JP6573533B2 - Manufacturing method of fiber reinforced cement material - Google Patents

Description

  The present invention relates to a method for manufacturing a fiber-reinforced cement material, and more particularly to a method for manufacturing a fiber-reinforced cement material suitable for driving into a sloped portion.

  BACKGROUND ART A fiber reinforced cement material (high toughness cement-based composite material) represented by UFC (Ultra High Strength Fiber Reinforced Concrete) takes a form in which fibers are mixed in mortar or cement paste. These fiber-reinforced cement materials have excellent performance as a hardened body (toughness), and at the same time, flow into thin and complex forms due to high fluidity (self-filling and self-leveling). It has the feature that can be.

  Such a fiber-reinforced cement material is usually manufactured by kneading cement, aggregate, water and the like in advance, adding fibers, and further kneading (for example, see Patent Document 1).

JP 2011-32129 A

  When a fiber-reinforced cement material having high fluidity is poured into a mold, it is difficult to secure a finished shape along the gradient due to a pre-flow at a portion having a gradient. In that case, the mold can be inverted so that a sloped part is not provided at the top of the implant, a cover frame is provided, the implantation range is finely divided by a comb frame, etc., or until the self-leveling property is lost (fluidity) The method of waiting (until it decreases) is used. These methods are mainly adopted during production in precast concrete factories.

  However, for example, in the case where the fiber-reinforced cement material is driven into a wide area having a gradient at the site, it is not easy to adopt the above-described method. In order to suppress the pre-flow at the time of driving into a portion having a gradient, it is conceivable to reduce the fluidity of the fiber-reinforced cement material. Here, the manufacturing procedure of the fiber-reinforced cement material is to produce a cement matrix containing cement, aggregate, water, etc. in advance (kneading) in order to exhibit high performance, and then to fiber. Is generally mixed. At this time, in order to reduce the fluidity of the fiber-reinforced cement material obtained, it is conceivable to suppress the fluidity of the cement matrix. In this case, the cement matrix is not sufficiently kneaded (the cement cannot be dispersed completely). ), Performance problems and manufacturing problems such as insufficient strength development, excessive load on the mixer at the time of fiber feeding, and fiber not uniformly dispersed, resulting in insufficient strength development. It will be.

  The present invention has been made in view of the above-described problems of the prior art, and has excellent workability that can be applied without causing a pre-flow when driven into a portion having a gradient, and has sufficient strength. It is an object of the present invention to provide a method for producing a fiber reinforced cement material that can easily produce a fiber reinforced cement material capable of forming an object.

  In order to achieve the above object, the present invention comprises a first step of kneading at least a binder, an aggregate, water, and an admixture to obtain a cement matrix, adding a fiber to the cement matrix and kneading, a base, A second step of obtaining a fiber reinforced cement material, and a flow adjusting material is added to the base fiber reinforced cement material in an external ratio and kneaded, and a mortar flow value by a mortar flow test specified in JIS R5201 is 130 to 230 mm. And a third step of obtaining a fiber-reinforced cement material.

  The above manufacturing method is a method of adjusting the fluidity of the fiber-reinforced cement material by mixing the flow-controlling material after kneading the fiber-reinforced cement material as a base mixed with the fiber. According to this method, the fiber and the components in the cement matrix can be sufficiently dispersed without causing an excessive load on the mixer when the fiber is fed, so that the fiber reinforced cement capable of forming a cured product having sufficient strength. The material can be manufactured easily. In addition, the flow control material is mixed after the fibers are dispersed, and the mortar flow value of the fiber reinforced cement material is adjusted to 130 to 230 mm. It is possible to obtain a fiber-reinforced cement material having excellent workability that can be constructed without causing a pre-flow when driven into a site. In addition, when the flow adjusting material is mixed so that the mortar flow value of the fiber reinforced cement material is 130 to 230 mm simultaneously with or before the mixing of the fibers, the mixer load is particularly peaked at the time of mixing. This will cause an excessive load on the mixer when dispersing the binder and feeding the fibers, resulting in insufficient mixing of the cement matrix and insufficient dispersion of the fibers in the fiber reinforced cement material, reducing the strength of the cured product formed. Will be invited.

