JP2012144406A - High-strength mortar composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-strength mortar composition that is excellent in workability and is capable of promptly exerting high compressive strength only by cold curing.SOLUTION: The high-strength mortar composition comprises cement, a silica fume, water, a water reducing agent, a defoaming agent, a fine aggregate and an inorganic fine powder. The cement comprises 40.0-75.0 mass% CS and <2.7 mass% CA and leaves <25.0 mass% residue on a 45 μm sieve. A mixture of the fine aggregate and the inorganic fine powder comprises 40-80 mass% particles having a particle size of ≤0.15 mm and 30-80 mass% particles having a particle size of ≤0.075 mm. The inorganic fine powder is at least one fine powder chosen from the group consisting of a lime stone powder, a silica stone powder and a crushed-stone powder.

Description

  The present invention relates to a high strength mortar composition.

In recent years, an ultra-high-strength material capable of obtaining a compressive strength of about 200 N / mm ² has been proposed in accordance with demands for reducing the weight of structural members and reducing the amount of reinforcing bars used. In these materials, cement, pozzolanic fine powder, aggregate, and a high-performance water reducing agent are used, and ultrahigh strength is achieved by heat curing. In addition, it has been proposed to impart high toughness and crack suppression function by adding metal fibers and organic fibers to these (see Patent Documents 1 to 3). And when the materials described in Patent Documents 2 and 3 are cured under standard conditions, it is known that the compressive strength at the age of 28 days remains at about 150 N / mm ² (see Non-Patent Document 1).

JP 2001-181004 A JP 2006-298679 A JP 2007-126317 A

Experimental study on strength development properties of ultra high strength fiber reinforced concrete, Annual report of concrete engineering, Vol. 30, no. 1, pp. 243-248, 2008

  However, in the existing technology, in order to realize the ultra-high strength of the concrete, heat curing is often required. Therefore, the production site of the concrete is limited, and it is necessary to transport the manufactured product. In addition, since the shape and size of the concrete product are restricted by the fluidity of the material, the shape of the formwork and the curing device, etc., the degree of freedom of construction and design is limited for the ultra-high strength material. On the other hand, a highly tough cement material having a crack suppressing effect can be applied on site, but the strength is only as high as that of ordinary concrete. For this reason, there is a need for a high-strength material that does not require heat curing and can be applied on site.

  Then, an object of this invention is to provide the high intensity | strength mortar composition which is excellent in workability | operativity and can express high compressive strength at an early stage only by normal temperature curing.

  As a result of intensive studies to solve the above problems, the present inventors have obtained a cement having a specific mineral composition and particle size distribution, a fine aggregate and a fine inorganic powder having a specific particle size, silica fume, water reducing agent and It has been found that by combining with an antifoaming agent, the fluidity of the mortar composition can be improved and the strength of the mortar composition can be improved without heat curing, and the present invention has been completed.

That is, the present invention is a high-strength mortar composition containing cement, silica fume, water, water reducing agent, antifoaming agent, fine aggregate, and inorganic fine powder, wherein the cement is C ₃ S. 40.0-75.0% by mass and C ₃ A less than 2.7% by mass, 45 μm sieve residue is less than 25.0% by mass, and a mixture of fine aggregate and inorganic fine powder Contains 40 to 80% by mass of particles having a particle size of 0.15 mm or less and 30 to 80% by mass of particles having a particle size of 0.075 mm or less, and the fine inorganic powder is limestone powder, quartzite powder and crushed stone Provided is a high-strength mortar composition that is one or more fine powders selected from the group consisting of powders. Such a mortar composition is excellent in workability and can exhibit high compressive strength at an early stage only by room temperature curing.

If the Blaine specific surface area of the inorganic fine powder is 3000 to 5000 cm ² / g, the fluidity of the high-strength mortar composition can be further improved.

  The intensity | strength of a mortar composition can be further improved as the average particle diameter of the said silica fume is 0.05-2.0 micrometers. And it is preferable that the high intensity | strength mortar composition of this invention contains 3-30 mass% of silica fume on the basis of a cement.

