WO1995018077A1

WO1995018077A1 - Concrete compositions and method of manufacturing concrete

Info

Publication number: WO1995018077A1
Application number: PCT/JP1994/002250
Authority: WO
Inventors: Hajime Okamura; Tokuaki Sone; Kouichi Tanigawa; Akihiro Koyanaka; Masahiro Kato
Original assignee: Chichibu Onoda Cement Co.
Priority date: 1993-12-28
Filing date: 1994-12-27
Publication date: 1995-07-06
Also published as: AU1282295A

Abstract

In concrete containing cement, aggregate, fine mineral powder and water, a ratio (F/A) or fine mineral powder F to aggregate A of grain size distribution RFM (a ratio of fineness modulus of total aggregate to that of coarse aggregate) of not less than 0.80 is set to not less than 10 vol.%, or a ratio (F/S) of fine mineral powder F to fine aggregate S contained in the aggreate to not less than 30 vol.% and preferably to at least not less than 45 vol.%, whereby even aggregate of unsuitable grain size distribution is rendered usable as a concrete material and aggregate of suitable grain size distribution is improved in its strength.

Description

Specification

Concrete composition and concrete manufacturing method

-The present invention provides a concrete composition that is rich in fluidity and has good strength by mixing an appropriate amount of fine mineral powder and adjusting the mixing ratio of concrete, even if aggregate having a discontinuous particle size distribution is used. And a method for producing a concrete.

Background technology Concrete is manufactured by kneading various materials such as cement, aggregate, and admixture. Among these materials, aggregate is fine aggregate. Coarse aggregate )are categorized. Fine aggregates are aggregates that pass through 5% or less of particles, specifically, 85% or more through a sieve with a sieve of 5mm.Coarse aggregates are defined as particles of 5mm or more. For each of the aggregate and coarse aggregate, an appropriate particle size distribution as a concrete material according to the maximum size of the particles is determined by, for example, the Japan Society of Civil Engineers or the Architectural Institute of Japan. Here, the appropriate particle size distribution is a particle size in which fine particles and coarse particles are appropriately contained. In the case of aggregate for concrete, the index of the particle size is indicated by the sum of the weight of the particles remaining on the specified sieve, and this L, which is fine aggregate, is called the fineness module of coarse aggregate. . More specifically, 10 types of sieves with sieve sizes of 80, 40, 20, 10, 5, 2.5, 1.2, 0.6, 0.3, and 0.15 mm were used. The value obtained by dividing the sum of the weight percentage of the sample remaining in the sample by 100. The larger the particle size, the higher the coarse particle ratio. In general, the coarse grain ratio of fine aggregate is about 2.3 to 3.0, and the coarse grain rate of coarse aggregate varies depending on the maximum dimension. For example, when the maximum dimension is 2 O mm, the coarse grain rate is 6.3. ~ 7.0 Range.

Concrete is manufactured based on the mixing design of the above materials. The formulation of the concrete is to determine the composition ratio of each of the above materials so that the desired performance can be obtained in fresh and hardened concrete. Here, the fine aggregate volume (S) with respect to the total aggregate volume in concrete (A) is called the fine aggregate ratio (S / A: sand percentage). It indicates that there are many. The fine aggregate ratio takes into account the particle size distribution of fine aggregate and coarse aggregate, and the particle size distribution of the total aggregate of fine aggregate and coarse aggregate is suitable for obtaining the specified performance for concrete. It is determined appropriately so that If the fine aggregate ratio is smaller than the predetermined value, the unitary water volume required to obtain the required slump value increases because the specificity of concrete deteriorates, and the fine aggregate ratio is set lower than the predetermined value. Increasing the value increases the surface area of the total aggregate, and in this case also increases the unit water required to obtain the required slump value. That is, usually, the fine aggregate ratio is determined so that the unit water volume is minimized within a range where an appropriate power level can be obtained.

In ordinary concrete, the coarse grain ratio of the total aggregate is, for example, in the range of 4.5 to 5.5 in the case of the maximum dimension of the coarse aggregate of 20 mm, and the coarse grain ratio of only the coarse aggregate. Is in the range of 0.70 to 0.80, and this ratio does not change even if the maximum size of the coarse aggregate changes. When the aggregate is out of this range, the particle size distribution becomes discontinuous, that is, the particle size balance between the coarse aggregate and the fine aggregate is poor, and it is not possible to obtain an appropriate concrete mixture.

Conventionally, as aggregate for concrete, river sand, land sand, sea sand and the like have been generally used as fine aggregate, and river gravel and crushed stone have been used as coarse aggregate. However, with the depletion of high quality natural aggregate resources, it is difficult to obtain aggregates with good particle composition. These have a discontinuous particle size distribution, such as a lack of fine-grained parts or conversely a coarse-grained part. Or, the grain size balance of these two is not good and it is not suitable as aggregate for concrete. In addition to artificial aggregate, artificial aggregate such as blast furnace slag and artificial lightweight aggregate is also used for concrete, but the amount used for the aggregate is extremely small.

When fine and coarse aggregates are used for concrete, the ability to adjust the fine aggregate ratio by combining fine and coarse aggregates so that the particle size distribution in the aggregates is appropriate. Since the aggregate or coarse aggregate itself has a discontinuous particle size distribution, that is, the amount of distribution of each particle size is not appropriate in the particle size distribution curve, the limit is naturally limited even if the fine aggregate ratio is significantly changed. Yes, it is difficult to obtain an ideal particle size distribution for the entire aggregate. In addition, it is difficult to obtain aggregates having an appropriate grain size composition, and there is a natural limit to permanently obtaining such aggregates as concrete materials.

When aggregates having such a discontinuous particle size distribution are used for concrete, the amount of water required to obtain the required fluidity (generally expressed as a slump value) increases. Concrete with increased water content increases the shrinkage due to drying, which increases the possibility of cracking, and also decreases the strength of concrete due to the decrease in the concentration of cement paste. Furthermore, if the cement paste concentration is reduced, the separation tendency of the materials is large and the uniformity of the concrete is impaired. The ability to increase the amount of cement to maintain the cement paste concentration is not only economical, but also impairs the performance of the concrete, such as the risk of temperature cracks due to the heat of hardening of the concrete and the increase in drying shrinkage.