  In the production method of the present invention, the flow control material contains a biopolymer thickener, and the blending amount of the biopolymer thickener in the third step is based on 100 parts by mass of water in the fiber-reinforced cement material. It may be 0.02 to 0.2 parts by mass. After kneading that gives sufficient strength in the second step of obtaining the fiber reinforced cement material as the base, blending the biopolymer thickener in a quantity within the above range as the flow control material It is possible to obtain a fiber-reinforced cement material having better workability while suppressing the load on the mixer. Here, since the said effect is more fully acquired, it is preferable that the said biopolymer type | system | group thickener is a dutan gum and / or welan gum. For example, when cellulosic thickeners are used for flow control materials, the viscosity increases but the yield value does not increase. The effect of suppressing the mortar flow value is not always sufficiently obtained as compared with the above-described biopolymer thickener.

In the production method of the present invention, the flow control material may include limestone fine powder, and the blending amount of the limestone fine powder in the third step may be 150 to 220 kg as an outer ratio per 1 m ^{3 of the} cement matrix. By blending limestone fine powder as a flow control material in an amount within the above range, a fiber reinforced cement material with better workability (pre-flow control effect) while suppressing the load on the mixer when the flow control material is charged. Can be obtained.

In the production method of the present invention, the flow control material may include Portland cement, and the blending amount of the Portland cement in the third step may be 100 to 250 kg as an outer ratio per 1 m ^{3 of the} cement matrix. By blending Portland cement as a flow control material in an amount within the above range, a fiber reinforced cement material having better workability (pre-flow control effect) while suppressing the load on the mixer when the flow control material is charged. Can be obtained.

  In the production method of the present invention, it is preferable that the fiber reinforced cement material which is the base produced in the second step has a 0-stroke mortar flow value of 230 to 300 mm according to a mortar flow test defined in JIS R5201. By making the zero-strike mortar flow value of the fiber reinforced cement material used as the base within the above range, it is possible to sufficiently disperse the components in the fiber and the cement matrix while further reducing the load on the mixer at the time of inputting the fiber. In addition, a fiber-reinforced cement material capable of forming a cured product having sufficient strength while having good workability (pre-flow suppressing effect) can be more easily produced.

  According to the present invention, it is possible to easily produce a fiber-reinforced cement material capable of forming a cured product having sufficient strength while having excellent workability capable of being applied without causing a pre-flow when driven into a site having a gradient. The manufacturing method of the fiber reinforced cement material which can be provided can be provided.

It is a schematic cross section which shows the method of evaluating the presence or absence of the pre-flow when a fiber reinforced cement material is driven into the site | part which has a gradient.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.

  The method for producing a fiber-reinforced cement material according to the present embodiment includes a first step of kneading at least a binder, an aggregate, water, and an admixture to obtain a cement matrix, and fibers in the cement matrix relative to the volume of the cement matrix. The second step to obtain the fiber reinforced cement material as the base by adding the outer split and kneading, and adding the flow control material to the fiber reinforced cement material as the base to the volume of the cement matrix and kneading. And a third step of obtaining a fiber-reinforced cement material having a mortar flow value of 130 to 230 mm according to a mortar flow test defined in JIS R5201. First, each component used for the fiber reinforced cement material will be described.

  As the binder, for example, a mixture containing at least cement and an admixture such as silica fume is used.

  Various cements such as normal, early strength, moderate heat, low heat, sulfate resistance, white, etc., cement mixed with blast furnace slag and normal fly ash mixed with Portland cement, eco cement, super early strength cement And quick-hardening cement. A cement obtained by mixing an arbitrary amount of a plurality of these cements can also be used. In addition, ordinary portland cement, early-strength portland cement, blast furnace slag cement, and the like suitable for generating ettringite are more preferable.

  Examples of the admixture include silica fume, expansion material, limestone fine powder, blast furnace slag, fly ash and the like. These may be used individually by 1 type and may be used in combination of 2 or more type.

Silica fume is spherical ultrafine particles by-produced when a silicon alloy such as metal silicon or ferrosilicon is produced in an electric furnace or the like, and the main component is amorphous SiO ₂ . The higher the amount of silica fume added, the higher the compressive strength of the fiber reinforced cement material cured product (hereinafter also referred to simply as “cured product”), but the ratio of the bending strength to the compressive strength is higher than that of the non-mixed case. May also decrease. Furthermore, since silica fume is spherical ultrafine particles, when used in combination with a high-performance water reducing agent or the like, the fiber-reinforced cement material tends to have appropriate fluidity.

Examples of the fly ash include coal gasification fly ash (CoAL Gasification Fly Ash, which may be abbreviated as “CGFA” hereinafter) and classified fly ash (Classified Fly Ash), among which CGFA is preferable. Here, CGFA is discharged as a by-product when generating electricity using gasified coal, and is discarded from the flue of the boiler together with the combustion gas, and the maximum particle recovered by the dust collector is 5 to 10 μm. Spherical fine particles. CGFA is characterized in that the particle diameter and particle surface properties are different from those of ordinary coal-fired fly ash and the SiO ₂ content is high. Since CGFA has a spherical particle size like silica fume, it has an effect of enhancing fluidity when used in combination with a high-performance water reducing agent, but its strength enhancement effect is small because pozzolanic activity is lower than that of silica fume.

