Mortar composition and method of using the same

Abstract

To provide a mortar composition that has proper flowability under a low-temperature environment, and expresses excellent strength in a short time.SOLUTION: A mortar composition contains cement, high-tensile fiber, quick-hardening material, retarder, and water-reducing agent. When the unit quantity of the quick-hardening material for 1 m3 of the mortar composition is A[kg / m3], the unit quantity of the retarder is B[kg / m3], and the unit quantity of the water-reducing agent is C[kg / m3], A is 100-180 kg / m3, B is 1-10 kg / m3, C is 5-30 kg / m3, A / B is 22.0-55.0, and C / B is 2.1-5.5.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a mortar composition and a method of using the same.

Background Art

[0002] As a road repair material, a cement composite material containing reinforcing fibers is known. For example, in Patent Document 1, a construction method is proposed in which ultra-high strength fiber-reinforced concrete produced by kneading reinforcing fibers, fine aggregate, water reducing agent, shrinkage reducing agent, defoaming agent and water is placed on the joint surface. According to this construction method, it is stated that the strength of the hardened body is higher than that of conventional repair materials, so that the thickness can be reduced.

[0003] In Patent Document 2, as a repair material used for repairing roads, bridges, etc., a cement paste obtained by adding water, water reducing agent, defoaming agent, thixotropic agent and quick hardening agent to a binder composed of cement, silica fume and limestone filler, and a cement-based repair material obtained by mixing reinforcing fibers is proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, the demand for repairing the road slabs of expressways has been increasing. Since the repairs need to be carried out in a planned manner, until the turn for repair comes, a technology is required that can temporarily reduce the damage of the expressway and continue the operation of the expressway. As such a technology, materials with strength, toughness, and durability that can suppress cracks without applying a waterproofing agent, and that exhibit appropriate fluidity during construction and excellent strength development in a short time in order to shorten the closure period of the repair work are considered effective. For example, since expressways have cross slopes and longitudinal slopes, by using materials that have excellent strength development in a short time and yet have appropriate fluidity, the repair work can be carried out smoothly.

[0006] However, even a mortar composition that has suitable fluidity in summer may not necessarily have sufficient fluidity in winter, and in that case, there is a concern that the repair work cannot proceed smoothly. Also, appropriate fluidity and strength development in a short time may be required not only for sloped expressways but also for the repair and coating of various structures. Therefore, the present invention provides a mortar composition that has appropriate fluidity even in a low-temperature environment and excellent strength development in a short time in various scenarios such as the repair of sloped expressways, as well as the repair and coating of structures such as roads, bridges, port structures, river structures, and underground structures. Further, the present invention provides a method of using a mortar composition that can smoothly perform repair work even in a low-temperature environment in the same scenarios.

Means for Solving the Problems

[0007] In one aspect, the present invention includes cement, high-tensile fibers, rapid hardening material, retarder, and water reducer. When the unit amount of the rapid hardening material per 1 m 3 of the mortar composition is A [kg / m 3 , the unit amount of the retarder is B [kg / m 3 , and the unit amount of the water reducer is C [kg / m 3 , A is 100 to 180 kg / m 3 , B is 1 to 10 kg / m 3 , and C is 5 to 30 kg / m 3Provided is a mortar composition wherein A / B is 22.0 to 55.0 and C / B is 2.1 to 5.5.

[0008] The above mortar composition contains a quick-setting material, a retarder, and a water-reducing agent together with high-tensile fibers. And it contains a predetermined amount of the quick-setting material, the retarder, and the water-reducing agent, and the ratio of the quick-setting material to the retarder (A / B) and the ratio of the water-reducing agent to the retarder (C / B) are within predetermined ranges respectively. Thus, since these three components are contained in a well-balanced manner, the fluidity of the mortar composition during construction can be kept within an appropriate range even in a low-temperature environment. Also, since the fluidity is within an appropriate range, the filling property is improved and the strength development property in a short time is also excellent. That is, the above mortar composition contains the quick-setting material, the retarder, and the water-reducing agent in a well-balanced manner together with the high-tensile fibers, so that it has appropriate fluidity in a low-temperature environment and is excellent in strength development property in a short time. Note that "in a low-temperature environment" in this specification means an environment where the air temperature is less than 20°C.

[0009] The mineral composition of the cement preferably has a C3S content of 25.0 to 75.0% by mass, a C3A content of less than 4.0% by mass, and a residue on a 45-μm sieve of the cement of less than 25.0% by mass. Thereby, fluidity and strength development property in a short time can be made compatible at a higher level.

