JP4813355B2 - Cement admixture, cement composition, mortar and concrete - Google Patents

Description

  The present invention relates to a cement admixture, a cement composition, mortar and concrete using the same. More specifically, it is an admixture containing silica fume and fly ash classified to 20 μm or less, and a cement composition in which this is added to cement. Furthermore, it is related with the mortar and concrete which raised bending strength using this cement composition.

  Mortar or concrete has a problem that the bending strength is basically lower than the compressive strength, and even if the compressive strength is increased, the bending strength is not so high. Therefore, road surfaces, beams, girders designed with flexural strength, and many concrete secondary products tend to be rich and uneconomical concrete mixes, and the cross section of the member is made thicker to increase bending strength, Prestress has been introduced. Further, in the case of a fume tube or the like, an external material is mixed with concrete and a chemical press or chemical prestress is introduced to increase the external pressure strength.

  On the other hand, silica fume has high pozzolanic activity and is used as a strength enhancer. Furthermore, by combining with a relatively large amount of high-performance water reducing agent, mortar flow, concrete slump or slump flow can be increased, and mortar and concrete with a low water binder ratio can be easily manufactured, so high strength and high strength mortar. Or it is often used as an admixture for concrete.

  Fly ash is a spherical particle coal ash containing hollow particles with a diameter of 100 μm or less that is by-produced from a pulverized coal-fired thermal power plant. Although its pozzolanic activity is low, it reacts in the long term and improves water tightness. Often used as fly ash cement. As shown in Patent Document 1, by classifying the particles to 20 μm or less or 10 μm or less, large hollow particles are removed, resulting in particles having a good spherical shape and no hollow. When combined with a high-performance water-reducing agent or a high-performance AE water-reducing agent due to its ball bearing action, it particularly increases mortar flow, concrete slump or slump flow and exhibits strong consistency. Furthermore, it is also known that even when the same flow or slump is used, the strength of the reduced amount of water is lower than that of non-classified fly ash mortar or concrete.

  Furthermore, for example, as shown in Patent Document 2, gypsum is frequently used as a high-strength admixture regardless of the presence or absence of steam curing, and it is also known that higher strength and durability can be obtained by combining with silica fume.

Further, as shown in Patent Document 3, as a classic method for increasing bending strength and toughness, there is a method of adding metal fibers. As a method for improving toughness by using metal fibers, it is also known that silica fume and needle-like or plate-like fine powder are added to cement and the maximum aggregate diameter is limited to be small.
[Patent Document 1] Japanese Patent Laid-Open No. 63-8248 [Patent Document 2] Japanese Patent Laid-Open No. 3-40947 [Patent Document 3] Japanese Patent Laid-Open No. 11-246255

  However, in the general-purpose technology in which only silica fume is blended, the compressive strength of concrete is increased, but there is a problem that the ratio of the bending strength to the compressive strength becomes lower than that when silica fume is not mixed. In addition, as shown in Patent Document 1, fly ash classified to 20 μm or less or 10 μm or less originally has low pozzolanic activity, so the strength of the reduced water is increased, but the classified fly ash is not mixed with the same water binder ratio. Compared to the case, the short-term intensity increase hardly increased even when steam curing was performed.

  Furthermore, as shown in Patent Document 2, high strength is easily expressed by using gypsum alone or in combination with silica fume, and the bending strength is increased with respect to the increase in compressive strength, but the ratio is the same as that of ordinary concrete. There was a problem that the area was not. As shown in Patent Document 3, in the method of reinforcing with metal fibers, the maximum aggregate diameter is 2 mm while the mortar or concrete fine aggregate used in the ready-mixed concrete factory and concrete product factory is 5 mm or less. Since it is an indispensable requirement below or 1 mm or less, there existed a subject that it cannot generally spread widely.

