JP4861931B2 - Ultra high strength high fluidity concrete and ultra high strength high fluidity fresh concrete - Google Patents

Description

The present invention relates to ultra-high-strength high-fluidity concrete and ultra-high-strength high-fluidity fresh concrete. More specifically, the present invention has high strength development and high fluidity compared to conventional concrete, and in particular, has a water binder ratio of 15. The present invention relates to a high-strength high-fluidity concrete and an ultra-high-strength high-fluidity fresh concrete capable of obtaining a compressive strength of 200 N / mm ² or more even when 0% or less.

In general, the compressive strength of a concrete structure depends greatly on the quality of the coarse aggregate and fine aggregate contained therein. Usually, natural river gravel, mountain gravel (land gravel), crushed stone, etc. are used as coarse aggregates, and natural river sand, mountain sand (land sand), sea sand, crushed sand, etc. are used as fine aggregates. However, there is an unavoidable problem that the quality varies greatly depending on the production area, host rock type, and lot. In particular, in extremely high strength areas where the compressive strength exceeds 200 N / mm ² , if poor quality aggregates are mixed into concrete such as concrete specimens or concrete structures, the quality is increased when external stress is applied. Stress concentrates on parts containing poor aggregates and breaks at a lower strength than is expected (expected), meaning that poor quality aggregates become structural defects. Become.

Similarly, the fluidity of concrete and fresh concrete is greatly influenced by physical properties such as aggregate density, particle shape, maximum particle size, particle size distribution, and water absorption. In particular, when natural aggregates are used, the fluidity of concrete and fresh concrete depends greatly on the quality of the aggregate used.
Therefore, blast furnace slag aggregate, ferrochrome slag aggregate, ferronickel slag aggregate, copper slag aggregate, electric furnace oxidation slag bone as aggregates with high crushing strength (hardness) and wear resistance and stable quality Various techniques using slag aggregate such as wood have been proposed.

  For example, ultra-fine powder such as hydraulic substance (cement), silica dust (silica fume) and siliceous dust, high-performance water reducing agent, ferrochrome slag pulverized product pulverized to a particle size of about 5 mm or less, and ultra-high Strong aggregate composition (Patent Document 1), fine aggregate composed of slag spheres or slag subspheres, part or all of fine aggregates used as a constituent material of concrete or mortar by kneading with cement and water ( Patent Document 2), a ferroalloy slag made of ferroalloy slag such as ferrochrome slag, ferronickel slag, silicon manganese slag, ferromanganese slag, etc., which is crushed into a diameter of 5 mm or less and mixed with sand to form a concrete aggregate. Method of use (Patent Document 3), Ferronickel slag produced by air-crushing method with a particle size of 2.5 mm And a fine aggregate for high fluidity concrete (patent document 4) prepared by mixing the mixture ratio in the fine aggregate to 30% or more, a fine mineral powder consisting of a fine natural powder or a fine artificial mineral powder, And a mortar and concrete composition excellent in fluidity and strength expression using a fine aggregate lacking fine particles such as ferronickel slag fine aggregate having a particle size of 0.3 to 5 mm (Patent Document 5), cement, A high-strength mortar composition (Patent Document 6) composed of granular cement clinker, water reducing agent, aggregate having a specific gravity of 2.7 or more, ultrafine powder, and the like has been proposed.

According to these technologies, mortar or concrete excellent in strength and fluidity can be obtained, and ferroalloy slag such as ferrochrome slag, ferronickel slag, silicon manganese slag, ferromanganese slag, etc., which has been limited in use until now, can be obtained. There is an effect that it can be effectively used as a fine aggregate.
Japanese Patent No. 2653402 Japanese Patent Laid-Open No. 5-32439 Japanese Patent Laid-Open No. 5-262542 JP-A-8-325047 Japanese Patent Laid-Open No. 9-52744 JP 2005-119885 A

By the way, in the conventional well-known technique, since all the fine aggregates have a maximum particle size of 2.5 to 5 mm or have been subjected to a special spheroidizing treatment, these fine aggregates are used. To obtain a compressive strength exceeding 200 N / mm ² , the concrete obtained by curing and hardening the cement composition in a super high strength region with a water binder ratio of 15.0% or less reaches its peak. There was a problem that it was insufficient.

The present invention has been made to solve the above-mentioned problems, and has high strength development and high fluidity compared to conventional concrete and fresh concrete, and further has a water binder ratio of 15.0%. An object is to provide an ultra-high-strength high-fluidity concrete and an ultra-high-strength high-fluidity fresh concrete capable of obtaining a compressive strength exceeding 200 N / mm ² even in the following ultra-high-strength region.