  When silica fume and / or fly ash is blended, the blending amount is preferably 5 to 40 parts by mass, and 7 to 30 parts by mass with respect to 100 parts by mass of cement. Is more preferable. When the blending amount is 5 parts by mass or more, there is a tendency that the effect of enhancing the strength with respect to the compressive strength and bending strength of the cured product is sufficiently obtained. On the other hand, even if it is added in excess of 40 parts by mass, there is a tendency that the effect of enhancing the strength according to the addition rate cannot be expected. Therefore, it is preferably 40 parts by mass or less from the viewpoint of performance and economy.

  Moreover, when mix | blending both a silica fume and fly ash, it is preferable that those compounding ratios (silica fume: fly ash) are 95-50 mass parts: 5-50 mass parts by mass ratio. It becomes possible to improve the bending strength of hardened | cured material by mix | blending both by the said specific ratio. Here, when the blending ratio of fly ash is 5 parts by mass or more, the effect of improving the bending strength of the cured product is large, and when it is 50 parts by mass or less, the compressive strength of the cured product can be increased. The blending ratio of fly ash to silica fume tends to increase the fluidity of the fiber-reinforced cement material and increase the bending strength of the cured product as the amount of fly ash increases. However, if the peak value is exceeded, the improvement in fluidity and bending strength decreases as the fly ash amount increases. Therefore, there is a preferable range for the blending ratio of silica fume and fly ash, and more preferable ranges are 90-60 parts by mass of silica fume and 10-40 parts by mass of fly ash.

  The inflating material relieves volume changes that occur during the curing process of the fiber-reinforced cement material. Examples of the expansion material suitable for the fiber reinforced cement material include calcium sulfoaluminate-based expansion material and quicklime-based expansion material.

  When mix | blending an expandable material, it is preferable that the compounding quantity is 1-10 mass parts with respect to 100 mass parts of cement, and it is more preferable that it is 2-6 mass parts. If the blending amount is 10 parts by mass or more, there is a risk of strength reduction due to overexpansion and pop-out, and defects due to delayed expansion due to re-reaction of the unreacted expansion material. There is a tendency that an expansion effect or a shrinkage compensation effect is hardly obtained.

  As the limestone fine powder and the blast furnace slag, known materials can be used without any particular limitation. When mix | blending limestone fine powder and / or blast furnace slag, it is preferable that it is 5-30 mass parts with respect to 100 mass parts of cement, respectively, and it is more preferable that it is 10-20 mass parts. When the blending amount is 30 parts by mass or more, there is a tendency that a decrease in strength occurs due to a decrease in the amount of cement, a viscosity and a yield value increase, and it is difficult to obtain a predetermined workability (pre-flow suppressing effect). If the amount is less than or equal to part by mass, the effect of increasing viscosity and yield value tends to be difficult to obtain.

  Moreover, you may mix | blend gypsum with a binder separately from cement. As the gypsum, various forms of gypsum such as dihydrate gypsum, hemihydrate gypsum, soluble anhydrous gypsum (type III), and insoluble anhydrous gypsum (type II) are used. More preferably, anhydrous gypsum, hemihydrate gypsum, And dihydrate gypsum. In the initial stage of hydration, gypsum temporarily suppresses hydration of calcium aluminate in cement to improve fluidity, and then generates ettringite in the form of needles by a hydration reaction. The ettringite fills the voids in the cured product to promote solidification and enables high strength.

  When mix | blending gypsum, it is preferable that the compounding quantity is 0.5-8 mass parts in conversion of an anhydride with respect to 100 mass parts of cement, and it is more preferable that it is 1-5 mass parts. The effect | action which improves fluidity | liquidity and intensity | strength is large as this compounding quantity is 0.5 mass part or more. On the other hand, even if the amount exceeds 8 parts by mass, there is a tendency that the effect of increasing the strength cannot be expected any more. Therefore, the amount is preferably 8 parts by mass or less from the viewpoint of performance and economy.

  The blending amount of the binder is preferably 10 to 25% by mass, and more preferably 13 to 18% by mass, based on the water binder ratio based on the unit water content of the fiber-reinforced cement material. A fiber reinforced cement material having a binder content (water binder ratio) within the above range tends to be able to form a cured product having excellent compressive strength and excellent bending strength.