The present invention has been made to solve the above-described problems in the prior art, and provides a mortar or concrete having an increased absolute value of compressive strength and bending strength and an increased ratio of bending strength to compressive strength. Objective.
Another object of the present invention is to provide a cement admixture for realizing the mortar or concrete, and a cement composition using the cement admixture.
Still another object of the present invention is to provide a hardened cement body obtained from the mortar or concrete.

As a cement admixture, conventionally used silica fume and fly ash and gypsum classified to a diameter of 20 μm or less are used alone, but in combination, the ratio of the bending strength to the bending strength and the compressive strength can be individually set. It was found that it can be increased synergistically as compared with the case of using in the above. Furthermore, since the bending strength of the mortar or concrete itself used as a base can be increased, the bending strength can be drastically improved by using metal fibers in combination even when using a commonly used mortar or fine aggregate for concrete. The present inventors have found a fact that can be increased and have completed the present invention.
That is, the present invention relates to the following cement admixture, cement composition, mortar, concrete, and hardened cement.
(1) A cement admixture comprising silica fume and fly ash classified to 20 μm or less, wherein the mixing ratio of silica fume: classified fly ash is 95: 5 to 10:90 by mass ratio.
(2) The cement admixture according to the above (1), further comprising gypsum.
(3) A cement composition comprising 1 to 35 parts of the cement admixture described in (1) above with 100 parts of cement.
(4) The cement composition according to the above (3), wherein 0.5 to 12 parts of gypsum in terms of anhydride is further added to 100 parts of cement.
(5) A mortar obtained by mixing the cement composition according to (3) or (4) above, a fine aggregate, a water reducing agent, and kneaded water.
(6) A mortar obtained by adding 1.0 to 6.0% by volume of metal fiber in an outer ratio to 1 m ³ of the mortar of (5).
(7) Concrete obtained by mixing the cement composition according to (3) or (4) above, a fine aggregate, a coarse aggregate, a water reducing agent, and water for mixing.
(8) Concrete obtained by adding 1.0 to 4.0% by volume of metal fiber in an outer ratio to 1 m ³ of the concrete described in (7) above.
(9) A hardened cement body obtained by curing the mortar according to (5) or (6).
(10) A hardened cement body obtained by curing the concrete according to (7) or (8).

  According to the present invention, the flow value of mortar or concrete that has been kneaded is improved, and good workability is obtained. In addition, the obtained mortar and concrete have high absolute values of compressive strength and bending strength, and a high ratio of bending strength to compressive strength is obtained. Furthermore, when metal fibers are blended and reinforced, the bending strength can be dramatically increased, and an economical and advantageous design is possible in manufacturing civil engineering and building structures and concrete secondary products.

The present invention will be described in detail below. In addition, the part and% which show the mixture ratio and addition amount which are used by this invention are a mass unit. However, in the case of metal fibers, it is the outer volume% relative to 1 m ³ of mortar or concrete.

The silica fume used in the present invention is a fine particle having a spherical diameter of 1 μm or less, which is a by-product when silicon alloy such as metal silicon or ferrosilicon and zirconia are produced in an electric furnace, and the main component is an amorphous reaction. It is highly functional SiO ₂ . The compressive strength gradually increases according to the amount of silica fume added, but the ratio of the bending strength to the compressive strength is lower than when silica fume is not mixed.

  As described above, silica fume is not only used as a strength-enhancing material, but when a relatively large amount of high-performance water reducing agent and silica fume of about 10% with respect to cement are used in combination, the fluidity is remarkably increased. However, the flow characteristics differ depending on the type of the high-performance water reducing agent, and the yield value of the paste is different for the water reducing agent of the so-called high-performance water reducing agent of the polyalkylallyl sulfonate type or melamine formalin resin sulfonate type. It shows fluidity with strong viscosity for a small amount. For the so-called high-performance AE water reducing agent that entrains air, the fluidity increases in a sticky plastic state rather than simply viscosity, and the former is heavy for the feeling of turning back with a scoop. The latter feels light. Therefore, the combined system of high performance AE water reducing agent and silica fume may be used simply because pumping is easy.