As a result of intensive studies to solve the above problems, the present inventors have controlled compressive strength compared to conventional products by controlling the varieties, particle size, density, and water absorption rate of coarse and fine aggregates. and it is possible to obtain a high fluidity concrete, further cement 10 wt% or more and 30% by weight a specific surface area by the BET method of 1 m 2 ^{/ g} or more and 20 m 2 / ^g or less siliceous fine powder A coarse binder with an average particle size of 10 mm or more and 20 mm or less, an absolute dry density of 2.60 g / cm ³ or more and a water absorption of 1.20% or less, and a maximum particle size of If it contains artificial high density fine aggregate with 1.2 mm or less, absolute dry density of 2.90 g / cm ³ or more and water absorption of 0.90% or less, and a chemical admixture, the compressive strength of the concrete Extremely high strength of 200 N / mm ² or more The present inventors have found that it is possible to impart degree of expressibility and good fluidity, and have completed the present invention.

In other words, ultra high strength and high fluidity concrete of the present invention, substituted or 10 wt% of the cement and of 30% by weight or less specific surface area by BET method at ^{1 m} 2 / g or more and ^{20 m} 2 / g or less siliceous fine powder A hydraulic binder, a coarse aggregate having an average particle size of 10 mm or more and 20 mm or less, an absolute dry density of 2.60 g / cm ³ or more and a water absorption of 1.20% or less, and a maximum particle size of 1.2 mm In the following, it is characterized by containing an artificial high-density fine aggregate having an absolute dry density of 2.90 g / cm ³ or more and a water absorption of 0.90% or less, and a chemical admixture.

The artificial high-density fine aggregate is preferably one or more selected from the group of ferronickel slag fine aggregate, copper slag fine aggregate, and electric furnace oxidized slag fine aggregate.
The coarse aggregate is composed of natural coarse aggregate and / or artificial coarse aggregate, and the natural coarse aggregate is one or two selected from the group of hard sandstone crushed stone, andesite crushed stone, basalt crushed stone, quartz schist crushed stone Preferably, the artificial coarse aggregate is made of artificial corundum and / or sintered bauxite.
The water binder ratio is 15.0% or less, and the unit volume of the artificial high-density fine aggregate is 100 L / m ³ or more and 200 L / m ³ or less, and the curing is performed at 20 ° C. The compressive strength is preferably 200 N / mm ² or more when performed for 91 days at 50 ° C. or more and 80 ° C. or less for 7 days.

High-strength and high fluidity of fresh concrete of the present invention, more than 10% by weight of cement and 30% by weight or less specific surface area by the BET method was replaced by 1 m 2 ^{/ g} or more and 20 m 2 / ^g or less siliceous fine powder Hydraulic binder, coarse aggregate having an average particle size of 10 mm or more and 20 mm or less, an absolute dry density of 2.60 g / cm ³ or more and a water absorption of 1.20% or less, and a maximum particle size of 1.2 mm or less And containing an artificial high-density fine aggregate having an absolute dry density of 2.90 g / cm ³ or more and a water absorption of 0.90% or less, a chemical admixture, and water. It is added as a slurry having a rate of 50% by weight or more.

According to ultra high strength and high fluidity concrete of the present invention, substituted or 10 wt% of the cement and of 30% by weight or less specific surface area by BET method at 1 m 2 ^{/ g} or more and 20 m 2 / ^g or less siliceous fine powder A hydraulic binder, a coarse aggregate having an average particle size of 10 mm or more and 20 mm or less, an absolute dry density of 2.60 g / cm ³ or more and a water absorption of 1.20% or less, and a maximum particle size of 1.2 mm Hereinafter, since it contains an artificial high-density fine aggregate having an absolute dry density of 2.90 g / cm ³ or more and a water absorption of 0.90% or less, and a chemical admixture, strength development and It can be excellent in fluidity.
Moreover, in the ultra high strength region where the water binder ratio is 15.0% or less, a compressive strength exceeding 200 N / mm ² can be obtained, and the compressive strength can be superior to that of conventional concrete. .

