High-strength mortar repair material

Abstract

To provide a high-strength mortar repair material having excellent workability in plasterer finishing and hardening property.SOLUTION: Provided is a high-strength mortar repair material including cement, a silica fume, a water-reducing agent, an antifoam agent, an inorganic fine powder, and a fine aggregate, wherein the inorganic fine powder and the fine aggregate include, in total, a grain group having a grain size of 0.15 mm or less of 10.0 mass% or more and less than 40.0 mass% and a grain group having a grain size of 0.075 mm or less of 5.0 mass% or more and 30.0 mass% or less, the inorganic fine powder comprises one or more kinds of fine powders selected from the group consisting of a limestone fine powder, a silica stone powder, and a crushed stone powder, and to a total amount of 100 pts.mass of the cement and the silica fume, the silica fume of 3-30 pts.mass and the water-reducing agent of 0.1-6.0 pts.mass are included, and the fine aggregate of 300-1,200 kg / m3 and the inorganic fine powder of 50-600 kg / m3 are included.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a high-strength mortar repair material. [Background technology]

[0002] Concrete and mortar harden with a binder such as cement to form a hardened product with desired properties. The hydraulic compositions that form such hardened products are required to have various properties depending on the application. For example, Patent Document 1 proposes a technology for repairing existing concrete structures by compounding reinforcing fibers and using the cross-linking effect of these reinforcing fibers to prevent cracking and form high-density, high-strength concrete. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-133344 Summary of the Invention [Problem to be solved by the invention]

[0004] When repairing existing structures, workers often use trowels or other tools on-site. Repair locations may be located at high altitudes or in narrow gaps. Therefore, the mortar repair material used for repairs must not only have high strength after hardening, but also be sufficiently easy to work with, for example, trowel application. Therefore, the present invention provides a high-strength mortar repair material that is excellent in workability for plastering and hardening properties. [Means for solving the problem]

[0005] The present invention provides a high-strength mortar repair material containing cement, silica fume, a water-reducing agent, an antifoaming agent, inorganic fine powder, and fine aggregate, wherein the cement contains 40.0 to 75.0 mass% of C3S and more than 0 mass% but less than 2.7 mass% of C3A, and the 45 μm sieve residue is less than 25.0 mass%, and the inorganic fine powder and fine aggregate together contain 10.0 mass% of particles with a particle size of 0.15 mm or less. The high-strength mortar repair material contains 3 to 30 parts by mass of silica fume and 0.1 to 6.0 parts by mass of a water-reducing agent relative to 100 parts by mass of the total amount of cement and silica fume, and the inorganic fine powder is one or more fine powders selected from the group consisting of limestone fine powder, silica stone powder and crushed stone powder. 3 Based on this, fine aggregate is 300 to 1200 kg / m 3 , and inorganic fine powder at 50 to 600 kg / m 3 To provide a high-strength mortar repair material including:

[0006] This high-strength mortar repair material contains a predetermined cement and each component in a predetermined content ratio. The inorganic fine powder and fine aggregate have a predetermined particle size in total. This high-strength mortar repair material becomes a slurry with a high yield value, and can achieve high levels of all properties, including good trowel release and trowel elongation when applied, crack resistance when applied, and sagging resistance after application. Therefore, it is easy to perform plastering finishing work and has excellent workability. In addition, it can achieve sufficiently high compressive strength after hardening, resulting in excellent hardening properties.

[0007] The high-strength mortar repair material preferably further contains a thickener. When a high-strength mortar repair material contains a water-reducing agent, the flow value increases, but the thickener imparts thixotropy to the high-strength mortar repair material when it is made into a slurry, thereby further improving trowel elongation, sagging resistance, and crack resistance during plastering finishing.

[0008] The thickener preferably includes a bentonite-based thickener or a polymer-based thickener, which allows the viscosity of the high-strength mortar repair material when made into a slurry to fall within an appropriate range, thereby further improving trowel elongation, sagging resistance, and crack resistance during plastering finishing.

[0009] The high-strength mortar repair material preferably contains 0.01 to 2.0 parts by mass of a thickener per 100 parts by mass of the total amount of cement and silica fume, thereby further improving trowel elongation, sagging resistance, and crack resistance during plastering finish.

[0010] The high-strength mortar repair material further contains fibers, and the fibers preferably contain at least one of inorganic fibers and organic fibers. This can further improve the hardening properties of the high-strength mortar repair material. Specifically, it can reduce the occurrence of cracks in the hardened product and sufficiently suppress spalling.

[0011] When the fibers include inorganic fibers, the inorganic fibers preferably include at least one selected from the group consisting of steel fibers, stainless steel fibers, amorphous alloy fibers, glass fibers, carbon fibers, and basalt fibers. When the fibers include organic fibers, the organic fibers preferably include at least one selected from the group consisting of vinylon fibers, aramid fibers, nylon fibers, PE fibers, PP fibers, PVA fibers, and PBO fibers. This can further improve the hardening properties of the high-strength mortar repair material.