  As mentioned above, fly ash is a spherical granular residue collected from a boiler flue together with combustion gas by coal ash by-produced from a pulverized coal fired thermal power plant and collected by a dust collector. It is blended with cement and used as fly ash cement. In the present invention, it is an indispensable condition to use one further classified to 20 μm or less, and the effect of the present invention cannot be obtained with fly ash that is not classified. There are two types of commercially available classified fly ash: those classified to 20 μm or less and those classified to 10 μm or less.

  In the cement admixture of the present invention, the mass ratio of silica fume to fly ash classified to 20 μm or less is 95: 5 to 10:90, preferably 90:10 to 15:85, more preferably 80:20 to 70:30. The ratio of If the classified fly ash is less than 5%, the effect of increasing the bending strength is small. Even if the classified fly ash exceeds 90%, the effect of increasing the bending strength is small. As the proportion of classified fly ash increases, the compressive strength gradually decreases, but the bending strength increasing effect has a peak at around 60:40.

  On the other hand, as the proportion of classified fly ash increases, mortar flow, slump or slump flow (hereinafter simply referred to as “flow”) also increases, and there is a peak at a silica fume: classified fly ash ratio of 50:50. Appropriate viscosity due to ash suppresses the separation of the aggregate and makes it easy to flow even if metal fibers are added.

  The admixture of the present invention is preferably added in an amount of 1 to 35 parts, more preferably 2 to 30 parts, and most preferably 3 to 25 parts per 100 parts of cement. Even if it is added in excess of 35 parts, the increase in bending strength reaches a peak, which is not economically preferable.

  The gypsum used in the present invention includes dihydrate gypsum, hemihydrate gypsum, soluble anhydrous gypsum (type III), and various forms of insoluble anhydrous gypsum (type II). preferable. Gypsum increases the compressive strength that decreases as the blending ratio of fly ash classified to 20 μm or less increases when cement admixture of “silica fume and fly ash classified to 20 μm or less” is added to cement. It has the effect of increasing the absolute value of both compressive strength and bending strength. The gypsum is added to 0.5 to 12 parts, more preferably 0.8 to 10 parts, and most preferably 1 to 8 parts per 100 parts of cement in terms of anhydride. Even if added in excess of 12 parts, no further strength effect can be obtained.

  In the present invention, the necessary amount of high performance water reducing agent or high performance AE water reducing agent is used in combination. High performance water reducing agent is mainly composed of polyalkylallyl sulfonate, aromatic amino sulfonate or melamine formalin sulfonate. One or more of these are used. It is what is done. Polyalkylallyl sulfonate-based high-performance water reducing agents include methyl naphthalene sulfonic acid formalin condensate, naphthalene sulfonic acid formalin condensate and anthracene sulfonic acid formalin condensate. Name “FT-500” and its series, Kao Co., Ltd. product name “Mighty-100” (powder) and “Mighty-150” and its series, Daiichi Kogyo Seiyaku Co., Ltd. product name “Cell Flow 110P” ( Powder), Takemoto Yushi Co., Ltd. trade name “Pole Fine 510N”, and Nippon Paper Industries Co., Ltd. trade name “Sunflow PS” and its series are typical. As aromatic aromatic sulfonate-based high-performance water reducing agents, there are Fujisawa Pharmaceutical Co., Ltd. product name “Pallic FP200H” and its series. Melamine formalin sulfonate-based high-performance water reducing agents include Grace Chemicals product name “ FT-3S ".