  The high-strength mortar composition of the present invention preferably contains 10 to 25 parts by mass of water and 0.5 to 6.0 parts by mass of a water reducing agent with respect to 100 parts by mass of the total amount of cement and silica fume. Thereby, the intensity | strength of a mortar composition improves further.

  The high-strength mortar composition of the present invention contains 10-60 parts by mass of fine aggregate and 10-60 parts by mass of inorganic fine powder with respect to 100 parts by mass of the total amount of cement and silica fume. Is further improved and the workability is further improved.

The high-strength mortar composition of the present invention can further contain high-tensile fibers. Further, the high-tensile fiber has a tensile strength of 100 to 10000 N / mm ² , an aspect ratio of 40 to 250, and a content with respect to the mortar composition is 0.3 to 5.0% by volume on an external basis. High toughness and high compressive strength and tensile strength can be obtained. Furthermore, the strength of the mortar composition can be further improved when the high-tensile fiber is one or more fibers selected from the group consisting of metal fibers, carbon fibers, and aramid fibers.

  ADVANTAGE OF THE INVENTION According to this invention, the mortar composition which is excellent in workability and can express high compressive strength at an early stage only by normal temperature curing can be provided.

It is a ¹ H-NMR spectrum of the antifoaming agents used in Examples. It is the photograph which image | photographed the state after the slump flow test of the mortar composition of Example 3. FIG. It is the photograph which image | photographed the state after the slump flow test of the mortar composition of the comparative example 7. FIG.

  The high-strength mortar composition of the present invention contains cement, silica fume, water, a water reducing agent, an antifoaming agent, fine aggregate, and an inorganic fine powder. Hereinafter, preferred embodiments of the mortar composition according to the present invention will be described.

As for the mineral composition of cement, the amount of C ₃ S is 40.0 to 75.0% by mass, and the amount of C ₃ A is less than 2.7% by mass. The amount of C ₃ S in the cement is preferably 45.0 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 amount of C ₃ A is preferably less than 2.3% by mass, more preferably less than 2.1% by mass, and even more preferably less than 1.9% by mass. If the amount of C ₃ S is less than 40.0% by mass, the compressive strength tends to be low, and if it exceeds 75.0% by mass, the cement itself tends to be difficult to fire. Further, when the amount of C ₃ A is 2.7% by mass or more, the fluidity is deteriorated. In addition, the lower limit of the amount of C ₃ A is not particularly limited, but is about 0.1% by mass.

Also, _{C 2} S content of the cement preferably 9.5 to 40.0 wt%, more preferably from 10.0 to 35.0 wt%, more preferably from 12.0 to 30.0 wt% . The amount of C ₄ AF 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. If it is the range of the mineral composition of such a cement, the high compressive strength and high fluidity | liquidity of a mortar composition are securable.

  The cement particle size is such that the 45 μm sieve residue is less than 25.0% by mass, preferably 20.0% by mass, more preferably 18.0% by mass, and still more preferably 16.5% by mass. 0% by mass. The lower limit of the 45 μm sieve residue is 0.0% by mass, preferably 1.0% by mass, and more preferably 2.0% by mass. If the particle size of the cement is within this range, high compressive strength can be secured, and the mortar slurry prepared using this cement has an appropriate viscosity. Therefore, when fibers are added, sufficient dispersibility is obtained. It can be secured.

The brane specific surface area of the cement is preferably 2500 to 4800 cm ² / g, more preferably 2800 to 4000 cm ² / g, still more preferably 3000 to 3600 cm ² / g, and particularly preferably 3100 to 3500 cm ² / g. When the brane specific surface area of the cement is less than 2500 cm ² / g, the strength of the mortar composition tends to be low, and when it exceeds 4800 cm ² / g, the fluidity at the low water cement ratio tends to decrease.

  In manufacturing the cement according to the present embodiment, it is not necessary to perform an operation different from that of normal cement. The cement is changed according to the target mineral composition such as limestone, silica, slag, coal ash, construction generated soil, blast furnace dust, etc., fired in the actual kiln, gypsum added And can be manufactured by pulverizing to a predetermined particle size. A general NSP kiln, SP kiln, or the like can be used for the kiln to be fired, and a general pulverizer such as a ball mill can be used for pulverization. Moreover, 2 or more types of cement can also be mixed as needed.