According to the ultra-high strength and high flow fresh concrete of the present invention, 10% by weight or more and 30% by weight or less of cement is a siliceous fine powder having a specific surface area by the BET method of 1 m ² / g to 20 m ² / g. A substituted hydraulic binder, a coarse aggregate having an average particle size of 10 mm or more and 20 mm or less, an absolute dry density of 2.60 g / cm ³ or more and a water absorption of 1.20% or less, and a maximum particle size of 1. 2 mm or less, an absolute dry density of 2.90 g / cm ³ or more and a water absorption of 0.90% or less, an artificial high-density fine aggregate, a chemical admixture, and water, the siliceous fine powder, Since it was added as a slurry having a solid content of 50% by weight or more, it was excellent in strength development and fluidity compared to conventional concrete, and 200 N / mm ² even in an ultrahigh strength region where the water binder ratio was 15.0% or less. Have compressive strength exceeding You can get concrete.

BEST MODE FOR CARRYING OUT THE INVENTION The best mode of the ultra-high-strength high-fluidity concrete and ultra-high-strength high-fluidity fresh concrete of the present invention will be described with reference to the drawings.
The present embodiment is specifically described for better understanding of the gist of the invention, and does not limit the invention unless otherwise specified.

Ultra high strength and high fluidity concrete of this embodiment, more than 10% by weight of cement and 30% by weight or less specific surface area by the BET method was replaced by 1 m 2 ^{/ g} or more and 20 m 2 / ^g or less siliceous fine powder Hydraulic binder, coarse aggregate having an average particle size of 10 mm or more and 20 mm or less, an absolute dry density of 2.60 g / cm ³ or more and a water absorption of 1.20% or less, and a maximum particle size of 1.2 mm or less A concrete comprising an artificial high-density fine aggregate having an absolute dry density of 2.90 g / cm ³ or more and a water absorption of 0.90% or less, and a chemical admixture.

Here, the ultra high strength and high fluidity concrete of the present embodiment will be described in detail.
The cement used in this ultra high strength high fluidity concrete is usually mixed heat, such as moderate heat, low heat, early strength, super early strength, various portland cements such as sulfate resistance, blast furnace cement, fly ash cement, silica cement, etc. , Ultrafast cement such as alumina cement and jet cement, Irwin cement and the like.
From these various cements, one type can be selected or two or more types can be selected and mixed in consideration of specifications and prices required for ultra-high strength and high fluidity concrete.

In order to obtain the ultra-high-strength and high-fluidity concrete of this embodiment, low-heat Portland cement containing a large amount of belite (C ₂ S = 2CaO · SiO ₂ : dicalcium silicate) (in Japanese Industrial Standard, the content of belite is 40% or more) and moderately hot Portland cement are particularly preferred.

The siliceous fine powder is for replacing 10% by weight or more and 30% by weight or less of the total amount of the above cement, and has a specific surface area of 1 m ² / g or more and 20 m ² / g or less by the BET method. Silica fine powder, for example, zirconia-derived siliceous fine powder produced as a by-product when producing electrofused zirconia, silica fume produced as a by-product when producing silicon or ferrosilicon, silica glass Siliceous fine powder produced as a by-product during production, amorphous siliceous fine powder synthesized from silicon or silicon dioxide, fly ash classified or finely pulverized to a particle size of 10 μm or less to enhance pozzolanic activity, etc. Is mentioned.

From these various siliceous fine powders, one type can be selected or two or more types can be selected and mixed in consideration of specifications and prices required for ultra-high strength and high fluidity concrete.
In particular, as a siliceous fine powder suitable for the ultra-high-strength high-fluidity concrete of the present embodiment, zirconia having a SiO ₂ content of 85% or more and a specific surface area by the BET method of 1 m ² / g or more and 20 m ² / g or less. Particular mention may be made of origin siliceous fine powder, silicon origin silica fume.

The substitution rate of the siliceous fine powder with respect to the cement is preferably 10% by weight or more and 30% by weight or less, and more preferably 10% by weight or more and 20% by weight or less in the total amount of the cement.
This is because if the substitution rate of the siliceous fine powder with respect to the cement is out of the above range, the compressive strength of the concrete is lowered and it becomes difficult to maintain it at 200 N / mm ² or more. This is because kneading becomes difficult when producing the material, and the practicality is greatly reduced.

  The siliceous fine powder used in the present embodiment is extremely bulky and difficult to handle such as transportation, storage, and stable supply. Therefore, when concrete is produced in an actual concrete factory, water is added to the siliceous fine powder. Is preferably added as a slurry having a solid content of 50% or more.

The hydraulic binder is a combination of the above cement and siliceous fine powder, and the unit volume of the hydraulic binder in the ultra-high-strength high-fluidity concrete of this embodiment is 300 L / m ³ or more and 400 L / m ³ or less is preferable, and more preferably 325 L / m ³ or more and 375 L / m ³ or less.
This is because when the unit volume of the hydraulic binder is out of the above range, the compressive strength of the concrete is lowered and it becomes difficult to keep it at 200 N / mm ² or more. This is because kneading becomes difficult at the time of production, and the practicality is greatly reduced.