[0012] The content of the above fibers is preferably 0.1 to 3% by volume based on the total volume of all components other than fibers, which can further improve the hardening properties of the high-strength mortar repair material.

[0013] The high-strength mortar repair material preferably contains 10 to 25 parts by mass of water per 100 parts by mass of the total amount of cement and silica fume. Such a slurry-like high-strength mortar repair material is sufficiently excellent in workability for plastering finish.

[0014] The high-strength mortar repair material has a compressive strength design standard of 150N / mm 2 It is preferable to use it for repairing the above structures. This high-strength mortar repair material has excellent hardening properties, so it can form a hardened product with sufficiently high compressive strength. For example, if the design standard for compressive strength is 150 N / mm 2 If conventional low-strength mortar repair materials are used to repair such high-strength structures, the resulting structure will have insufficient strength. For this reason, as mentioned above, the high-strength mortar repair materials are designed to have a compressive strength of 150 N / mm 2 It can be suitably used as a repair material for the above-mentioned high-strength structures. [Effects of the Invention]

[0015] It is possible to provide a high-strength mortar repair material that is excellent in workability for plastering and hardening properties. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a photograph showing the appearance of a test specimen after 26 weeks of accelerated testing in the evaluation of resistance to carbonation. [Figure 2] 1 is a graph showing the distribution of chloride ion concentration along the depth direction from the surface of mortar. [Figure 3] Graph (A) shows the relationship between the number of freeze-thaw cycles and the mass loss rate, and graph (B) shows the relationship between the number of freeze-thaw cycles and the relative dynamic modulus of elasticity. DETAILED DESCRIPTION OF THE INVENTION

[0017] An embodiment of the present invention will be described below. However, the following embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content.

[0018] A high-strength mortar repair material according to one embodiment includes cement, silica fume, a water-reducing agent, an antifoaming agent, an inorganic fine powder, and fine aggregate. The high-strength mortar repair material may be in a powder form or may further contain water to form a slurry. A slurry of the high-strength mortar repair material may be prepared by blending water with the powder of the high-strength mortar repair material.

[0019] The mineral composition of the cement contains 40.0 to 75.0 mass% C3S and more than 0 but less than 2.7 mass% C3A. The mineral composition of the cement contains preferably 45.0 to 73.0 mass% C3S, more preferably 48.0 to 70.0 mass%, and even more preferably 50.0 to 68.0 mass% C3A. The mineral composition of the cement contains preferably more than 0 but less than 2.3 mass%, more preferably more than 0 but less than 2.1 mass%, and even more preferably more than 0 but less than 1.9 mass% C3A. If the C3S content is less than 40.0 mass%, the compressive strength tends to decrease, and if it exceeds 75.0 mass%, the burning of the cement itself tends to become difficult. Furthermore, if the C3A content is 2.7 mass% or more, the fluidity tends to decrease. The lower limit of the C3A content is not particularly limited and may be, for example, 0.1 mass%.

[0020] The mineral composition of the cement preferably contains 9.5 to 40.0 mass% of C2S, more preferably 10.0 to 35.0 mass%, and even more preferably 12.0 to 30.0 mass%. The mineral composition of the cement preferably contains 9.0 to 18.0 mass%, more preferably 10.0 to 15.0 mass%, and even more preferably 11.0 to 15.0 mass% of C4AF. Within this range of the mineral composition of the cement, the high-strength mortar repair material can achieve both sufficiently high levels of fluidity and compressive strength after hardening.

[0021] The particle size of the cement is such that the 45 μm sieve residue is less than 25.0 mass%, preferably less than 20.0 mass%, more preferably less than 18.0 mass%, and even more preferably less than 15.0 mass%. The lower limit of the 45 μm sieve residue is 0.0 mass%, preferably 1.0 mass%, and more preferably 4.0 mass%. If the particle size of the cement is within this range, a hardened product with sufficiently high compressive strength can be formed. Furthermore, a high-strength mortar repair material in a slurry form containing this cement has appropriate viscosity. Therefore, sufficient dispersibility can be ensured even when fibers are added.

[0022] The Blaine specific surface area of ​​the cement is preferably 2500 to 4800 cm 2 / g, and more preferably 2800 to 4000 cm 2 / g, and more preferably 3000 to 3600 cm 2 / g, and particularly preferably 3100 to 3500 cm 2 / g. If the Blaine specific surface area of ​​cement is too low, the strength of the hardened product of high-strength mortar repair material tends to be low. If the Blaine specific surface area of ​​cement is too high, the fluidity at low water-cement ratios tends to be low.

[0023] The cement can be produced by adjusting the blend of raw materials such as limestone, silica, slag, coal ash, construction soil, and blast furnace dust according to the desired mineral composition, burning the mixture in a kiln, adding gypsum to the resulting clinker, and pulverizing it to the desired particle size. A typical NSP kiln or SP kiln can be used for the firing, and a typical pulverizer such as a ball mill can be used for pulverization. If necessary, two or more types of cement can be used.