[0010] The high-tensile fibers preferably contain at least one fiber selected from the group consisting of metal fibers, carbon fibers, aramid fibers, PP fibers, PVA fibers, PE fibers, glass fibers, nylon fibers, and PBO fibers. Thereby, a mortar hardened body having sufficiently high strength and durability can be formed.

[0011] The tensile strength of the high-tensile fibers is 100 to 10000 N / mm 2 and the aspect ratio of the high-tensile fibers is 40 to 250, and the unit amount of the high-tensile fibers is preferably 10 to 500 kg / m 3 By including such high-tensile fibers, the toughness and tensile strength of the mortar hardened body can be made sufficiently high.

[0012] The above mortar composition further includes fine aggregate and inorganic fine powder, and the Blaine specific surface area of the inorganic fine powder is preferably 3000 to 5000 cm 2 / g. Thereby, the fluidity of the mortar composition can be further increased. The Blaine specific surface area of the inorganic fine powder in this specification can be measured using the Blaine air permeability apparatus described in JIS R 5201:1997.

[0013] The above mortar composition preferably further includes silica fume. The average particle size of the silica fume is preferably 0.05 to 2.0 μm. The unit amount of silica fume per 1 m 3 of the above mortar composition is preferably 30 to 350 kg / m 3 Thereby, the compressive strength of the hardened body of the mortar composition and the fluidity of the mortar composition can be further increased.

[0014] The above mortar composition is preferably used for road repair in an environment below 20°C. In such an environment, the above mortar composition has appropriate fluidity and excellent strength development. Therefore, it has excellent workability and reliability.

[0015] In one aspect, the present invention provides a method for using a mortar composition, which includes a step of repairing a road using any of the above mortar compositions, and placing the mortar composition on the road in a low-temperature environment below 20°C. In this method of use, a mortar composition having appropriate fluidity for the fluidity during construction is used even in a low-temperature environment. Therefore, according to this method of use, the road repair work can be smoothly carried out even in a low-temperature environment below 20°C.

[0016] In the above-mentioned usage method, it is preferable to have a step of adjusting at least one blending ratio selected from the group consisting of quick-setting materials, retarders, and water reducers according to the temperature. The fluidity of the mortar composition varies greatly according to the temperature. By having the above step, the properties of the mortar composition can be adjusted to an appropriate range according to the temperature.

Advantages of the Invention

[0017] According to the present invention, it is possible to provide a mortar composition having appropriate fluidity even in a low-temperature environment and excellent strength development property in a short time. In addition, it is possible to provide a usage method of a mortar composition capable of smoothly performing repair work even in a low-temperature environment.

Brief Description of the Drawings

[0018]

Figure 1

Modes for Carrying Out the Invention

[0019] Hereinafter, an embodiment of the present invention will be described. However, the following embodiments are examples for explaining the present invention and are not intended to limit the present invention to the following contents.

[0020] A mortar composition according to an embodiment includes cement, high-tensile fibers, quick-setting materials, retarders, and water reducers.

[0021] The mineral composition of the cement may be, for example, a C3S content of 25.0 to 75.0% by mass and a C3A content of less than 4.0% by mass. The C3S content is preferably 40.0 to 73.0% by mass, more preferably 48.0 to 70.0% by mass, and still more preferably 50.0 to 68.0% by mass. The C3A content is preferably less than 2.7% by mass, more preferably less than 2.3% by mass. Note that the lower limit of the C3A content is not particularly limited and may be, for example, 0.1% by mass. By having such a mineral composition, it is possible to sufficiently increase the fluidity while sufficiently increasing the compressive strength of the hardened mortar body.

[0022] The C2S content is preferably 9.5 to 40.0% by mass, more preferably 10.0 to 35.0% by mass, and still more preferably 12.0 to 30.0% by mass. The C4AF content is preferably 9.0 to 18.0% by mass, more preferably 10.0 to 15.0% by mass, and still more preferably 11.0 to 15.0% by mass. By having such a mineral composition, it is possible to sufficiently increase the fluidity while sufficiently increasing the compressive strength of the hardened mortar body.

[0023] The above mineral composition is a value calculated by the following Bogue formula. Each chemical component of the cement used in the Bogue formula can be measured in accordance with JIS R 5202:2010 "Chemical Analysis Method for Cement".