Silica fume is a byproduct obtained by collecting dust in the exhaust gas generated when producing metal silicon, ferrosilicon, fused zirconia, etc., and the main component is an amorphous substance that dissolves in an alkaline solution. SiO ₂ . The average particle diameter of the silica fume is preferably 0.05 to 2.0 μm, more preferably 0.10 to 1.5 μm, and still more preferably 0.18 to 0.28 μm. By using such silica fume, the high compressive strength and high fluidity of the mortar composition can be ensured.

In the high-strength mortar composition of the present invention, the silica fume content based on cement is preferably 3 to 30% by mass, more preferably 5 to 20% by mass, and still more preferably 10 to 18% by mass. The unit amount of silica fume per 1 m ^{3 of} mortar is preferably 35 to 380 kg / m ³ , more preferably 58 to 253 kg / m ³ , and still more preferably 116 to 228 kg / m ³ .

As the water reducing agent, lignin-based, naphthalenesulfonic acid-based, aminosulfonic acid-based, polycarboxylic acid-based water reducing agents, high-performance water reducing agents, high-performance AE water reducing agents, and the like can be used. From the viewpoint of ensuring fluidity at a low water cement ratio, it is preferable to use a polycarboxylic acid-based water reducing agent, a high-performance water reducing agent or a high-performance AE water reducing agent as the water reducing agent, and a polycarboxylic acid-based high-performance water reducing agent. It is more preferable to use The mortar composition according to the present embodiment is preferably 0.5 to 6.0 parts by mass, more preferably 1.0 to 4.0 parts by mass of the water reducing agent with respect to 100 parts by mass of the total amount of cement and silica fume. More preferably, it is 1.8 to 3.0 parts by mass. The unit amount of the water reducing agent per 1 m ^{3 of} mortar is preferably 7 to 86 kg / m ³ , more preferably 13 to 58 kg / m ³ , and still more preferably 18 to 43 kg / m ³ .

Examples of antifoaming agents include special nonionic compounding surfactants, polyalkylene derivatives, hydrophobic silica, and polyethers. In this case, the antifoaming agent is preferably 0.01 to 2.0 parts by weight, more preferably 0.02 to 1.5 parts by weight, and still more preferably 0.000 parts by weight with respect to 100 parts by weight of the total amount of cement and silica fume. It is 03-1.0 mass part. The unit amount of the antifoaming agent per 1 m ^{3 of} mortar is preferably 0.13 to 29 kg / m ³ , more preferably 0.26 to 22 kg / m ³ , and still more preferably 0.39 to 15 kg / m ³ . is there.

  Fine aggregates include river sand, land sand, sea sand, crushed sand, quartz sand, limestone aggregate, blast furnace slag fine aggregate, ferronickel slag fine aggregate, copper slag fine aggregate, electric furnace oxidation slag fine aggregate, etc. Can be used. In addition, the particle size of the fine aggregate passes through the 10 mm sieve and passes through the 5 mm sieve by 85% by mass or more.

Moreover, limestone powder, quartzite powder, crushed stone powder, etc. can be used as the inorganic fine powder. Inorganic fine powder is a fine powder obtained by pulverizing or classifying limestone powder, silica stone powder, crushed stone powder, etc. until the Blaine specific surface area is 2500 cm ² / g or more, and is blended for the purpose of supplementing fine particles of fine aggregate, The fluidity of the composition can be improved. Preferably Blaine specific surface area of the powder inorganic fine powder is 3000~5000cm ² / g, more preferably 3200~4500cm ² / g, and further preferably from 3400~4300cm ² / g.

  The mixture of fine aggregate and inorganic fine powder according to this embodiment contains 40 to 80% by mass, preferably 45 to 80% by mass, more preferably 50 to 75% by mass of a particle group having a particle size of 0.15 mm or less. Including. Moreover, the said mixture contains 30-80 mass% of particle groups with a particle size of 0.075 mm or less, Preferably it contains 35-70 mass%, More preferably, it contains 40-65 mass%. When the content of the inorganic fine powder is 30% by mass or less, since the viscosity of the mortar slurry is too low, the high tension fiber may not be sufficiently dispersed. When the content of the inorganic fine powder exceeds 90% by mass, the amount of fine powder is too large and the viscosity becomes high, and it is necessary to increase the water-cement ratio in order to give a predetermined flow, which may lead to a decrease in strength.