[0024] Silica fume is a by-product obtained by collecting dust in the exhaust gas generated during the production of metal silicon, ferrosilicon, electrofused zirconia, etc., and its main component is amorphous SiO2 that dissolves in alkaline solutions. The average particle size of silica fume is preferably 0.05 to 2.0 μm, more preferably 0.10 to 1.5 μm, and even more preferably 0.18 to 0.28 μm. The use of such silica fume can improve the mixability of high-strength mortar repair materials while further increasing the compressive strength of the hardened product.

[0025] The high-strength mortar repair material contains 3 to 30 parts by mass, preferably 10 to 25 parts by mass, and more preferably 15 to 20 parts by mass of silica fume per 100 parts by mass of the total amount of cement and silica fume. By using such a blending ratio, the high-strength mortar repair material can be easily mixed and mixed while achieving sufficiently high compressive strength after hardening.

[0026] Examples of water-reducing agents include polycarboxylic acid-based, lignin-based, naphthalenesulfonic acid-based, and aminosulfonic acid-based water-reducing agents, high-performance water-reducing agents, and high-performance air-entraining water-reducing agents. From the viewpoint of ensuring fluidity at a low water-cement ratio, the water-reducing agent preferably contains at least one selected from the group consisting of polycarboxylic acid-based water-reducing agents, high-performance water-reducing agents, and high-performance air-entraining water-reducing agents, and more preferably contains a polycarboxylic acid-based high-performance water-reducing agent.

[0027] The high-strength mortar repair material contains 0.1 to 6.0 parts by mass, preferably 0.2 to 4.0 parts by mass, and more preferably 0.3 to 3.0 parts by mass of a water-reducing agent per 100 parts by mass of the total amount of cement and silica fume.

[0028] Examples of antifoaming agents include special nonionic surfactants, polyalkylene derivatives, hydrophobic silica, polyethers, etc. The high-strength mortar repair material preferably contains 0.01 to 2.0 parts by mass of antifoaming agent per 100 parts by mass of the total amount of cement and silica fume, more preferably 0.02 to 1.5 parts by mass, and even more preferably 0.03 to 1.0 part by mass.

[0029] The inorganic fine powder includes at least one selected from the group consisting of limestone fine powder, silica stone powder, and crushed stone powder. The inorganic fine powder includes limestone fine powder, silica stone powder, and / or crushed stone powder, etc., in a powder having a Blaine specific surface area of ​​2500 cm. 2 / g or more, and is mixed to adjust the fine particle content. By having such inorganic fine powder and a fine aggregate (described later) with a predetermined particle size, the viscosity and yield value of the high-strength mortar repair material are in an appropriate range, and the suitability for plastering finishes, such as trowel elongation, trowel release, sagging resistance, and crack resistance, is improved. The Blaine specific surface area of ​​the inorganic fine powder is 3000 to 5500 cm 2 / g, and 3500 to 5000 cm 2 / g, and more preferably 4000 to 4500 cm 2 / g is more preferred.

[0030] High-strength mortar repair material is high-strength mortar repair material 1m 3 Based on this, inorganic fine powder is added at 50 to 600 kg / m 3 Preferably 100 to 500 kg / m 3 More preferably, 150 to 400 kg / m 3 More preferably, 200 to 300 kg / m 3 This allows for a higher level of both workability and hardening properties for plastering finishes.

[0031] The inorganic fine powder contains preferably 85.0% to 100.0% by mass, more preferably 90.0% to 100.0% by mass, and even more preferably 95.0% to 100.0% by mass of particle groups having a particle size of 0.15 mm or less. The inorganic fine powder contains preferably 80.0% to 100.0% by mass, more preferably 85.0% to 100.0% by mass, and even more preferably 90.0% to 100.0% by mass of particle groups having a particle size of 0.075 mm or less.

[0032] Examples of fine aggregate include river sand, land sand, sea sand, crushed sand, silica sand (crushed silica sand), limestone aggregate, blast furnace slag fine aggregate, ferronickel slag fine aggregate, copper slag fine aggregate, and electric furnace oxidizing slag fine aggregate. The particle size of the fine aggregate is such that all of it passes through a 10 mm sieve and at least 85% by mass passes through a 5 mm sieve.

[0033] High-strength mortar repair material is high-strength mortar repair material 1m 3 Based on this, fine aggregate is 300 to 1200 kg / m 3 Preferably 400 to 1000 kg / m 3 More preferably, 500 to 900 kg / m 3 More preferably, 600 to 800 kg / m 3 This allows for a higher level of both workability and hardening properties for plastering finishes.

[0034] It is preferable to use a combination of fine aggregates with different particle sizes. For example, when using first and second fine aggregates with different particle sizes, the particle size of the first fine aggregate is preferably 0.2 to 1.0, more preferably 0.4 to 0.8, and the particle size of the second fine aggregate is preferably 1.5 to 3.0, more preferably 2.0 to 2.8. By using multiple fine aggregates with different particle sizes in this way, it is possible to achieve both higher levels of workability and hardening properties in the plastering finish. The particle size is calculated by dividing the sum of the mass percentages of aggregates retained on 10 sieves with mesh sizes ranging from 80 mm to 0.15 mm by 100.

