulose has a degree of substitution of methoxy groups of 1.7 to 1.9 and a degree of substitution of hydroxypropoxy groups of 0.1 to 0.2.

[0011] 4. The sulfuric acid-resistant grout composition according to any one of items 1 to 3, wherein the sulfuric acid resistance imparting agent comprises a naphthalene sulfonate condensate.

[0012] 5. The sulfuric acid-resistant grout composition according to any one of items 2 to 4, wherein the content of the hydroxypropyl methylcellulose is 0.2 to 1.0 parts by mass relative to 100 parts by mass of the total of the first admixture and the second admixture.

[0013] 6. The sulfuric acid-resistant grout composition according to any one of items 1 to 5, which comprises a first admixture (d1) in addition to the components (a), (b), (c) and (e).

[0014] 7. The sulfuric acid-resistant grout composition according to any one of items 2 to 6, which has a first admixture (d1) and a second admixture (d2) in addition to the components (a), (b), (c) and (e).

[0015] 8. Components other than the first admixture (d1) and the second admixture (d2) 1m 3 8. The sulfuric acid-resistant grout composition according to any one of items 2 to 7, wherein the total content of the first admixture (d1) and the second admixture (d2) is 5 to 30 kg relative to the total weight of the grout composition.

[0016] 9. A cured product of the sulfuric acid resistant grout composition according to any one of items 1 to 8.

[0017] 10. (a) First cement; (b) fine limestone powder, (c) sulfuric acid resistance imparting agent; (d1) a first admixture containing 1% by weight to 5% by weight of hydroxypropyl methylcellulose, the viscosity of a 2% by weight aqueous solution of which at 20°C is 1,000 mPa·s or more and 18,000 mPa·s or less, and a second cement; (e) water, and (f) Fine aggregate A sulfate-resistant mortar composition comprising:

[0018] 11. A hardened product of the sulfuric acid resistant mortar composition according to item 10.

[0019] 12. (a) First cement; (b) fine limestone powder, (c) sulfuric acid resistance imparting agent; (d1) a first admixture containing 1% by weight to 5% by weight of hydroxypropyl methylcellulose, the viscosity of a 2% by weight aqueous solution of which at 20°C is 1,000 mPa·s or more and 18,000 mPa·s or less, and a second cement; (e) water; (f) fine aggregate, and (g) Coarse aggregate 1. A sulfate-resistant concrete composition comprising:

[0020] 13. Furthermore, (d2) A second admixture which is one or more selected from the group consisting of attapulgite, sepiolite, bentonite, talc, and silica fume. Item 13. The sulfate resistant concrete composition according to item 12, comprising:

[0021] 14. A hardened product of the sulfate-resistant concrete composition according to item 12 or 13.

[0022] 15. (d1) An admixture for preparing a sulfuric acid-resistant grout composition, a sulfuric acid-resistant mortar composition, or a sulfuric acid-resistant concrete composition, comprising a first admixture consisting of 1% by weight to 5% by weight of hydroxypropyl methylcellulose, the viscosity of a 2% by weight aqueous solution at 20°C of which is 1,000 mPa·s or more and 18,000 mPa·s or less, and cement.

[0023] 16. Furthermore, (d2) A second admixture which is one or more selected from the group consisting of attapulgite, sepiolite, bentonite, talc, and silica fume. Item 16. An admixture for preparing a sulfuric acid-resistant grout composition, a sulfuric acid-resistant mortar composition, or a sulfuric acid-resistant concrete composition according to item 15, comprising:

[0024] 17. A dilution step (d1) of preparing a first admixture by diluting hydroxypropyl methylcellulose, whose viscosity as a 2% by mass aqueous solution at 20°C is 1,000 mPa·s or more and 18,000 mPa·s or less, with a second cement to a concentration of 1% by weight to 5% by weight; A mixing step of mixing (a) a first cement, (b) limestone fine powder, (c) a sulfuric acid resistance imparting agent, the first admixture (d1), and (e) water; 1. A method for producing a sulfuric acid resistant grout composition, comprising:

[0025] 18. A dilution step of preparing a first admixture (d1) by diluting hydroxypropyl methylcellulose, whose viscosity of a 2% by mass aqueous solution at 20°C is 1000 mPa·s or more and 18,000 mPa·s or less, with a second cement to a concentration of 1% by weight to 5% by weight; A mixing step of mixing (a) a first cement, (b) limestone fine powder, (c) a sulfuric acid resistance imparting agent, the first admixture (d1), (e) water, and (f) fine aggregate; A method for producing a sulfuric acid resistant mortar composition, comprising:

[0026] 19. A dilution step of preparing a first admixture (d1) by diluting hydroxypropyl methylcellulose, whose viscosity of a 2% by mass aqueous solution at 20°C is 1000 mPa·s or more and 18,000 mPa·s or less, with a second cement to a concentration of 1% by weight to 5% by weight; a mixing step of mixing (a) a first cement, (b) limestone fine powder, (c) a sulfuric acid resistance imparting agent, the first admixture (d1), (e) water, (f) fine aggregate, and (g) coarse aggregate; A method for producing a sulfate-resistant concrete composition, comprising:

[0027] 20. A sulfuric acid-resistant grout composition according to any one of items 1 to 8, which contains each component individually.

[0028] 21. A sulfuric acid resistant grout composition according to any one of items 1 to 8, wherein the components are mixed together.

[0029] 22. A cured product of the sulfuric acid resistant grout composition according to either item 20 or 21.

[0030] 23.Furthermore, (d2) A second admixture which is one or more selected from the group consisting of attapulgite, sepiolite, bentonite, talc, and silica fume. Item 11. The sulfuric acid resistant mortar composition according to item 10, comprising:

[0031] 24. The sulfuric acid-resistant mortar composition according to item 10 or 23, wherein the hydroxypropyl methylcellulose has a degree of substitution of methoxy groups of 1.7 to 1.9 and a degree of substitution of hydroxypropoxy groups of 0.1 to 0.2.

[0032] 25. The sulfuric acid-resistant mortar composition according to item 10, 23 or 24, wherein the sulfuric acid resistance imparting agent comprises a naphthalene sulfonate condensate.

[0033] 26. The sulfuric acid-resistant mortar composition according to any one of items 23 to 25, wherein the content of the hydroxypropyl methylcellulose is 0.2 to 1.0 parts by mass per 100 parts by mass of the total of the first admixture and the second admixture.

[0034] 27. The sulfuric acid-resistant mortar composition according to any one of items 10 and 23 to 26, which contains a first admixture in addition to other components.

[0035] 28. The sulfuric acid-resistant mortar composition according to any one of items 23 to 27, which contains a first admixture (d1) and a second admixture (d2) in addition to components (a), (b), (c), (e), and (f).

[0036] 29. Components other than the first admixture (d1) and the second admixture (d2) 1m 3 29. The sulfuric acid resistant mortar composition according to any one of items 23 to 28, wherein the total content of the first admixture (d1) and the second admixture (d2) is 3 to 20 kg relative to the total weight of the mortar.

[0037] 30. A hardened product of the sulfuric acid resistant mortar composition according to any one of items 23 to 29.

[0038] 31. The sulfate-resistant concrete composition according to item 12 or 13, wherein the hydroxypropyl methylcellulose has a degree of substitution of methoxy groups of 1.7 to 1.9 and a degree of substitution of hydroxypropoxy groups of 0.1 to 0.2.

[0039] 32. The sulfate-resistant concrete composition according to item 12, 13 or 31, wherein the sulfate resistance imparting agent comprises a naphthalene sulfonate condensate.

[0040] 33. The sulfate-resistant concrete composition according to item 13, 31, or 32, wherein the content of the hydroxypropyl methylcellulose is 0.2 to 1.0 part by mass per 100 parts by mass of the total of the first admixture and the second admixture.

[0041] 34. A sulfate-resistant concrete composition according to any one of items 12, 13, or 31 to 33, which contains a first admixture in addition to other components.

[0042] 35. A sulfate-resistant concrete composition according to any one of items 13 and 31 to 34, which contains a first admixture (d1) and a second admixture (d2) in addition to components (a), (b), (c), (e), (f), and (g).

[0043] 36. Components other than the first admixture (d1) and the second admixture (d2) 1m 3 Item 13 or 31 to 35, wherein the total content of the first admixture (d1) and the second admixture (d2) is 2 to 15 kg.

[0044] 37. A hardened product of the sulfate resistant concrete composition according to any one of items 31 to 36. [Effects of the Invention]

[0045] According to one aspect of the present invention, it is possible to provide a sulfuric acid-resistant grout composition, a sulfuric acid-resistant mortar composition, and a sulfuric acid-resistant concrete composition that have good fluidity after mixing, little change in fluidity over time, and excellent workability. Also, according to one aspect of the present invention, it is possible to provide a sulfuric acid-resistant concrete composition that has excellent air retention. DETAILED DESCRIPTION OF THE INVENTION

[0046] The sulfuric acid-resistant grout composition, sulfuric acid-resistant mortar composition, and sulfuric acid-resistant concrete composition of the present embodiment, as well as methods for producing these compositions, will now be described.

[0047] In this specification, a grout composition containing cement, water, etc. to which fine aggregate has been added is referred to as a "mortar composition," and a grout composition to which fine aggregate and coarse aggregate have been added is referred to as a "concrete composition." In this specification, the sulfuric acid-resistant grout composition, sulfuric acid-resistant mortar composition, and sulfuric acid-resistant concrete composition are collectively referred to as a "sulfuric acid-resistant composition" or "composition." The "composition" may be the composition before or after mixing of the components, or may be a composition in which some of the components have been mixed in advance.