It is preferable to contain 10-60 parts by mass of fine aggregate and 10-60 parts by mass of fine inorganic powder, and 15-50 parts by mass of fine aggregate, inorganic fine powder with respect to 100 parts by mass of the total amount of cement and silica fume. It is more preferable that 15-50 mass parts is included, and it is still more preferable that 15-30 mass parts of fine aggregates and 15-30 mass parts of inorganic fine powder are included. The unit amount of fine aggregate and inorganic fine powder per 1 m ^{3 of} mortar is preferably 140 to 980 kg / m ³ , more preferably 300 to 900 kg / m ³ , and still more preferably 600 to 900 kg / m ³ .

The mortar composition according to the present embodiment can further include high-tensile fibers. Examples of the high-tensile fiber include metal fiber, carbon fiber, and aramid fiber. As the metal fiber, steel fiber, stainless steel fiber, amorphous alloy fiber, or the like can be used. The fiber diameter of the high-tensile fiber is preferably 0.05 to 1.20 mm, more preferably 0.08 to 0.70 mm, still more preferably 0.10 to 0.35 mm, and particularly preferably 0.12 to 0.20 mm. The fiber length of the high-tensile fiber is preferably 3 to 60 mm, more preferably 5 to 35 mm, still more preferably 7 to 20 mm, and particularly preferably 9 to 15 mm. The aspect ratio (fiber length / fiber diameter) of the high-tensile fiber is preferably 40 to 250, more preferably 50 to 200, still more preferably 60 to 170, and particularly preferably 70 to 140. The tensile strength of the high strength fiber is preferably 100~10000N / mm ^2, preferably from 500~5000N / mm ^2, more preferably ^{2000~3000N / mm 2, 1500~2500N / mm} 2 is particularly preferred. The density of high-tensile fibers, preferably from 1 to 20 g / cm ^3, more preferably 3 to 15 g / cm ^3, more preferably 5 to 10 g / cm ^3. By using such a high-tensile fiber, high toughness, high compressive strength, high tensile strength, and high fluidity can be imparted to the mortar composition.

In addition, the mortar composition according to the present embodiment is preferably made of high-tensile fibers on an external basis with respect to the mortar composition (that is, with respect to 100% by volume of the composition excluding high-tensile fibers in the mortar composition). High toughness can be obtained by including 0.3 to 5.0% by volume, more preferably 0.5 to 3.0% by volume, and still more preferably 1.0 to 2.5% by volume. In addition, when it exceeds 5.0 volume%, mixing of mortar may become difficult. The amount of high-tensile fibers to mortar 1 m ³ is preferably 23～393Kg, more preferably 39～236Kg, more preferably 79～196Kg.

Moreover, the mortar composition according to the present embodiment is preferably 10 to 25 parts by mass of water, more preferably 12 to 20 parts by mass, and still more preferably 13 to 18 parts by mass with respect to 100 parts by mass of the total amount of cement and silica fume. Including parts by mass. Unit water per mortar 1 m ³ is preferably 180~280kg / ^{m 3,} more preferably 190~270kg / ^{m 3,} more preferably a 200~250kg / ^{m 3.}

  In the mortar composition according to the present embodiment, an expansion material, a shrinkage reducing agent, a setting accelerator, a setting retarding agent, a thickening agent, a glass fiber, an organic fiber, a synthetic resin powder, a polymer emulsion, and a polymer disperse are included as necessary. One or more of John and the like may be added.

  Furthermore, concrete may be prepared by combining an appropriate amount of coarse aggregate with the mortar composition according to the present embodiment. The amount of coarse aggregate and the amount of water may be changed as appropriate according to the target compressive strength, toughness, and target slump. As the coarse aggregate, gravel, crushed stone, limestone aggregate, blast furnace slag coarse aggregate, electric furnace oxidized slag coarse aggregate and the like can be used. Moreover, the coarse aggregate which stays at 85 mass% or more on a 5 mm sieve is more preferable.