Coarse aggregate is for adding extremely high strength development and good fluidity exceeding 200 N / mm ² in compressive strength to concrete, has high hardness and excellent wear resistance, and has an average particle size of 10 mm or more and 20 mm. Hereinafter, those having an absolutely dry density of 2.60 g / cm ³ or more and a water absorption of 1.20% or less, preferably 1.00% or less are suitably used.

As this coarse aggregate, Japanese Industrial Standard JIS A 5005 “Crushed stone for road” No. 5 or 6 or Japanese Industrial Standard JIS A 5055 “Crushed stone for concrete” crushed stone 2015 or crushed stone 2005 can be used. For example, natural coarse aggregates such as hard sandstone crushed stones, andesite crushed stones, basalt crushed stones, quartz schist crushed stones, and artificial coarse bones such as artificial corundum and sintered bauxite with an average particle size range of 10 mm to 20 mm. One or two or more kinds arbitrarily selected from the materials can be mixed and used.
Here, if the average particle size, absolute dry density, or water absorption rate of the coarse aggregate is out of the above range, the compressive strength or fluidity of the concrete is greatly reduced, which is not preferable.

Unit volume of coarse aggregate occupying the concrete of this embodiment is preferably 250L / ^{m 3} or more and 350L / ^{m 3} or less, and more preferably 300L / ^{m 3} or more and 330L / ^{m 3} or less.
Here, when the unit volume of the coarse aggregate is less than 250 L / m ³ , the ultrahigh strength and high fluidity of the concrete is not sufficiently exhibited, and when it exceeds 350 L / m ³ , the compressive strength and fluidity of the concrete are not improved. This is because the decrease is large, and kneading becomes difficult when producing fresh concrete, and the practicality is greatly reduced.

Artificial high-density fine aggregate is a fine aggregate for imparting ultra-high strength and high fluidity, has high hardness and excellent wear resistance, has a maximum particle size of 1.2 mm or less, and an absolutely dry density. An artificial high-density fine aggregate having 2.90 g / cm ³ or more and a water absorption rate of 0.90% or less, preferably 0.70% or less is suitably used.
Here, if any one of the maximum particle size, the absolute dry density, and the water absorption rate of the artificial high-density fine aggregate is out of the above range, the cement composition containing the artificial high-density fine aggregate is made into a hardened cement body. In this case, the compressive strength or fluidity is greatly reduced, which is not preferable.

Unit volume for ultra-high strength, high fluidity concrete of the artificial dense fine aggregate is preferably 100L / ^{m 3} or more and 200L / ^{m 3} or less, and more preferably not more than 130L / ^{m 3} or more and 170L / ^{m 3.}
Here, if the unit volume of the artificial high-density fine aggregate is less than 100 L / m ³ , the ultrahigh strength and high fluidity of the concrete cannot be sufficiently exhibited, and if it exceeds 200 L / m ³ , the compression of the concrete This is because the strength and fluidity are greatly reduced, and it becomes difficult to knead when producing fresh concrete, resulting in a significant decrease in practicality.
The fine aggregate ratio (s / a) of the ultra-high strength and high fluidity concrete is preferably 27% or more and 35% or less, preferably 30% or more and 33% in consideration of the compressive strength and fluidity required for the concrete. The following is more preferable.

  As this artificial high-density fine aggregate, for example, ferronickel slag fine aggregate (Japanese Industrial Standard JIS A 501-2-2 FNS1.2 compliant product), copper slag fine aggregate (Japanese Industrial Standard JIS A 5011-3 CUS1.2 compliant product), electric furnace oxidation slag fine aggregate (Japan Industrial Standard JIS A 5011-4 EFS1.2 N or H compliant product) Can be used.

As the chemical admixture, a general polycarboxylic acid-based high performance AE water reducing agent having a high water reduction rate is preferably used, and it is preferable to use a defoaming agent such as a polyoxyalkylene alkyl ether if necessary. .
The addition amount of this polycarboxylic acid-based high-performance AE water reducing agent is appropriately adjusted according to the target fluidity of ultra-high-strength high-fluidity concrete, but the general addition amount is from cement and siliceous fine powder. It is preferable to add in the range of 0.5 wt% or more and 4.0 wt% or less with respect to the total amount of the hydraulic binder.