[0024] C3S content = (4.07 × CaO) - (7.60 × SiO2) - (6.72 × Al2O3) - (1.43 × Fe2O3) - (2.85 × SO3) C2S content = (2.87 × SiO2) - (0.754 × C3S) C3A content = (2.65 × Al2O3) - (1.69 × Fe2O3) C4AF content = 3.04 × Fe2O3

[0025] The residue on a 45-μm sieve of the cement may be, for example, less than 25.0% by mass, preferably less than 20.0% by mass, more preferably less than 18.0% by mass, and even more preferably less than 16.0% by mass. The residue on the 45-μm sieve may be 0% by mass or may be 1.0% by mass or more. If the particle size of the cement is within the above range, high compressive strength can be ensured. Further, since the mortar composition containing such cement has appropriate viscosity, sufficient dispersibility can be ensured even if high-tensile fibers are contained. The residue on the 45-μm sieve of the cement can be measured in accordance with the standard test method of the Cement Association, JCAS K-02, "Test method for fineness of cement by 45-μm wire sieve".

[0026] The Blaine specific surface area of the cement is preferably 2500 to 4800 cm 2 / g, more preferably 2800 to 4000 cm 2 / g, even more preferably 3000 to 3600 cm 2 / g, and particularly preferably 3100 to 3500 cm 2 / g. When the Blaine specific surface area of the cement is too small, the strength of the mortar composition tends to be low, and when it is too large, the fluidity at a low water-cement ratio tends to decrease. The Blaine specific surface area of the cement can be measured in accordance with JIS R 5201:1997, "Physical test methods for cement".

[0027] The unit amount of cement per 1 m 3 of the mortar composition may be 700 to 1100 kg / m 3 or may be 750 to 1000 kg / m 3 .

[0028] The high-tensile fiber contains at least one kind of fiber selected from the group consisting of metal fibers, carbon fibers, aramid fibers, PP (polypropylene) fibers, PVA (polyvinyl alcohol) fibers, PE (polyethylene) fibers, glass fibers, nylon fibers, and PBO (polyparaphenylene benzobisoxazole) fibers. Examples of the metal fiber include steel fibers, stainless steel fibers, and amorphous alloy fibers. The tensile strength of the high-tensile fiber is preferably 100 to 10,000 N / mm 2 and more preferably 500 to 5,000 N / mm 2 and even more preferably 2,000 to 3,000 N / mm 2 and particularly preferably 2,000 to 2,500 N / mm 2 The aspect ratio (fiber length / fiber diameter) of the high-tensile fiber is preferably 40 to 250, more preferably 50 to 200, and even more preferably 60 to 170. By including such high-tensile fibers, the toughness and tensile strength of the mortar hardened body can be sufficiently increased.

[0029] The fiber diameter of the high-tensile fiber may be, for example, 0.05 to 1.20 mm. The fiber length of the high-tensile fiber may be 3 to 60 mm. The unit amount of the high-tensile fiber is preferably 10 to 500 kg / m 3 and more preferably 50 to 300 kg / m 3 and even more preferably 100 to 200 kg / m 3 and still more preferably 120 to 180 kg / m 3 and may be.

[0030] The quick-hardening material is an admixture that promotes the strength development of the mortar composition, and examples thereof include a mixture of calcium aluminate and inorganic sulfate. Such a quick-hardening material contains Al2O3, CaO, and SO3 as chemical components. As a commercially available product, for example, Befoam (registered trademark) manufactured by Denka Co., Ltd. can be used.

[0031] If the content of the quick-setting material is too small, the mortar composition cannot develop sufficient strength in a short time. On the other hand, if the content is excessive, hardening progresses too rapidly in a short time, resulting in a decrease in fillability and an inability to develop sufficient strength. In addition, the fluidity decreases and the workability deteriorates. Therefore, from the perspective of obtaining a mortar composition that has appropriate fluidity even in a low-temperature environment and is excellent in strength development in a short time, the unit amount A [kg / m 3 of the quick-setting material per 1 m of the mortar composition 3 is 100 to 180 kg / m 3 . The lower limit of the unit amount A [kg / m 3 of the quick-setting material is preferably 110 kg / m 3 , more preferably 120 kg / m 3 , and even more preferably 125 kg / m 3 . The upper limit of the unit amount A [kg / m 3 of the quick-setting material is preferably 170 kg / m 3 , more preferably 160 kg / m 3 , and even more preferably 150 kg / m 3 .

[0032] A retarder is an admixture also known as a setting regulator or a setting retarder, and has the effect of delaying the initial hardening of the mortar composition. Examples of retarders include lignin sulfonic acid, silicofluoride, or those mainly composed of alkali carbonate and citric acid. As commercial products, for example, Setter D-300 manufactured by Denka Co., Ltd. can be used.