  Although the manufacturing method of the mortar composition according to the present embodiment is not particularly limited, a part or all of materials other than water and a water reducing agent are mixed in advance, and then water and a water reducing agent are added to the mixer. Add and knead. Moreover, when mix | blending a fiber, after manufacturing a mortar, it adds to a mixer, and also mixes. The mixer used for kneading mortar is not particularly limited, and a mortar mixer, a biaxial forced kneading mixer, a pan mixer, a grout mixer, and the like can be used.

  The high-strength mortar composition of the present invention is effective for PC beams, high-durability panels, block earthquake resistant walls and the like that require high strength. By adding high-tensile fiber, the amount of reinforcing bars such as bridges can be reduced. It is also effective for bridge repair and reinforcement.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  Hereinafter, the contents of the present invention will be described more specifically with reference to examples and comparative examples. In addition, this invention is not limited to the following Example.

[Preparation of materials used]
In order to prepare the mortar compositions of Examples and Comparative Examples, the following materials were prepared.

(1) Cement (C)
Portland cement was prepared by blending raw materials such as limestone, silica stone, slag, coal ash, construction generated soil, copper gravel, etc., calcining with kiln, adding gypsum and grinding. The chemical components of the obtained cement were measured according to JIS R 5202-2010 “Cement chemical analysis method”, and the mineral composition was calculated by the following Borg equation. The mineral composition of the obtained cement is shown in Table 1.

C ₃ S amount = (4.07 × CaO) − (7.60 × SiO ₂ ) − (6.72 × Al ₂ O ₃ ) − (1.43 × Fe ₂ O ₃ ) − (2.85 × SO ₃ )
C ₂ S amount = (2.87 × SiO ₂ ) − (0.754 × C ₃ S)
C ₃ A amount = (2.65 × Al ₂ O ₃ ) − (1.69 × Fe ₂ O ₃ )
C ₄ AF amount = 3.04 × Fe ₂ O ₃

  Also, the 45 μm sieve residue of the obtained cement was determined according to JIS R 5201-1997 “Cement physics” according to JIS R 5201-1997 “Cement physics”. It measured according to the "test method". The results are shown in Table 1.

(2) Silica fume (SF): average particle size 0.24 μm
The average particle size of silica fume is calculated from a particle size distribution measured using a laser diffraction / scattering particle size distribution measuring device (trade name “LA-950V2” manufactured by Horiba, Ltd.), and a particle size-passage integrated% curve is calculated. Then, the particle diameter at which the accumulated amount of the passage was 50% by volume was determined from the particle diameter-accumulated amount of passage% curve. A 0.2% sodium hexametaphosphate aqueous solution was used as a sample dispersion medium, and the sample was dispersed for 10 minutes with a homogenizer with an output of 600 W before measurement. The calculation of the particle size distribution followed Mie scattering theory. The particle refractive index was 1.45-0.00i, and the solvent refractive index was 1.333. Table 2 shows the accumulated amount (volume%) of each particle size.

(3) Fine aggregate Crushed sand: Andesite crushed sand, surface dry density 2.62 g / cm ³ , coarse particle ratio 2.80
(4) Fine inorganic powder Limestone fine powder, density 2.71 g / cm ³ , Blaine specific surface area 4280 cm ² / g
Silica powder, density 2.63 g / cm ³ , Blaine specific surface area 3820 cm ² / g

  The particle size of the crushed sand and inorganic fine powder was measured with reference to JIS A 1102-2006 “Aggregate Screening Test Method”. Subsequently, the fine aggregate and the inorganic fine powder were mixed and adjusted so as to have a predetermined particle size. The results are shown in Table 3.