[0048] The sulfuric acid-resistant composition of this embodiment contains a specific admixture, which can suppress material separation during and after mixing (i.e., has high resistance to material separation). Material separation here refers to the separation of some of the constituent components in the composition from the other constituent components, resulting in uneven distribution of the constituent components. When material separation occurs, problems such as floating of water, precipitation of fine particles associated with floating of water, and settling of aggregate are likely to occur. Furthermore, the sulfuric acid-resistant composition of this embodiment has good fluidity (flow) and little change in fluidity over time. Because the change in fluidity over time is little, the composition has a long usable life and excellent workability. Furthermore, the sulfuric acid-resistant concrete composition of this embodiment has a high air retention rate after mixing.

[0049] Each component constituting the composition of the present invention will be described below. In this specification, the term "unit amount (kg / m)" is used. 3 )" is 1m 3 The term "unit water volume" refers to the amount of each material used to manufacture grout, mortar, or concrete. 3 The term "water" refers to the amount of water used in producing grout, mortar, or concrete.

[0050] <Sulfuric acid resistant grout composition> One aspect of the present invention relates to a sulfuric acid resistant grout composition (also simply referred to as a "grout composition"). The sulfuric acid resistant grout composition of the present invention comprises: (a) a first cement; (b) fine limestone powder, (c) sulfuric acid resistance imparting agent; (d1) A first admixture containing 1% by weight to 5% by weight of hydroxypropyl methylcellulose having a viscosity of 1,000 mPa·s or more and 18,000 mPa·s or less in a 2% by weight aqueous solution at 20 ° C., and a second cement; and (e) water In a preferred embodiment, the grout composition further comprises (d2) a second admixture, which is one or more selected from the group consisting of attapulgite, sepiolite, bentonite, talc, and silica fume. In this specification, the components are also referred to as component (a), component (b), component (c), component (d1), component (d2), and component (e), respectively. The sulfuric acid-resistant grout composition can be used in the form of a slurry by mixing the components together.

[0051] <(a) First cement> Examples of the first cement include ordinary Portland cement, high-early-strength Portland cement, ultra-high-early-strength Portland cement, sulfate-resistant Portland cement, moderate-heat Portland cement, low-heat Portland cement, blast-furnace cement, fly ash cement, silica fume cement, alumina cement, etc. One type of cement may be used, or two or more types may be used in combination.

[0052] The amount of the first cement in the grout composition is not particularly limited, but is preferably 550 kg / m 3 More preferably, 600 kg / m 3 or more, and preferably 1280 kg / m 3 or less, more preferably 1100 kg / m 3 The following is the result.

[0053] <(b) Fine limestone powder> The Blaine specific surface area of ​​the limestone powder (measured in accordance with JIS R 5201 "Physical Testing Methods for Cement") is preferably 2000 cm 2 / g or more, more preferably 3000 cm 2 / g or more, more preferably 4000 cm 2 / g or more, and preferably 8000 cm 2 / g or less. The inclusion of limestone fine powder in the composition improves sulfuric acid resistance. The mechanism by which limestone fine powder exhibits sulfuric acid resistance is not clear, but it is thought to be related to the fact that it is easy to form gypsum, which acts as a barrier, and that there is little expansion when the gypsum is formed.

[0054] In the grout composition, the mass ratio (a:b) of the first cement to the limestone fine powder is preferably in the range of 20:80 to 80:20, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40. When the mass ratio of the first cement to the limestone fine powder is within this range, it is possible to sufficiently prevent a decrease in resistance to erosion when the grout is immersed in an aqueous sulfuric acid solution.

[0055] <(c) Sulfuric acid resistance imparting agent> The sulfuric acid resistance-imparting agent is a compound that, when a hardened body formed from a grout composition, a mortar composition, or a concrete composition is exposed to sulfuric acid, forms a dense gypsum layer on the surface of the hardened body, thereby improving sulfuric acid resistance. Such sulfuric acid resistance-imparting agents are preferably aromatic polymers having sulfonic acid groups and / or sulfonate salt groups, and the weight-average molecular weight of the aromatic polymer having sulfonic acid groups and / or sulfonate salt groups is preferably 3,000 to 2,000,000. Specific examples of sulfuric acid resistance-imparting agents include at least one compound selected from the group consisting of naphthalene sulfonate condensates, polystyrene sulfonic acid or its salts, aromatic aminosulfonic acid polymers, and lignin sulfonate compounds. In one aspect of this embodiment, the sulfuric acid resistance-imparting agent is preferably a naphthalene sulfonate condensate. These compounds may be used alone or in combination.

[0056] Although the reason why the aromatic polymer having sulfonic acid groups and / or sulfonate groups improves sulfuric acid resistance is unclear, the following mechanism is presumed. Sulfate corrosion is a phenomenon in which sulfate ions generated in environments such as sewers and hot springs react with calcium ions eluted from grout, mortar, or concrete to form brittle gypsum. After the gypsum layer is removed, new gypsum is formed, resulting in the erosion of grout, mortar structures, or concrete structures. One possible reason is that the aromatic polymer having sulfonic acid groups and / or sulfonate groups acts on the precipitation mechanism of gypsum produced when cement or cement hydrate in the hardened body reacts with sulfuric acid, forming a dense gypsum layer on the surface of the hardened body, thereby inhibiting the removal of the gypsum layer and suppressing the penetration of sulfuric acid.

[0057] The naphthalenesulfonate condensate used as the sulfuric acid resistance imparting agent may be, for example, a formalin condensate of naphthalenesulfonate. The naphthalenesulfonate is preferably a salt with an alkali metal such as sodium (Na) or potassium (K), an alkaline earth metal such as magnesium (Mg) or calcium (Ca), ammonium, or an amine.

[0058] Furthermore, the number average molecular weight of the naphthalene sulfonate condensate is not limited, but is preferably 2,000 to 6,000. Furthermore, the weight average molecular weight of the naphthalene sulfonate condensate is not limited, but is preferably 3,000 to 30,000. When the number average molecular weight and weight average molecular weight of the naphthalene sulfonate condensate are within the above ranges, sufficient sulfuric acid resistance can be obtained.

[0059] The number-average molecular weight and weight-average molecular weight of a naphthalenesulfonate condensate are calculated by converting the number-average molecular weight and weight-average molecular weight of the main component peak alone into a calibration curve of a standard substance (e.g., polystyrene) when measuring the molecular weight of a naphthalenesulfonate condensate by gel filtration chromatography (GFC). The main component peak is the peak with the greatest peak intensity (area) on the high-molecular-weight side detected early in the measurement among a molecular weight distribution having multiple peaks.

[0060] In the formalin condensate salt of naphthalenesulfonic acid, some or all of the hydrogen atoms in the naphthalene ring may be substituted with, for example, an alkyl group. There are no particular limitations on the alkyl group, but it is preferably an alkyl group having 1 to 3 carbon atoms (methyl group, ethyl group, propyl group).

[0061] In one embodiment, it is preferable to use a compound represented by the following formula as the formalin condensate salt of naphthalenesulfonic acid.

[0062] [ka]

[0063] The amount of (c) sulfuric acid resistance imparting agent in the sulfuric acid-resistant grout composition is not limited, but is preferably 0.3 to 15 parts by weight, more preferably 1 to 12 parts by weight, even more preferably 2 to 10 parts by weight, and even more preferably 2 to 5 parts by weight, based on the solid content, per 100 parts by weight of (a) first cement. If the amount of naphthalene sulfonate condensate in the composition is within the above range, the resulting hardened product can have sufficient sulfuric acid resistance.

[0064] <(d) Admixture> <(d1) First admixture> The grout composition includes a first admixture ("component (d1)") that includes 1 to 5% by weight of hydroxypropyl methylcellulose, a 2% by weight aqueous solution of which has a viscosity of 1,000 mPa·s to 18,000 mPa·s at 20°C, and a second cement. In this specification, "hydroxypropyl methylcellulose" is also referred to as "HPMC."

[0065] The inventors of the present invention have discovered that by using a first admixture (d1) in which hydroxypropyl methylcellulose, a 2% by mass aqueous solution of which viscosity at 20°C is 1,000 mPa·s or more and 18,000 mPa·s or less, is diluted with a second cement to a concentration of 1% to 5% by weight, separation of materials during and after mixing is prevented, and the mixed composition exhibits excellent fluidity. Furthermore, the inventors have discovered that the inclusion of component (d1) results in a composition with reduced flow elongation after mixing (i.e., minimal change in flow over time) and excellent workability. The examples described below demonstrate that mortar compositions mixed with the composition of the present invention exhibit good fluidity (mortar flow) without aggregation, suppressed mortar flow elongation, and exhibited favorable properties such as a low 250 mm flow time (also referred to as "250 mmFT"). Mortar flow elongation (also simply referred to as "flow elongation") is the phenomenon in which the fluidity of a mortar composition increases over time after mixing, i.e., the mortar flow increases over time. If the flow elongation is too large, the problem of material separation in grout, mortar, or concrete occurs easily. The detailed mechanism by which flow elongation occurs is unknown, but it is presumed to be caused by the interaction between the admixture and the sulfuric acid resistance imparting agent.

[0066] The hydroxypropyl methylcellulose used in the first admixture is a water-soluble compound obtained by reacting cellulose with an etherifying agent such as methyl chloride or propylene oxide to replace some of the hydrogen atoms of the hydroxyl groups of the cellulose with alkyl groups, thereby eliminating hydrogen bonds. Hydroxypropyl methylcellulose may be used alone or in combination of two or more types.