Conventionally, aggregates that do not have a suitable particle size distribution for concrete such as L, which has other fine particles, may be adjusted to the particle size composition by adding coarse particles. Cost. Therefore, many of the aggregates having such a discontinuous particle size composition are discarded, and valuable resources are used effectively. There is no fact. Purpose of the invention The object of the present invention is to use L ヽ aggregate suitable as a concrete material, which does not have a suitable particle size distribution as a concrete aggregate as described above, by mixing with a mineral fine powder. Is to make it possible. Another object of the present invention is to enable the use of fine mineral powder in concrete compositions by replacing a part of ordinary aggregate with fine mineral powder.

Mineral fine powder has been used as a concrete material in the past, for example, it is preliminarily mixed into cement as a mixed cement, or water, cement, fine bone is used as an admixture for concrete during the production of concrete. Some are used simultaneously with wood and coarse aggregate. The former mixed cement includes blast furnace slag fine powder, fly ash and siliceous fine powder, and the cement mixed with these is specified in the JIS standard as blast furnace cement, fly ash cement and silica cement, respectively. In addition to the above, there are a wide variety of admixtures such as silica fume, rice husk ash, and natural pozzolans.

By mixing this mineral powder, the properties of concrete can be improved. For example, in the case of concrete using fly ash, firstly, the fly ash particles are smooth and spherical, thereby improving the single-strength viability of the concrete.Thus, the unit water volume for obtaining the required consistency is reduced by fly ash. It can be reduced from unused ones, and the water-cement ratio can be reduced. Second, by performing sufficient curing, the pozzolanic reaction of fly ash is excited, and the reaction product densifies the concrete structure, increases long-term strength, and improves water tightness, resistance to chemicals, etc. I do. Third, the mixing of fly ash mitigates the heat of hydration of cement. Therefore, it is suitable for mass concrete structures where temperature cracking due to self-heating is a problem. Original Various advantages are obtained by mixing the mineral fine powder as described above _c which also has inhibitory effect on the alkali-aggregate reaction Fourth, on the other hand, many of the fine mineral fines, concrete Since they have extremely low reactivity or are inactive, mixing them in concrete in a large amount delays setting, lowers initial strength, and delays strength development in low-temperature environments. For example, fly ash cement specified in the JIS standard has the maximum value (upper limit) of the replacement ratio of fly ash in the case of fly ash. Limited to 30%.

On the other hand, there are natural mineral powders and artificial mineral powders, and especially artificial mineral powders such as fly ash and blast furnace slag fine powder are industrial by-products due to the recent rise of industry. The output is on the rise, and various studies are being conducted on how to effectively use these precious recycled resources. That is, for example, in concrete called HVFC (High Volume Flyash Concrete), a part of the cement in the concrete is replaced with fly ash, and mass use is attempted, but when the replacement ratio increases, the above-mentioned various drawbacks become apparent. Practical mass utilization technology has not yet been established.

In view of the above, the present invention has been made by mixing an appropriate amount of a fine mineral substance powder into an aggregate which has not been conventionally used as a concrete material because of an inappropriate particle size composition and a low quality. Aggregates can be used as concrete materials. Also, the present invention provides a concrete composition having excellent strength, even if the aggregate has an appropriate particle size distribution, by replacing a part of the fine aggregate with mineral fine powder within a range that does not impair the particle size distribution. Based on this finding, it is possible to use a large amount of fine mineral powder. Furthermore, the present invention uses fly ash as a mineral fine powder in combination with other mineral fine powders, so that it can be used for replacement with the above-mentioned aggregate, and also for replacement with part of cement. ^^ of fly ash : Enables use. DISCLOSURE OF THE INVENTION The present invention adjusts the mix of concrete by mixing an appropriate amount of fine mineral powder into aggregates that were not conventionally used for concrete because of the inadequate particle size composition and low quality. By doing so, it is possible to provide a concrete composition and a concrete production method which are rich in fluidity and exhibit good strength. In addition, the present invention reduces the unit aggregate amount in concrete by replacing mineral oil with fine mineral powder to replace it and reduce the amount of unit aggregate in concrete. It provides a concrete composition and a method of producing concrete with excellent strength while reducing the amount of fine aggregate.According to the present invention, practically large quantities of industrial by-products such as fly ash and blast furnace slag powder are effective. It can be used.

That is, according to the present invention, a method for producing a concrete composition and a concrete having the following constitutions is provided.

(1) A concrete composition containing cement, aggregate, mineral fine powder and water, and the particle size distribution of the aggregate is RFM (the ratio of the coarse aggregate ratio to the coarse aggregate ratio of the coarse aggregate). (Ratio) 0.80 or more, wherein the ratio (FZA) of the mineral powder (F) to the aggregate (A) is 10% by volume or more.

(2) A concrete composition containing cement, aggregate, mineral powder, and water, which is equivalent to fine aggregate (S) in the aggregate of mineral powder (F). Concrete composition characterized in that the mineral fine powder is replaced by a part of aggregate so that the ratio (FZS) is at least 30% by volume or more, preferably at least 45% by volume or more. object.

(3) The concrete composition according to the above (1) or (2), further comprising a high-performance water reducing agent.

(4) The concrete composition according to any one of the above (1) to (3), wherein the cement is ordinary Portland cement or early-strength Portland cement.

(5) The concrete composition according to any one of the above (1) to (4), wherein the mineral substance fine powder contains a natural mineral substance fine powder or an artificial mineral substance fine powder, preferably at least fly ash. object.

(6) The concrete composition according to any one of the above (1) to (5), wherein the concrete composition is a composition for an ultra-high-strength concrete or a composition for hot concrete.

(7) The coarse aggregate in the aggregate is an artificial aggregate, preferably an artificial aggregate mainly composed of fly ash, an artificial aggregate mainly composed of anti-firestone, or an artificial aggregate mainly composed of expanded shale. The concrete composition according to any one of the above (1) to (6), wherein

(8) A method for producing concrete by mixing water with cement, aggregate, or mineral fine powder, wherein the particle size distribution is RFM (ratio of coarse aggregate to coarse aggregate). Concrete concrete characterized by mixing fine mineral powder (F) with at least 0.80 aggregate so that the ratio (F / A) to the aggregate (A) becomes 10% by volume or more. Production method.

(9) A method for producing concrete by mixing water with cement, aggregate, and mineral fine powder, and the ratio of fine mineral powder (F) to fine aggregate (S) in the aggregate (FS) At least 30% by volume, preferably 45% by volume or less As described above, a method for producing concrete, comprising replacing fine mineral powder with a part of aggregate and mixing fine mineral powder.