[0035] The inorganic fine powder and fine aggregate, in combination, contain particles with a particle size of 0.15 mm or less in an amount of 10.0% by mass or more but less than 40.0% by mass, preferably 20.0% by mass or more but less than 37.0% by mass, and more preferably 25.0% by mass or more but less than 35.0% by mass. The inorganic fine powder and fine aggregate, in combination, contain particles with a particle size of 0.075 mm or less in an amount of 5.0% by mass or more but less than 30.0% by mass, preferably 10.0% by mass or more but less than 27.0% by mass, and more preferably 20.0% by mass or more but less than 25.0% by mass. By ensuring that the particle size of the inorganic fine powder and fine aggregate combined falls within the above range, a highly uniform slurry can be prepared in a short time. This shortens the slurry preparation time. In addition, when the high-strength mortar repair material is made into a slurry, the viscosity and yield value are maintained within an appropriate range, improving the suitability for plastering finishes, such as trowel application, trowel release, sagging resistance, and cracking resistance.

[0036] The particle size of the inorganic fine powder and fine aggregate combined may be measured by actually preparing a mixture of the inorganic fine powder and fine aggregate and using a sieve, or may be calculated from the particle sizes of the inorganic fine powder and fine aggregate and their blending ratios. Note that when producing a high-strength mortar repair material, it is not essential to prepare a mixture of the inorganic fine powder and fine aggregate; the inorganic fine powder and fine aggregate may be blended and mixed together with other raw materials.

[0037] In this specification, the content of particles having a particle size of 0.15 mm or less is determined as the mass ratio of the particles that fall under the sieve when sieved using a sieve with a mesh size of 0.15 mm, and the content of particles having a particle size of 0.075 mm or less is determined as the mass ratio of the particles that fall under the sieve when sieved using a sieve with a mesh size of 0.075 mm.

[0038] The high-strength mortar repair material may contain optional components, such as a thickener, fiber, synthetic resin powder, and a setting retarder.

[0039] Examples of thickeners include bentonite-based, cellulose-based, acrylic-based, and polymer-based thickeners. Among these, bentonite-based or polymer-based thickeners are preferred, with bentonite-based thickeners being more preferred. This allows the viscosity of the high-strength mortar repair material when made into a slurry to fall within a suitable range, further improving trowel elongation, sagging resistance, and crack resistance during plastering. Furthermore, the slurrying time can be shortened, improving workability.

[0040] The high-strength mortar repair material preferably contains 0.01 to 2.0 parts by mass of thickener, more preferably 0.03 to 1.5 parts by mass, and even more preferably 0.05 to 1.0 part by mass, per 100 parts by mass of the total amount of cement and silica fume. By including the thickener in such a range, the viscosity of the high-strength mortar repair material when made into a slurry can be maintained within a more suitable range.

[0041] Examples of the expansive agent that can be used include metal powder, calcium sulfoaluminate (CSA-based), and lime-based agents whose main component is CaO. Examples of calcium sulfoaluminate-based expansive agents include auin, and expansive agents that produce elintgate are particularly preferred. Examples of lime-based expansive agents include quicklime, quicklime-gypsum mixtures, and calcined dolomite, and among these, quicklime and / or quicklime-gypsum mixtures are preferred. These expansive agents can be used alone or in combination of two or more.

[0042] The content of the expansive material is 1m of high-strength mortar repair material. 3 The amount is preferably 5 to 40 kg, more preferably 10 to 35 kg, still more preferably 15 to 35 kg, and particularly preferably 20 to 35 kg per unit weight. A low content does not contribute to expansion, whereas a high content leads to excessive expansion, which is not preferred.

[0043] The fibers may include at least one of inorganic and organic fibers. The inorganic fibers preferably include at least one selected from the group consisting of steel fibers, stainless steel fibers, amorphous alloy fibers, glass fibers, carbon fibers, and basalt fibers. The organic fibers preferably include at least one selected from the group consisting of vinylon fibers, aramid fibers, nylon fibers, PE fibers, PP fibers, PVA fibers, and PBO fibers. The inclusion of such fibers further improves the hardening properties of the high-strength mortar repair material. Examples of hardening properties include compressive strength and splitting tensile strength. Therefore, cracking and the resulting spalling of the hardened product can be sufficiently suppressed. The fiber content in the high-strength mortar repair material is preferably 0.1 to 3 vol%, more preferably 0.1 to 2 vol%, even more preferably 0.1 to 1 vol%, and even more preferably 0.2 to 0.5 vol%, based on the total components of the high-strength mortar repair material other than the fibers. This further improves the hardening properties of the high-strength mortar repair material.

