Mortar composition and mortar

Abstract

To provide a cement mortar composition and a cement mortar having chloride ion osmosis resistance and excellent strength development property, crack resistance, and workability.SOLUTION: A cement mortar composition includes a cement, amorphous aluminosilicate, a fly ash, an expansive admixture, and a fine aggregate, wherein a total content of the amorphous aluminosilicate and the fly ash is 3-35 pts.mass to 100 pts.mass of the cement and the content of the expansive admixture is 1-25 pts.mass to 100 pts.mass of the cement.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to mortar compositions and mortar. [Background technology]

[0002] In recent years, there has been a growing demand for extending the lifespan of concrete structures from the perspective of reducing environmental impact and life cycle costs. One type of deterioration in concrete structures is salt damage. Salt damage occurs when chloride ions penetrate into the concrete, accelerating the corrosion of reinforcing steel and thus reducing the performance of the concrete structure. One way to suppress salt damage is to impart chloride ion penetration resistance to the concrete.

[0003] One method for imparting chloride ion penetration resistance to concrete structures is to reduce the water-cement ratio. However, this method results in poor workability and may lead to poor placement, thus not providing a fundamental solution. Another method involves adding admixtures. Examples of admixtures include fly ash, silica fume, and blast furnace slag powder, which exhibit pozzolanic reactions and latent hydraulic properties. Adding these admixtures to concrete improves durability and watertightness, and suppresses the penetration of chloride ions.

[0004] Other admixtures include calcium aluminate and amorphous aluminosilicate. Patent Document 1 describes a Blaine specific surface area value of 2000 to 7000 cm² with a CaO / Al2O3 molar ratio of 0.15 to 0.7. 2A cement admixture is disclosed that contains a calcium aluminate compound and a pozzolanic substance in a mass ratio of 1 / g, wherein the ratio of the calcium aluminate compound to the pozzolanic substance is 10 / 1 to 1 / 10. Patent Document 2 discloses a mortar / concrete admixture containing silica fume and metakaolin, wherein the mass ratio of the silica fume to the metakaolin is 3:7 to 7:3, the mullite content in 100 parts by mass of the metakaolin is 5 parts by mass or less, and the kaolinite content is 0.1 parts by mass or more. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2010-100473 [Patent Document 2] Japanese Patent Publication No. 2021-008375 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, the method of adding calcium aluminate to the cement composition had the problem that as the neutralization of the cement composition progressed, the composition containing the harmless chloride ions decomposed, and the chloride ions became harmful again. In addition, the method of adding amorphous aluminosilicate and silica fume had the problem that drying shrinkage increased, making it prone to cracking.

[0007] Therefore, the present invention aims to provide a mortar composition and mortar that have chloride ion penetration resistance and excellent strength development, crack resistance, and workability. [Means for solving the problem]

[0008] As a result of diligent research into the above-mentioned problems, the present inventors have found that by adjusting the content of the combination of amorphous aluminosilicate and fly ash, and the content of the expansive agent, it is possible to obtain a mortar composition and mortar that have chloride ion penetration resistance and excellent strength development, crack resistance, and workability.

[0009] In other words, the present invention is as follows. [1] A mortar composition comprising cement, amorphous aluminosilicate, fly ash, an expansive agent, and fine aggregate, wherein the total content of amorphous aluminosilicate and fly ash is 3 to 35 parts by mass per 100 parts by mass of cement, and the content of the expansive agent is 1 to 25 parts by mass per 100 parts by mass of cement. [2] The mortar composition according to [1], further comprising a polymer for cement. [3] The mortar composition according to [1] or [2], further comprising a thickening agent. [4] A mortar composition according to any one of [1] to [3], further comprising a shrinkage reducing agent. A mortar comprising a cement composition described in any of [5][1] to [4] and water, wherein the water content is 30 to 80 parts by mass per 100 parts by mass of cement. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a mortar composition and mortar that have chloride ion penetration resistance and excellent strength development, crack resistance, and workability. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described in detail below, but the present invention is not limited thereto. In this specification, all content figures are given on an anhydrous basis and on a solids basis.

[0012] The mortar composition of this embodiment comprises cement, amorphous aluminosilicate, fly ash, an expansive agent, and fine aggregate.

[0013] Various types of cement can be used, including, for example, various types of Portland cement such as ordinary, rapid-hardening, ultra-rapid-hardening, low-heat, and moderate-heat cements, as well as eco-cement and fast-setting cement. From the viewpoint of easily obtaining high strength development, ordinary Portland cement, rapid-hardening Portland cement, ultra-rapid-hardening Portland cement, and eco-cement are preferred. One type of cement may be used alone, or two or more types may be used in combination.