(10) The method for producing concrete according to any one of the above (8) or (9), wherein fly ash is mixed as a fine mineral substance powder.

(11) The method for producing concrete as described in (8) to (10) I above, further comprising a high-performance water reducing agent.

(12) The method for producing concrete according to any one of the above (8) to (11), wherein ΔS Portland cement or early-strength Portland cement is used as the cement. Further, according to the present invention, the above-mentioned replacement with the aggregate is, of course, not limited to the replacement with the aggregate, but by replacing a part of the cement, thereby enabling mass use of fly ash. A concrete composition having the following constitution is provided.

(13) In the hydraulic component consisting of cement and mineral fine powder in concrete, the blending amount of mineral fine powder in the hydraulic component is 30 to 50% by weight (in percentage), and the mineral powder is Concrete composition mainly composed of fly ash, part of which is replaced by other fine mineral powder.

(14) other mineral fine powders force substituted fly ash, plain specific surface area 150000cm "/ g or more Shirikafuyu Ichimu plain specific surface area 40 00cm ² / g or more blast furnace slag powder, the Blaine specific surface area of 5000 cm ² / g or more limestone powder or classified fly ash with a maximum particle size of 20 or less, and the content of mineral powder is 20% by weight or less of the total amount of fly ash and concrete composition (13) above object.

(15) The other mineral powder to be replaced by fly ash is gypsum powder having a plain surface area of 5000c or more, and the content of the gypsum powder is fry. The concrete composition according to the above (13), which is not more than 6% by weight (inner part) of the total amount with ash. BRIEF DESCRIPTION OF THE FIGURES

-FIG. 1 is a graph showing the relationship between FZA and compressive strength in Example 1 of the present invention, and FIG. 2 is a graph showing the relationship between FZS and compressive strength in Example 1 of the present invention. FIG. 3 is a graph showing an example of the particle size distribution of the total aggregate in Example 1, FIG. 4 is a graph showing the relationship between the age and the compressive strength in the 30 ° C. water curing in Example 3 of the present invention, and FIG. Is a graph showing the compressive strength per unit weight of concrete using various artificial aggregates in Example 4 of the present invention. 0 DETAILED DESCRIPTION OF THE INVENTION First, the present invention provides cement, aggregate, and fine minerals. In the concrete containing powder and water, the particle size distribution of RFM (ratio of total aggregate coarse grain ratio to coarse aggregate coarse grain ratio) 0.80 ) To the aggregate (A) (FZA) is at least 10% by volume. Secondly, the present invention relates to a concrete containing cement, aggregate, mineral fine powder and water, wherein the ratio of fine mineral powder (F) to fine aggregate (S) in the aggregate (FZ S ) Is at least 30% by volume or more, preferably 45% by volume or more, characterized in that the mineral fine powder is replaced by a part of the aggregate. Thirdly, the present invention relates to a hydraulic component composed of cement and mineral fine powder in concrete, wherein the blending amount of the mineral fine powder in the hydraulic component is 30 to 50% by weight (inner percentage). Yes, and minerals It is characterized in that the fine powder mainly consists of fly ash, and a part of the fine powder is replaced by other fine powder of mineral substances.

Hereinafter, the present invention will be described in detail.

(1) Concrete material

As the cement used in the present invention, any of various portland cements such as ordinary, fast-strength, ultra-fast, moderate heat, sulfate-resistant, and white can be used. For this purpose, it is preferable to use ordinary Portland cement or early-strength Portland cement.

Next, aggregates include ordinary aggregates such as sand, gravel, and crushed stones used in ordinary concrete, as well as metal aggregates such as iron and stainless steel, and ceramic aggregates made from alumina and the like. However, it can be used regardless of the types of aggregates, such as artificial aggregates mainly made of fly ash, anti-firestone, expansive shale, etc. Aggregates having a discontinuous particle size distribution as described above, which are not suitable as ordinary concrete aggregates, can be suitably used as the aggregates of the present invention, and are difficult to obtain year by year. It can contribute to securing good quality aggregate resources in the situation. Further, in the concrete of the present invention produced using the artificial aggregate, a high-strength lightweight concrete having a long-term strength equal to or higher than that of ordinary concrete can be obtained.

Mineral fine powder is used in addition to conventional concrete materials, and if it has a particle composition approximately the same as cement, natural minerals such as various rock powders, diatomaceous earth, and natural pozzolans Either fine powder or fine powder of artificial mineral such as blast furnace slag or fly ash may be used. Above all, the use of fly ash, which is largely disposed of by landfill, is preferably used from the viewpoint of recycling unused resources. Here, the above mineral powder is

0 Can be used alone or in combination of two or more. In this case, the mineral fine powder preferably contains at least fly ash. Fly ash means, in general, coal ash in a broad sense, including fly ash specified by JIS and fly ash, which is usually referred to as raw powder, and cinder ash. The degree of hydration activity of the mineral powder in concrete does not matter.

(2) Mixing ratio of aggregate and mineral powder

In the present invention, the mineral fine powder is used in place of a part of the aggregate. In the following description, the ratio of the amount of fine mineral powder to the amount of aggregate is described as follows. That is, the ratio of the volume of fine mineral powder (F) to the total aggregate volume (A: the sum of the volume of fine aggregate and coarse aggregate) is FZA, and the volume of fine aggregate in the aggregate (S The ratio of the volume (F) of the mineral matter powder to) is expressed as FZS. In the present invention, first, the ratio (RFM = TFMZGFM) of the coarse aggregate ratio (TFM) of the total aggregate of the fine aggregate and the coarse aggregate to the coarse aggregate ratio (GFM) of the coarse aggregate is 0.1%. For 80 or more aggregates, the FZA should be 10% or more. Second, the present invention sets FZS to 30% or more, preferably 45% or more, regardless of the value of RFM.