  As the aggregate, fine aggregate can be used. The fine aggregate is an aggregate through which all of the 10 mm sieve passes and 85% by mass or more passes through the 5 mm sieve. The fine aggregate is preferable because river sand and crushed sand used in ready-mix factories are most readily available, but is not particularly limited. There are no restrictions on the use of high-hardness calcined bauxite, iron ore, quartz porphyry or other fine aggregates to obtain higher strength. Moreover, in order to obtain a better fiber dispersion effect and fluidity, as the fine aggregate, for example, 5-6 silica sand is used, or the maximum aggregate dimension is set so as to pass through a 2.5 mm sieve by 85% by mass or more. It is preferable to use one having a particle size configuration such as making it smaller.

  The blending amount of the fine aggregate is preferably 5 to 45% by volume, more preferably 15 to 35% by volume based on the total volume (100% by volume) of the cement matrix. When the blending amount is 35% by volume or less, the dispersibility of the fibers is good, the toughness of the cured product is improved, and the bending strength tends to increase. Moreover, there exists a tendency for the compressive strength and elastic modulus of hardened | cured material to improve that it is 15 volume% or more.

  Further, as the aggregate, an arbitrary amount of coarse aggregate can be used in combination. Coarse aggregate is an aggregate that remains at 85% by mass or more in a 5 mm sieve. The quality of the coarse aggregate is not particularly limited as in the case of the fine aggregate, and those used in the ready-mix factory can be used.

  Examples of the admixture include water reducing agents, high performance water reducing agents, antifoaming agents, fluidizing agents, shrinkage reducing agents and the like. These may be used individually by 1 type and may be used in combination of 2 or more type. Among these, since the fiber-reinforced cement material has a lower water binder ratio than general concrete, a high-performance water reducing agent is preferable from the viewpoint of mixing performance and fluidity. As described above, the fiber-reinforced cement material has a low water binding material and has excellent freeze-thaw resistance. Therefore, it is preferable to reduce the amount of air that affects the strength characteristics as much as possible. Therefore, as the admixture, it is desirable to use a high-performance water reducing agent that does not contain an air entraining component (AE agent), or to use an antifoaming agent in combination.

  High performance water reducing agents are polyalkylallyl sulfonate high performance water reducing agents, aromatic amino sulfonate high performance water reducing agents, melamine formalin sulfonate high performance water reducing agents, and polycarboxylate salts. One of the water-reducing agents is used as a main component, and one or more of these are used. 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. Although it has the characteristic that the setting delay is small, it has a problem that the flow and slump retention are small. Commercially available products of high-performance water reducing agents include trade name “FT-500” manufactured by Denki Kagaku Kogyo Co., Ltd. and its series, trade names “Mighty 3000TH” and “Mighty 100 (powder)” manufactured by Kao Corporation. “Mighty 150” and its series, Daiichi Kogyo Seiyaku Co., Ltd. trade name “Cellflow 155”, Takemoto Yushi Co., Ltd. trade name “Paul Fine MF”, etc. "Floric SF500U" and "Floric 500R" and its series, Takemoto Yushi Co., Ltd. trade name "Tupole SSP-104" and its series, Grace Chemicals Co., Ltd. trade name "Super 1000N" and its series , Product name “SEICAMENT 1200N” and its series made by Sika Japan, and product name “MASTER GRENUM SP8HU” made by BASF Japan The series is such as is typical. Aromatic aminosulfonate-based high-performance water reducing agents include the product name “Floric VP200” manufactured by Floric Co., Ltd. and its series. Gramel Chemicals is a melamine formalin sulfonate-based high-performance water reducing agent. The product name “Darlex FT-3S” manufactured by the company, and the product names “Molmaster F-10 (powder)” and “Molmaster F-20 (powder)” manufactured by Showa Denko Construction Materials Co., Ltd. may be mentioned.

  When a high-performance water reducing agent is used, the blending amount with respect to 100 parts by mass of the binder is preferably 4 parts by mass or less, and more preferably 3 parts by mass or less, regardless of their type. There are many cases where the water reduction rate cannot be further increased even if the amount exceeds 4 parts by mass.

  When manufacturing the fiber reinforced cement material of this embodiment, it is preferable that the compounding quantity of a high performance water reducing agent shall be 1-4 mass parts with the total amount of a high performance water reducing agent with respect to 100 mass parts of binders. 1 to 3 parts by mass is more preferable. However, the high-performance water reducing agent in this case indicates a water reducing agent that is commercially available in a liquid state regardless of the solid content concentration. When using the high-performance water reducing agent marketed in a powder state, it is not included in 1 to 4 parts by mass (or 1 to 3 parts by mass). If the blending amount is 4 parts by mass or more, the cement matrix may cause material separation, which may adversely affect the predetermined fluidity and strength development. There is a possibility that a cured product having mixing performance, fluidity and high strength cannot be obtained.