  The high-performance AE water reducing agent is usually called a polycarboxylate-based water reducing agent, and is a copolymer or a salt thereof containing an unsaturated carboxylic acid monomer as one component. For example, polyalkylene glycol monoacrylate, polyalkylene glycol monomethacrylate, a copolymer of maleic anhydride and styrene, a copolymer of acrylic acid or methacrylate, and a monomer copolymerizable with these monomers. Examples thereof include a copolymer derived from a monomer. NMB Co., Ltd., trade name “Leo Build SP8N” series, Fujisawa Pharmaceutical Co., Ltd., trade name “Palic FP100S, 300S” series, Takemoto Yushi Co., Ltd., trade name “Tupol HP8,11” series, Grace Chemicals Co., Ltd. ) Company product name “Darlex Super 100, 200, 300, 1000” series and others are commercially available.

  The cement used in the present invention is various portland cements, various mixed cements or ecocements. Moreover, the cement which mixed these arbitrary amounts may be sufficient.

  There is no special restriction | limiting in manufacturing the mortar and concrete of this invention, The fine aggregate and coarse aggregate generally used can be used. Further, the ratio of the bending strength to the compressive strength of the mortar or concrete and the absolute value of the bending strength can be arbitrarily selected because they increase appropriately regardless of the water binder ratio and the fine aggregate ratio.

Furthermore, in the present invention, metal fibers can be used in combination. The metal fiber is not special either, and may be a commercially available mortar or concrete. Metal fiber is added in an amount of 1.0 to 6.0% by volume with respect to 1 m ³ of mortar or concrete, but the maximum addition amount in the case of mortar and concrete from the viewpoint of increasing bending strength and workability, and The preferred range is different. Further, the maximum addition amount and the preferred range also differ depending on the molding method of concrete such as vibration molding and centrifugal force molding.

  In the case of vibration molding, when the mortar is less than 2% by volume, the increase in bending strength is small, but it is 2% by volume or more. As the added amount is increased, the bending strength increases gradually, reaching a peak at 5.5% by volume or more. If it exceeds 6.0% by volume, it is difficult to flow and cannot be molded, and the outer ratio is 1.0 to 6.0% by volume, preferably 2.5 to 5.0% by volume. In the case of concrete, the effect is exhibited from 1.5% by volume or more, and if it exceeds 4% by volume, the workability deteriorates, so the outer ratio is 1.0 to 4.0% by volume, preferably 1.5 to 3.5%. % By volume.

  In the case of centrifugally molded products, both the mortar and the concrete increase the bending tensile strength from 1.0% by volume of the metal fiber, and in the case of mortar, the workability is preferably 5.0% by volume or less. Then, 3.0 volume% or less is preferable. In order to increase the external pressure strength of the fume tube, it is sufficient to concentrate the steel fiber on the inner side. Therefore, it is economically preferable to reinforce the thickness of about 2/3 or less of the inner side of the tube thickness.

  The method for adding the admixture of the present invention is not particularly limited. When kneading mortar or concrete, a mixture of silica fume and fly ash classified to 20 μm or less may be added, or gypsum may be further mixed and added. In addition, each component may be prepared separately and added to the mixer together with other mortar or concrete material. The kneading method is not particularly limited, and a usual kneading method may be used. The method for adding the metal fiber is not particularly limited, but a method in which mortar or concrete is mixed and then added to the mixer while continuing to stir the mixer is preferable because it is difficult to produce fiber balls.

  Moreover, there is no restriction | limiting in the curing method of the mortar and concrete of this invention, Standard curing, steam curing, and autoclave curing are also possible.