By increasing FZA or FS, it is possible to use aggregates with a discontinuous particle size distribution as described above (coarse and fine aggregates have an unbalanced particle size), and greatly increase the use of good quality aggregates. The initial strength and long-term strength of the concrete can be increased. The initial strength and long-term strength increase proportionally with F / or F / S, but especially with respect to long-term strength, when a fine mineral powder containing a large amount of amorphous siliceous material is used. Due to the pozzolanic activity of the fine mineral powder, it is possible to increase the compressive strength standard concrete at 91 days of age (concrete without fine mineral powder) to about 1.5 times. If FZA or F / S is further increased, the volume of fine powder in concrete (sum of the volume of cement and mineral fine powder) increases, and even if the amount of the high-performance AE water reducing agent described later is increased, concrete increases. The fluidity of the concrete is lost, making it impossible to mix the concrete. In this case, a method of adding a large amount of a high-performance water reducing agent is also conceivable, but the excessive addition of the agent greatly impairs concrete hardening and causes a serious adverse effect, which is not practical. The maximum value of FZA depends on the amount of cement, unit water, mineral powder, or specific composition of mineral powder in him ^{3 or} concrete composition. The FZA when using is approximately 40 to 50%. Therefore, there is a maximum value of FA or a maximum value of fine powder volume from the viewpoint of concrete mixing. The same can be said for FZS. For fly ash, the maximum value is about 250-370%.

(3) Concrete properties and admixtures

In the present invention, by replacing the fine mineral powder with a part of the aggregate as described above, it is possible to easily produce ultra-high strength concrete. In other words, the use of a large amount of mineral powder is excellent in workability, even in concrete with an increased amount of cement, combined with the action of a high-performance water reducing agent described later, and it is extremely easy to use 100 OKgf / cm. Ultra-high-strength concrete exceeding ² can be achieved, and the heat of hydration of concrete can be relatively suppressed.

In addition, in the high-temperature environment, hydration is promoted in the early stage to form a dense structure, which hinders the increase in long-term strength. If applied to concrete, it can be converted into concrete with a large increase in strength under high-temperature environments due to a long-term proper pozzolanic reaction. Further, in the present invention, concrete is manufactured by using artificial aggregates mainly composed of fly ash, anti-firestone, expansive shale, etc. as coarse aggregates, and replacing a part of ordinary fine aggregates with fine mineral powder. By doing so, it is possible to obtain high-strength lightweight concrete that can be suitably used for lightweight slabs and the like. Examples of such artificial aggregates include those described in Japanese Patent Application No. 5-304046 previously filed by the present applicant, as well as commercially available artificial aggregates and Various artificial aggregates such as 400365 can be used.

In addition to the above, combined use of a high-performance water reducing agent not only eliminates disadvantages such as a decrease in initial strength and an increase in drying shrinkage due to an increase in the unit water volume, but also a large amount of fine mineral powder mixed with concrete. In addition, a large amount of fine mineral powder can be mixed, and the production of concrete having better initial and long-term strength than concrete without fine mineral powder can be achieved.

As the above-mentioned high-performance water reducing agent, those which have been conventionally used as admixtures for concrete can be used. For example, any one having an alkylaryl-based, naphthalene-based, melamine-based, or triazine-based chemical composition can be used. Desirably, a polycarboxylate-based admixture is preferably used. Of course, it is also possible to apply a high-performance A E water reducer with air entrainment performance. Commercially available admixtures of this type include Leobuild SP-8S (product name), Mighty-1 2000WHS (product name, Kao, product name), Tupole HP-8 (product name, Takemoto Yushi) , Trade name) and the like. Increasing the amount of the fine mineral powder while maintaining the unit cement amount per Ιπ ^ at a predetermined amount increases the volume occupied by the fine powder in the concrete, and impairs the fluidity of the concrete. By properly adjusting the amount of the above-mentioned high-performance water reducing agent, it is possible to provide a concrete! ^ (Slump value) can be obtained. The amount of the superplasticizer added depends on the Portland cement, aggregate, mineral

Three It is adjusted in consideration of the water reduction effect, etc., but for ~ ¾, 0.1 to 10% by weight is added to 100 parts by weight of Portland cement. If it is less than 0.1% by weight, there is virtually no water reducing effect, and even if it is added in excess of 10% by weight, not only does the effect of reducing water and improve fluidity reach a plateau, but there is also a delay in setting of concrete. The effect is large. .

In the present invention, the air entraining agent which has been conventionally used as an air entraining agent for concrete, for example, has a chemical composition of a nonionic type, an anionic type, an oxyethylene type, a higher fatty acid salt type, or a natural resinate type. Can be used. For example, A E -775S containing an alkyl carboxylic acid compound as a main component

(Made by N'M'B) (trade name), natural resin acid-based Vinsol (trade name, manufactured by Yamamune Chemical), alkylphenol-based AER (Nippon Shi-Ichiri, trade name) And the like. In the present invention, except for the case of the above-described cemented cement concrete, the air entrainment amount of the concrete is adjusted to 4.5 to 5.5% by adjusting the addition ratio of the air entraining agent. Is desirable.

In addition to the above-described components, the present invention relates to various concrete admixture materials such as quick-hardening and quick-setting materials, high-strength admixtures, hydration accelerators, setting modifiers and the like which are usually used in concrete. Various fibers, steel, etc. can be used as the strong material.There is no limitation on the method of mixing and kneading the above-mentioned components, as long as they can be uniformly mixed and kneaded. Absent. Furthermore, various curing methods can be applied to the curing after placing concrete, and any of normal temperature curing, high temperature curing, normal pressure steam curing, and high temperature and high pressure curing can be used. It is possible to make a high-strength concrete hardened body by performing the combination.

The concrete according to the present invention can be used by replacing mineral fine powder with a part of the aggregate to use a large amount of the mineral

Four By the action of the fine powder, the initial strength and the long-term strength are improved as compared with the concrete that does not use mineral fine powder under the same water-cement ratio (the ratio of water to cement in the concrete).

(4) Combined use of fly ash and other mineral fines

By using fly ash in combination with other mineral fine powders as the mineral fine powder used in the above concrete of the present invention, it is possible to obtain concrete with even higher strength by replacing and using a part of the above-mentioned aggregate. In addition to the use of aggregate, it is possible to obtain concrete with excellent strength by replacing it with part of cement instead of using it with aggregate.

In the following, description will be made mainly on the example of replacing and using a part of cement. Fly ash itself has no hydraulic properties, but when used as a mixture with cement, pozzolan, which gradually reacts with the hydroxylating power generated during the hydration process to form stable compounds such as calcium gayate It has been used as a cement admixture and a concrete admixture to show a reaction. A mixture of fly ash in an appropriate amount can (1) have good workability because fly ash is spherical particles, and can reduce the unit water content of concrete. (2) improve long-term strength, water tightness and durability. It has the advantages of improved chemical properties, (3) reduced calorific value of concrete, increased resistance to temperature cracks caused by heat of curing, and (4) greater effect of suppressing reaction to alkaline aggregate. ing.