  Moreover, you may mix | blend an antifoamer with a cement matrix further. Examples of the antifoaming agent include polyalkylene glycol derivatives and nonionic surfactants. Examples of commercially available antifoaming agents include BASF Japan's trade name “Master Air 404” and its series, Floric's trade name “Floric DF325” and its series, and the like.

  When using an antifoamer, it is preferable that the compounding quantity is 0.01-1 mass part with respect to 100 mass parts of binders, and it is more preferable that it is 0.05-0.5 mass part. When the blending amount is within the above range, a good bubble suppression effect can be obtained.

  The cement matrix may further contain a shrinkage reducing agent. Examples of the shrinkage reducing agent (liquid) include a composition containing a hydrocarbon compound and a glycol ether derivative, and a composition containing a low molecular weight ethylene oxide and a propylene oxide copolymer. As a commercial item of the shrinkage reducing agent mentioned above, the trade name “Shrink Guard” manufactured by Floric Co., Ltd. and the trade name “Denka SK Guard” manufactured by Denki Kagaku Kogyo, respectively, may be mentioned.

  When using a shrinkage reducing agent, the blending amount is preferably 0.5 to 4 parts by mass and more preferably 1 to 2 parts by mass with respect to 100 parts by mass of the binder. When the blending amount is within the above range, there is no problem such as insufficient strength, and a good shrinkage suppressing effect can be obtained.

  As the fiber, an organic fiber or an inorganic fiber can be used. A fiber may be used individually by 1 type and may be used in combination of 2 or more type.

  Examples of the organic fibers include polyolefin fibers such as polyester fibers, polyamide fibers, polyethylene fibers, and polypropylene fibers, and polyvinyl alcohol fibers such as polystyrene fibers, polyacrylonitrile fibers, and vinylon fibers. Examples of polyamide fibers include aliphatic polyamide fibers and aramid fibers.

  Examples of inorganic fibers include metal fibers, carbon fibers, basalt fibers (basalt fibers), and the like. Among these, metal fibers are preferable from the viewpoint of tensile strength, strength stability, and cost. The material of the metal fiber is not particularly limited, but steel and stainless steel are preferable because they are easily available.

  The fibers used in the fiber reinforced cement material of the present embodiment are preferably fibers having a length of 5 to 30 mm and a diameter of 0.1 to 1 mm. When the length is 30 mm or less, the workability of the fiber-reinforced cement material is improved, and the bending strength of the cured product tends to be increased. On the other hand, when the length is 5 mm or more, there is a tendency that a fiber reinforcing effect at the time of bending stress acting on the cured product can be sufficiently obtained and good bending strength can be obtained. The length of the fiber is more preferably 10 to 30 mm. Further, when the fiber diameter is 0.1 mm or more, the strength of the fiber itself tends to increase, and the bending strength of the cured product tends to be increased. On the other hand, when the diameter is 1 mm or less, the number of fibers per unit volume in the fiber-reinforced cement material can be sufficiently increased, and the bending strength of the cured product tends to be increased.

  The blending amount of the fiber is preferably 0.5 to 3% by volume based on the total volume of the cement matrix (100% by volume). If this amount is 0.5% by volume or more, the effect of improving the bending strength of the cured product tends to increase. On the other hand, even if the fiber exceeds 3% by volume, there is a tendency that an increase according to the blending ratio of the bending strength of the cured product cannot be expected. The blending amount of the fiber is more preferably 0.7 to 2.5% by volume.

  The flow control material is a material for moderately reducing the fluidity of the fiber reinforced cement material and imparting excellent workability to the fiber reinforced cement material that can be applied without causing a pre-flow when driven into a portion having a gradient. It is. The flow control material is superior to the fiber reinforced cement material not only by increasing the viscosity of the fiber reinforced cement material, but also by increasing the yield value of the fiber reinforced cement material or by making the fiber reinforced cement material have thixotropy. It may be one that imparts workability.

  Specific examples of the flow control material include biopolymer thickeners, fine limestone powder, and Portland cement. Examples of the biopolymer thickener include dutan gum, welan gum, xanthan gum and the like. Examples of Portland cement include various Portland cements such as normal, early strength, moderate heat, low heat, sulfate resistance, and white color. A flow control material may be used individually by 1 type, and may be used in combination of 2 or more type.