(5) Water reducing agent: polycarboxylic acid-based high-performance water reducing agent (solid content concentration 25% by mass)
(6) Antifoaming agent: special non-ion-containing surfactant FIG. 1 shows ¹ H measured by dissolving the antifoaming agent in deuterated methanol and using an NMR measuring apparatus (trade name “AVANCE” manufactured by BRUKER). -NMR spectrum. The structural unit of the antifoaming agent is a structural unit of polyoxypropylene (hereinafter abbreviated as “POP”), a structural unit of polyoxyethylene (hereinafter abbreviated as “POE”), and a structural unit of an alkyl chain. The molar ratio was calculated based on the integrated value of the signal derived from the methyl group in POP. Among these, the molar ratio of POE to POP is determined based on the integral value of signals derived from hydrocarbon groups other than the POP methyl group appearing in the vicinity of 3.5 ppm and signals derived from the POE hydrocarbon group. It was calculated by subtracting the integral value of the signal derived from the hydrocarbon group. Table 4 shows the molar ratio of the structural units of POP, POE and alkyl chain in the antifoaming agent.

(7) High tensile fiber: Steel fiber, manufactured by Tokyo Seizuna 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
(8) Mixing water (W): Tap water

[Preparation of mortar composition]
Preparation of the mortar composition was performed as follows based on the formulation composition of Table 5.

  Cement, silica fume, fine aggregate, inorganic fine powder and antifoaming agent were added to the biaxial forced kneading mixer, and kneading water containing a water reducing agent was put into the mixer and stirred for 10 minutes to prepare a mortar composition. In Examples 3 to 10 and Comparative Examples 5 to 7, steel fibers were further added to prepare a mortar composition.

* 1: The amount of water with respect to 100% by mass of the total amount of cement and silica fume * 2: The amount of silica fume with respect to 100% by mass of cement * 3: The value added on an external basis with respect to cement and silica fume. The water content in the water reducing agent is included in the unit water volume.
* 4: Value added externally to the mortar composition.

[Evaluation of mortar composition]
(1) Fresh properties (test method)
Using the mortar compositions prepared in Examples 1 to 10 and Comparative Examples 1 to 6, the mortar zero-stroke flow or slump flow was measured. Mortar 0 striking flow was measured in accordance with JIS R 5201-1997 “Cement physical testing method” under the condition of no dropping, and the mortar containing no steel fiber was tested. In addition, the slump flow was observed visually according to JIS A 1150-2007 “Concrete slump flow test method” for the dispersion state of the steel fibers after the test.

(2) Strength test According to JIS A 1132-2006 “How to make a specimen for concrete strength test”, a 5 cm × 10 cm cylindrical specimen is prepared and according to JIS A 1108-2006 “Concrete compressive strength test method”. Then, a split tensile strength test was conducted according to the compressive strength test, JIS A 1113-2006 “Concrete tensile strength test method for concrete”. The specimens were standard cured until the test material age.

(Evaluation results)
Table 6 shows the results of a mortar zero-stroke flow test, a slump flow test, a fiber dispersion state, a compressive strength test, and a split tensile strength test. Moreover, the photograph which image | photographed the state after the slump flow test of the mortar composition of Example 3 in FIG. 2 and the mortar composition of Comparative Example 7 in FIG. 3 is shown, respectively. Note that the photograph (b) in FIGS. 2 and 3 is an enlarged part of the photograph (a).

The fluidity was evaluated according to the following criteria from the value of mortar zero stroke flow. When the mortar zero hit flow is small, workability, filling property of the mortar composition into a narrow portion, and the like are insufficient, and therefore, it is determined that the workability is poor.
○: The value of the mortar zero stroke flow is 200 mm or more, and the fluidity is high.
X: The value of the mortar zero hit flow is less than 200 mm, and the fluidity is poor.

The fluidity was evaluated according to the following criteria from the slump flow value. When the slump flow is small, the workability and the filling property of the mortar composition into the narrow part are insufficient, and therefore it is judged that the workability is poor.
(Double-circle): The value of slump flow exceeds 750 mm, and fluidity | liquidity is very high.
○: The slump flow value is 700 mm or more and less than 750 mm, and the fluidity is high.
(Triangle | delta): The value of slump flow is 650 mm or more and less than 700 mm, and there is no problem in fluidity | liquidity.
X: The slump flow value is less than 650 mm, and the fluidity is poor.