[0033] If the content of the retarder is too small, hardening is promoted too rapidly in a short time, resulting in a decrease in fillability and an inability to develop sufficient strength. In addition, the fluidity decreases and the workability deteriorates. On the other hand, if the content of the retarder becomes excessive, the flow becomes small, the workability decreases, and there is a tendency that the target strength cannot be obtained in a short time. From the perspective of ensuring a mortar composition that has appropriate fluidity in a low-temperature environment and is excellent in strength development in a short time, the unit amount B [kg / m 3 of the retarder per 1 m of the mortar composition 3 is 1 to 10 kg / m 3is as follows. The lower limit of the unit amount B [kg / m 3 of the retarder is preferably 2 kg / m 3 and more preferably 3 kg / m 3 is as follows. The lower limit of the unit amount B [kg / m 3 of the retarder is preferably 8 kg / m 3 and more preferably 7 kg / m 3 and even more preferably 5 kg / m 3 is as follows.

[0034] As the water reducing agent, those having an effect of improving the fluidity of the mortar composition can be used, such as lignin-based, naphthalene sulfonic acid-based, amino sulfonic acid-based, polycarboxylic acid-based water reducing agents, high-performance water reducing agents, and high-performance AE water reducing agents. From the viewpoint of improving the fluidity of the mortar composition, the water reducing agent is preferably a polycarboxylic acid-based one. Such a water reducing agent can form a steric hindrance between cement clinkers to improve the fluidity of the mortar composition.

[0035] If the content of the water reducing agent is too small, the fluidity of the mortar composition will decrease and the workability will deteriorate. On the other hand, if the content of the water reducing agent is excessive, material separation will occur and the mortar composition will not be able to exhibit sufficient strength. From the viewpoint of obtaining a mortar composition having appropriate fluidity and excellent strength development in a short time under a low-temperature environment, the unit amount C [kg / m 3 of the water reducing agent per 1 m of the mortar composition 3 is 5 to 30 kg / m 3 is as follows. The lower limit of the unit amount C [kg / m 3 of the water reducing agent per 1 m of the mortar composition 3 is preferably 7 kg / m 3 and more preferably 9 kg / m 3 and even more preferably 10 kg / m 3 is as follows. The upper limit of the unit amount C [kg / m 3 of the water reducing agent 3 is preferably 25 kg / m 3 and more preferably 22 kg / m 3 and even more preferably 20 kg / m

[0036] As described above, the mortar composition of the present embodiment contains, as admixtures, a quick-setting material, a retarder, and a water reducer. The ratio (A / B) of the unit amount A of the quick-setting material to the unit amount B of the retarder is 22.0 to 55.0. The upper limit of the ratio (A / B) is preferably 51.0, more preferably 45.0, and particularly preferably 41.0. Thereby, it is possible to suppress the rapid hardening of the mortar composition and improve the workability. The lower limit of the ratio (A / B) is preferably 23.0, more preferably 25.0. Thereby, the strength development property of the mortar composition in a short time can be sufficiently increased. Further, when placed on a road or the like having a cross slope and / or a longitudinal slope, it is possible to sufficiently suppress the mortar composition from flowing too much.

[0037] The ratio (C / B) of the unit amount C of the water reducer to the unit amount B of the retarder is 2.1 to 5.5. The upper limit of the ratio (C / B) is preferably 5.2, more preferably 4.5. Thereby, the fluidity of the mortar composition can be sufficiently ensured. The lower limit of the ratio (C / B) is preferably 2.2, more preferably 2.3, and even more preferably 2.4. Thereby, even if the amount of water added is reduced, the excellent fluidity of the mortar composition can be sufficiently maintained.

[0038] The ratio (A / C) of the unit amount A of the quick-setting material to the unit amount C of the water reducer is 20.0 or less, preferably 16.0 or less, and more preferably 14.0 or less. Thereby, it is possible to suppress the rapid hardening of the mortar composition, ensure the fluidity, and improve the workability. The ratio (A / C) is preferably 4.0 or more, more preferably 6.0 or more. Thereby, the strength development property of the mortar composition in a short time can be sufficiently increased.

[0039] The mortar composition of this embodiment contains a quick-setting material, a retarder, and a water reducer as admixtures in a well-balanced manner. Therefore, even in a low-temperature environment, it has appropriate fluidity during construction and is excellent in strength development in a short time. For this reason, it is particularly useful, for example, for repair applications of highways where good workability and strength development in a short time are required.