Hereinafter, materials used in the examples and comparative examples of the present invention, test items, and methods thereof are collectively shown.
<Materials used>
Cement: Ordinary Portland cement manufactured by Denki Kagaku Kogyo Co., Ltd., density 3.16 g / cm ³
Fine aggregate: River sand from Himekawa, Niigata Prefecture (5mm below), density 2.62g / cm ³
Coarse aggregate: Crushed stone from Himekawa, Niigata Prefecture (13-5mm), density 2.64g / cm ³
Silica fume: Russian product, granulated (SF), density 2.44 g / cm ³
Fly ash: manufactured by Shikoku Electric Power Co., Inc., classified to 20 μm or less (referred to as FA20), classified to 10 μm or less (referred to as FA10), unclassified fly ash (referred to as FA), density 2.44 g / cm ³
Gypsum: insoluble anhydrous gypsum (naturally produced, density 2.82) and industrial dihydrate gypsum powder, density 2.30 g / cm ³
Metal fiber: manufactured by Tokyo Seizuna Co., Ltd., “Diepack” iron, width 0.9 mm, thickness 0.34 mm, length 30 mm, density 8.00 g / cm ³
Water-reducing agent: High-performance AE water-reducing agent WRA (1), “Super 1000N” manufactured by Grace Chemicals Co., Ltd., High-performance water reducing agent WRA (2), “Cell Flow 110P” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
<Test items and methods>
[Measurement of mortar flow]
According to JIS R 5201, the flow value when it was pulled out was measured. However, a 50 × 50 × 2 cm acrylic glass plate was placed on the flow table.
[Method for measuring mortar strength]
The bending strength was in accordance with JIS R 5201, and the compression strength was molded into a mold having a diameter of 5 × 10 cm.
[Measurement of concrete flow]
The lateral spread of the concrete when it was pulled out according to JIS A 1101 was measured.
[Measurement of bending strength and compressive strength of concrete]
According to JIS A 1132, JIS A 1106, JIS A 1132 and JIS A 1108.
[Measurement of bending tensile strength of centrifugal molding]
17.5kg of concrete is packed in a cylindrical form with an outer diameter of 20cm x length of 30cm, initial speed 1.5G x 2 minutes, low speed 3G x 5 minutes, medium speed I: 8G x 1 minute, medium speed II: 15G x 2 minutes Then, it was subjected to centrifugal force molding under the condition of high speed 30G × 3 minutes, and after curing, the bending pressure strength was calculated by measuring the external pressure load and pipe thickness where cracks occurred. In addition, when the inner 1/3 was made of metal fiber-containing mortar, 12.5 kg of concrete was packed and subjected to centrifugal force molding under the above conditions, and then 5 kg of mortar was repacked and similarly subjected to centrifugal force molding.

  In addition, mortar (or concrete) is kneaded by mixing cement, each component of the admixture, and fine aggregate (and coarse aggregate) for 30 seconds, and then adding kneaded water in which a water reducing agent is dissolved in water. For 3 minutes. When adding metal fiber, mortar or concrete was kneaded for 3 minutes, then the metal fiber was added little by little without stopping stirring, and then kneaded for another 3 minutes.

(mortar)
100 parts of cement, 100 parts of fine aggregate, silica fume and fly ash are mixed as shown in Table 1, and kneaded water in which 3 parts of a high performance AE water reducing agent is dissolved in 20 parts of water is combined with a binder (cement or The flow value of the mortar mixed with 20 parts of the mixture (cement + silica fume and / or fly ash) and kneaded was measured and listed in Table 1. The test piece molded with this mortar was heated to 80 ° C. at a heating rate of 20 ° C./hour for 8 hours in advance, held for 5 hours and then slowly cooled in a steam curing tank until the next day, The bending strength and compressive strength at the age of 1 day were measured, and the results are also shown in Table 1.

  As is apparent from Table 1, non-mixing experiment No. 1-1, in which only the silica fume of Comparative Example was added. In 1-2, the flow value was increased and workability was improved, and the compressive strength and bending strength were increased. However, the increase of the bending strength with respect to the increase of the compressive strength was slight, and the ratio of the bending strength to the compressive strength was decreased. In addition, No. 1 to which only the classified fly ash was added. 1-14 also shows an improvement in flow value, but compressive strength and bending strength hardly increase. On the other hand, Experiment No. 1-3 to No. 1-13, No. 1 1-26-No. As shown in 1-30, the flow value is increased by blending silica fume and classified fly ash. It was found that the increase in compressive strength gradually decreases as the proportion of silica fume decreases, but the increase in flexural strength is remarkable and the ratio of flexural strength to compressive strength also increases. The bending strength reached its maximum when the silica fume / classified fly ash ratio was 60:40.