[0067] In the present invention, the viscosity of a 2% by weight aqueous solution of hydroxypropyl methylcellulose at 20°C is preferably 1,000 mPa·s or more, more preferably 2,000 mPa·s or more, even more preferably 3,000 mPa·s or more, and preferably 18,000 mPa·s or less, more preferably 15,000 mPa·s or less, and even more preferably 10,000 mPa·s or less. The viscosity of a 2% by weight aqueous solution of HPMC at 20°C can be measured using a B-type viscometer. Using HPMC with an aqueous solution viscosity within the above range can suppress separation of the materials during and after kneading, resulting in a composition with good fluidity and little post-flow elongation. Using HPMC with an aqueous solution viscosity that is too high can result in excessively high viscosity of the composition, and significant change in flow over time. Using HPMC with an aqueous solution viscosity that is too low can result in significant post-flow elongation of mortar flow.

[0068] The degree of substitution (DS) of hydroxypropyl methylcellulose is not limited, but for example, the degree of substitution of methoxy groups in HPMC is preferably 1.5 or more, more preferably more than 1.6, even more preferably 1.7 or more, and preferably 2.2 or less, more preferably less than 2.0, even more preferably 1.9 or less. In one embodiment, the degree of substitution of hydroxypropoxy groups in HPMC is preferably 0.05 or more, more preferably 0.1 or more, and preferably 0.3 or less, more preferably 0.2 or less. When the methoxy groups and hydroxypropoxy groups in HPMC are within these ranges, it becomes easier to suppress changes in the flow of the composition over time.

[0069] Here, the degree of substitution (hereinafter also referred to as "DS") of hydroxypropylmethylcellulose generally refers to the average number of hydroxyl groups substituted with methoxy or hydroxypropoxy groups per glucose ring unit of cellulose. The type and degree of substitution of the substituents introduced into the cellulose molecule can be measured according to Zeisel-GC (a method in which the substituents in a water-soluble cellulose ether are converted to alkyl iodides with hydroiodic acid and then quantified by gas chromatography) described in JG Obler, EPS Samsel and GH Beaber, Talanta, 9, 474 (1962).

[0070] In one embodiment, the HPMC preferably has a viscosity of 1,000 mPa·s or more and 18,000 mPa·s or less in a 2% by mass aqueous solution at 20°C, a degree of substitution with methoxy groups of 1.7 to 1.9, and a degree of substitution with hydroxypropoxy groups of 0.1 to 0.2.

[0071] As the hydroxypropyl methylcellulose, commercially available products may be used, for example, Marporose 65MP-4000 (manufactured by Matsumoto Yushi Co., Ltd.).

[0072] In this embodiment, the first admixture is preferably diluted with the second cement so that the hydroxypropyl methylcellulose, whose 2% by mass aqueous solution at 20°C has a viscosity of 1,000 mPa·s to 18,000 mPa·s, is 1% to 5% by weight. By diluting HPMC with cement in this manner, it is easier to mix uniformly with other components when kneaded with other materials, preventing material separation and allowing the formation of a composition with good fluidity. The concentration of hydroxypropyl methylcellulose, whose 2% by mass aqueous solution at 20°C has a viscosity of 1,000 mPa·s to 18,000 mPa·s, in the first admixture is preferably 1% by mass or more, more preferably 1.5% by mass or more, and preferably 5% by mass or less, more preferably 4.5% by mass or less, and even more preferably 3% by mass or less. If the concentration is too high, sufficient fluidity may not be obtained, while if the concentration is too low, material separation may occur. In the first admixture, the total amount of the above-mentioned specified HPMC and second cement is preferably 95% by weight or more, more preferably 98% by weight or more, and even more preferably 100% by weight.

[0073] Examples of the second cement used in the first admixture include ordinary Portland cement, high-early-strength Portland cement, ultra-high-early-strength Portland cement, sulfate-resistant Portland cement, moderate-heat Portland cement, low-heat Portland cement, blast-furnace cement, fly ash cement, silica fume cement, and alumina cement. The second cement may be used alone or in combination with two or more other cements. In the composition, the compound of the second cement may be the same as or different from the compound of the first cement.

[0074] The first admixture can be prepared by diluting hydroxypropyl methylcellulose, whose 2% aqueous solution has a viscosity of 1,000 mPa·s to 18,000 mPa·s, with the second cement to a concentration of 1 to 5 wt %. The method for diluting HPMC with the second cement is not limited, but examples include hand mixing and mechanical mixing. When mixing HPMC, it is preferable to mix the cement and hydroxypropyl methylcellulose in powder form.

[0075] The amount of the first admixture in the composition is 1 ml of components other than the admixture. 3 The amount of the first admixture (including the specified HPMC and second cement) in the sulfuric acid resistant grout composition can be adjusted appropriately depending on the concentration of HPMC, etc., but the amount of the components other than the admixture can be expressed as an external ratio to the total amount. 3 It is preferably 2 kg or more, more preferably 4 kg or more, and is preferably 15 kg or less, more preferably 10 kg or less. As will be described later, when the composition contains a second admixture, the amount of "components other than the admixture 1 m 3 " refers to 1 m of components other than the first and second admixtures. 3 means:

[0076] In one embodiment, in the sulfuric acid resistant grout composition, the amount of hydroxypropyl methylcellulose alone (i.e., not including the second cement) having a viscosity of 1,000 mPa·s or more and 18,000 mPa·s or less in a 2 mass% aqueous solution is 1,000 mPa·s or more and 18,000 mPa·s or less. 3 The weight is preferably 0.02 kg or more, more preferably 0.05 kg or more, and is preferably 2 kg or less, more preferably 1 kg or less.

[0077] In one embodiment of the sulfuric acid-resistant grout composition of the present invention, the first admixture (d1) may be present separately from the components (a), (b), (c), and (e). In this case, the components (a), (b), (c), and (e) other than the first admixture may be present separately from one another, or all or some of them may be mixed together. In another embodiment, the component (d1) may be mixed with some or all of the other components. As used herein, the terms "separately containing the components" and "separately containing the components" refer to a state in which the components are not in direct contact with each other. For example, a state in which the admixture is present separately from the other components may include a state in which the admixture and the other components are contained in separate containers (including bag-shaped containers), or a state in which the admixture and the other components are contained separately in multiple compartments within a single container with partitions between the compartments.

[0078] <(d2) Second admixture> In one embodiment of the present invention, the sulfuric acid-resistant grout composition preferably includes, in addition to the first admixture, (d2) a second admixture selected from the group consisting of attapulgite, sepiolite, bentonite, talc, and silica fume. These inorganic admixtures are used to manufacture high-flow concrete or to improve the workability of plastering mortar. The second admixture is more preferably selected from the group consisting of attapulgite, sepiolite, and bentonite, and even more preferably attapulgite. The use of the first and second admixtures allows for concrete with good fresh properties to be obtained. This is thought to be because the first admixture increases the viscosity of water, and the second admixture increases the viscosity of grout, mortar, or concrete, thereby achieving a good balance of the properties of both admixtures.

[0079] The amount of the second admixture in the composition is 1 / m of the components other than the admixture. 3 In the sulfuric acid resistant grout composition, the amount of the second admixture is expressed as the ratio of the amount of the components other than the admixture to the total amount of the components other than the admixture. 3On the other hand, the weight is preferably 2 kg or more, more preferably 5 kg or more, and is preferably 20 kg or less, more preferably 15 kg or less.

[0080] The mixing weight ratio of the first admixture (d1) to the second admixture (d2) is not limited, but (d1):(d2) is preferably 10:90 to 90:10, more preferably 20:80 to 80:20, and even more preferably 30:70 to 50:50.

[0081] The amount of hydroxypropyl methylcellulose having a viscosity of 1,000 mPa·s or more and 18,000 mPa·s or less as a 2% by mass aqueous solution relative to a total of 100 parts by mass of the first admixture and the second admixture is preferably 0.2 parts by mass or more, more preferably 0.3 parts by mass or more, and preferably 1 part by mass or less.

[0082] In sulfuric acid resistant grout composition, 1m of components other than admixtures 3 The total content of the first admixture (d1) and the second admixture (d2) relative to the total amount of the first admixture (d1) and the second admixture (d2) is, for example, preferably 5 to 30 kg, more preferably 10 to 25 kg. If the content of the admixture is too high, the viscosity may increase, resulting in a decrease in workability and fluidity, and if the content of the admixture is too low, material separation may occur.

[0083] One aspect of the present invention relates to an admixture comprising a first admixture (d1) and a second admixture (d2). The admixture is suitable for use in preparing a sulfuric acid-resistant grout composition, a sulfuric acid-resistant mortar composition, or a sulfuric acid-resistant concrete composition. The total content of the first admixture and the second admixture in 100 parts by mass of the admixture is preferably 95 parts by mass or more, more preferably 98 parts by mass or more, and may be 100 parts by mass.

[0084] One embodiment of the sulfuric acid-resistant grout composition of the present invention may contain the first and second admixtures separately from the other components. In this case, the first and second admixtures may be present separately or as a mixture of admixtures, which are mixed with the other components during kneading of the sulfuric acid-resistant grout composition. The other components (a), (b), (c), and (e) may be present separately, all of them may be mixed, or only some of them may be mixed. In another embodiment, component (d1) and component (d2) may be mixed with some or all of the other components.

[0085] <(e)Water> The water used in the sulfuric acid-resistant grout composition is not particularly limited, and any water that does not affect the strength development or fluidity of concrete, such as tap water, treated sewage water, or supernatant water from ready-mixed concrete, can be used. In one embodiment, the amount of water in the sulfuric acid-resistant grout composition is, for example, preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and preferably 65 parts by mass or less, more preferably 60 parts by mass or less, per 100 parts by mass of the first cement (a). If the amount of water is too small, sulfuric acid resistance tends to decrease, while if the amount of water is too large, setting tends to be delayed and watertightness tends to decrease.