On the other hand, because fly ash has low reactivity, mixing it in cement in a large amount causes (1) delay in setting, (2) lower initial strength, and (3) strength in a low temperature environment. There are problems such as delayed onset, and in particular, the decrease in initial strength is a major obstacle to mass use of fly ash. For this reason, in the JIS standard, the mixing amount of fly ash in fly ash cement is limited to a maximum of 30% by weight (inner percentage).

Five However, by replacing a part of fly ash with other fine powder of minerals, even if a large amount of fly ash, which greatly exceeds the conventional limit amount, is mixed with cement, the decrease in initial strength is small. Is obtained. Therefore, according to the present invention, in recent years, a large amount of fly ash discharged due to an increase in power generation can be effectively used.

Specifically, it is as follows.

(1) In the hydraulic component composed of cement and mineral fine powder in concrete, the compounding amount of the mineral fine powder in the hydraulic component is 30 to 50% by weight (inner percentage), and Concrete composition in which the fine powder is mainly fly ash, part of which is replaced by other mineral fine powder.

(2) other mineral fine powders force substituted fly ash, plane ratio surface area ^{1 5 0 0 0 0 cm 2} / g or more silica fume, Blaine specific surface area 4 0 0 0 cm ² / g or more blast furnace slag Powder, limestone powder with a specific surface area of 500 cm ² / g or more, or classified fly ash with a maximum particle size of 2 O ^ m or less, and the content of mineral fine powder is the total amount with fly ash 20% by weight or less of the concrete composition, or the other fine mineral powder to be replaced by fly ash is a gypsum powder having a specific surface area of 50,000 cm ² / g or more, A concrete composition wherein the content of the gypsum powder is not more than 6% by weight (inner portion) of the total amount with fly ash.

In the hydraulic component consisting of cement and mineral fine powder, the lower limit of the mixing amount (internal ratio) of the mineral powder in the hydraulic component is 30% by weight, and the upper limit of the mixing amount is 50% by weight. . If the mixing amount is less than 30% by weight, there is not much difference from the conventional fly ash cement. If the mixing amount exceeds 50% by weight, even if a part thereof is replaced with a fine mineral substance powder, the initial strength is greatly reduced, which is not preferable.

By using a predetermined amount of other mineral substance powder together with fly ash, it is possible to suppress the decrease in the initial strength of concrete, etc.

6 The amount of fly ash mixed in the product can be increased.

Examples of other mineral powders include silica fume, blast furnace slag powder, limestone powder, classified fly ash obtained by adjusting the particle size of existing fly ash, and gypsum powder. These mineral powders may be used as a mixture of two or more kinds.

When used together with fly ash, these mineral fine powders have the effect of promoting the hydration of the cement itself, and form various hydrates between the cement and these fine powders. It is presumed that the effect of suppressing the decrease in the initial strength due to the high mixing amount is given. For example, in the case of classified fly ash, cement enters the cement or concrete stiffener to promote densification of the structure, and enters the floc structure of the cement particles to form a space in which hydrates can be precipitated. Acceleration of sum curing. In addition, in the case of silica fume, blast furnace slag powder, limestone powder, and gypsum powder, various hydrate forces are formed between the fine powder and cement in addition to these effects. Suppress the decrease in initial strength due to the mixing amount.

Mixing amount of other mineral fine powder to be replaced by fly ash (Breakdown substitution ratio: ratio of mineral fine powder replaced to total amount of fly ash and other mineral fine powder to be replaced) Depends on the type and fineness of the fine powder. Specifically, plain specific surface area mineral fine powders 1 5 0 0 0 0 cm ² / g or more silica fume, Blaine specific surface area 4 0 0 0 cm ² / g or more blast furnace slag powder, the Blaine specific surface area 5 0 For limestone powder of 0 cm ² or more, or classified fly ash with a maximum particle size of 20 β or less, it is appropriate that the content is 20% by weight or less (inner percentage) or less. For gypsum powder with a specific surface area of 50,000 cm ^ / g or more, 6% by weight (inner percentage) or less is appropriate.

The particle size of silica fume generally has an average particle size of around 0.1 and a specific surface area.

7 It is an ultrafine powder having a size of 1500 to 20000 cm ² / g, and a commercially available product can be used. Further, blast furnace slag powder having a specific surface area of 400 to 800 O cm ^ / g is usually used as a concrete admixture depending on the purpose of use, and thus can be used. On the other hand, fly ash has a fineness of JIS standard of more than 240 Ocm ^ / g of Blaine specific surface area, and it can be used as a main component of mineral fine powder without classifying it. Other mineral powders that have been classified to a maximum particle size of 20 m or less should be used. Use limestone powder and gypsum powder with the above fineness.

If the fineness of the mineral substance powder is out of the above range, the effect as the fine powder is low, and the effect of suppressing the reduction of the initial strength becomes insufficient, which is not preferable. On the other hand, if the ratio of the fine powder of mineral matter to the fly ash is higher than the above range, the amount of the fly ash used is relatively reduced, which is not preferred because the object of the present invention is not met and the cost is increased.

In the above hydraulic composition, despite the large amount of fly ash mixed, the mineral fine powder suppresses the decrease in the initial strength. If it is less than 10% by weight, an initial strength suitable for practical use can be obtained.

The method of using the hydraulic composition of the present invention is the same as that of ordinary cement, and the unit hydraulic composition amount, the unit water amount, the water-Z hydraulic composition ratio, the amount of aggregate, etc. are the same as those when using ordinary cement. Is determined.

As mentioned above, fly ash has mainly been described as being replaced with cement. However, the unit hydraulic composition amount is increased, that is, as described above, a part of the aggregate is replaced according to the increased fly ash amount, and the strength is further increased. It is possible to obtain an improved concrete.

8 BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, examples of the present invention will be described. This embodiment is an exemplification, and does not limit the scope of the invention.

Example 1-Concrete was prepared according to the materials shown below and the concrete mix shown in Table 1, and its compressive strength was measured. Coarse aggregate used was the maximum dimension is 2 0 mm, Sotsuburitsu GFM 6. a 6 6, _c each sample fineness modulus of fine aggregate 2. a 7 5 particle size distribution of the total aggregates not The mixing ratio of fine aggregate and coarse aggregate was changed so as to be continuous, and RFM (ratio of coarse aggregate to coarse aggregate) was changed.