[0014] Amorphous aluminosilicates are derived from clay minerals and are not particularly limited as long as they contain an amorphous portion; any type can be used. Examples of clay minerals used as raw materials include (1) kaolin minerals, (2) mica clay minerals, (3) smectite-type minerals, and mixed-layer minerals formed by mixing these. Amorphous aluminosilicates are obtained by amorphousizing these crystalline aluminosilicates, for example, by calcination and dehydration. From the viewpoint of having even better resistance to chloride ion penetration, amorphous aluminosilicates derived from kaolin minerals such as kaolinite, halosite, and dickite are preferred, and metakaolin obtained by calcining kaolinite is more preferred. Amorphous aluminosilicates may be used individually or in combination of two or more types. The BET specific surface area of ​​amorphous aluminosilicate is 10,000 to 40,000 cm². 2 It is preferable that the value is / g, and the range is 15,000 to 30,000 cm². 2 It is more preferable that it be / g. In this specification, "amorphous" means that, in the measurement by a powder X-ray diffractometer, almost no peak derived from the clay mineral as the raw material is observed. The amorphous aluminosilicate mineral powder according to this embodiment only needs to have an amorphous ratio of 70% by mass or more, preferably 90% by mass or more, more preferably 100% by mass, that is, it is most preferable that no peak is observed in the measurement by a powder X-ray diffractometer. Here, the ratio of the amorphous content is a value obtained by the standard addition method. An aluminosilicate with a high amorphous ratio, that is, an aluminosilicate with a low crystalline ratio, tends to have better strength development at the same mixing amount compared to an aluminosilicate with a low amorphous ratio. Examples of the heating for the amorphization of aluminosilicate include firing using an external heating kiln, an internal heating kiln, an electric furnace, etc., and melting using a melting furnace.

[0015] The content of the amorphous aluminosilicate is preferably 1 to 30 parts by mass, more preferably 2 to 25 parts by mass, and still more preferably 3 to 20 parts by mass with respect to 100 parts by mass of the cement. If the content of the amorphous aluminosilicate is within the above range, the chloride ion penetration resistance and the adhesion strength will be further improved.

[0016] Any fly ash generally used as an admixture for concrete (specified in JIS ash: JIS A 6201:2015) may be used. From the viewpoint that better strength development can be obtained in a low-temperature environment, type I or type II JIS ash is preferable. The Blaine specific surface area of the fly ash is preferably 2500 to 6000 cm 2 / g, and more preferably 3000 to 5000 cm 2 / g.

[0017] The content of the fly ash is preferably 1 to 30 parts by mass, more preferably 2 to 25 parts by mass, and still more preferably 3 to 20 parts by mass with respect to 100 parts by mass of the cement. If the content of the fly ash is within the above range, the crack resistance and the workability will be further improved.

[0018] The total content of the amorphous aluminosilicate and fly ash is 3 to 35 parts by mass with respect to 100 parts by mass of cement. If the total content of the amorphous aluminosilicate and fly ash is outside the above range, it is impossible to achieve both chloride ion penetration resistance and crack resistance, and the adhesive strength is not excellent. From the viewpoint of having a high chloride ion penetration suppression effect, ensuring high strength, and easily ensuring good workability, the total content of the amorphous aluminosilicate and fly ash is preferably 8 to 30 parts by mass, and more preferably 12 to 28 parts by mass with respect to 100 parts by mass of cement.

[0019] Any expansive agent may be used as long as it is a JIS-compliant expansive agent (JIS A 6202:2008) generally used as an expansive agent for concrete. Examples of the expansive agent include an expansive agent mainly composed of free quicklime (quicklime-based expansive agent), an expansive agent mainly composed of ettringite (ettringite-based expansive agent), and a composite expansive agent of free quicklime and ettringite-forming substances. The expansive agent may be used alone or in combination of two or more kinds. It is preferable to use an expansive agent having a Blaine specific surface area of 2000 to 6000 cm 2 / g.

[0020] The content of the expansive agent is 1 to 25 parts by mass with respect to 100 parts by mass of cement. If the content of the expansive agent is outside the above range, the crack resistance and strength development property are not excellent. From the viewpoint of further excellent dimensional stability and strength development property, the content of the expansive agent is preferably 3 to 20 parts by mass, and more preferably 5 to 15 parts by mass with respect to 100 parts by mass of cement.