[0086] The sulfuric acid-resistant grout composition may contain each component individually, some of the components may be premixed, or all of the components may be premixed. In a preferred embodiment, the sulfuric acid-resistant grout composition may contain admixtures (a first admixture and, if necessary, a second admixture) separately from the other components. When the sulfuric acid-resistant grout composition is used, all of the components are mixed together.

[0087] The method for producing the sulfuric acid resistant grout composition of the present invention comprises the steps of: A dilution step (d1) of preparing a first admixture by diluting hydroxypropyl methylcellulose, whose viscosity as a 2% by mass aqueous solution at 20°C is 1000 mPa·s or more and 18,000 mPa·s or less, with a second cement to a concentration of 1% by weight to 5% by weight; A mixing step of mixing (a) a first cement, (b) limestone fine powder, (c) a sulfuric acid resistance imparting agent, the first admixture (d1), and (e) water; Includes:

[0088] The dilution step is the same as that described for the first admixture. The method for diluting HPMC, whose 2% by mass aqueous solution at 20°C has a viscosity of 1,000 mPa·s to 18,000 mPa·s, with the second cement is not limited, but examples include hand mixing and mechanical mixing.

[0089] In the mixing step, when mixing the components of the sulfuric acid-resistant grout composition, the order of mixing is not limited and they may be mixed in any order. Examples of kneading machines used for mixing include tilting mixers, twin-shaft mixers, and hand mixers. The temperature of the grout composition at the time of mixing is not limited, but is preferably adjusted to, for example, about 10°C to 40°C, and more preferably about 15°C to 35°C. The longer the mixing time of the composition, the greater the flow, and then the flow saturates and becomes almost constant.

[0090] The mixing time of the grout composition is, for example, preferably 3 minutes or more in an environment of 20° C. or higher, more preferably 4 minutes or more, even more preferably 5 minutes or more, and even more preferably 6 minutes or more. In a low-temperature environment of less than 20° C., the mixing time of the grout composition is, for example, preferably 5 minutes or more, more preferably 6 minutes or more, even more preferably 7 minutes or more, and even more preferably 8 minutes or more.

[0091] <Sulfuric acid resistant mortar composition> The sulfuric acid resistant mortar composition (also simply referred to as "mortar composition") contains fine aggregate in addition to the sulfuric acid resistant grout composition. That is, the mortar composition of the present invention comprises: (a) a first cement; (b) fine limestone powder, (c) sulfuric acid resistance imparting agent; (d1) a first admixture containing 1% by weight to 5% by weight of hydroxypropyl methylcellulose, the viscosity of a 2% by weight aqueous solution of which at 20°C is 1,000 mPa·s or more and 18,000 mPa·s or less, and a second cement; (e) water, and (f) Fine aggregate Includes:

[0092] The compound used as the first cement (a) in the mortar composition is the same as the component (a) in the grout composition. The amount of the first cement in the mortar composition is not limited, but is preferably 320 kg / m 3 More preferably, 350 kg / m 3 or more, and preferably 750 kg / m 3 Less than or equal to 650 kg / m 3 The following is the result.

[0093] The compound used as (b) limestone fine powder in the sulfuric acid-resistant mortar composition is the same as the component (b) in the grout composition. In the mortar composition, the mass ratio (a:b) of the first cement to the limestone fine powder is preferably in the range of 20:80 to 80:20, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40. When the mass ratio of the first cement to the limestone fine powder is within this range, it is possible to sufficiently prevent a decrease in resistance to erosion when the mortar is immersed in an aqueous sulfuric acid solution.

[0094] The compound used as the (c) sulfuric acid resistance imparting agent in the sulfuric acid-resistant mortar composition is the same as the component (c) in the grout composition. The amount of the (c) sulfuric acid resistance imparting agent in the sulfuric acid-resistant mortar composition is not limited, but is preferably 0.3 to 15 parts by weight, more preferably 1 to 12 parts by weight, even more preferably 2 to 10 parts by weight, and even more preferably 2 to 5 parts by weight, based on the solid content, per 100 parts by weight of the (a) first cement. If the amount of naphthalene sulfonate condensate in the composition is within the above range, the resulting cured product can have sufficient sulfuric acid resistance.

[0095] For the compound used as the first admixture (d1) in the mortar composition, the description of the component (d1) in the grout composition above applies.

[0096] The first admixture used in the mortar composition can be prepared by diluting hydroxypropyl methylcellulose (HPMC), whose 2% aqueous solution has a viscosity of 1,000 mPa·s to 18,000 mPa·s, with the second cement to a concentration of 1 to 5 wt %. The method for diluting HPMC with the second cement is not limited, but examples include hand mixing and mechanical mixing. When mixing HPMC, it is preferable to mix the cement and hydroxypropyl methylcellulose in powder form.

[0097] The amount of the first admixture in the composition is 1 ml of components other than the admixture. 3 The amount of the first admixture (including the specified HPMC and the second cement) in the sulfuric acid resistant mortar composition can be appropriately adjusted depending on the concentration of HPMC, etc. For example, when the amount of the components other than the admixture is 1 m 3 On the other hand, it is preferably 1 kg or more, more preferably 2 kg or more, and is preferably 10 kg or less, more preferably 7 kg or less, even more preferably 5 kg or less, and even more preferably 4 kg or less.

[0098] In the sulfuric acid resistant mortar composition, 1m of components other than admixtures 3 The amount of hydroxypropyl methylcellulose with a viscosity of 1,000 mPa·s or more and 18,000 mPa·s or less in a 2% by mass aqueous solution at 20°C is not limited, but is 3 The weight is preferably 0.01 kg or more, more preferably 0.03 kg or more, and is preferably 1 kg or less, more preferably 0.5 kg or less, and even more preferably 0.2 kg or less.

[0099] The sulfuric acid-resistant mortar composition preferably contains, as an admixture, a second admixture (d2) in addition to the first admixture (d1). The above description of component (d2) in the grout composition applies to the compound used as the second admixture (d2) in the mortar composition.

[0100] The mixing weight ratio of the first admixture (d1) to the second admixture (d2) is not limited, but (d1):(d2) is preferably 10:90 to 90:10, more preferably 20:80 to 80:20, and even more preferably 30:70 to 50:50.

[0101] The amount of the second admixture in the sulfuric acid resistant mortar composition is 1 / m of the components other than the admixture. 3 In the sulfuric acid resistant mortar composition, the amount of the second admixture is expressed as the ratio of the amount of the components other than the admixture (including the first admixture and the second admixture) to the total amount of the components. 3 On the other hand, the weight is preferably 3 kg or more, more preferably 4 kg or more, and is preferably 10 kg or less, more preferably 8 kg or less.

[0102] In the sulfuric acid resistant mortar composition, the components other than the first admixture (d1) and the second admixture (d2) are 3 The total content of the first admixture (d1) and the second admixture (d2) relative to the total amount of the first admixture (d1) and the second admixture (d2) is preferably 3 to 20 kg, more preferably 5 to 15 kg, and even more preferably 7 to 10 kg. If the content of the admixture is too high, the viscosity may increase, resulting in a decrease in workability and fluidity, and if the content of the admixture is too low, material separation may occur.

[0103] In one embodiment, when the viscosity of a 2% by mass aqueous solution of HPMC (also referred to as "raw material A") contained in the first admixture in the sulfuric acid resistant mortar composition at 20°C is α, "Z = α × (1 m of components other than admixtures)" is 3The value of "Z / total amount of admixtures added (kg)" is, for example, preferably 120 or more, more preferably 150 or more, and preferably 450 or less, more preferably 400 or less. In one embodiment, the value of (Z / total amount of admixtures added (kg)) is, for example, preferably 15 or more, more preferably 20 or more, and preferably 60 or less, more preferably 50 or less. Here, "total amount of admixtures added" refers to the amount of components other than admixtures added per 1 m 3 This refers to the total amount of admixture added relative to the total amount of admixture.

[0104] In one embodiment of the present invention, although not limited thereto, it is preferable that the total amount of the first admixture and the second admixture and the upper and lower limits of the flow of the resulting mortar satisfy the criteria in the following Table 1. Note that the "total amount of the first admixture and the second admixture" is the amount of components other than the admixture per 1 ml 3 The mortar flow can be measured by the method described in the examples.

[0105] [Table 1]

[0106] One embodiment of the sulfuric acid-resistant mortar composition of the present invention may contain the first admixture and the second admixture separately from other components. In this case, the first admixture and the second admixture may be present separately, or may be present as an admixture in which the first admixture and the second admixture are mixed, and the admixture is mixed with the other components when the sulfuric acid-resistant mortar composition is used.

[0107] The above description of component (e) in the grout composition applies to the water (e) in the mortar composition. In one embodiment, the amount of water in the sulfuric acid-resistant mortar composition is, for example, preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and preferably 65 parts by mass or less, more preferably 60 parts by mass or less, per 100 parts by mass of the first cement (a). If the amount of water is too small, sulfuric acid resistance tends to decrease, while if the amount of water is too large, setting tends to be delayed and watertightness tends to decrease.