[0044] The high-strength mortar repair material preferably contains 10 to 25 parts by mass, more preferably 12 to 20 parts by mass, and even more preferably 13 to 18 parts by mass of water per 100 parts by mass of the total amount of cement and silica fume. 3 The unit amount of water per unit is preferably 150 to 250 kg / m 3 and more preferably 160 to 240 kg / m 3 and more preferably 180 to 220 kg / m 3 Such a high-strength mortar repair material in a slurry form is excellent in workability for plastering finishes.

[0045] The fluidity of the slurry-like high-strength mortar repair material is preferably 120 to 140 mm at 15 strokes. This allows for smooth plastering. The hardened product of the high-strength mortar repair material has a sufficiently high compressive strength. For this reason, for example, when the design standard for compressive strength is 150 N / mm 2The high-strength mortar repair material can be suitably used as a repair material for the above structures. The compressive strength of the hardened product (age: 28 days) is preferably 150 N / mm 2 More preferably, it is 160N / mm 2 More preferably, it is 165N / mm 2 This high-strength mortar repair material can be more suitably used as a repair material for the above-mentioned structures. The compressive strength is a value measured by the method described in the Examples.

[0046] The manufacturing method of the repair mortar repair material is not particularly limited. For example, some or all of the raw materials other than water are mixed in advance, and then water is added and mixed in a mixer to form a slurry. Then, some or the remaining raw materials other than water are mixed. In this way, the raw materials other than water may be added to the slurry in multiple batches. When fibers are added, after the slurry is prepared, the fibers are added to the mixer and further mixed. The mixers used for each mixing step are not particularly limited, and a mortar mixer, a twin-screw forced mixer, a pan mixer, a grout mixer, a hand mixer, etc. can be used. As described above, various mixers can be used because the material is easy to mix even with a low water-cement ratio. For example, the use of a hand mixer makes it easy to prepare on-site and provides excellent workability for plastering finishes.

[0047] The high-strength mortar repair material is suitable for plastering, and is therefore useful as a mortar repair material for plastering. Such a high-strength mortar repair material is suitable for small-scale repair applications, such as repairs where the design standard for compressive strength is 150 N / mm 2 It can be suitably used for repairing the above structures.

[0048] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. [Example]

[0049] The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0050] [Preparation of mortar repair material 1] The following raw materials (1) to (10) were prepared. (1) Cement (C) Portland cement was prepared by mixing raw materials such as limestone, silica, slag, coal ash, construction soil, and copper vitreous, then firing the mixture in a kiln, adding gypsum, and pulverizing the mixture. The chemical components of the prepared Portland cement were measured in accordance with JIS R 5202:2010 "Methods for Chemical Analysis of Cement," and the mineral composition was calculated using the Bogue formula below. The mineral composition is shown in Table 1.

[0051] C3S=(4.07×CaO)-(7.60×SiO2)-(6.72×Al2O3)-(1.43×Fe2O3)-(2.85×SO3) C2S = (2.87 × SiO2) - (0.754 × C3S) C3A=(2.65×Al2O3)-(1.69×Fe2O3) C4AF = 3.04 × Fe2O3

[0052] The 45 μm sieve residue of Portland cement was measured in accordance with the Cement Association Standard Test Method JCAS K-02 "Test method for cement fineness using a 45 μm mesh sieve," and the Blaine specific surface area was measured in accordance with JIS R 5201-1997 "Physical test methods for cement." The results are shown in Table 1.

[0053] [Table 1]

[0054] (2) Silica fume (SF) Average particle size: 0.24 μm The average particle size of silica fume was determined using the following procedure. The particle size distribution of silica fume was measured using a laser diffraction / scattering particle size distribution analyzer (Horiba, Ltd., product name "LA-950V2"). From the measurement results, a particle size vs. cumulative percent passing curve was calculated, and the particle size at which the cumulative percent passing was 50% by volume was determined from the curve. This particle size was taken as the average particle size. A sodium hexametaphosphate aqueous solution (sodium hexametaphosphate concentration: 0.2% by mass) was used as the sample dispersion medium. Before measuring the particle size distribution, the measurement sample was dispersed for 10 minutes using a 600W homogenizer. The particle size distribution was calculated according to Mie scattering theory. The particle refractive index was 1.45-0.00i, and the solvent refractive index was 1.333. The cumulative percent passing (volume %) for each particle size is shown in Table 2.

[0055] [Table 2]

[0056] (3) Inorganic fine powder: limestone fine powder Density 2.71g / cm 3 , Blaine specific surface area 4280cm 2 / g (4) Fine aggregate Silica sand A: Crushed silica sand, bone dry density 2.56g / cm 3 , coarse grain ratio 0.57 Silica sand B: Crushed silica sand, bone dry density 2.56g / cm 3 , coarse grain ratio 2.33

[0057] The particle sizes of the inorganic fine powder and fine aggregate were measured with reference to JIS A 1102-2006 "Sieving test method for aggregates." The results are shown in Table 3.