[0040] In addition to the above-mentioned admixtures, the mortar composition of this embodiment may contain inorganic fine powder and fine aggregate. Examples of the inorganic fine powder include limestone powder, silica powder, and crushed stone powder. The inorganic fine powder may be a fine powder obtained by pulverizing and / or classifying limestone powder, silica powder, crushed stone powder, etc. The inorganic fine powder may be blended for the purpose of supplementing the fine particles of the fine aggregate. The Blaine specific surface area of the inorganic fine powder is preferably 3000 - 5000 cm 2 / g, more preferably 3200 - 4700 cm 2 / g, and even more preferably 3400 - 4600 cm 2 / g. By containing such inorganic fine powder, the fluidity of the mortar composition can be further improved. The unit amount of the inorganic fine powder per 1 m 3 of the mortar composition is preferably 100 - 300 kg / m 3 , more preferably 150 - 250 kg / m 3 .

[0041] Examples of the fine aggregate include river sand, land sand, sea sand, crushed sand, silica sand, limestone aggregate, blast furnace slag fine aggregate, ferronickel slag fine aggregate, copper slag fine aggregate, and electric furnace oxidized slag fine aggregate. The fine aggregate may have a particle size that completely passes through a 10 mm sieve and passes through an 85 mass% or more of a 5 mm sieve. The particle diameter of the fine aggregate measured in accordance with JIS A 1102:2014 is preferably 5.0 mm or less, and the coarse grain ratio is preferably 2.0 - 2.5. The fine particle content of the fine aggregate measured in accordance with JIS A 1103:2014 is preferably 9% or less. The unit amount of the fine aggregate per 1 m 3 of the mortar composition is preferably 600 - 1050 kg / m 3 , more preferably 700 - 950 kg / m 3and more preferably 800 to 900 kg / m 3 is. The fine aggregate may be prepared by mixing a plurality of fine aggregates having different particle sizes.

[0042] The total unit amount of the fine aggregate and the inorganic fine powder per 1 m 3 of the mortar composition is preferably 800 to 1200 kg / m 3 and more preferably 900 to 1150 kg / m 3 and even more preferably 1000 to 1100 kg / m 3 is.

[0043] The mortar composition of this embodiment may contain silica fume. Silica fume is a by-product obtained by collecting dust in the exhaust gas generated during the production of metal silicon, ferrosilicon, or electromelted zirconia, etc. Silica fume mainly contains amorphous SiO2 that dissolves in an alkaline solution. 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. By using such silica fume, it is possible to sufficiently increase the compressive strength of the mortar hardened body while maintaining high fluidity of the mortar composition.

[0044] The content of silica fume based on cement is preferably 3 to 30% by mass, more preferably 5 to 20% by mass, and even more preferably 8 to 18% by mass. Also, the unit amount of silica fume per 1 m 3 of the mortar composition is preferably 30 to 350 kg / m 3 and more preferably 50 to 250 kg / m 3 and even more preferably 100 to 130 kg / m 3 is.

[0045] The mortar composition of this embodiment may contain water. The unit water amount per 1 m 3 of the mortar composition is preferably 150 to 280 kg / m 3 and more preferably 180 to 250 kg / m3 and more preferably 190 to 230 kg / m 3 The water-binder ratio is preferably 10 to 30% by mass, more preferably 15 to 25% by mass, from the viewpoint of achieving appropriate fluidity. The binder includes cement, silica fume, and a quick-setting material.

[0046] The mortar composition may, if necessary, contain at least one selected from an expansion agent, an antifoaming agent, a shrinkage reducing agent, a thickening agent, glass fiber, organic fiber, synthetic resin powder, polymer emulsion, and polymer dispersion, in addition to the above components. The expansion agent is commercially available, and for example, an ettringite-lime composite type or lime type one can be used. The unit amount of the expansion agent per 1 m 3 of the mortar composition is preferably 1 to 50 kg / m 3 and more preferably 2 to 40 kg / m 3 and even more preferably 5 to 30 kg / m 3 .

[0047] Examples of the antifoaming agent include a special nonionic compound type surfactant, a polyalkylene derivative, hydrophobic silica, and a polyether type. The unit amount of the antifoaming agent per 1 m 3 of the mortar composition is preferably 0.1 to 20 kg / m 3 and more preferably 0.5 to 10 kg / m 3 and even more preferably 1 to 5 kg / m 3 .

[0048] When the mortar composition of this embodiment is used in a low-temperature environment where the temperature is less than 20°C, it has appropriate fluidity and excellent strength development in a short time. For example, the fluidity can be evaluated by the mortar zero-slump flow. The mortar zero-slump flow immediately after mixing the mortar composition is preferably 130 mm or more, more preferably 140 mm or more, and even more preferably 150 mm or more. Such a mortar composition is excellent in filling property during placement, so it has excellent workability and can achieve a sufficiently high compressive strength. The mortar zero-slump flow immediately after mixing the mortar composition is preferably 300 mm or less, more preferably 250 mm or less. With such a mortar composition, for example, when there is a transverse gradient and / or a longitudinal gradient at the placement location, it can suppress the mortar composition from flowing down immediately downward. Therefore, it has excellent workability. Note that the mortar zero-slump flow in this specification is a value measured under the condition of no dropping in accordance with JIS R 5201:1997 "Methods of physical tests for cement".