[0108] <(f) Fine aggregate> The fine aggregate is not particularly limited, and fine aggregates commonly used in the production of ordinary concrete can be used. The particle size of the fine aggregate is as specified in JIS, and the particle size of the fine aggregate is less than 5 mm. In this specification, fine aggregates that fall under the category of limestone fine powder are not considered to be fine aggregates. Examples of fine aggregates include river sand, mountain sand, land sand, sea sand, crushed sand, silica sand, lightweight fine aggregate, blast furnace slag fine aggregate, and limestone fine aggregate. The use of limestone fine aggregate further improves sulfuric acid resistance. This is thought to be due to the same effect as the addition of limestone fine powder, and using limestone as an aggregate is preferable because it allows for a further increase in the amount of limestone. Fine aggregates may be used alone or in combination of two or more types.

[0109] The amount of fine aggregate in the mortar composition is preferably 50 to 800 parts by mass, more preferably 100 to 650 parts by mass, even more preferably 110 to 500 parts by mass, and particularly preferably 120 to 300 parts by mass, per 100 parts by mass of the first cement.

[0110] The sulfuric acid-resistant mortar composition may contain each component separately, some components may be premixed, or all components may be premixed. In a preferred embodiment, the sulfuric acid-resistant mortar composition may contain admixtures (first admixture and, if necessary, second admixture) separately from other components. The sulfuric acid-resistant grout composition is prepared by mixing all components when used.

[0111] The method for producing the sulfuric acid resistant mortar composition of the present invention comprises the steps of: A dilution step of preparing a first admixture (d1) by diluting hydroxypropyl methylcellulose, whose viscosity of a 2% by mass aqueous solution at 20 ° C. is 1000 mPa·s or more and 18,000 mPa·s or less, with a second cement to a concentration of 1% by weight to 5% by weight; A mixing step of mixing (a) a first cement, (b) limestone fine powder, (c) a sulfuric acid resistance imparting agent, the first admixture (d1), (e) water, and (f) fine aggregate; Includes:

[0112] For the dilution step, the explanation for the first admixture above applies.

[0113] In the mixing step, when mixing the components of the sulfuric acid-resistant mortar composition, the order of mixing is not limited and may be any order. Examples of kneading machines used for mixing include tilting mixers, twin-shaft mixers, and hand mixers. The temperature of the mortar composition at the time of mixing is not limited, but is preferably adjusted to, for example, about 10°C to 40°C, more preferably about 15°C to 35°C. The longer the mixing time of the composition, the greater the flow, and then the flow saturates and becomes approximately constant.

[0114] The mixing time of the mortar composition is, for example, preferably 3 minutes or more, more preferably 4 minutes or more, even more preferably 5 minutes or more, and even more preferably 6 minutes or more in an environment of 20° C. or higher. Also, in a low-temperature environment of less than 20° C., the mixing time of the mortar composition is, for example, preferably 5 minutes or more, more preferably 6 minutes or more, even more preferably 7 minutes or more, and even more preferably 8 minutes or more.

[0115] <Sulfate-resistant concrete composition> The sulfuric acid resistant concrete composition (also simply referred to as "concrete composition") contains fine aggregate and coarse aggregate in addition to the sulfuric acid resistant grout composition. That is, the sulfuric acid resistant concrete composition of the present invention is (a) a first cement; (b) fine limestone powder, (c) sulfuric acid resistance imparting agent; (d1) a first admixture containing 1% by weight to 5% by weight of hydroxypropyl methylcellulose, the viscosity of a 2% by weight aqueous solution of which at 20°C is 1,000 mPa·s or more and 18,000 mPa·s or less, and a second cement; (e) water; (f) fine aggregate, and (g) Coarse aggregate The concrete composition of the present invention exhibits little change over time in the air content in the composition after mixing, and has a high air content retention property.

[0116] The compound used as the (a) first cement in the concrete composition is the same as the component (a) in the grout composition. The amount of the first cement in the concrete composition is not particularly limited, but is preferably 230 kg / m 3 More preferably, 250 kg / m 3 or more, and preferably 600 kg / m 3 Less than or equal to 500 kg / m 3 The following is the result.

[0117] The compound used as (b) limestone fine powder in the sulfate-resistant concrete composition is the same as the component (b) in the grout composition. In the concrete composition, the mass ratio (a:b) of the first cement to the limestone fine powder is preferably in the range of 20:80 to 80:20, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40. When the mass ratio of the first cement to the limestone fine powder is within this range, it is possible to sufficiently prevent a decrease in resistance to erosion when the concrete is immersed in an aqueous sulfuric acid solution.

[0118] The compound used as the (c) sulfuric acid resistance imparting agent in the sulfate-resistant concrete composition is the same as the component (c) in the grout composition. The amount of the (c) sulfuric acid resistance imparting agent in the sulfate-resistant concrete composition is not limited, but is preferably 0.3 to 15 parts by weight, more preferably 1 to 12 parts by weight, even more preferably 2 to 10 parts by weight, and even more preferably 2 to 5 parts by weight, based on the solid content, per 100 parts by weight of the (a) first cement. If the amount of naphthalene sulfonate condensate in the sulfate-resistant concrete composition is within the above range, the resulting hardened product can have sufficient sulfuric acid resistance.

[0119] For the compound used as the first admixture (d1) in the concrete composition, the description of component (d1) in the grout composition above applies.

[0120] The first admixture used in the concrete composition can be prepared by diluting hydroxypropyl methylcellulose, whose 2% aqueous solution has a viscosity of 1,000 mPa·s to 18,000 mPa·s, with the second cement to a concentration of 1 to 5 wt %. The method for diluting HPMC with the second cement is not limited, but examples include hand mixing and mechanical mixing. When mixing HPMC, it is preferable to mix the cement and hydroxypropyl methylcellulose in powder form.

[0121] The amount of the first admixture in the concrete composition is 1 / m of the components other than the admixture. 3 In the sulfate resistant concrete composition, the amount of the first admixture (including the specified HPMC and the second cement) can be appropriately adjusted depending on the concentration of HPMC. For example, 3 The weight is preferably 0.5 kg or more, more preferably 1 kg or more, and even more preferably 2 kg or more, and is preferably 8 kg or less, more preferably 6 kg or less, and even more preferably 5 kg or less.

[0122] In the sulfate-resistant concrete composition, 1m of components other than admixtures3 In contrast, the amount of hydroxypropyl methylcellulose, whose viscosity as a 2% by mass aqueous solution at 20°C is 1,000 mPa·s or more and 18,000 mPa·s or less, is preferably 0.01 kg or more, more preferably 0.03 kg or more, and is preferably 0.3 kg or less, more preferably 0.1 kg or less.

[0123] The sulfate-resistant concrete composition preferably contains a second admixture (d2) in addition to the first admixture (d1). The above description of component (d2) in the grout composition applies to the compound used as the second admixture (d2) in the concrete composition.

[0124] The mixing weight ratio of the first admixture (d1) to the second admixture (d2) is not limited, but (d1):(d2) is preferably 10:90 to 90:10, more preferably 20:80 to 80:20, and even more preferably 30:70 to 50:50.

[0125] The amount of the second admixture in the sulfate-resistant concrete composition is 1 / m of the components other than the admixture. 3 In the sulfate resistant concrete composition, the amount of the second admixture is expressed as the ratio of the amount of the components other than the admixture (including the first admixture and the second admixture) to the total amount of the components. 3 On the other hand, the weight is preferably 2 kg or more, more preferably 3 kg or more, and is preferably 10 kg or less, more preferably 8 kg or less.

[0126] In the sulfate-resistant concrete composition, the components other than the first admixture (d1) and the second admixture (d2) are 3 The total content of the first admixture (d1) and the second admixture (d2) relative to the total amount of the first admixture (d1) and the second admixture (d2) is, for example, preferably 2 to 15 kg, more preferably 6 to 12 kg. If the content of the admixture is too high, the viscosity may increase, resulting in a decrease in workability and fluidity, and if the content of the admixture is too low, material separation may occur.

[0127] In one embodiment, when the viscosity of a 2 mass% aqueous solution of HPMC (also referred to as "raw material A") contained in the first admixture in the sulfate-resistant concrete composition at 20°C is α, "Z = α × (1 m of components other than admixtures)" is 3 The value of "Z / total amount of admixtures added (kg)" is, for example, preferably 100 or more, more preferably 150 or more, even more preferably 200 or more, and preferably 400 or less, more preferably 300 or less. In one embodiment, the value of (Z / total amount of admixtures added (kg)) is, for example, preferably 15 or more, more preferably 20 or more, and preferably 60 or less, more preferably 50 or less. Here, "total amount of admixtures added" refers to the amount of components other than admixtures added per 1 m 3 This refers to the total amount (kg) of admixture added to the concrete.

[0128] One embodiment of the sulfate-resistant concrete composition of the present invention may contain the first and second admixtures separately from other components. In this case, the first and second admixtures may be present separately, or they may be present as a mixture of admixtures, which are mixed with the other components when the sulfate-resistant concrete composition is used.

[0129] The above description of component (e) in the grout composition applies to the water (e) in the concrete composition. In one embodiment, the amount of water in the sulfate-resistant concrete composition is, for example, preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and preferably 65 parts by mass or less, more preferably 60 parts by mass or less, per 100 parts by mass of the first cement (a). If the amount of water is too small, sulfuric acid resistance tends to decrease, while if the amount of water is too large, setting tends to be delayed and watertightness tends to decrease.

[0130] The above description of component (f) in the mortar composition applies to the fine aggregate (f) in the concrete composition. The amount of fine aggregate in the mortar composition is preferably 50 to 800 parts by mass, more preferably 100 to 650 parts by mass, even more preferably 110 to 500 parts by mass, and particularly preferably 120 to 300 parts by mass, per 100 parts by mass of the first cement.