  In addition, Experiment No. 1-15-No. As is apparent from 1-25, as the admixture is added in an increased amount, the flow value, bending strength and compressive strength increase, but the bending strength begins to increase from 1 part to 100 parts of cement. However, when the amount is 35 parts or more, the flow value, bending strength, and compressive strength reach the peak, and 30 parts or less is preferable in consideration of economic efficiency.

(mortar)
Experiment No. 1 of Example 1 1-1, no. 1-2, no. 1-7, No. 1 1-14 was further blended with the types and amounts of gypsum shown in Table 2 (amount relative to 100 parts of cement), the same test as in Example 1 was performed, and the results are shown in Table 2.

  From Table 2, gypsum promotes both compressive strength and bending strength to increase strength. In this example, the effect is manifested when 0.5 part or more is added with respect to 100 parts of cement, becomes more prominent when 0.8 part or more or 1.0 part or more, and exceeds 12 parts. However, no further strength effect can be obtained. As a result, it was found that adding 10 parts or less, preferably 1 to 8 parts of gypsum to 100 parts of cement increases the absolute values of both compressive strength and bending strength.

(Metal fiber-containing mortar)
Experiment No. 1 of Example 1 1-8 mortar 1m ³ (4% air content) Change the amount of metal fibers added (extra addition to the mortar), knead and mold the sample by pouring, steam curing as in Example 1 After that, a bending strength test was carried out for one day of age. The results are shown in Table 3.

  From Table 3, the metal fiber dramatically increases the bending strength of the mortar, but 1.5 volume% has no effect at all, and it becomes effective from 2 volume%, and the bending strength gradually increases as the addition amount increases. Increased. When it exceeded 5.0% by volume, it reached a peak, and at 6.5% by volume, workability was poor and moldability was deteriorated. It was found that the most preferable range in the case of vibration-molded mortar is 2.5 to 5% by volume.

(concrete)
Concrete 1 m ³ per 900 kg / ^{m 3} of coarse aggregate was added, and except for adjusting the air amount of 2.5% and is, for example 1 Experiment No. 1-1 to Experiment No. 1-14 and Experiment No. 2 of Example 2. 2-5 Experiment No. 2 2-13 mortar was mixed and concrete was mixed to a total of 1 m ³ to form a specimen, and the compression and bending strengths of the standard curing 91 days were measured. The results are shown in Table 4. .

  As is apparent from Table 4, the experiment No. 1 in which only cement and silica fume were added as binders. Experiment No. 4 in which only fly ash classified with concrete and cement of 4-2 was added. 4-14 concrete has a small increase rate of bending strength. On the other hand, Experiment No. 4-3 Experiment No. 4 As shown in 4-13, it was found that the increase in flexural strength was remarkable in the case of concrete containing both silica fume and classified fly ash. It is particularly remarkable when the ratio of silica fume: classified fly ash is 95: 5 to 10:90, preferably 90:10 to 20:80.

  When gypsum is used in combination, Experiment No. 4-15 to Experiment No. As is apparent from 4-23, it has been shown to increase both compressive and bending strength. As in the case of mortar, the combined use of gypsum is not more than 10 parts, preferably 1-8, even if it is added in excess of 12 parts with respect to 100 parts of cement. Part.

(Concrete containing metal fiber)
Experiment No. 4 in Example 4 Mix 4-8 concrete 1m ³ with metal fiber in the amount shown in Table 5 (additional split to concrete) and place the mold on a table vibrator so that the metal fiber does not separate. Concrete was poured while slightly vibrating, the specimen was molded, and steam curing was conducted in the same manner as in Example 1 and then a bending strength test was conducted on the age of one day. The results are shown in Table 5.