  When a biopolymer thickener is used as the flow control material, the blending amount is preferably 0.02 to 0.2 parts by mass with respect to 100 parts by mass of water in the cement matrix. It is more preferable that it is 03-0.15 mass part, and it is still more preferable that it is 0.05-0.1 mass part. When the blending amount is 0.02 parts by mass or more, it is possible to give a sufficient yield value to the fluidity of the fiber-reinforced cement material, and it is possible to perform construction without causing pre-flow when driven into a portion having a gradient. There is a tendency that the workability can be imparted to the fiber-reinforced cement material. On the other hand, when it is 0.2 parts by mass or less, it is possible to suppress the fluidity of the fiber-reinforced cement material from being excessively lowered, and there is a tendency that good workability can be ensured by vibration compaction using a vibrator or the like.

When limestone fine powder is used as the flow control material, the blending amount is preferably 150 to 220 kg, more preferably 150 to 210 kg, more preferably 175 to 200 kg per 1 m ^{3 of the} cement matrix. Is more preferable. When this blending amount is 150 kg or more, a sufficient yield value can be given to the fluidity of the fiber-reinforced cement material, and excellent workability that allows construction without causing a pre-flow when driven into a site having a gradient. There is a tendency to be able to be applied to fiber reinforced cement materials. On the other hand, when it is 220 kg or less, it is possible to suppress the fluidity of the fiber-reinforced cement material from being excessively lowered, and there is a tendency that good workability can be secured by vibration compaction using a vibrator or the like.

When Portland cement is used as the flow control material, the blending amount is preferably 100 to 250 kg, more preferably 100 to 200 kg, and more preferably 150 to 200 kg per 1 m ^{3 of the} cement matrix. Further preferred. When this blending amount is 100 kg or more, a sufficient yield value can be given to the fluidity of the fiber-reinforced cement material, and excellent workability that can be constructed without causing a pre-flow when driven into a site having a gradient. There is a tendency to be able to be applied to fiber reinforced cement materials. On the other hand, when it is 250 kg or less, it is possible to suppress the fluidity of the fiber-reinforced cement material from being excessively lowered, and there is a tendency that good workability can be secured by vibration compaction using a vibrator or the like. In addition, when using Portland cement as the flow control material in the outer part of the cement matrix, the contribution to strength development cannot be ignored, so it is regarded as a part of the binder of the fiber reinforced cement material manufactured in the third step, The water binder ratio will also change (see Table 1).

  In addition, the blending amount of the above-described flow control material is the blending amount in the third step, and the same kind of material as the flow control material is used in the cement matrix in the first step or the fiber reinforced cement material which is the base in the second step. When blended, these blending amounts are not included.

  Next, each process of the manufacturing method of the fiber reinforced cement material of this embodiment is demonstrated.

  In the first step, at least a binder, an aggregate, water, and an admixture are kneaded to obtain a cement matrix. Here, as a kneading method, it is not necessary to use a special method, and a kneading method which is usually performed can be used. The same applies to the second step and the third step. As the kneading apparatus, a test mixer (manual charging of materials), a batch type plant mixer (automatic charging), a batch type mobile mixer (automatic charging), or the like can be used.

  In the first step, the binder, the aggregate, the water, and the admixture may be kneaded at one time, but may be kneaded in a plurality of times. For example, the cement matrix may be prepared by first kneading powders such as a binder and an aggregate and then kneading the mixture with water and an admixture. At this time, the main kneading may be performed in a plurality of times by adding water and an admixture in a plurality of times. Moreover, you may add a part or all of an admixture at the time of empty kneading. The air kneading may be performed for about 30 seconds or more, for example. The main kneading can be performed for about 5 to 10 minutes (including when divided into a plurality of times). By performing kneading in a plurality of times, each material can be more uniformly dispersed, and a cured product having high strength can be stably obtained.

  In the second step, fibers are added to the cement matrix and kneaded to obtain a fiber-reinforced cement material as a base. The kneading can be performed for about 2 to 5 minutes.

  The fiber reinforced cement material that is the base obtained in the second step preferably has a 0-stroke mortar flow value in a mortar flow test specified in JIS R5201 of 230 to 300 mm, and more preferably 230 to 270 mm. By setting the mortar flow value within the above range, the fiber can be uniformly dispersed while further reducing the load on the mixer. Here, the zero-strike mortar flow value is the same as the mortar flow test stipulated in JIS R5201, but the falling diameter of the sample collapsed by its own weight when the flow cone is pulled up without performing 15 drop motions. Is a measured value. In addition, the mortar flow value of the fiber reinforced cement material obtained in the third step to be described later is a 15-stroke mortar flow value obtained by performing 15 drop motions as defined in JIS R5201.