In addition, the amount of antifoaming agent is appropriately adjusted according to the target air amount of ultra-high strength and high fluidity concrete, but the general amount of addition is a hydraulic binder composed of cement and siliceous fine powder. It is preferable to add in the range of 0.01% by weight or more and 0.1% by weight or less with respect to the total amount.
Moreover, as this chemical admixture, either powder form or liquid form can be used. In particular, a powdery material is preferable because it can be premixed with cement or the like.

  In addition, in order to add various performances to the ultra-high-strength high-fluidity concrete of the present embodiment, an expansion material, shrinkage reducing agent, synthetic resin powder, synthetic resin fiber, metal fiber, carbon fiber, glass fiber, polymer, monomer, You may add 1 type, or 2 or more types selected from the group of an oligomer, a limestone fine powder, a fluidizing agent, a setting accelerator, and a setting retarder.

The ultra-high-strength, high-fluidity concrete of the present embodiment is a concrete composition containing the hydraulic binder, coarse aggregate, artificial high-density fine aggregate, and chemical admixture, with a water binder ratio of 15.0% or less. This is a concrete that is kneaded with water and cured, and the compressive strength of this ultra-high-strength, high-fluidity concrete is either 91 ° C. at 20 ° C. ± 1 ° C. or 7 days at 50 ° C. or more and 80 ° C. or less When it is cured under the above conditions, it is 200 N / mm ² or more.

The ultra-high-strength, high-fluidity fresh concrete of this embodiment (so-called ready-mixed concrete) is the above-mentioned hydraulic binder, coarse aggregate, artificial high-density fine aggregate, chemical admixture and water, that is, 10% by weight of cement. or more and a hydraulic binder 30 wt% or less specific surface area by the BET method was replaced by ^{1 m} 2 / g or more and ^{20 m} 2 / g or less siliceous fine powder, the average particle diameter of 10mm or more and 20mm or less, absolute Coarse aggregate having a dry density of 2.60 g / cm ³ or more and a water absorption rate of 1.20% or less, a maximum particle size of 1.2 mm or less, an absolute dry density of 2.90 g / cm ³ or more and a water absorption rate of 0 .90% or less artificial high-density fine aggregate, chemical admixture and water, and this siliceous fine powder is added as a slurry having a solid content of 50% by weight or more.

Here, the reason why the siliceous fine powder is added as a slurry having a solid content of 50% by weight or more is that the siliceous fine powder itself is extremely bulky, and handling such as transportation, storage, and stable supply is difficult.
In this ultra high strength high flow fresh concrete, the weight ratio of the hydraulic binder composed of the cement and the siliceous fine powder and the mixed water (the chemical admixture is regarded as water), that is, the water binder ratio is 15.0% or less is preferable. The reason is that if the water binder ratio exceeds 15.0%, the compressive strength of the concrete will be less than 200 N / mm ² .

EXAMPLES Hereinafter, although an Example , a reference example, and a comparative example demonstrate this invention concretely, this invention is not limited by these Examples.

The followings were used as cement, siliceous fine powder, coarse aggregate, artificial high-density fine aggregate, chemical admixture, antifoaming agent and water used in Examples , Reference Examples and Comparative Examples.
"cement"
Low heat Portland cement (C2S content 56%, absolute dry density 3.24 g / cm ³ , Blaine specific surface area 3300 cm ² / g, manufactured by Sumitomo Osaka Cement Co., Ltd.) (hereinafter abbreviated as LC) “silica fine powder”
Zirconia-derived siliceous fine powder: SF-SILICAFUME (SiO ₂ content 94.7%, absolute dry density 2.26 g / cm ³ , BET specific surface area 9.1 m ² / g, manufactured by Sakai Kogyo Co., Ltd.) , Abbreviated as ZSF)

"Coarse aggregate A"
Hard sandstone crushed stone from Ibaraki No. 5 (Japanese Industrial Standard JIS A 5001 “Crushed stone for road” No. 5 conforming product, maximum particle size 20 mm or less, absolute dry density 2.65 g / cm ³ , water absorption 0.6%, actual rate 60 .1%, hereinafter abbreviated as KS20)
"Coarse aggregate B"
Hard sandstone crushed stone from Ibaraki No. 6 (Japanese Industrial Standard JIS A 5001 “Crushed stone for road” No. 6 compliant product, maximum particle size 13 mm or less, absolute dry density 2.63 g / cm ³ , water absorption rate 0.8%, performance rate 62 .5%, hereinafter abbreviated as KS13)