[0021] Examples of the fine aggregate include river sand, silica sand, crushed sand, gypsum stone, limestone sand, slag aggregate, etc. As the fine aggregate, it is preferable to use aggregates such as silica sand and limestone adjusted to a particle size that does not contain fine powder or coarse aggregate from these. The fine aggregate may be used alone or in combination of two or more kinds. It is preferable to use the commonly used fine aggregate having a particle size of 5 mm or less (the part passing through a 5 mm sieve).

[0022] The particle size of the fine aggregate is not particularly limited and can be adjusted within the required range. The particle size of the fine aggregate can be considered based on the coarseness ratio specified in JIS A 1102:2014 "Method for sieving aggregates". From the viewpoint of obtaining better fluidity and suppressing bleeding in mortar, the coarseness ratio of the fine aggregate is preferably 1 to 4, more preferably 1.5 to 3.5, and even more preferably 2 to 3.

[0023] The fine aggregate content is preferably 150 to 400 parts by mass, more preferably 200 to 350 parts by mass, and even more preferably 240 to 340 parts by mass, per 100 parts by mass of cement. If the fine aggregate content is within the above range, sufficient strength development can be easily obtained while suppressing cracking.

[0024] The mortar composition of this embodiment may contain a cement polymer. The cement polymer is preferably one specified in JIS A 6203:2015 "Polymer Dispersions and Re-emulsifiable Powder Resins for Cement Admixture". Examples of such cement polymers include polymer dispersions and re-emulsifiable powder resins. Examples of polymer dispersions include synthetic rubber types such as styrene-butadiene rubber (SBR); natural rubber types; rubber asphalt types; ethylene vinyl acetate types; acrylic acid ester types; and resin asphalt types. Among polymer dispersions, synthetic rubber types, ethylene vinyl acetate types, and acrylic acid ester types are preferred, and specifically, synthetic rubber latex, polyacrylic acid ester, and ethylene vinyl acetate are more preferred. Examples of re-emulsifiable powder resins include synthetic rubber types such as styrene-butadiene rubber; acrylic acid ester types; ethylene vinyl acetate types; vinyl acetate / versatile vinyl ester; vinyl acetate / versatile vinyl / acrylic acid ester. As the polymer for cement, a polymer dispersion may be used, a re-emulsifying powder resin may be used, or a polymer dispersion and a re-emulsifying powder resin may be used in combination. Among cement polymers, acrylic acid ester-based polymer dispersions and / or re-emulsified powder resins are preferred from the viewpoint of improving chloride ion penetration resistance and adhesion to concrete. Cement polymers may be used individually or in combination of two or more types.

[0025] The content of the cement polymer is preferably 1 to 18 parts by mass, more preferably 2 to 15 parts by mass, and even more preferably 3 to 12 parts by mass, per 100 parts by mass of cement. When the cement polymer content is within the above range, it is easier to apply, and the strength development and adhesive strength are further improved.

[0026] The mortar composition of this embodiment may contain fibers. Examples of fibers include organic fibers such as vinylon fibers, polypropylene fibers, nylon fibers, acrylic fibers, polyethylene, and cellulose fibers. From the viewpoint of better dispersibility, organic fibers are preferred, and nylon fibers, vinylon fibers, and polypropylene fibers are more preferred. One type of fiber may be used alone, or two or more types may be used in combination.

[0027] The length of the fibers is preferably 1 to 20 mm, more preferably 2 to 15 mm, and even more preferably 3 to 12 mm. If the length of the fibers is within the above range, the mortar will be easier to prepare.

[0028] The fiber content is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 4 parts by mass, and even more preferably 0.2 to 3 parts by mass, per 100 parts by mass of cement. If the fiber content is within the above range, it can be mixed more uniformly during mortar preparation, and even better crack resistance can be obtained.

[0029] The mortar composition of this embodiment may contain a shrinkage reducing agent. Examples of shrinkage reducing agents include polyoxyalkylene compounds, polyether compounds, alkylene oxide compounds, etc. Specific examples of shrinkage reducing agents include polyoxyethylene alkylallyl ether, polypropylene glycol, lower alcohol alkylene oxide adducts, glycol ether amino alcohol derivatives, polyethers, polyoxyalkylene glycol, ethylene oxide methanol adducts, ethylene oxide propylene oxide polymers, phenyl ethylene oxide polymers, cycloalkylene ethylene oxide polymers, and dimethylamine ethylene oxide polymers. A single shrinkage reducing agent may be used, or two or more may be used in combination.