Test Nos. 1 and 2 are reference concretes showing comparative examples using ordinary Portland cement. Test Nos. 3 to 6 were tests using fly ash A as a mineral powder, tests Nos. 7 to 20 were tests using fly ash B, and tests Nos. If 5%, test No.

12 to 18 indicate the case where the water-cement ratio of the concrete is 60%, and Test Nos. 9 and 20 indicate the case where the unit cement amount is reduced, respectively. Furthermore, Test Nos. 21 to 23 are examples using early-strength Portland cement (No. 21 is a reference concrete showing a comparative example), and Test No. 24 is a concrete test result without using a high-performance admixture. . In Test Nos. 24 to 30, blast furnace slag C (Test Nos. 25 and 26), stone powder D (Test Nos. 27 and 28), and silica powder E (Test No. 29, Here is an example using each of them.

The test results are also shown in Table 1.Figures 1 and 2 show the relationship between FZA and FZS using fly ash B as a mineral powder and the compressive strength, respectively. Examples of particle size distributions of aggregates used in Test Nos. 1 and 7 (Comparative Example) and Test Nos. 9 and 11 (Example) are shown.

9 (I) Materials used

Cement

N: Onoda Cement Ordinary Portland Cement

H: Portland cement made by Onoda Cement Co., Ltd.

Mineral powder-A: Fly ash, specific gravity 2.23, brane specific surface area 3350cm ² / g

B: Fly ash, specific gravity 2.23, Blaine specific surface area 3750cm ² / g C: Blast furnace slag (from NKK Fukuyama), specific gravity 2.89,

Brain specific surface area 3500cn ^ / g

D _: Stone powder (lime from Tsukumi), specific gravity 2.70

Brain specific surface area 4050cm ² I

E: Silica powder (silica from Oita Shiura), specific gravity 2.64

Brain specific surface area 3550cm ² / g

Fine aggregate: land sand (from Shizuoka) Specific gravity 2.59, FM 2.75

Coarse aggregate: crushed stone (from Ibaraki) Maximum dimensions 20 recitations, specific gravity 2.64, GFM 6.66 High-performance A E water reducer: NEM'B-Leobuild SP-8S

Air entraining agent: A'E-775S manufactured by Nu'em'B

(Π) Test method

The concrete slump was adjusted to 12 to 19 cm and the air volume to 4.5 to 5.5, 5%, and the mixing time was 150 seconds. The compressive strength was carried out in accordance with JIS-A-11 08, and the curing conditions were curing in water at 20 ° C.

(M) Test results

As is evident from Table 1, compared with the comparative samples in Test Nos. 1, 2, and 21, which do not use fine mineral powder, and in Test Nos. 7 and 12, in which FZA or FZS is below the scope of the present invention. However, it can be clearly seen that the present invention has excellent workability and extremely high strength. Tests Nos. 6 and 18 are examples where kneading was not possible. It can be seen that it is desirable to set an upper limit on the amount of mineral matter powder used depending on the mixing conditions of concrete. Example 2

Using fly ash F1 shown below as mineral fine powder, according to the concrete composition shown in Table 2, prepare ultra-high-strength concrete with slump target 2 l cni ± 2.5, as in Example 1. The compressive strength was measured. The results are shown in Table 2. Each of the samples of the present invention was an ultra-hard concrete having excellent strength, particularly excellent long-term strength.

Materials used

Cement

N: Onoda Cemented clay ordinary Portland cement

Mineral fine powder

Fly ash, specific gravity 2.20, Blaine specific surface area 3220cm ² / g Fine aggregate Land sand (from Shizuoka) Specific gravity 2.59, FM 2.75

Coarse aggregate crushed stone (from Ibaraki) Maximum dimension 20 mm, specific gravity 2.64, GFM 6.66 High-performance water reducing agent: Mighty 2000WHZ manufactured by Kao Corporation Example 3

Concrete was prepared by using fly ash F2 shown below as the fine powder of mineral matter and by mixing the concrete shown in Table 3, and a compressive strength test was conducted by changing the mixing temperature and curing temperature of the concrete. The results are shown in Table 3. As is evident from Table 3, the present invention exhibits excellent strength characteristics at both low and high temperatures. This indicates that it is extremely excellent as concrete to be poured in the summer, that is, in the heat. Materials used

Cement

N: Onoda Cement Ordinary Portland Cement

Mineral fine powder

F 2: Fly ash, specific gravity 2.23, Blaine specific surface area 3220cm ² / g Fine aggregate: land sand (from Shizuoka) Specific gravity 2.59, FM 2.75

Coarse aggregate: crushed stone (from Ibaraki) Maximum dimension 20 im Specific gravity 2.64, G F M 6.66 High performance water reducing agent: Leobuild SP-8S manufactured by N'em'B

Air entraining agent: N-M'B A-775S Example 4

The same fly ash F1 as in Example 2 was used as the fine mineral powder, and the three types of artificial aggregates shown below were used as coarse aggregates in the aggregates. Lightweight concrete was prepared and subjected to a compressive strength test. The results are shown in Table 4. According to the present invention, all exhibit excellent strength properties, but exhibit particularly remarkable strength in concrete using aggregates mainly made of fly ash, and also aggregates made of ultra low specific gravity anti-firestone. On the other hand, the long-term strength shows more strength characteristics than ordinary concrete. As shown in Fig. 5, it can be seen that the compressive strength per unit weight of concrete is extremely high.