[0131] <(g) Coarse aggregate> The coarse aggregate is not particularly limited, and can be any coarse aggregate commonly used in the production of ordinary concrete. The particle size of the coarse aggregate is as specified in the JIS, with a particle size of 5 mm to 25 mm. In this specification, limestone fine powder is not considered to be coarse aggregate. Examples of coarse aggregate include andesite, rhyolite, hard sandstone, crushed limestone, river gravel, mountain gravel, land gravel, blast furnace slag coarse aggregate, and recycled coarse aggregate. The use of limestone coarse aggregate further improves sulfuric acid resistance. This is thought to be due to the same effect as the addition of limestone fine powder. Using limestone as an aggregate is preferable because it allows for a further increase in the amount of limestone. Coarse aggregates may be used alone or in combination.

[0132] The amount of coarse aggregate in the concrete composition is preferably 50 to 800 parts by mass, more preferably 100 to 650 parts by mass, even more preferably 110 to 500 parts by mass, and particularly preferably 120 to 300 parts by mass, per 100 parts by mass of the first cement.

[0133] The sulfate-resistant concrete composition may contain each component individually, some of the components may be premixed, or all of the components may be premixed. In a preferred embodiment, the sulfate-resistant concrete composition may contain admixtures (a first admixture and, if necessary, a second admixture) separately from the other components. When using the sulfate-resistant concrete composition, all of the components are mixed together.

[0134] The method for producing the sulfate-resistant concrete composition of the present invention comprises: A dilution step of preparing a first admixture (d1) by diluting hydroxypropyl methylcellulose, whose viscosity of a 2% by mass aqueous solution at 20 ° C. is 1000 mPa·s or more and 18,000 mPa·s or less, with a second cement to a concentration of 1% by weight to 5% by weight; A mixing step of mixing (a) a first cement, (b) limestone fine powder, (c) a sulfuric acid resistance imparting agent, the first admixture (d1), (e) water, (f) fine aggregate, and (g) coarse aggregate; Includes:

[0135] For the dilution step, the explanation for the first admixture above applies.

[0136] In the mixing step, when mixing the components of the sulfate-resistant concrete composition, the order of mixing is not limited and they may be mixed in any order. Examples of kneading machines used for mixing include tilting barrel mixers, twin-shaft mixers, and hand mixers. The temperature of the concrete composition when mixed is not limited, but is preferably adjusted to, for example, about 10°C to 40°C, and more preferably about 15°C to 35°C. The longer the mixing time of the composition, the greater the flow, and then the flow saturates and becomes almost constant.

[0137] The mixing time of the concrete composition is, for example, preferably 3 minutes or more in an environment of 20° C. or higher, more preferably 4 minutes or more, even more preferably 5 minutes or more, and even more preferably 6 minutes or more. Also, in a low-temperature environment of less than 20° C., the mixing time of the concrete composition is, for example, preferably 5 minutes or more, more preferably 6 minutes or more, even more preferably 7 minutes or more, and even more preferably 8 minutes or more.

[0138] <Other ingredients> The sulfuric acid-resistant grout composition, sulfuric acid-resistant mortar composition, and sulfuric acid-resistant concrete composition of the present invention may contain components other than the above components (a) to (g), as long as the effects of the present invention are not impaired. Examples of other components include inorganic powders such as ground granulated blast furnace slag and fly ash, which are used in ordinary grout, mortar, and concrete, and expansive materials (lime-based expansive materials containing free lime as the main component, calcium sulfoaluminate-based expansive materials, etc.).

[0139] In one embodiment, the composition of the present invention preferably contains a small amount of admixtures (e.g., a specific acrylic water-soluble polymer or hydroxypropyl methylcellulose, the viscosity of which in a 2% by weight aqueous solution at 20°C is significantly different from the range of 1,000 mPa·s to 18,000 mPa·s) as used in the comparative examples described below, and the content of these compounds is preferably 0.01% by weight or less, and more preferably 0% by weight. The inclusion of these admixtures can cause problems such as material separation during kneading or increased elongation after flow.

[0140] In one embodiment, the total content of components (a), (b), (c), (d1), (d2), (e), (f), and (g) in the sulfuric acid resistant composition of the present invention is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be 100% by mass.

[0141] <Cured product> One aspect of the present invention relates to hardened products of the sulfuric acid-resistant grout composition, the sulfuric acid-resistant mortar composition, and the sulfuric acid-resistant concrete composition. A gypsum layer is formed on the surface of the hardened product obtained by hardening the sulfuric acid-resistant composition according to this embodiment when the hardened product comes into contact with an aqueous solution containing sulfuric acid. The hardened product having a gypsum layer on its surface is protected from sulfuric acid corrosion by the gypsum layer, improving its sulfuric acid resistance.

[0142] The grout, mortar, or concrete obtained by kneading the components of the sulfuric acid-resistant composition of the present invention, molding, and curing the composition has excellent sulfuric acid resistance. For example, in one embodiment, the sulfuric acid-resistant concrete has a sulfuric acid penetration depth of 5 mm or less when immersed in a 5% by mass sulfuric acid aqueous solution (pH about 0.3) for 112 days, and can achieve a sulfuric acid penetration depth of 3.5 mm or less. Note that this sulfuric acid penetration depth is a value when aggregates other than limestone aggregate are also used; when only limestone aggregate is used, sulfuric acid resistance can be further improved.

[0143] The conditions and method for measuring the sulfuric acid penetration depth when immersed in a 5% by mass sulfuric acid solution can be measured in accordance with Appendix C, Mortar Lining Method, of JIS A 7502-2, "Concrete Corrosion Prevention Technology for Sewerage Structures." Specifically, a cylindrical specimen measuring φ100 x 200 mm was immersed in 5% sulfuric acid for 112 days, after which a phenolphthalein solution was sprayed onto the cut surface to measure the length of the healthy portion that retained alkalinity. This was then subtracted from the dimensions before immersion to determine the sulfuric acid penetration depth. The resulting sulfuric acid penetration depth is the sum of the depth of the defect (dissolution) caused by sulfuric acid and the depth of the remaining concrete surface that has lost its alkalinity.

[0144] The sulfuric acid penetration depth is measured as follows. First, the diameter of the center of the exposed surface of the concrete specimen before immersion is measured and defined as L (≈100 mm). Then, to stain the uneroded areas, the specimen is cut in the center after immersion and phenolphthalein solution (phenolphthalein solution specified in JIS K8001, 4.4 (Indicators)) is sprayed onto the cross section. This causes the uneroded, basic areas to turn reddish-purple. The diameter of the exposed surface in the reddish-purple area is measured with a vernier caliper and its width is defined as L1 (mm). The sulfuric acid penetration depth can be calculated as (L - L1) / 2 (mm), which indicates that the sulfuric acid solution has eroded the area to a depth of (L - L1) / 2 (mm). The diameters before and after immersion are the average of measurements taken at five locations (dividing the circumference into five equal parts).

[0145] The mass loss rate is measured as follows: First, the total mass of the concrete specimen before immersion is measured and designated as W. Then, to measure the mass of the uneroded sound portion, the front of the immersed surface is washed with tap water opened to the fullest, any brittle layers of gypsum that have formed are removed, and the mass is then measured and designated as W1. The mass loss rate can be calculated by (W-W1) / W x 100 (%).

[0146] The sulfuric acid-resistant grout composition, sulfuric acid-resistant mortar composition, and sulfuric acid-resistant concrete composition of the present invention can be advantageously used in structures, secondary products, and repair materials for sewerage-related facilities such as sewer pipes, sewage treatment plants, and culverts, which require excellent sulfuric acid resistance, hot spring-related facilities such as water supply and drainage systems for hot spring facilities and agricultural and drainage channel structures in hot spring areas, and chemical plants. In concrete facilities related to sewage treatment, the sulfuric acid-resistant composition of the present invention can be used, for example, in pumping stations, settling tanks, distribution tanks, reaction tanks, sludge storage tanks, connecting channels, and sludge digester tanks. Examples of concrete facilities in hot spring areas include bathtubs, bathroom interior materials, and internal equipment in hot spring facilities, as well as foundations and walls of buildings in hot spring areas that are affected by hot spring water and hot spring steam, underground beams, concrete tunnels, utility poles, and concrete pavements.

[0147] The sulfuric acid-resistant composition of the present invention has excellent self-compacting properties. Generally, "self-compacting properties" refers to the workability of concrete, and refers to the ability of concrete to evenly fill every corner of a formwork, etc., using only its own weight, without the need for vibration compaction during pouring. Self-compacting concrete is used in areas with dense reinforcement, narrow filling gaps, and areas where vibration compaction is difficult for construction reasons. As with conventional concrete, an expansive agent and / or a shrinkage-reducing agent can be added to compensate for shrinkage, apply chemical prestress, and reduce cracking. As with conventional concrete, a hardening accelerator or a set retarder can also be added to control the setting time. [Example]

[0148] The present invention will be specifically explained by the following examples, but the present invention is not limited to these examples.

[0149] <Materials used> The materials used in the following examples and their abbreviations are shown below. (a) First cement (C1) Ordinary Portland cement: Blaine specific surface area 3270 cm 2 / g

[0150] (b) Limestone fine powder (LSP) Blaine specific surface area 4500cm 2 / g

[0151] (c) Sulfuric acid resistance agent The formalin condensate salt of naphthalenesulfonic acid (NS) represented by the following formula was used.

[0152] [ka]

[0153] (e) water Tap water (W) (f) Fine aggregate ·Mixed sand (S) (mountain sand: crushed lime sand (mass ratio) = 7:3, surface dry density 2.62g / cm 3 ) (g) Coarse aggregate Limestone crushed stone 2005 (G) (surface dry density 2.69 g / cm 3 )

[0154] (d) Admixtures The following compounds were used as the first admixture A and the second admixture B, respectively.