[0030] The content of the shrinkage reducing agent is preferably 0.1 to 5 parts by mass, more preferably 0.3 to 3 parts by mass, and even more preferably 0.5 to 2 parts by mass, per 100 parts by mass of cement. If the content of the shrinkage reducing agent is within the above range, drying shrinkage after hardening can be suppressed without causing any significant delay in setting, and durability can be further improved.

[0031] The mortar composition of this embodiment may contain a thickening agent. The type of thickening agent is not particularly limited, and examples include cellulose-based thickening agents, acrylic-based thickening agents, and guar gum-based thickening agents. Cellulose-based thickening agents are preferred. Examples of cellulose-based thickening agents include carboxymethylcellulose, methylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, and hydroxypropylcellulose. One type of thickening agent may be used alone, or two or more types may be used in combination.

[0032] The amount of thickener is preferably 0.005 to 3 parts by mass, more preferably 0.01 to 2 parts by mass, and even more preferably 0.015 to 1 part by mass, based on solid content, per 100 parts by mass of cement. When the amount of thickener is within the above range, better water retention and workability are more easily obtained when it is made into mortar, and the compressive strength is also easily improved.

[0033] The mortar composition of this embodiment may contain a water-reducing agent. The water-reducing agent may include a high-performance water-reducing agent, a high-performance AE water-reducing agent, an AE water-reducing agent, and a fluidizing agent. Examples of such water-reducing agents include those specified in JIS A 6204:2011 "Chemical admixtures for concrete". Examples of water-reducing agents include polycarboxylic acid-based water-reducing agents, naphthalene sulfonic acid-based water-reducing agents, lignin sulfonic acid-based water-reducing agents, and melamine-based water-reducing agents. Among these, naphthalene sulfonic acid-based water-reducing agents are preferred. A single water-reducing agent may be used alone, or two or more may be used in combination.

[0034] The water-reducing agent content is preferably 0.1 to 5 parts by mass, more preferably 0.15 to 3 parts by mass, and even more preferably 0.2 to 1 part by mass, based on solid content, per 100 parts by mass of cement. When the water-reducing agent content is within the above range, better mixability (water compatibility) is more easily obtained when forming mortar, and the compressive strength is also more easily improved.

[0035] The mortar composition of this embodiment may contain organic admixtures. Organic admixtures may include the shrinkage reducing agent, thickener, and water-reducing agent mentioned above, as well as defoaming agents, foaming agents, waterproofing agents, water-repellent agents, dust-reducing agents, etc. One type of organic admixture may be used alone, or two or more types may be used in combination. Among the organic admixtures, it is preferable that at least two or more types are selected from shrinkage reducing agents, water-reducing agents, thickeners, and defoaming agents.

[0036] The content of the organic admixture is preferably 0.01 to 3 parts by mass, more preferably 0.02 to 2 parts by mass, and even more preferably 0.05 to 1.8 parts by mass, per 100 parts by mass of cement. Good workability can be easily ensured if the content of the organic admixture is within the above range.

[0037] The mortar composition of this embodiment may contain various admixtures (materials) to the extent that the effects of the present invention are not impaired. Examples of admixtures (materials) include foaming agents, rust inhibitors, pigments, and efflorescence inhibitors.

[0038] The method for producing the mortar composition of this embodiment is not particularly limited, and can be produced by mixing it with a mixer such as a gravity mixer such as a V-type mixer or a tiltable concrete mixer, a Henschel mixer, a jet mixer, a ribbon mixer, or a paddle mixer.

[0039] The mortar composition of this embodiment can be mixed with water to form mortar, and the water content can be adjusted as appropriate depending on the application. The water content is preferably 35 to 80 parts by mass, more preferably 35 to 75 parts by mass, and even more preferably 40 to 70 parts by mass, per 100 parts by mass of cement. If the water content is within the above range, workability is further ensured, and chloride ion penetration resistance, adhesion, and strength development are further improved.

[0040] The preparation of the mortar in this embodiment can be done using the same mixing equipment as described above for the mortar composition, and is not particularly limited. Examples of mixing equipment include gravity mixers such as V-type mixers and tiltable concrete mixers, Henschel mixers, jet mixers, ribbon mixers, and paddle mixers.

[0041] The mortar composition and mortar of this embodiment have good workability and, upon hardening, exhibit excellent resistance to chloride ion penetration, strength development, and crack resistance. Therefore, the mortar composition and mortar of this embodiment can be suitably used for repairing reinforced concrete structures, building structures, and the like. The application method is not particularly limited, and can be selected from methods such as plastering with a trowel, wet spray application using a pump, and formwork application by filling into formwork. [Examples]

[0042] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. All content figures in the table are on an anhydrous basis and on a solids basis.