[0049] The strength development in a short time can be evaluated, for example, by the compressive strength at an age of 3 hours. The compressive strength of the mortar composition at an age of 3 hours is preferably 20 N / mm 2 or more, more preferably 24 N / mm 2 or more. The compressive strength can be measured by preparing a 5 cm × 10 cm cylindrical specimen with reference to JIS A 1132:2006 "Method of making specimens for strength test of concrete" and performing a compressive strength test with reference to JIS A 1108:2006 "Method of test for compressive strength of concrete".

[0050] The mortar composition may be used in an environment where the temperature is 15°C or lower, 10°C or lower, or 5°C or lower. From the viewpoint of maintaining good workability, the mortar composition is preferably used in an environment where the temperature exceeds 0°C. The use of the mortar composition is not particularly limited, and for example, it may be used as a repair material or a coating material. Specifically, it may be used as a repair material or a coating material for roads (expressways), bridges, port structures, river structures, and underground structures, etc. Since the mortar composition is excellent in workability and excellent in initial strength development, it can be suitably used for repairing expressways that require construction in a short period of time.

[0051] Regarding the manufacturing method of the mortar composition, all the raw materials may be simultaneously blended, mixed, and prepared, or only some of the raw materials may be pre-mixed, and then the remaining raw materials may be simultaneously or sequentially blended, mixed, and prepared. For example, the raw materials other than water may be blended and mixed, water may be added to the powdery mixture, and it may be put into a mixer and kneaded to prepare the mortar composition. As the mixer used for kneading, a mortar mixer, a forced kneader, a pan mixer, a grout mixer, etc. can be used. Note that the above manufacturing method is an example, and it may be manufactured by a manufacturing method other than the above.

[0052] The usage method of the mortar composition according to one embodiment includes a step of repairing a road using the mortar composition. The mortar composition can use the mortar composition according to the above embodiment. Therefore, the description content of the above-described mortar composition can be applied to this usage method. Also, the description content of this usage method can be applied to the description of the above-described mortar composition. In the above step, the mortar composition is placed on the road in an environment where the temperature is less than 20°C. The road is preferably an expressway that requires construction in a short period of time. The above step may be performed in an environment where the temperature is 15°C or lower, 10°C or lower, or 5°C or lower. From the viewpoint of maintaining good workability, the above step is preferably performed in an environment where the temperature exceeds 0°C.

[0053] In the above usage method, it is preferable to have a step of adjusting at least one blending ratio selected from the group consisting of a quick-setting material, a retarder, and a water-reducing agent according to the temperature at which the mortar composition is used before the above steps. The fluidity of the mortar composition varies greatly depending on the temperature. Therefore, for example, based on the measured value of the temperature, the blending ratios (unit amounts) of the quick-setting material, the retarder, and the water-reducing agent may be determined, and the mortar composition may be prepared so as to have the blending ratios (unit amounts). By having such steps, the properties of the mortar composition can be adjusted so as to have an optimal fluidity corresponding to the temperature.

[0054] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above embodiments at all.

Examples

[0055] The content of 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.

[0056] [Preparation of Mortar Composition] In order to prepare the mortar compositions of each Example and each Comparative Example, the following raw materials were prepared.

[0057] (1) Cement The chemical components of the cement were measured in accordance with JIS R 5202:2010 "Chemical Analysis Method of Cement", and the mineral composition was calculated by the above-mentioned Bogue formula. In addition, the 45 μm sieve residue of the cement was measured in accordance with the standard test method of the Cement Association JCAS K-02 "Powderiness Test Method of Cement by 45 μm Mesh Sieve", and the Blaine specific surface area of the cement was measured in accordance with JIS R 5201:1997 "Physical Test Method of Cement". The results were as shown in Table 1.

[0058]

Table 1

[0059] (2) Silica Fume (SF) Silica fume was prepared. The average particle size of this silica fume was 0.24 μm. This average particle size was determined by the following procedure. First, the particle size distribution of this silica fume was measured using a laser diffraction / scattering particle size distribution measuring device (manufactured by Horiba, Ltd., trade name "LA-950V2"). Based on the measurement results, a particle size - cumulative passing percentage curve was calculated, and the particle size at which the cumulative passing percentage was 50% by volume was determined from the particle size - cumulative passing percentage curve. This particle size was taken as the average particle size.