"Coarse aggregate C"
Hard sandstone crushed stone from Ibaraki No. 7 (Japanese Industrial Standard JIS A 5001 “Crushed stone for road” No. 7 compliant product, maximum particle size 5 mm or less, absolute dry density 2.62 g / cm ³ , water absorption rate 1.5%, performance rate 58 .8%, hereinafter abbreviated as KS5)
"Coarse aggregate D"
Yamagata andesite crushed stone 2005 (Japanese Industrial Standard JIS A 5055 "crushed stone for concrete" crushed stone 2005 compliant product, maximum particle size 20mm or less, absolute dry density 2.66g / cm ³ , water absorption 1.3%, actual rate 60.8 %, Hereinafter abbreviated as AS20)

“Fine Aggregate A”
1.2 mm ferronickel slag fine aggregate (JIS A 5011-2 FNS 1.2 compliant product, maximum particle size 1.2 mm or less, absolute dry density 3.01 g / cm ³ , water absorption 0.7%, FM: 2 .21) (hereinafter abbreviated as FNS1.2)
"Fine Aggregate B"
5 mm ferronickel slag fine aggregate (JIS A 501-2 FNS5 compliant product, maximum particle size 5 mm or less, absolute dry density 2.97 g / cm ³ , water absorption 0.9%, FM: 2.47) (hereinafter, (Abbreviated as FNS5)
"Fine Aggregate C"
1.2 mm copper slag fine aggregate (JIS A 5011-3 CUS1.2 compliant product, maximum particle size 1.2 mm or less, absolute dry density 3.35 g / cm ³ , water absorption 0.9%, FM: 2. 24) (hereinafter abbreviated as CUS1.2)
"Fine Aggregate D"
5 mm copper slag fine aggregate (JIS A 5011-3 CUS5 compliant product, maximum particle size 5 mm or less, absolute dry density 3.30 g / cm ³ , water absorption 1.2%, FM: 2.64) (hereinafter, CUS5 Abbreviated)

“Fine Aggregate E”
1.2mm electric furnace oxidized slag fine aggregate (JIS A 5011-4 EFS1.2N compliant product, maximum particle size 1.2mm or less, absolute dry density 3.52g / cm ³ , water absorption 1.0%, FM: 2.89) (hereinafter abbreviated as EFS1.2)
"Fine Aggregate F"
5mm electric furnace oxidation slag fine aggregate (JIS A 5011-4 EFS5N compatible product, maximum particle size 5mm or less, absolute dry density 3.49g / cm ³ , water absorption 1.7%, FM: 3.10) (below , Abbreviated as EFS5)
"Fine Aggregate G"
Aichi Prefecture dry silica sand No. 4 and No. 7 mixed sand (maximum particle size 1.2 mm or less, absolute dry density 2.66 g / cm ³ , water absorption 0.7%, FM: 2.46) (hereinafter SS1. (Abbreviated as 2)

`` Chemical admixture ''
Polycarboxylic acid-based high-performance AE water reducing agent: SEICAMENT 1200N (manufactured by Nippon SEICA Co., Ltd.) (hereinafter abbreviated as SP)
"Antifoaming agent"
Seeker Anti-Form W (Nihon Seeca Co., Ltd.)
"water"
Tap water

Using the above cement, fine siliceous powder, coarse aggregate, fine aggregate, chemical admixture, antifoaming agent and water, ultrahigh strength high flow fresh concretes of Examples , Reference Examples and Comparative Examples were prepared.
Table 1 shows the compositions of the ultra-high-strength, high-fluidity fresh concrete in each of the Examples , Reference Examples and Comparative Examples.
In these ultra high strength and high flow fresh concrete, the unit water volume of the concrete was 150 kg / m ³ and the unit volume of the coarse aggregate was 320 L / m ³ . The target air amount was 1.5%.

In Examples 1 to 3, Reference Examples 1 and 2, and Comparative Examples 1 to 9, the water binder ratio was 13.7%, the ZSF substitution rate was 20% by weight, and the fine aggregate unit volume was 148 L / m ³ . did.
In Comparative Example 10, the water binder ratio was 13.7%, the substitution rate of ZSF was 5% by weight, and the unit volume of the fine aggregate was 170 L / m ³ .
In Comparative Example 11, the water binder ratio was 13.7%, the ZSF substitution rate was 35% by weight, and the fine aggregate unit volume was 126 L / m ³ .
In Comparative Example 12, the water binder ratio was 16.0%, the ZSF substitution rate was 20% by weight, and the fine aggregate unit volume was 200 L / m ³ .