[0058] [Table 3]

[0059] (5) Antifoaming agent: Special non-ionic surfactant (6) Water reducing agent: Polycarboxylic acid-based high-performance water reducing agent (powder type) (7) Thickener Thickener A: Bentonite-based thickener Thickener B: Polymer-based thickener (8) Expansive agent: Calcium sulfoaluminate-lime composite, JIS A 6202:2017 "Expansive agent for concrete" compliant product (9) Fiber Fiber A: Steel fiber, fiber diameter: 220 μm, fiber length: 6 mm Fiber B: Vinylon fiber, fiber diameter: 26 μm, fiber length: 6 mm (10) Mixing water (W): Tap water

[0060] <Mixing method> A mortar mixer, model CB-34, high-power mixer manufactured by Maruto Manufacturing Co., Ltd., was used to mix the raw materials. First, all raw materials except the mixing water were placed in a vinyl bag, which was then mixed by hand with air. After manual mixing, the mixed materials were placed in a mixing container and mixed dry at low speed for 30 seconds. The mixer was then stopped, and all of the mixing water was added. After adding the mixing water, mixing was started at low speed, and this point was marked as the start time for measuring the slurry time. The state of the material changing from the powder state at the beginning of mixing to a slurry state was determined visually, and the time required for this to happen was recorded as the slurry time.

[0061] After the slurry was formed, the mixture was mixed at low speed for 1 minute, the mixer was stopped, and a spatula was used to scrape off the mortar lumps and powder adhering to the mixing container and paddle. Then, the mixture was mixed at low speed for another 1 minute, and the mixing was completed. The amount of the mixed mortar repair material (mortar composition) containing water was 1.3 L. In this way, the mortar repair materials of each Example and Comparative Example were prepared.

[0062] The blending ratios and blending amounts of raw materials in each Example and Comparative Example are as shown in Tables 4 and 5. In Table 4, "W / (C+SF)" indicates the parts by mass of mixing water relative to 100 parts by mass of the total amount of cement and silica fume, and "SF / (C+SF)" indicates the parts by mass of silica fume relative to 100 parts by mass of the total amount of cement and silica fume. Furthermore, the "parts by mass" of inorganic fine powder, fine aggregate, antifoaming agent, water-reducing agent and thickener in Tables 4 and 5 indicate the parts by mass relative to the total amount of cement and silica fume. Furthermore, the "kg / m" of inorganic fine powder and fine aggregate in Table 4 and the expansive additive in Table 5 3 " is a high-strength mortar repair material 1m 3 The "Fiber A" and "Fiber B" in Table 5 indicate the proportion (volume %) of the raw materials added based on the total amount of raw materials other than fiber.

[0063] [Table 4]

[0064] [Table 5]

[0065] From the particle sizes (Table 3) and blending ratios (Table 4) of the inorganic fine powder and fine aggregate used in each Example and Comparative Example, the mass ratio of the particle group with a particle size of 0.15 mm or less and the mass ratio of the particle group with a particle size of 0.075 mm or less when the inorganic fine powder and fine aggregate were mixed were calculated. In other words, these values ​​are the sum of the particle sizes of the inorganic fine powder and the fine aggregate. The results are shown in Table 6.

[0066] [Table 6]

[0067] [Plastering Finishing Suitability Assessment] The suitability of the mortar repair materials prepared in each Example and Comparative Example for plastering finish was evaluated based on the following criteria from the viewpoints of trowel release, trowel elongation, sagging resistance, and crack resistance. The evaluation results are shown in Table 7.

[0068] <Soldering iron release> The mortar repair material was applied to the repair area with a trowel, and the ease of removing the trowel from the applied mortar repair material was ranked from 1 to 3 using the following evaluation criteria. Of the following evaluation criteria, "1" indicates the worst trowel removability, and "3" indicates the best trowel removability. 1: When removing the trowel from the mortar repair material, the mortar repair material sticks to the trowel and becomes stuck. 2: When removing the trowel from the mortar repair material, some of the mortar repair material will stick to the trowel, but it will come off if you remove it slowly. 3: The trowel easily comes off the mortar repair material.

[0069] <Stretchability of iron> The ease of application of the mortar repair material to the repair area with a trowel was ranked from 1 to 3 based on the following evaluation criteria. Of the following evaluation criteria, "1" indicates the worst trowel spreadability, and "3" indicates the best trowel spreadability. 1: When applying the mortar repair material, the trowel is heavy and the mortar repair material breaks up and cannot be spread widely. 2: Although some force is required when applying the mortar repair material, it can be spread widely without breaking. 3: When applying the mortar repair material, it can be spread widely with almost no effort.

[0070] <Sagging resistance> The mortar repair material was applied to the repaired area with a trowel and left to stand, and the presence or absence of sagging was evaluated and ranked from 1 to 3 according to the following criteria: "1" indicates the worst sagging resistance, and "3" indicates the best sagging resistance. 1: Mortar repair material will drip if left standing. 2: Mortar repair material does not sag when left standing, but sagging occurs when subjected to slight vibration. 3: The mortar repair material will not sag even if it is subjected to slight vibration.