[0043] [material] Cement: Ordinary Portland cement Fly ash: Blaine specific surface area 4100 cm 2 / g Metakaolin: BET specific surface area 21000 cm 2 / g Silica fume: BET specific surface area 180000 cm 2 / g Fine aggregate: Silica sand Fine aggregate A: Coarse grain ratio 2.46 Fine aggregate B: Coarse grain ratio 2.53 Fine aggregate C: Coarse grain ratio 2.21 Fine aggregate D: Coarse grain ratio 2.50 Expansion agent: Quicklime-based expansion agent, Blaine specific surface area 4100 cm<OO00010> / g Polymer for cement Resin A: Acrylic ester-based re-emulsified powder resin Resin B: SBR-based emulsion Resin C: Acrylic ester-based emulsion Fiber: Nylon-based fiber, fiber length 5 mm Shrinkage reducing agent: Alkylene oxide adduct of lower alcohol Thickener: Methyl cellulose-based thickener Water reducing agent: Naphthalene sulfonic acid-based water reducing agent

[0044] [Mortar composition and production of mortar] Each material was put into a Henschel mixer at the mixing ratios shown in Table 1 and Table 2, and mixed for 3 minutes to adjust the mortar composition. The numerical values of each material in Table I are shown in parts by mass when the cement is 100 parts by mass. The mortar composition and water were kneaded with a basket-type high-speed hand mixer (1000 rpm) for 90 seconds to prepare the mortar. The mixing ratio of water is as shown in Table 1 and Table 2.

[0045] [Measurement conditions] The various measurement conditions are as follows. The measurement results are shown in Table 1 and Table 2. · Apparent diffusion coefficient<00002OO>Based on JSCE-G573-2003 "Draft Method for Measuring Total Chloride Ion Distribution in Concrete in Actual Structures," the apparent diffusion coefficient was measured and evaluated as chloride ion penetration resistance. An apparent diffusion coefficient of 1 cm² was used. 2 We rated those with a year or less as good. • Crack resistance Based on JIS A 1129-3:2010 "Method for measuring length change of mortar and concrete, Part 3: Dial gauge method," the rate of length change at 28 days of age was measured. The rate of length change was evaluated as crack resistance. A rate of length change of 0.1% or less was evaluated as good. • Compressive strength Compressive strength was measured on specimens aged 28 days, based on JIS A 1171:2016 "Test methods for polymer cement mortar". Curing involved demolding the hardened specimens 24 hours after molding and air curing in a constant temperature chamber at 20°C until 28 days of age. The compressive strength was 35 N / m². 2 The above items were rated as good. ·Adhesion strength Adhesion strength was measured on 28-day-old specimens based on JIS A 1171:2016 "Test Methods for Polymer Cement Mortar". Curing involved demolding the hardened specimens 24 hours after molding and air curing in a constant temperature chamber at 20°C until 28 days of age. Adhesion strength was 1.0 N / m 2 The above items were rated as good. ·Workability When applying mortar to a wall, products with excellent trowel workability (trowel spread, trowel cut, and surface smoothness) were marked with a circle (○), while those with poor trowel spread, stickiness to the trowel, and difficulty in creating a smooth surface were marked with a cross (×).

[0046] [Table 1]

[0047] [Table 2]

[0048] The mortar in the example demonstrated excellent resistance to chloride ion penetration, crack resistance, strength development, adhesive strength, and workability. In contrast, the mortar in the comparative example was insufficient in at least one of the measured parameters.

Claims

1. It contains cement, amorphous aluminosilicate, fly ash, an expansive agent, and fine aggregate. The total content of the amorphous aluminosilicate and the fly ash is 3 to 35 parts by mass per 100 parts by mass of the cement. The content of the expansive material is 10 to 25 parts by mass per 100 parts by mass of the cement. A mortar composition in which the fine aggregate content is 300 to 400 parts by mass per 100 parts by mass of cement.

2. The mortar composition according to claim 1, further comprising a polymer for cement.

3. The mortar composition according to claim 1 or 2, further comprising a thickening agent.

4. A mortar composition according to any one of claims 1 to 3, further comprising a shrinkage reducing agent.

5. A cement composition according to any one of claims 1 to 4, and water, Mortar in which the water content is 30 to 80 parts by mass per 100 parts by mass of cement.

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