In Examples 1 to 3, Reference Examples 1 and 2, and Comparative Examples 1 to 11, the amount of polycarboxylic acid-based high-performance AE water reducing agent (SP) added is 2.8% by weight, and the amount of antifoaming agent added is 0.04% by weight, and in Comparative Example 12 (water binder ratio 16.0%), the amount of polycarboxylic acid-based high-performance AE water reducing agent (SP) added is 1.9% by weight, and the amount of antifoaming agent added Was 0.04 wt%.
The coarse aggregates A to D are used for mixing after being adjusted to the surface dry state in advance, and the high-performance AE water reducing agent (SP) and the antifoaming agent are regarded as mixing water and the amount of water is determined. Corrected.

Next, a kneading test of each of Examples 1 to 3, Reference Examples 1 and 2, and Comparative Examples 1 to 12 was performed on ultrahigh strength and high flow fresh concrete.
For each ultra-high strength high flow fresh concrete, coarse aggregate, cement, siliceous fine powder (ZSF) and fine aggregate having a capacity of 100 L in a constant temperature room at 20 ° C. to have the composition shown in Table 1. Put into a biaxial forced kneading mixer (manufactured by Taiheiyo Kiko Co., Ltd.) and perform kneading for 15 seconds. Then, mix water, high-performance AE water reducing agent (SP) and antifoaming agent so as to have the composition shown in Table 1. The mixture was added and kneaded for 120 seconds, then scraped off, and further kneaded for 120 seconds. In addition, the mixing amount of 1 batch was constant at 55L.

  Immediately after the kneading, the slump flow and the air amount are measured in accordance with Japanese Industrial Standards JIS A 1150 “Concrete Slump Flow Test” and Japanese Industrial Standards JIS A 1128 “Testing Method Based on Air Pressure of Fresh Concrete” Next, 20 cylindrical specimens for measuring compressive strength each having a diameter of 100 mm and a height of 200 mm were produced.

These specimens were sealed with vinyl and rubber bands until just before demolding to prevent water evaporation, and sealed and cured in a constant temperature room at 20 ° C. until 2 days of age.
Fifteen of these specimens were demolded at the age of 2 days, and were standardly cured in water at 20 ° C. until a predetermined age. The remaining 5 pieces were immersed in warm water of 70 ° C. together with the mold with the specimen head sealed from the second day of material age, heat-cured, removed from the warm water at the age of 7 days, and brought to room temperature in the air. After standing to cool, it was demolded.

Next, the compressive strength of these specimens was measured according to Japanese Industrial Standard JIS A 1108 “Concrete Compression Test Method”. The number of specimens of one age was five, and the coefficient of variation was calculated from the compression strength data of the five specimens measured. In addition, the material age for measuring the compressive strength was 3 types for standard curing, 7 days, 28 days, and 91 days, and the heating curing at 70 ° C. was one type for 7 days. All these specimens were polished on both end faces immediately before the compression test.
Table 2 shows the results of the kneading test of each of Examples 1 to 3, Reference Examples 1 and 2, and Comparative Examples 1 to 12 of ultra high strength and high flow fresh concrete.

According to these measurement results, in Examples 1 to 3 and Reference Examples 1 and 2 , the fluidity of the obtained fresh concrete is extremely good, and the compressive strength is 203 to 203 at a age of 91 ° C. of standard curing at 20 ° C. the 212N / ^mm 2, 70 ℃ heat curing at the age of 7 days and 209~220N / mm ^2, are over 200 N / mm ^2, was very good. In particular, the compressive strength of Example 2 using KS13 as the coarse aggregate and FNS1.2 as the fine aggregate was the highest.

On the other hand, Comparative Examples 1 to 5 were the same in Examples 1 to 3 and Reference Examples 1 and 2 , but the coarse aggregate was as large as 5 mm. The fluidity of the concrete was comparable to or slightly inferior to Examples 1-3 and Reference Examples 1 and 2 , but the compressive strength was lower than that of Examples 1-3 and Reference Examples 1 and 2 .
In Comparative Example 6, the fine aggregate was the same as in Examples 1 and 2 and Reference Example 1 , but the maximum particle size of coarse aggregate (KS) was as small as 5 mm, and the fluidity of the obtained concrete was Although it was slightly inferior to Examples 1 and 2 and Reference Example 1 , the compressive strength was lower than that of Examples 1 and 2 and Reference Example 1 .
In Comparative Examples 7 to 9, the coarse aggregate was the same as in Examples 1 and 2 and Reference Example 1 , but because silica sand (SS1.2) was used for the fine aggregate, the flow of the obtained concrete Although the properties were slightly inferior to those of Examples 1 and 2 and Reference Example 1 , the compressive strength was significantly lower than those of Examples 1 and 2 and Reference Example 1 .