[0060] (3) Fine aggregate Silica sand (produced in Tochigi Prefecture, particle size: 5.0 mm or less, fine particle content: 0.62%, coarse particle ratio: 2.35) was prepared.

[0061] (4) Inorganic fine powder Limestone fine powder (density: 2.71 g / cm 3 , Blaine specific surface area: 4570 cm 2 / g) was prepared.

[0062] (5) Quick-setting material As the quick-setting material, Befoam (registered trademark) manufactured by Denka Co., Ltd. was prepared. The analysis results of the chemical components of this quick-setting material were as shown in Table 2.

[0063]

Table 2

[0064] (6) Retarder As the retarder, Setter D-300 (trade name) manufactured by Denka Co., Ltd. was prepared. (7) Water-reducing agent As the water-reducing agent, a polycarboxylic acid-based high-performance water-reducing agent (solid content concentration: 25% by mass) was prepared. (8) Defoaming agent As the defoaming agent, a special non-ionic compound type surfactant was prepared. Figure 1 shows that this defoaming agent was dissolved in heavy methanol and measured using an NMR measuring device (manufactured by BRUKER, trade name "AVANCE") 1It is an H-NMR spectrum. The molar ratios of the structural units of polyoxypropylene (hereinafter abbreviated as "POP"), polyoxyethylene (hereinafter abbreviated as "POE"), and the alkyl chain, which are the structural units of the defoamer, were calculated based on the integral value of the signal derived from the methyl group in POP. Among these, the molar ratio of POE to POP was calculated by subtracting the integral value of the signal derived from the hydrocarbon group other than the methyl group of POP that appears around 3.5 ppm and the integral value of the signal derived from the hydrocarbon group of POE from the integral value of the signal derived from the hydrocarbon group other than the methyl group of POP. Table 3 shows the molar ratios of the structural units of POP, POE, and the alkyl chain in the defoamer.

[0065]

Table 3

[0066] (9) Expansive agent As the expansive agent, an ettringite-lime composite expansive agent manufactured by DENKA Co., Ltd. was prepared. (10) High-tensile fiber As the high-tensile fiber, steel fiber (manufactured by Tokyo Seitetsu Co., Ltd., trade name "CW9416", density: 7.87 g / cm 3 , fiber diameter: 0.16 mm, fiber length: 13 mm, aspect ratio: 81.25, tensile strength: 2200 N / mm 2 ) was prepared. (11) Mixing water (W) Tap water was prepared.

[0067] (Examples 1-1 to 1-9) In an environment with an air temperature of 5°C, the above raw materials were blended at the ratios shown in Table 4 to prepare a mortar composition. The mixing was carried out using a Hobart mixer. Cement, silica fume, inorganic fine powder, defoamer, expansive agent, and fine aggregate were dry-mixed for 30 seconds, and then water and high-performance water reducer were added and mixed for 5 minutes. Then, a retarder was added and mixed for 1 minute, and steel fiber was added and further mixed for 2 minutes. Furthermore, a rapid hardening material was added and mixed for 1 minute. The units of the numerical values in Table 4 are kg / m 3 and for 1 m 3It shows the mass per hit (unit amount). The water / binder ratio was kept constant at 19% by mass.

[0068] (Examples 2-1 to 2-14) In an environment with an air temperature of 10°C, the above raw materials were blended at the ratios shown in Table 4 to prepare a mortar composition. The mixing was carried out in the same manner as in Example 1-1. The units of the numerical values in Table 4 are kg / m 3 and it shows the mass per hit (unit amount) of 1 m 3 of the mortar composition. The water / binder ratio was kept constant at 19% by mass.

[0069] (Examples 3-1 to 3-9) In an environment with an air temperature of 15°C, the above raw materials were blended at the ratios shown in Table 4 to prepare a mortar composition. The mixing was carried out in the same manner as in Example 1-1. The units of the numerical values in Table 4 are kg / m 3 and it shows the mass per hit (unit amount) of 1 m 3 of the mortar composition. The water / binder ratio was kept constant at 19% by mass.

[0070] (Examples 4-1, Comparative Examples 4-1, 4-2) In an environment with an air temperature of 19°C, the above raw materials were blended at the ratios shown in Table 4 to prepare a mortar composition. The mixing was carried out in the same manner as in Example 1-1. The units of the numerical values in Table 4 are kg / m 3 and it shows the mass per hit (unit amount) of 1 m 3 of the mortar composition. The water / binder ratio was kept constant at 19% by mass.