  In the third step, the flow-regulating material is added to the base fiber-reinforced cement material and kneaded to obtain a fiber-reinforced cement material having a mortar flow value of 130 to 230 mm according to the mortar flow test specified in JIS R5201. . The kneading can be performed for about 2 to 5 minutes.

  The fiber reinforced cement material has a mortar flow value of 130 to 230 mm, preferably 130 to 200 mm, and more preferably 160 to 200 mm. If the mortar flow value is less than 130 mm, the load on the mixer at the time of kneading in the third step becomes excessive, the fluidity of the fiber-reinforced cement material becomes too low and the self-leveling property is impaired, and the driving site It becomes difficult to pour the material into the. On the other hand, when it exceeds 230 mm, it becomes difficult to suppress the forward flow of the fiber-reinforced cement material when driven into a portion having a gradient.

  The resulting fiber reinforced cement material can be cured. The curing method is not limited, and a conventional curing method (hot air curing, electric heating mat curing, etc.) is possible for cast-in-place concrete, and steam curing, autoclave curing, hot water curing, etc. are possible for concrete in a product factory.

  The first step, the second step, and the third step may be performed continuously or discontinuously. When performing it discontinuously, for example, the first step and the second step may be performed at the factory, the third step may be performed at another place such as the site, the first step is performed at the factory, the second step and the second step You may perform 3 processes in another places, such as the spot.

  The fiber-reinforced cement material obtained by the manufacturing method of the present embodiment is suitable for driving into floor slabs and members such as sloped bridges and roads for the purpose of repair and preventive maintenance (pre-reinforced). Can be used.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

(Examples 1-8 and Comparative Examples 1-5)
Each component shown in the following Table 1 was mixed by the following procedure in the blending amounts shown in the same table to produce a fiber reinforced cement material. Moreover, the forced biaxial mixer (The Kitakawa iron company make, brand name: WHQ-120) was used for mixing. First, the binder, fine aggregate, high-performance water reducing agent and antifoaming agent were kneaded for 30 seconds, then water was added and kneaded for 8 minutes to obtain a cement matrix (first step). Next, fibers were added to the cement matrix and kneaded for 2 minutes to obtain a fiber-reinforced cement material as a base (second step). The flow control material was added to the kneaded base fiber reinforced cement material, kneaded for 2 minutes, and then discharged from the mixer to obtain a fiber reinforced cement material (third step). In Comparative Example 1, the third step was not performed, and the fiber-reinforced cement material serving as the base after the second step was used as the fiber-reinforced cement material.

  The mortar flow value of the fiber reinforced cement material produced in the examples and comparative examples was measured by a mortar flow test defined in JIS R5201. Here, about the fiber reinforced cement material of the comparative example 1, the 0-stroke mortar flow value was measured. The mortar flow value other than Comparative Example 1 is a 15-stroke mortar flow value obtained by performing a falling motion 15 times as defined in JIS R5201.

The details of each component in Table 1 are as follows.
Binder: Ordinary Portland cement (manufactured by Denki Kagaku Kogyo Co., Ltd., density 3.16 g / cm ³ ), silica fume (manufactured by Elchem, density 2.44 g / cm ³ ), CGFA (Netherlands, density 2.44 g / cc) ) And gypsum (insoluble anhydrous gypsum, natural product, density 2.82 g / cm ³ ) (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: premix binder for saxem)
Fine aggregate: mountain sand from Kimitsu, Chiba Prefecture, 5 mm or less, density 2.62 g / cm ³
High-performance water reducing agent (admixture): Polycarboxylic acid-based high-performance water reducing agent (manufactured by BASF Japan, trade name “Master Glenium SP8HU”)
Antifoaming agent: polyalkylene glycol derivative (manufactured by BASF Japan, trade name: Master Air 404)
Fiber: High-strength steel fiber (manufactured by Sumitomo Electric Steel Wire Co., Ltd., trade name: steel fiber for saxem, diameter 0.2 mm, length 15 mm and 22 mm blend, density 7.85 g / cm ³ )
Dutan gum (flow control material): Dutan gum (manufactured by CP Kelco, USA, trade name: KELCO-CRETE DG)
Welan gum (flow control material): Welan gum (manufactured by CP Kelco, USA, trade name: K1A96)
Limestone fine powder (flow control material): Limestone fine powder (manufactured by Shimizu Trading Co., Ltd., trade name: Neoflow 80, specific surface area: 3060 cm ² / g)
Portland cement (flow control material): ordinary Portland cement (density 3.16 g / cm ³ , manufactured by Denki Kagaku Kogyo Co., Ltd.)