[0071] <Crack resistance> The surface of the mortar repair material applied to the repair area was finished by running a trowel over it several times. The degree of cracking on the finished surface was ranked from 1 to 3 using the following evaluation criteria. Of the following evaluation criteria, "1" indicates the worst cracking resistance and "3" indicates the best cracking resistance. 1: Many fine cracks appear on the surface of the repaired area. 2: A few fine cracks appear on the surface of the repaired area. 3: No microcracks occur on the surface of the repaired area.

[0072] The average values ​​of the above evaluation results were calculated and shown in Table 7 with two significant figures.

[0073] [Table 7]

[0074] [Evaluation of fresh properties] The fresh properties of the mortar repair materials prepared in each Example and Comparative Example were evaluated according to the following procedure. The evaluation results are shown in Table 8.

[0075] <Slurrying time> This is the slurrying time described in the "Kneading and Mixing Method" above.

[0076] <15 shots of mortar flow> The 15-shot flow of mortar was measured under conditions where there was no drop, in accordance with JIS R 5201:1997 "Physical Testing Methods for Cement." If the 15-shot flow of mortar is 120-140mm, it can be said that the mortar repair material is easy to apply with a plastering finish.

[0077] [Evaluation of hardening properties] The hardening properties of the mortar repair materials prepared in each Example and Comparative Example were evaluated according to the following procedure. The evaluation results are shown in Table 8.

[0078] <Compression strength> Cylindrical specimens measuring 5 cm (diameter) x 10 cm (height) were prepared in accordance with JIS A 1132:2020 "Method for preparing specimens for strength tests of concrete." The specimens were cured at standard curing conditions until the test age (28 days). Compressive strength was measured in accordance with JIS A 1108:2018 "Testing method for compressive strength of concrete."

[0079] <Splitting tensile strength> Cylindrical specimens were prepared using the same procedure as for measuring compressive strength. Splitting tensile strength was measured in accordance with JIS A 1113:2006 "Test method for splitting tensile strength of concrete."

[0080] [Table 8]

[0081] The "Overall Evaluation" in Table 8 was evaluated according to the following criteria, taking into consideration the evaluation results of suitability for plastering finish, fresh properties, and hardened properties. ◎: Plastering finish suitability rating of 2.5 or higher, slurry formation time of less than 1 minute 30 seconds, and compressive strength of 160 N / mm 2 If it is more than Good: Plastering finish suitability rating is 1.5 or more and less than 2.5, slurry formation time is 1 minute 30 seconds or more, and compressive strength is 160 N / mm 2 If it is more than △: Plastering finish suitability rating is less than 1.5, slurry time is 1 minute 30 seconds or more, and compressive strength is 160 N / mm 2 If it is more than ×: Plastering finish suitability rating is less than 1.5, slurry formation time is 1 minute 30 seconds or more, and compressive strength is 160 N / mm 2 If it is less than

[0082] The overall evaluation of each example was ⊚ or ◯, and it was confirmed that the evaluations of suitability for plastering finish, fresh properties, and hardened properties were all good.

[0083] [Durability] Using the hardened mortar repair material of Example 5, resistance to carbonation, penetration of chloride ions, and freeze-thaw cycles was evaluated according to the following procedures.

[0084] <Evaluation of resistance to neutralization> Rectangular specimens (40 mm x 40 mm x 160 mm) were prepared, and the carbonation depth was measured in accordance with JIS A 1153:2012 "Test method for accelerated carbonation of concrete." The number of specimens was 3. As a result, as shown in Table 9, the carbonation depth was 0.0 mm for all specimens at each time point of the accelerated period from 2 to 26 weeks. This result confirmed that the cured product of the mortar repair material of Example 5 has sufficiently excellent resistance to carbonation. Figure 1 is a photograph showing the appearance of the specimen after the accelerated period of 26 weeks.

[0085] [Table 9]

[0086] <Evaluation of resistance to chloride ion penetration> Rectangular specimens (40mm x 40mm x 160mm) were prepared and immersed in a 10% by mass sodium chloride aqueous solution for six months in accordance with JSCE-G572-2010 "Test Method for the Apparent Diffusion Coefficient of Chloride Ions in Concrete Due to Immersion (Draft)." The chloride ion penetration status of the specimens was then analyzed and evaluated using an EPMA. For EPMA measurements, specimens cut from the specimens after immersion were divided into 520 x 520 points within a 40mm x 40mm area and surface analysis was performed. The chloride ion concentration distribution along the depth direction from the mortar surface was then investigated. The results are shown in Figure 2.

[0087] In accordance with JSCE-G572-2010, the apparent diffusion coefficient of chloride ions was calculated from the measurement results in Figure 2 using the least squares method. The surface chloride ion concentration was calculated using the concentration of a 10 mass% sodium chloride aqueous solution converted to a unit volume (64.9 kg / m 3 As a result, the chloride ion penetration depth after 6 months of immersion was 2 mm or less, and the apparent diffusion coefficient of chloride ions was 0.0055 cm 2 / year. These values ​​are significantly smaller than those of ordinary concrete. These results confirm that the hardened mortar repair material of Example 5 has sufficiently excellent resistance to chloride ion penetration.