[0071] [Table 4]

[0072] [Evaluation of Mortar Composition] (1) Fresh Properties The mortar zero-slump flow immediately after mixing was measured for each mortar composition prepared in each example and each comparative example under each temperature environment. The mortar zero-slump flow was measured under the condition of no dropping in accordance with JIS R 5201:1997 "Methods of Physical Tests for Cement". The measurement results were as shown in the "immediately after" column of the flow values in Table 5. The columns of "after 15 minutes" and "after 30 minutes" of the flow values in Table 5 are the flow values after 15 minutes and 30 minutes have elapsed after mixing.

[0073] (2) Strength test Cylindrical specimens of 5 cm × 10 cm were prepared with reference to JIS A 1132:2006 "Method of Making Specimens for Strength Tests of Concrete", and the compressive strength under each temperature environment was measured with reference to JIS A 1108:2006 "Method of Compressive Strength Test for Concrete". The measurement results at the age of 3 hours and the age of 7 days are shown in Table 5. Table 5 also shows the ratio of the rapid hardening material to the retarder (A / B), the ratio of the water reducing agent to the retarder (C / B), and the ratio of the rapid hardening material to the water reducing agent (A / C).

[0074]

Table 5

[0075] As shown in Table 5, the values of the mortar zero-slump flow "immediately after" mixing in each example were in the range of 139 to 230 mm, and it was confirmed that they had appropriate fluidity even under low temperature environments. Also, the compressive strength at the age of 3 hours was 24 N / mm 2 or more, and it was confirmed that they were excellent in strength development in a short time.

[0076] Table 6 shows the extracted data of Examples 1-1, 2-9, and 3-1, which have almost the same formulation among the examples shown in Tables 4 and 5.

[0077]

Table 6

[0078] As shown in Table 6, it was confirmed that even when the formulations were almost the same, the values of the mortar zero slump flow changed depending on the air temperature. Therefore, it can be said that it is preferable to adjust the formulation ratio according to the temperature environment during construction.

Industrial Applicability

[0079] According to the present invention, it is possible to provide a mortar composition having appropriate fluidity in a low-temperature environment and excellent strength development in a short time. Further, it is possible to provide a method of using a mortar composition capable of smoothly performing repair work in a low-temperature environment.

Claims

1. A cement having a mineral composition with a C3S content of 40.0 to 75.0% by mass and a C3A content of less than 4.0% by mass, and a residue on a 45-μm sieve of less than 25.0% by mass, silica fume with an average particle size of 0.05 to 2.0 μm, inorganic fine powder with a Blaine specific surface area of 3000 to 5000 cm2 / g, fine aggregate, high-strength fiber, accelerating agent, retarder, water reducer, and the unit amount of the cement per 1 m3 of the mortar composition is 750 to 1000 kg / m3, the unit amount of the silica fume is 100 to 130 kg / m3, the unit amount of the inorganic fine powder is 150 to 250 kg / m3, the unit amount of the fine aggregate is 800 to 900 kg / m3, and the unit amount of the high-strength fiber is 120 to 200 kg / m3, Per 1 m of the mortar composition ３ When the unit amount of the quick-setting material is A [kg / m ３ , the unit amount of the retarder is B [kg / m ３ , and the unit amount of the water reducer is C [kg / m ３ , A is 110 to 160 kg / m ３ B is 2 to 7 kg / m ３ C is 9 to 22 kg / m ３ and A / B is 22.0 to 55.0, C / B is 2.1 to 5.5, a mortar composition.

2. The aforementioned C ３ The mortar composition according to claim 1, wherein the content of A is less than 2.7% by mass.

3. The high-strength fiber contains at least one fiber selected from the group consisting of metal fiber, carbon fiber, aramid fiber, PP fiber, PVA fiber, PE fiber, glass fiber, nylon fiber, and PBO fiber, and the mortar composition according to Claim 1 or 2.

4. The tensile strength of the high-strength fiber is 100 to 10,000 N / mm ２ , and the aspect ratio of the high-strength fiber is 40 to 250. The mortar composition according to any one of claims 1 to 3.

5. The average particle size of the silica fume is 0.18 to 0.28 μm, and the mortar composition according to any one of Claims 1 to 4.

6. Further containing an antifoaming agent, and the unit amount of the antifoaming agent per 1 m3 of the mortar composition is 0.1 to 20 kg / m3, and the mortar composition according to any one of Claims 1 to 5.

7. Used for road repair in an environment below 20°C, and the mortar composition according to any one of Claims 1 to 6.

8. Having a step of repairing a road using the mortar composition according to any one of Claims 1 to 7, Placing the mortar composition on the road in an environment below 20°C, a method of using the mortar composition.

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