  As can be seen from Table 5, metal fiber increases the bending strength of concrete, but 1.0% by volume has almost no effect, and 1.5% by volume has been shown to be effective. Although the strength increases, it gradually reaches a peak. At 4.5% by volume, workability is poor and molding becomes difficult. In the case of vibration-molded concrete, the most preferable range including workability was found to be 2.0 to 4.0% by volume.

Using the composition of Table 6, the mortar or concrete is mixed by changing the addition amount of the metal fiber, the centrifugal force molded specimen is prepared, the steam curing is performed in the same manner as in Example 1, and the crack of the age of 1 day is observed. The external pressure load at the time of entering was measured, and the bending tensile strength was calculated. The middle column is the mix of concrete, the upper column is the mix of concrete for comparison, and the mortar mix in the lower column is expressed by converting coarse aggregate from the concrete mix in the middle column to 1 m ³ . In addition, the symbol in Table 6 represents the following, respectively.
Gmax: Maximum aggregate size air: Air volume sL: Slump s / a: Fine aggregate ratio W / B: Water binder ratio W: Water C: Cement S: Fine aggregate G: Coarse aggregate

  Centrifugal force molding specimens were prepared by changing the amount of metal fiber added to the mortar or concrete and then forming the outer 3 cm with mortar or concrete without metal fiber. Two layers of the inner 2 cm were formed with the changed mortar or concrete. The results are shown in Table 7.

  As can be seen from Table 7, when 1.0% by volume of metal fiber is added, the bending tensile strength increases, and the bending tensile strength increases as the added amount increases. In the case of concrete, even if metal fibers are added to concrete having high fluidity, if the volume is 3.5% by volume, the elongation of the concrete is poor and the fiber ball floats on the inner surface.

  In the case of mortar, when it exceeds 5.0 volume%, it became impossible to mold, and it was found that 5.0 volume% or less is preferable. In addition, when a fume tube is assumed, it is more economical to mix and mold metal fibers only inside the tube thickness than to mix and mold metal fibers throughout the tube, which is more economical. It turned out to be.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on March 17, 2004 (Japanese Patent Application No. 2004-075718), the contents of which are incorporated herein by reference.

  According to the present invention, the flow value of mortar or concrete that has been kneaded is improved, and good workability is obtained. In addition, the obtained mortar and concrete have high absolute values of compressive strength and bending strength, and a high ratio of bending strength to compressive strength is obtained. Furthermore, when metal fibers are blended and reinforced, the bending strength can be dramatically increased, and an economical and advantageous design is possible in manufacturing civil engineering and building structures and concrete secondary products.

Claims (6)

On cement 100 parts by weight of silica fume: the proportions are by weight ratio of the fly ash classified to 20μm or less 95: 5-10: 0 90 and the ones with 3 to 25 parts by weight, gypsum on a dry solid basis. 5 to 12 parts by mass, a fine aggregate below 5 mm, a water reducing agent , and 14 to 28% by mass of mixing water with respect to the cement, silica fume, fly ash and gypsum binder , and Mortar that does not contain epoxy resin. For the mortar 1 m ³ , 2 . The mortar according to claim 1, wherein 0 to 6.0% by volume of metal fiber is added. On cement 100 parts by weight of silica fume: the proportions are by weight ratio of the fly ash classified to 20μm or less 95: 5-10: 0 90 and the ones with 3 to 25 parts by weight, gypsum on a dry solid basis. Mixing water of 14 to 28% by mass with respect to a binder composed of 5 to 12 parts by mass, a fine aggregate below 5 mm, a coarse aggregate, a water reducing agent, and the cement, silica fume, fly ash, and gypsum. Concrete that is made of and contains no epoxy resin. The concrete according to claim ³ , wherein 1.0 to 4.0% by volume of metal fiber is added to the concrete 1m3.   A hardened cement body obtained by curing the mortar according to claim 1 or 2.   A hardened cement body obtained by curing the concrete according to claim 3 or 4.