[0088] <Evaluation of freeze-thaw resistance> Rectangular specimens (100 mm x 100 mm x 400 mm) were prepared, and the mass loss rate and relative dynamic modulus of elasticity were measured in accordance with JIS A 1148:2010 "Concrete Freeze-Thaw Test Method (Method A)." The results are shown in Figure 3 and Table 7. As shown in Table 10, Example 5 showed almost no mass loss and no decrease in the relative dynamic modulus of elasticity even after more than 1,000 freeze-thaw cycles. These results confirmed that the hardened product of the mortar repair material of Example 5 has sufficiently excellent freeze-thaw resistance.

[0089] [Table 10]

[0090] <Preparation of mortar repair material 2> A hand mixer was used instead of a mortar mixer to prepare the mortar repair materials of Examples 7 and 8. The raw materials used in Examples 7 and 8, and the blending ratios and amounts of each raw material, were the same as those of Examples 5 and 6. The hand mixer used was a mixer UM15V manufactured by Koki Holdings Japan Co., Ltd., sold under the HiKOKI brand, and the screw used was a HiKOKI model number: 981706 screw (A1) (standard accessory for the UM15, outer diameter: 115 mm).

[0091] All materials except the mixing water were placed in a plastic bag, and a hand-mixed mixture was prepared by incorporating air. The mixing was carried out by first placing the entire amount of mixing water and half of the hand-mixed materials into an 18L steel pail and mixing for one minute to turn the powder into a slurry. Then, one-quarter of the hand-mixed materials were added and mixed for two minutes to turn the mixture into a slurry again. Finally, the remaining hand-mixed materials were added and mixed for five minutes to turn the mixture into a slurry again, completing the mixing. In this way, the mortar repair materials of Examples 7 and 8 were prepared.

[0092] The mortar repair materials of Examples 7 and 8 prepared in this manner were evaluated for their suitability for plastering, their fresh properties, and their hardened properties. The evaluation methods were as described above. The results are shown in Table 11.

[0093] [Table 11]

[0094] It was confirmed that even when a hand mixer was used instead of a mortar mixer, the suitability for plastering finish, fresh properties, and hardened properties were all evaluated to be good. [Industrial Applicability]

[0095] It is possible to provide a high-strength mortar repair material that is easy to work with for plastering and has excellent hardening properties.

Claims

1. A high-strength mortar repair material containing cement, silica fume, a water-reducing agent, an antifoaming agent, inorganic fine powder, fine aggregate, and an expansive material, The cement is C ３ S is 40.0 to 75.0 mass %, and C ３ A content of more than 0% by mass and less than 2.7% by mass, and a 45 μm sieve residue of less than 25.0% by mass; The inorganic fine powder and the fine aggregate contain, in total, 10.0% by mass or more but less than 40.0% by mass of a particle group having a particle size of 0.15 mm or less, and 5.0% by mass or more but less than 30.0% by mass of a particle group having a particle size of 0.075 mm or less, The inorganic fine powder contains limestone fine powder, The composition contains 3 to 30 parts by mass of the silica fume and 0.1 to 6.0 parts by mass of the water-reducing agent relative to 100 parts by mass of the total amount of the cement and the silica fume, 1 m of the high-strength mortar repair material ３ Based on this, the fine aggregate is 300 to 1200 kg / m ３ and the inorganic fine powder is fed at a rate of 50 to 600 kg / m ３ High-strength mortar repair material.

2. The high-strength mortar repair material according to claim 1 , further comprising a thickener.

3. The high-strength mortar repair material according to claim 2 , wherein the thickener comprises a bentonite-based thickener or a polymer-based thickener.

4. The high-strength mortar repair material according to claim 2 or 3, wherein the thickener is contained in an amount of 0.01 to 2.0 parts by mass per 100 parts by mass of the total amount of the cement and the silica fume.

5. Further comprising fiber, The high-strength mortar repair material according to any one of claims 1 to 4, wherein the fibers include at least one of inorganic fibers and organic fibers.

6. When the fibers include the inorganic fibers, the inorganic fibers include at least one selected from the group consisting of steel fibers, stainless steel fibers, amorphous alloy fibers, glass fibers, carbon fibers, and basalt fibers; 6. The high-strength mortar repair material according to claim 5, wherein when the fibers include the organic fibers, the organic fibers include at least one selected from the group consisting of vinylon fibers, aramid fibers, nylon fibers, PE fibers, PP fibers, PVA fibers, and PBO fibers.

7. 7. The high-strength mortar repair material according to claim 5, wherein the content of said fibers is 0.1 to 3% by volume in terms of the total volume of all components other than said fibers.

8. The high-strength mortar repair material according to any one of claims 1 to 7, comprising 10 to 25 parts by mass of water per 100 parts by mass of the total amount of the cement and the silica fume.

9. The high-strength mortar repair material has a compressive strength design standard of 150 N / mm ２ The high-strength mortar repair material according to any one of claims 1 to 8, which is used for repairing the above structures.

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