[0155] (First admixture A) The following raw materials A1 to A6 were used as raw material A for admixture A. Raw materials A1 to A5 are hydroxypropyl methylcelluloses from the Marpolose series (manufactured by Matsumoto Oil & Fat Co., Ltd.). The characteristics of each compound are shown in Table 2. In the table, the viscosity of a 2% by mass aqueous solution of each compound is the value measured at 20 rpm using a Brookfield viscometer when each compound was made into a 2.0% by mass aqueous solution at 20°C. The "substitution rate by functional group" is the proportion of substituents based on the mass of each compound, expressed in "% by mass."

[0156] [Table 2]

[0157] The admixture A6 used in the reference example is as follows. A6: TNS-100 (acrylic thickener, manufactured by Pacific Materials Corporation. The composition includes (i) 85 to 95% by weight of cement (viscosity of 7% aqueous solution: 200 to 400 mPa·s), and (ii) 5 to 15% by weight of a polymer of 2-methyl-2-[(1-oxo-2-propenyl)amino]-monosodium salt.)

[0158] <Example 1: Mortar composition> (First admixture) <Preparation of Admixture A> The raw material A of the admixture A used as the first admixture in each of the Examples, Comparative Examples, and Reference Examples for the mortar composition and its dilution ratio are shown in Table 3. The diluted raw material A in the composition of admixture A was prepared by mixing raw material A with cement C2 (ordinary Portland cement: Blaine specific surface area 3270 cm) as a diluent. 2 / g). Specifically, admixture A was prepared by placing raw material A and cement C2 in a bag and thoroughly mixing them by hand to achieve the mixing ratio shown in "Composition of admixture A" in Table 3. The values ​​shown in "Composition of admixture A" indicate the weight percentages of raw material A and cement C2 in 100% by weight of admixture A.

[0159] (Second admixture) As the second admixture B, the following admixture B1 was used. Admixture B1: MINUGEL-400 (Attapulgite (manufactured by AMI) (Needle crystals: average length 1.5 × 10 -6 m~2.0×10 -6 m, average diameter 30nm))

[0160] <Preparation of admixture> Admixtures of admixtures were prepared by placing admixture A and admixture B in a bag and thoroughly mixing them by hand so as to meet the "admixture ratio" in Table 3. In the table, the "admixture ratio" indicates the weight ratio of admixture A and admixture B in 100% by weight of the total amount of admixtures. In addition, the "amount of admixture added" in Table 3 indicates the amount of admixture added per 1 ml of the components of the mortar composition excluding the admixtures. 3 It represents the amount of admixture (kg) to be added as a percentage of the total weight of the admixture.

[0161] [Table 3]

[0162] The results of calculations of the compounding ratio of ingredients based on Table 3 are shown in Table 4. In the table, the "addition amount of raw material A" is the amount of ingredients other than the admixture per 1 ml 3 The "proportion of raw material A to total cement" indicates the proportion of raw material A to the total mass of the first cement (C1) and the second cement (C2). X is the calculated value of (amount of raw material A added / amount of admixture B added). Y is the calculated value of (amount of raw material A added / total amount of admixtures added). Here, the total amount of admixtures added is the sum of the amounts of admixture A and admixture B added. Z is the value calculated by (viscosity α of a 2 mass% aqueous solution of raw material A at 20°C x amount of raw material A added (kg)). "Z / total amount of admixtures added" is the calculated value of Z multiplied by the total amount of admixtures added (1 ml of components other than admixtures). 3 The total amount of admixtures added to the concrete is divided by kg. The amount of each admixture added is also calculated by dividing the amount of components other than the admixture by kg. 3 This represents the amount of admixture added.

[0163] [Table 4]

[0164] <Preparation of mortar composition> In preparing the mortar composition, the components other than the admixture were used in the proportions shown in Table 5. The units of the proportions in Table 5 are unit amounts (kg / m 3 ) The composition of Table 5 is 3 Each admixture was used in the amounts shown in Table 3.

[0165] [Table 5]

[0166] The mortar composition was prepared according to the mixing method in JIS R 5201:2015 "Physical Test of Cement." Specifically, it was prepared as follows.

[0167] All ingredients except water were added to a mixer in the proportions shown in Tables 3 and 5, and mixed at a low speed (rotation speed: 140±5 rpm, revolution speed: 62±5 rpm) for 30 seconds. The mixer was then stopped, and water was added. The ingredients were then mixed for a predetermined time (the "mixing time" listed in Table 6) to obtain a mortar composition. The mixer used was a mixer specified in JIS R 5201-2015 "Physical Tests of Cement." The mortar flow and 250 mm reaching time (250 mmFT) were measured immediately after mixing, and for mortar compositions left to stand in a bowl covered with a wet towel for 30 minutes (or 60 minutes), using the methods described below.

[0168] <Evaluation of mortar composition> <Measurement of mortar flow and 250mm flow time> Using the obtained mortar composition, the value measured without impact (hereinafter referred to as "mortar flow") and the time taken for the mortar flow to reach 250 mm were measured according to the method described in JIS R 5201-2015 "Physical Test Methods for Cement 11. Flow Test." 3 When the amount of admixture is less than 11 kg, the target value of mortar flow is 250 to 290 mm, and the target time to reach 250 mm is 20 to 40 seconds. 3 When the load was 11 kg or more, the target mortar flow was 210 to 270 mm, and the target time to reach 250 mm was 30 to 60 seconds. Furthermore, the presence or absence of separation of the mortar composition after mixing was visually confirmed. Mortar flow elongation was evaluated by comparing the mortar flow value immediately after mixing with the mortar flow value after 30 minutes (or 60 minutes), and a difference of 10 mm or less was deemed satisfactory. The results are shown in Table 6.

[0169] [Table 6]

[0170] Examples 1-1 to 1-5 had good mortar flow and 250 mmFT, and no material separation was observed. Furthermore, Examples 1-1 to 1-5 also had good, small elongation after flow.

[0171] Comparative Examples 1-1 to 1-10 are compositions using hydroxypropyl methylcellulose as admixture A, whose viscosity of a 2.0% by mass aqueous solution at 20°C was outside the range of 1,000 to 18,000 mPa·s. In Comparative Examples 1-1 and 1-2, the compositions did not flow when kneaded, making it impossible to measure mortar flow and other properties. In Comparative Examples 1-3, 1-5, 1-6, 1-7, and 1-10, the post-flow elongation exceeded 10 mm. Furthermore, in Comparative Examples 1-3, 1-4, 1-5, 1-8, and 1-9, at least one of the mortar flow and the 250 mm flow time did not achieve the target value.

[0172] Comparative Examples 1-11 and 1-12 use raw material A1, but the contents of raw material A1 in the admixture A are 0.1% by weight and 7% by weight, respectively. In Comparative Example 1-11, the mortar flow was too large, and material separation was observed, while in Comparative Example 1-12, the mortar flow was too small, resulting in poor fluidity.

[0173] (Comparative Example) Instead of the admixture A, the following compounds (a1') to (a6') were used, respectively, to prepare mortar compositions in the same manner as above. The raw materials were prepared so that the ratio of each of the compounds (a1') to (a6') to the admixture B1 was 39:61, and the composition other than the admixture was 1 ml. 3 However, it was observed that the kneaded material did not become fluid in either case, and the more it was kneaded, the more it aggregated into granular particles. (a1') Product name: CS-80 (acrylic ester compound, manufactured by Tomooka Kaken Co., Ltd.) (a2') Product name: CS-60H (acrylic ester compound, manufactured by Tomooka Kaken Co., Ltd.) (a3') Product name: CSR-9310 (methacrylic acid ester compound, manufactured by Tomooka Kaken Co., Ltd.) (a4') Product name: CSR-5260 (acrylic ester compound, manufactured by Tomooka Kaken Co., Ltd.) (a5') Product name: A-56 (polyacrylamide compound, manufactured by Tomooka Kaken Co., Ltd.) (a6') Product name: NF-60 (polyacrylamide compound, manufactured by Tomooka Kaken Co., Ltd.)

[0174] <Example 2: Concrete composition> (Preparation of admixture) Admixtures for evaluation of concrete compositions were prepared.

[0175] (First Admixture (Preparation of Admixture A)) Table 7 shows the raw material A of the admixture A used as the first admixture in each of the examples, comparative examples, and reference examples for the concrete composition, and the dilution ratio thereof. The explanation in Table 2 of Example 1 applies to raw material A. The diluted raw material A in the composition of admixture A was prepared by mixing raw material A listed in each table with cement C2 (ordinary Portland cement: Blaine specific surface area 3270 cm) as a diluent. 2 / g). Specifically, admixture A was prepared by placing raw material A and cement C2 in a bag and thoroughly mixing them by hand to achieve the mixing ratio shown in "Composition of admixture A" in Table 7. The values ​​shown in "Composition of admixture A" indicate the weight percentages of raw material A and cement C2 in 100% by weight of admixture A.

[0176] (Preparation of admixture) Admixtures of admixtures were prepared by placing admixture A and admixture B in a bag and thoroughly mixing them by hand so as to meet the "admixture ratios" in Table 7. Compound B1 was used as admixture B, as in Example 1. In the table, the "admixture ratios" represent the weight percentages of admixture A and admixture B in 100% by weight of the total amount of admixtures. Furthermore, the "amount of admixture added" in Table 7 represents the amount of admixture added per 1 ml of the components of the concrete composition excluding the admixtures. 3 It represents the amount of admixture (kg) to be added as a percentage of the total weight of the admixture.