Materials used

Cement

Ν: Onoda Cement Ordinary Portland Cement

Mineral fine powder

F 1: Fly ash, specific gravity 2.20, Blaine specific surface area 3220cm ² / g Fine aggregate: land sand (from Shizuoka) Specific gravity 2.59, FM 2.75 Coarse aggregate

Crushed stone: Crushed stone for comparison (from Ibaraki) Maximum dimension 20mm, specific gravity 2.64, GFM6.66 FA: Fly ash as the main raw material, a small amount of bentonite added thereto, granulated and fired after granulation to prepare artificial aggregate (specific gravity) 1.87, GF M6.84) ML: Commercially available expanded shale artificial raw material

Product name Mesalite 1505 (specific gravity 1.55, GFM6.40)

NL: Artificial aggregate made mainly of anti-firestone powder, with a small amount of silicon carbide powder added as bentonite and foaming agent, granulated and fired (specific gravity 0.80, GFM 6.40)

High-performance water reducing agent: Leobuild SP-8S manufactured by Nuem B

Air entraining agent: AE-775S, manufactured by ヱ NU · ι-M-Bee, Inc. Example 5

Concrete was prepared using the hydraulic composition of the blending amount shown in Table 5, cured at room temperature, and the strength of fly ash alone (no other mineral powder was used) as mineral powder was set to 100 The strength ratio (compression strength ratio) on days 3, 7, and 28 was determined. The results are summarized in Table 6. In the table, C: Cement, FA: Fly ash, M: Mineral fine powder other than fly ash, Cement weight ratio: C / (C + M + FA), Mineral fine powder weight ratio: (FA + M) / (C + M + FA), the percentage replacement ratio of mineral powder other than fly ash: M / (FA + M). Samples A11 to A56 had an FA content of 30%, samples B11 to B56 had an FA content of 40%, samples C11 to C56 had an FA content of 50%, and samples D11 to D56 had an FA content of 60%. The numerical values in Table 5 are the constituent weights (kg) of C, FA, and M in 300 kg of the hydraulic composition.

Materials used

Cement: Onoda cement Fly ash: specific gravity 2.23, Blaine specific surface area 2750cm ² / g

Fine aggregate: land sand (from Shizuoka) Specific gravity 2.59, F M 2.75

Coarse aggregate: crushed stone (from Ibaraki) Maximum size 20 Marauder, specific gravity 2.64, F M6.66 A E Water reducer: N.M.

A E preparation: N 3 '3 A

The unit amount of concrete was 30 O Kg / m ³ , water 1 65 g / m ^u , coarse aggregate 104 4 Kg / m ³ , water / hydraulic composition The fine aggregate is 732 Kg / m ^J , 7 when the fine mineral powder in the hydraulic composition is 30%, 40%, 50%, and 60%, respectively. 22 Kg / m ³ , 71 Kg / m ³ and 70 2 Kg / m ³ .

As shown in Table 6, when the content of fine mineral powder in the hydraulic composition is 30 to 50% by weight, the fly ash in which part of fly ash is replaced by other fine powder of mineral is used alone. Less decrease in initial strength compared to. The specific substitution rate for fly ash varies depending on the type of mineral fine powder. Gypsum powder is less than 6% by weight and other fine powder is less than 20% by weight. For gypsum powder, when the replacement ratio exceeds 6% by weight, the initial strength on days 3 and 7 becomes lower than when the replacement ratio is 0% (without using mineral fine powder), and no improvement effect on the initial strength is observed. . Other mineral fine powders have the ability to increase initial strength in proportion to the mixing amount, even if the internal substitution rate is more than 20% by weight. It is not preferable because the content is reduced, the cost is increased, and the kneading work becomes difficult in the case of silica film because it is an ultrafine powder.

The effect can be recognized even with a substitution rate of about 1 to 2% for all mineral fine powders. On the other hand, in the case where the content of the mineral fine powder in the hydraulic composition is 60% by weight, the initial strength is greatly reduced even when the other mineral fine powder is replaced, and reaches a strength suitable for practical use. do not do.

Note) N: {5} cement, H: early strength cement

AB: Fly ash, C: Furnace slag, D: Stone powder, E: Silica powder W / C; Water / cement weight Sit F / A; Mineral ffi¾r powder / Total aggregate profession F / S: Mineral powder Fine aggregate Hoof, TF; Coarse-grain ratio of total aggregate RFM; Coarse-grain ratio of coarse aggregate to coarse aggregate

W _: Water, C: Cement, S: Fine aggregate, G: Coarse aggregate, F: Material Table 2

Note) F1; Indicates fly ash, and other symbols are the same as 丧 1.

Table 3

S: Indicates concrete mixing and underwater regenerated fi¾, and other symbols are the same as in Table 1. Table 4

) Crushing: crushed stone, FA; ア made with fly ash ΛΙ aggregate

ML: Artificial aggregate using expansive rock NL: Artificial aggregate using anti-firestone ^ Other symbols are the same as Table 1.

Table 5 Mineral powder content after fly ash

Outer mineral powder 30% by weight 40% by weight

Type Replacement% Charge C · Η FA Sample C HFA Not used 0 Α00 210 0.0 90.0 BOO 180 0.0 120.0 Gypsum 2 All 210 1.8 88.2 Bll 180 2.4 117.6 Powder 4 A12 210 3.6 86.4 B12 180 4.8 115.2

6 A13 210 5.4 84.6 B13 180 7.2 112.8

10 A14 210 9.0 81.0 B14 180 12.0 108.0

14 A15 210 12.6 77.4 B15 180 16.8 103.2

20 A16 210 18.0 72.0 B16 180 24.0 96.0 Silica 2 A21 210 1.8 88.2 B21 180 2.4 117.6 Fuse 4 A22 210 3.6 86.4 Β22 180 4.8 115.2 6 6 A23 210 5.4 84.6 Β23 180 7.2 112.8

10 A24 210 9.0 81.0 Β24 180 12.0 108.0

14 A25 210 12.6 77.4 Β25 180 16.8 103.2

20 A26 210 18.0 72.0 Β26 180 24.0 96.0 Blast furnace 2 A31 210 1.8 88.2 B31 180 2.4 117.6 Lag powder 4 A32 210 3.6 86.4 Β32 180 4.8 115.2 End 6 A33 210 5.4 84.6 Β33 180 7.2 112.8

10 A34 210 9.0 81.0 Β34 180 12.0 108.0

14 A35 210 12.6 77.4 Β35 180 16.8 103.2

20 A36 210 18.0 72.0 Β36 180 24.0 96.0 Limestone 2 A41 210 1.8 88.2 B41 180 2.4 117.6 Powder 4 A42 210 3.6 86.4 Β42 180 4.8 115.2

6 A43. 210 5.4 84.6 Β43 180 7.2 112.8

10 A44 210 9.0 81.0 Β44 180 12.0 108.0

14 A45 210 12.6 77.4 Β45 180 16.8 103.2

20 A46 210 18.0 72.0 Β46 180 24.0 96.0 Classification 2 A51 210 1.8 88.2 B51 180 2.4 117.6 Lia 4 A52 210 3.6 86.4 Β52 180 4.8 115.2 ash 6 A53 210 5.4 84.6 Β53 180 7.2 112.8