In Comparative Example 10, since the substitution rate of ZSF was 5% by weight, fresh concrete could not be kneaded under the test conditions of this time.
In Comparative Example 11, the flow rate of fresh concrete was equivalent to Example 1 because the substitution rate of ZSF was 35% by weight, but the compressive strength was lower than Example 1.
In Comparative Example 12, since the water binder ratio was 16.0% and the substitution rate of ZSF was 20% by weight, the fluidity of the concrete was the same as that of Example 1, but the compressive strength was significantly higher than that of Example 1. For example, it was lower than 200 N / mm ² in both the age of standard curing at 20 ° C. and the age of heat curing at 70 ° C. for 7 days.
In addition, the air quantity of the concrete was 1.4% to 1.7% in all of the examples , reference examples, and comparative examples, which was almost as targeted.

As described above, the coarse aggregate having an average particle diameter of 10 mm or more and 20 mm or less, an absolute dry density of 2.60 g / cm ³ or more and a water absorption of 1.20% or less, and a maximum particle diameter of 1.2 mm or less , Artificial high density fine aggregate with absolute dry density of 2.90 g / cm ³ or more and water absorption of 0.90% or less (ferronickel slag fine aggregate, copper slag fine aggregate, electric furnace oxidized slag fine aggregate) Compared to other concretes using artificial high-density fine aggregates and silica sand, the concrete using is superior in fluidity and compressive strength, and the coefficient of variation of the compressive strength of the specimen is significantly smaller. It was.

In addition, when the substitution rate of the siliceous fine powder (ZSF) with respect to the cement is out of the range of 10% by weight or more and 30% by weight or less, the decrease in the compressive strength of the concrete becomes large, or the kneading is difficult. As a result, it was found that the practicality was greatly reduced.
Furthermore, in order for the compressive strength to exceed 200 N / mm ² in both the age of standard curing at 20 ° C. and the age of heat curing at 70 ° C., the water binder ratio is 15.0%. It turns out that it is necessary to knead as follows.

Claims (5)

A hydraulic binder that 10 wt% or more and 30 wt% or less specific surface area by BET method was replaced by ^{1 m} 2 / g or more and ^{20 m} 2 / g or less siliceous fine powder cement, the average particle diameter of more than 10mm And 20 mm or less, an absolute dry density of 2.60 g / cm ³ or more and a water absorption of 1.20% or less, a coarse aggregate, a maximum particle size of 1.2 mm or less, and an absolute dry density of 2.90 g / cm ³ or more. An ultra-high-strength, high-fluidity concrete comprising an artificial high-density fine aggregate having a water absorption rate of 0.90% or less and a chemical admixture.   The artificial high-density fine aggregate is one or more selected from the group consisting of ferronickel slag fine aggregate, copper slag fine aggregate, and electric furnace oxidized slag fine aggregate. 1. Ultra high strength high fluidity concrete according to 1.   The coarse aggregate is composed of natural coarse aggregate and / or artificial coarse aggregate, and the natural coarse aggregate is one or two selected from the group of hard sandstone crushed stone, andesite crushed stone, basalt crushed stone, quartz schist crushed stone The ultra-high-strength, high-fluidity concrete according to claim 1 or 2, wherein the artificial coarse aggregate is made of artificial seeds and / or sintered bauxite. The water binder ratio is 15.0% or less, and the unit volume of the artificial high-density fine aggregate is kneaded and cured at 100 L / m ³ or more and 200 L / m ³ or less,
The compressive strength when the curing is performed at any one of 91 days at 20 ° C and 7 days at 50 ° C or more and 80 ° C or less is 200 N / mm ² or more. 2. Ultra high strength high fluid concrete as described in 2 or 3. A hydraulic binder that 10 wt% or more and 30 wt% or less specific surface area by BET method was replaced by ^{1 m} 2 / g or more and ^{20 m} 2 / g or less siliceous fine powder cement, the average particle diameter of more than 10mm And 20 mm or less, an absolute dry density of 2.60 g / cm ³ or more and a water absorption of 1.20% or less, a coarse aggregate, a maximum particle size of 1.2 mm or less, and an absolute dry density of 2.90 g / cm ³ or more. And the artificial high density fine aggregate whose water absorption is 0.90% or less, a chemical admixture, and water,
The ultrafine high-fluidity fresh concrete, wherein the siliceous fine powder is added as a slurry having a solid content of 50% by weight or more.