[0177] [Table 7]

[0178] The results of calculations of the compounding ratio of ingredients based on Table 7 are shown in Table 8. The "addition amount of raw material A" is the amount of ingredients other than the admixture per 1 ml 3The "proportion of raw material A to total cement" indicates the proportion of raw material A to the total mass of the first cement (C1) and the second cement (C2). X is the calculated value of (amount of raw material A added / amount of admixture B added). Y is the calculated value of (amount of raw material A added / total amount of admixtures added). Here, the total amount of admixtures added is the sum of the amounts of admixture A and admixture B added. Z is the value calculated by (viscosity α of a 2 mass% aqueous solution of raw material A at 20°C x amount of raw material A added (kg)). "Z / total amount of admixtures added" is the calculated value of Z multiplied by the total amount of admixtures added (1 ml of components other than admixtures). 3 The total amount of admixtures added to the concrete is divided by kg. The amount of each admixture added is also calculated by dividing the amount of components other than the admixture by kg. 3 This represents the amount of admixture (kg) added.

[0179] [Table 8]

[0180] <Preparation of concrete> In preparing the concrete composition, the components other than the admixtures were used to obtain the mix proportions shown in Table 9. The units of the mix proportions in Table 9 are unit amounts (kg / m 3 ) The composition of Table 9 is 3 The admixtures were used in the amounts shown in Table 7.

[0181] Concrete was prepared by mixing cement (C1), limestone powder (LSP), fine aggregate (S), coarse aggregate (G), powdered formalin condensate of naphthalenesulfonic acid (NS), and admixtures in the proportions shown in Tables 7 and 9, and mixing for 30 seconds in a twin-screw forced mixer. Tap water (W) was then added to the mixer as mixing water, and the mixture was further mixed for the mixing time shown in Table 10 (for example, 300 seconds in Examples 2-1 to 2-4) to prepare concrete.

[0182] [Table 9]

[0183] <Evaluation of concrete composition> (Evaluation of fresh properties) The fresh properties of each concrete composition before hardening were measured according to the following test methods. "Slump flow" was measured as an index of deformability, "50 cm flow time in the slump flow test" as an index of viscosity, and air content as an index of freeze-thaw resistance and frost resistance. (2-1) Slump flow and time to reach 50 cm flow: This was done in accordance with JIS A 1150:2001 "Slump flow test for concrete." The target value for slump flow was 70±5 cm, and the target value for time to reach 50 cm flow was 10±5 seconds. (2-2) Air content: The air content of the concrete was measured in accordance with JIS A 1128 "Test method for air content of fresh concrete by pressure - air chamber pressure method." The target value of the air content was 4.5±1.5%. (2-3) Separation of the materials in the composition during kneading was observed visually.

[0184] The evaluation results of the concrete compositions are shown in Table 10.

[0185] [Table 10]

[0186] Changes over time in concrete compositions mixed with the same composition were compared. In Examples 2-1 to 2-4, no material separation was observed, the slump flow was good, and post-expansion (change in slump flow over time) was small. Furthermore, in Examples 2-1 to 2-4, the change in air content over time was small compared to the Comparative Example and Reference Example, and the air content retention was high. Therefore, it was shown that when an admixture in which raw material A1 is diluted with cement to a predetermined concentration is used, concrete with good slump flow, suppressed post-expansion, and high air content retention can be obtained.

[0187] Comparative Examples 2-1 to 2-9 are compositions using hydroxypropyl methylcellulose as admixture A, whose viscosity of a 2.0% by mass aqueous solution at 20°C was outside the range of 1,000 to 18,000 mPa·s. In Comparative Examples 2-1 to 2-3, slight separation of the materials was observed during mixing, and the air retention was low. In Comparative Examples 2-4 to 2-6 and 2-7 to 2-9, slight separation of the materials was observed during mixing, and the post-flow elongation was somewhat large. The air retention was also low. In Reference Examples 2-1 to 2-3, the post-flow elongation was small, but the air retention was lower than in the Examples.

[0188] While preferred embodiments of the present invention are described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only, and that various modifications, changes, and substitutions may be made by those skilled in the art without departing from the invention. It should be understood that various alternative embodiments of the invention described herein may be used in practicing the invention. Furthermore, the contents of all publications, including patents and patent applications, referenced herein should be construed as incorporated by reference as if expressly set forth herein.

Claims

1. (a) a first cement; (b) fine limestone powder, (c) sulfuric acid resistance imparting agent; (d1) A first admixture containing 1% by weight to 5% by weight of hydroxypropyl methylcellulose having a viscosity of 1,000 mPa s or more and 18,000 mPa s or less in a 2% by weight aqueous solution at 20 ° C., and a second cement; and (e) Water 1. A sulfuric acid resistant grout composition comprising:

2. moreover, (d2) A second admixture which is at least one selected from the group consisting of attapulgite, sepiolite, bentonite, talc, and silica fume.

2. The sulfuric acid resistant grout composition of claim 1, comprising:

3. 3. The sulfuric acid resistant grout composition according to claim 1, wherein the degree of substitution of the methoxy group of the hydroxypropyl methylcellulose is 1.7 to 1.9, and the degree of substitution of the hydroxypropoxy group is 0.1 to 0.

2.

4. 3. The sulfuric acid resistant grout composition of claim 1, wherein the sulfuric acid resistance agent comprises a naphthalene sulfonate condensate.

5. The sulfuric acid resistant grout composition according to claim 2, wherein the content of the hydroxypropyl methylcellulose is 0.2 to 1.0 parts by mass relative to 100 parts by mass of the total of the first admixture and the second admixture.

6. 3. The sulfuric acid resistant grout composition according to claim 1 or 2, comprising a first admixture (d1) in addition to components (a), (b), (c) and (e).

7. 3. The sulfuric acid resistant grout composition of claim 2, further comprising a first admixture (d1) and a second admixture (d2) in addition to components (a), (b), (c) and (e).

8. Components other than the first admixture (d1) and the second admixture (d2) 1m ３ The sulfuric acid resistant grout composition according to claim 2, wherein the total content of the first admixture (d1) and the second admixture (d2) is 5 to 30 kg.

9. A cured product of the sulfuric acid resistant grout composition according to claim 1 or 2.

10. (a) a first cement; (b) fine limestone powder, (c) sulfuric acid resistance imparting agent; (d1) A first admixture containing 1% by weight to 5% by weight of hydroxypropyl methylcellulose having a viscosity of 1,000 mPa s or more and 18,000 mPa s or less in a 2% by weight aqueous solution at 20 ° C., and a second cement; (e) water, and (f) Fine aggregate A sulfate-resistant mortar composition comprising:

11. A hardened product of the sulfuric acid resistant mortar composition according to claim 10.

12. (a) a first cement; (b) fine limestone powder, (c) sulfuric acid resistance imparting agent; (d1) A first admixture containing 1% by weight to 5% by weight of hydroxypropyl methylcellulose having a viscosity of 1,000 mPa s or more and 18,000 mPa s or less in a 2% by weight aqueous solution at 20 ° C., and a second cement; (e) water; (f) fine aggregate; and (g) Coarse aggregate 1. A sulfate-resistant concrete composition comprising:

13. moreover, (d2) A second admixture which is at least one selected from the group consisting of attapulgite, sepiolite, bentonite, talc, and silica fume.

13. The sulfate resistant concrete composition of claim 12, comprising:

14. A hardened product of the sulfate-resistant concrete composition according to claim 12 or 13.

15. (d1) An admixture for preparing a sulfuric acid-resistant grout composition, comprising 1% by weight to 5% by weight of hydroxypropyl methylcellulose having a viscosity of 1000 mPa·s or more and 18,000 mPa·s or less in a 2% by weight aqueous solution at 20°C, and a first admixture consisting of cement.

16. moreover, (d2) A second admixture which is at least one selected from the group consisting of attapulgite, sepiolite, bentonite, talc, and silica fume.

16. An admixture for preparing the sulfuric acid resistant grout composition of claim 15, comprising:

17. A dilution step (d1) of preparing a first admixture by diluting hydroxypropyl methylcellulose having a viscosity of 1000 mPa s or more and 18,000 mPa s or less in a 2% by mass aqueous solution at 20 ° C. with a second cement to a concentration of 1% by weight to 5% by weight; A mixing step of mixing (a) a first cement, (b) limestone fine powder, (c) a sulfuric acid resistance imparting agent, the first admixture (d1), and (e) water; 1. A method for producing a sulfuric acid resistant grout composition, comprising:

18. A dilution step of preparing a first admixture (d1) by diluting hydroxypropyl methylcellulose having a viscosity of 1000 mPa s or more and 18,000 mPa s or less in a 2% by mass aqueous solution at 20 ° C. with a second cement to a concentration of 1% by weight to 5% by weight; A mixing step of mixing (a) a first cement, (b) limestone fine powder, (c) a sulfuric acid resistance imparting agent, the first admixture (d1), (e) water, and (f) fine aggregate; A method for producing a sulfuric acid resistant mortar composition, comprising:

19. A dilution step of preparing a first admixture (d1) by diluting hydroxypropyl methylcellulose having a viscosity of 1000 mPa s or more and 18,000 mPa s or less in a 2% by mass aqueous solution at 20 ° C. with a second cement to a concentration of 1% by weight to 5% by weight; a mixing step of mixing (a) a first cement, (b) limestone fine powder, (c) a sulfuric acid resistance imparting agent, the first admixture (d1), (e) water, (f) a fine aggregate, and (g) a coarse aggregate; A method for producing a sulfate-resistant concrete composition, comprising:

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