10 A54 210 9.0 81.0 Β54 180 12.0 108.0

14 A55 210 12.6 77.4 Β55 180 16.8 103.2

20 A56 210 18.0 72.0 Β56 180 24.0 96.0 Continuation of Table 5 Content of fine powder after fly ash

Mineral powder outside 50% by weight 60

Type Substitution ¾ C H FA sample C M FA Not used 0 coo 1-50 0.0 150.0 D00 120 0.0 180.0 Gypsum 2 Cll 150 3.0 147.0 Dll 120 3.6 176.4 Powder 4 C12 150 6.0 144.0 D12 120 7.2 172.8

6 C13 150 9.0 141.0 D13 120 10.8 169.2

10 C14 150 15.0 135.0 D14 120 18.0 162.0

14 C15 150 21.0 129.0 D15 120 25.2 154.8

20 C16 150 30.0 120.0 D16 120 36.0 144.0 Silica 2 C21 150 3.0 147.0 D21 120 3.6 176.4 Fuse 4 C22 150 6.0 144.0 D22 120 7.2 172.8 6 C23 150 9.0 141.0 D23 120 10.8 169.2

10 C24 150 15.0 135.0 D24 120 18.0 162.0

14 C25 150 21.0 129.0 D25 120 25.2 154.8

20 C26 150 30.0 120.0 D26 120 36.0 144.0 Blast furnace 2 C31 150 3.0 147.0 D31 120 3.6 176.4 Lag powder 4 C32 150 6.0 144.0 D32 120 7.2 172.8 End 6 C33 150 9.0 141.0 D33 120 10.8 169.2

10 C34 150 15.0 135.0 D34 120 18.0 162.0

14 C35 150 21.0 129.0 D35 120 25.2 154.8

20 C36 150 30.0 120.0 D36 120 36.0 144.0 Limestone 2 C41 150 3.0 147.0 D41 120 3.6 176.4 Powder 4 C42 150 6.0 144.0 D42 120 7.2 172.8

6 C43 150 9.0 141.0 D43 120 10.8 169.2

10 C44 150 15.0 135.0 D44 120 18.0 162.0

14 C45 150 21.0 129.0 D45 120 25.2 154.8

20 C46 150 30.0 120.0 D46 120 36.0 144.0 Classification 2 C51 150 3.0 147.0 D51 120 3.6 176.4 Lia 4 C52 150 6.0 144.0 D52 120 7.2 172.8

, Reso 6 C53 150 9.0 141.0 D53 120 10.8 169.2

10 C54 150 15.0 135.0 D54 120 18.0 162.0

14 C55 150 21.0 129.0 D55 120 25.2 154.8

20 C56 150 30.0 120.0 D56 120 36.0 144.0 Table 6

(Note) Compressed ¾S ratio is the value when mineral powder other than fly ash is not used.

Relative value assuming 1 0 0 Table 6 continued

(Note) Compressed ¾s ratio is a relative value when ¾e is set to 100 when L is used without using mineral fine powder other than fly ash.

* Indicates "not cured". '

Three

Claims

The scope of the claims

(1) Concrete composition containing cement, aggregate, mineral powder and water, and the particle size distribution of the aggregate is RFM (ratio of coarse aggregate to coarse aggregate) A concrete composition characterized by being at least 0.80, and having a ratio (FZA) of mineral powder (F) to aggregate (A) of at least 10% by volume.

(2) A concrete composition containing cement, aggregate, mineral fine powder and water, and the ratio of the fine mineral powder (F) to the fine aggregate (S) in the aggregate (S) Concrete composition characterized by replacing mineral fine powder with a part of aggregate so that FZS) is at least 30% by volume or more, preferably at least 45% by volume or more.

(3) The concrete composition according to any one of claims 1 and 2, further comprising a high-performance water reducing agent.

(4) The concrete composition according to any one of claims 1 to 3, wherein the cement is ordinary Portland cement or early strength Portland cement.

(5) The concrete composition according to any one of claims 1 to 4, wherein the mineral substance fine powder contains natural mineral substance fine powder or 鉱 mineral substance fine powder, preferably at least fly ash. object.

(6) The concrete composition according to any one of claims 1 to 5, wherein the concrete composition is an ultra-high strength concrete composition or a hot concrete composition.

(7) The coarse aggregate in the aggregate is an artificial aggregate, preferably an artificial aggregate mainly composed of fly ash, an artificial aggregate mainly composed of anti-firestone or an artificial bone mainly composed of expanded shale. Claims 1 to 6 characterized by being a material A concrete composition according to any of the preceding claims.

(8) A method for producing concrete by mixing water with cement, aggregate, or fine mineral powder, and the particle size distribution is RFM (ratio of coarse aggregate to coarse aggregate). A method for producing concrete, comprising mixing fine mineral powder (F) with at least 80 aggregate in such a manner that the ratio (FZA) to aggregate (A) is at least 10% by volume.

(9) A method of producing concrete by mixing water with cement, aggregate, and mineral fine powder. The ratio of fine mineral powder (F) to fine aggregate (S) in the aggregate (F / The concrete is characterized in that the mineral fine powder is replaced with a part of the aggregate and mixed with the mineral fine powder so that S) is at least 30% by volume or more, preferably 45% by volume or more. Production method.

(10) The method for producing concrete according to claim 8 or 9, wherein fly ash is mixed as the fine powder of mineral matter.

(11) The method for producing concrete according to claim 8, wherein a high-performance water reducing agent is further added.

(12) The method for producing concrete according to any one of claims 8 to 11, wherein ^ 1 Portland cement or early-strength Portland cement is used as the cement.

(14) other mineral fine powders force substituted fly ash Blaine specific surface area 150000cm ² / g or more silica fume, the above plain specific surface area 40 00cm ² / g blast furnace slag powder, plain specific surface area 5000 cm "/ g or more Limestone powder or classified fly ash with a maximum particle size of 20 or less, 14. The concrete composition according to claim 13, wherein the content of the mineral fine powder is 20% by weight or less of the total amount with the fly ash.

(15) The other mineral fine powder to be replaced with fly ash is a gypsum powder having a Blaine ratio table area of 500 cm ² / g or more, and the content of the gypsum powder is the total amount of the gypsum and the fly ash. The concrete composition according to claim 13, which is not more than 6% by weight (inner percentage) 0