Table 1 shows water binder ratio values (unit: mass%) indicating the ratio of water to binder in the fiber-reinforced cement material. Here, when Portland cement was used as the flow control material, the amount was also included in the amount of the binder when calculating the value of the water binder ratio. In Table 1, the amount of water is the amount including the amount of water contained in the high-performance water reducing agent and antifoaming agent. In Table 1, the total volume of each component (basic formulation) excluding the fibers and the flow control material was 1 m ³ . Moreover, in each Example and Comparative Example, the compounding amount of the fine aggregate is 34.5% by volume based on the total volume (100% by volume) of the basic compounding (cement matrix), and the compounding amount of the fiber (steel fiber) Was 1.75% by volume based on the total volume (100% by volume) of the basic blend (cement matrix).

(Evaluation of workability)
The workability was evaluated based on the presence or absence of pre-flow when the fiber-reinforced cement materials obtained in Examples and Comparative Examples were driven into a site having a gradient. Specifically, as shown in FIGS. 1A to 1C, a flat formwork 1 (1000 mm × 1000 mm × 50 mm) simulating 12% which is the maximum longitudinal gradient in the road structure ordinance (Ministry of Land, Infrastructure, Transport and Tourism). Then, after filling the fiber reinforced cement material 2 and finishing the top end by grinding, evaluation and determination were performed based on the difference “Δh” from the top of the formwork on the slope mountain side to the top of the concrete. When no pre-flow occurs (Δh: 0 mm to 10 mm, the state shown in FIG. 1A or FIG. 1B), “A”, when pre-flow occurs (Δh: more than 10 mm to 50 mm or less, FIG. As shown in FIG. 1 (c), the workability was evaluated with “B” as the state where the pre-flow 3 occurred. However, “C” was used when the mold could not be filled easily by vibration compaction or tamping with a vibrator. The results are shown in Table 2. In addition, in addition to being inferior to workability, the fiber reinforced cement material of Comparative Example 5 also had problems of strong viscosity and high heat of hydration.

(Measurement of compressive strength)
In accordance with JIS A1108, the compressive strength of a cylindrical specimen of φ100 mm × 200 mm produced using the fiber reinforced cement material obtained in Examples and Comparative Examples was measured. The results are shown in Table 2.

(Measurement of bending strength)
Based on the bending strength test method defined in JSCE-G552, the bending strength of a prismatic specimen of 100 mm × 100 mm × 400 mm produced using the fiber reinforced cement material obtained in Examples and Comparative Examples was measured. The results are shown in Table 2.

  As is apparent from the results shown in Table 2, the fiber-reinforced cement materials obtained in Examples 1 to 8 can form a cured product having sufficient strength, and are previously put into a site having a gradient. It was confirmed that it has excellent workability that allows construction without causing flow.

DESCRIPTION OF SYMBOLS 1 ... Flat form frame, 2 ... Fiber reinforced cement material, 3 ... Pre-flow.

Claims (3)

A first step of kneading at least a binder, an aggregate, water and an admixture to obtain a cement matrix;
A second step of adding fibers to the cement matrix and kneading to obtain a fiber-reinforced cement material as a base;
A third step of obtaining a fiber reinforced cement material having a mortar flow value of 130 to 230 mm according to mortar flow test defined in JIS R5201, by adding a flow control material to the fiber reinforced cement material serving as the base and kneading the mixture; ,
Have
The flow control material comprises Portland cement;
The amount of the Portland cement in the third step, a 100~250kg in the cement matrix 1 m ³ per outer split method for producing a fiber-reinforced cement material. A first step of kneading at least a binder, an aggregate, water and an admixture to obtain a cement matrix;
A second step of adding fibers to the cement matrix and kneading to obtain a fiber-reinforced cement material as a base;
A third step of obtaining a fiber reinforced cement material having a mortar flow value of 130 to 230 mm according to mortar flow test defined in JIS R5201, by adding a flow control material to the fiber reinforced cement material serving as the base and kneading the mixture; ,
Have
The flow control material comprises fine limestone powder;
It said third amount of powder the limestone fines in the process is the 150~220kg in the cement matrix 1 m ³ per outer split method for producing a fiber-reinforced cement material. The method for producing a fiber-reinforced cement material according to claim 1 or 2 , wherein the base fiber-reinforced cement material has a 0-stroke mortar flow value of 230 to 300 mm according to a mortar flow test defined in JIS R5201.

Images