The fiber dispersibility was evaluated according to the following criteria.
A: Fiber ball (fiber lump) is not recognized.
○: Slight fiber balls are observed.
X: Many fiber balls are recognized.

(Mineral composition and particle size of cement)
By changing the type of cement, the flowability and strength development of the mortar composition were evaluated. In Examples 1 and 2, it was confirmed that the fluidity was excellent and a sufficiently high compressive strength was obtained at a material age of 7 days. On the other hand, in Comparative Examples 1, 3 and 4, the fluidity was inferior, and in Comparative Example 2, although the fluidity was excellent, the compressive strength was not sufficient.

(Particle size of fine aggregate and inorganic fine powder)
In Examples 3 to 10 in which the mixture of the fine aggregate and the inorganic fine powder according to the present invention was blended, the fluidity was excellent, and the sample after the test was observed. It was confirmed that it was excellent (see FIG. 2).

  On the other hand, in Comparative Examples 5 and 6 in which only inorganic fine powder was blended, since there were many particle groups having a particle diameter of 0.15 mm or less, the viscosity of the composition was high and sufficient fluidity could not be obtained. Moreover, although the comparative example 7 was excellent in fluidity | liquidity, a lot of fiber balls were recognized by the sample after a test, and there was concern about uneven distribution of the steel fiber after hardening (refer FIG. 3).

  In Examples 3 to 10, it was confirmed that the compressive strength was sufficiently high. On the other hand, the compressive strength of Comparative Example 5 was slightly low, and when the specimen of Comparative Example 5 was polished before the compression test, bubbles remained in the sample. In Comparative Example 5, it is considered that the internal bubbles are difficult to escape due to poor fluidity, which causes a decrease in strength.

  Furthermore, in Examples 3, 4 and 10, the split tensile strength was excellent. On the other hand, in Comparative Example 7, since the fibers were unevenly distributed in the cured body of the mortar composition, the split tensile strength was low.

  From the above, it was confirmed that according to the mortar composition of the present invention, the fluidity was sufficiently high and the workability was excellent, and high compressive strength could be expressed at an early stage only by room temperature curing.

Claims (9)

A high-strength mortar composition comprising cement, silica fume, water, water reducing agent, antifoaming agent, fine aggregate, and inorganic fine powder,
The cement contains 40.0-75.0% by mass of C ₃ S and less than 2.7% by mass of C ₃ A, and a 45 μm sieve residue is less than 25.0% by mass,
The mixture of the fine aggregate and the inorganic fine powder contains 40-80% by mass of a particle group having a particle size of 0.15 mm or less, and 30-80% by mass of a particle group having a particle size of 0.075 mm or less,
A high-strength mortar composition, wherein the inorganic fine powder is one or more fine powders selected from the group consisting of limestone powder, silica stone powder, and crushed stone powder. The high intensity | strength mortar composition of Claim 1 whose brane specific surface area of the said inorganic fine powder is 3000-5000cm < ² > / g.   The high intensity | strength mortar composition of Claim 1 or 2 whose average particle diameter of the said silica fume is 0.05-2.0 micrometers.   The high-strength mortar composition according to any one of claims 1 to 3, comprising 3 to 30% by mass of the silica fume based on the cement.   5 to 10 parts by mass of water and 0.5 to 6.0 parts by mass of a water reducing agent are contained according to any one of claims 1 to 4, with respect to 100 parts by mass of the total amount of the cement and the silica fume. High strength mortar composition.   The high according to any one of claims 1 to 5, comprising 10 to 60 parts by mass of fine aggregate and 10 to 60 parts by mass of inorganic fine powder with respect to 100 parts by mass of the total amount of the cement and the silica fume. Strength mortar composition.   The high-strength mortar composition according to any one of claims 1 to 6, further comprising high-tensile fibers. The high-strength fibers have a tensile strength of 100~10000N / mm ^2, the aspect ratio is 40 to 250, weight content with respect to the mortar composition is 0.3 to 5.0% by volume, according to claim 7 High strength mortar composition.   The high-strength mortar composition according to claim 7 or 8, wherein the high-tensile fibers are one or more fibers selected from the group consisting of metal fibers, carbon fibers, and aramid fibers.