JP2002080261A - High fluid concrete and concrete secondary product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To create a recycling destination of molten slag grain while securing sufficient strength and homogeneity of a secondary product even mixing molten slag grain and preventing elution of harmful matter and reducing material cost. SOLUTION: High fluid concrete contains water of 160-190 kg/m3, binding material of 480-620 kg/m3, fine aggregate of 700-900 kg/m3, coarse aggregate of 700-900 kg/m3 and admixture of 4-8 kg/m3, and the slump blow value of which is >=65 cm or <=80 cm, and the binding material contains cement and micro powder of blast-furnace slag, and the fine aggregate contains sand and molten slag grain.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-fluidity concrete (high-fluidity fresh concrete) and a secondary concrete product (precast product) formed by the high-fluidity concrete.

[0002]

2. Description of the Related Art The incineration ash remaining after incineration of garbage in a garbage incinerator continues to increase under mass production and mass consumption, and its disposal is an important problem. In recent years, in order to reduce the volume of incinerated ash and reduce pollution, after melting the incinerated ash at a high temperature and thermally decomposing the organic matter, the molten material consisting of the inorganic matter etc. is cooled and the vitreous molten slag is cooled. The processing method of changing the value to "." The molten slag can be formed into various powder sizes such as fine powder, sand or gravel depending on the cooling method.

[0003] As a method of recycling the molten slag, a method of blending the molten slag particles as a part of fine aggregate of ordinary concrete (referred to as a concrete having no high fluidity in the present specification) has been studied. (For example, see
0-296206, JP-A-10-226556, JP-A-11-246256).

[0004]

However, the method of blending molten slag particles into ordinary concrete has the following problems, and the reuse of molten slag by this method has not progressed as expected.

[0005] (A) Strength of secondary products [0005] Compared to the case where fine aggregate is only high-quality sand, ordinary concrete has a higher compressive strength when mixed (replaced) with molten slag particles as a part of the sand. Tends to slightly decrease. Although the compressive strength of ordinary concrete has a necessary safety factor with respect to the design standard strength of concrete secondary products such as retaining wall blocks, gutter blocks and box culverts, the margin is not so large. For this reason, when a secondary product is manufactured from ordinary concrete containing molten slag particles, the safety factor may not be sufficient due to the decrease in the compressive strength.

(B) Uniformity of the secondary product as a structure When considering a concrete secondary product as one structure, it is an absolute condition that the entire product is uniform. However, when manufacturing the secondary product with ordinary concrete, in order to flow the ordinary concrete to each corner of the formwork,
As shown in FIG. 1 (a), in many cases, a vibrator 21 is mounted on the formwork 1 and a vibrator 22 is inserted into the concrete as needed, and the ordinary concrete 20 is poured while applying vibration. When the vibration is applied in this manner, the molten slag particles that are sandy and have a higher density than the sand are separated, and the molten slag particles are unevenly distributed in a part of the secondary product, so that a uniform structure may not be formed. . Also,
Even if an attempt is made to fulfill the environmental purpose of reusing molten slag, noise generated by the vibration of the vibrator may cause trouble in the surrounding area, and the purpose and means may not match.

(C) Dissolution of harmful substances Even when the molten slag particles are used alone, the results of the dissolution test reveal that the dissolution amount of harmful substances such as heavy metals is below the reference value and is safe. ing. However, in view of future anxiety, more complete prevention of elution of harmful substances is desired. In this respect, wrapping and solidifying the molten slag particles with the solidified cement has much higher safety than contacting the molten slag particles alone with air or water. However, ordinary concrete has a larger amount of bleeding than high-fluidity concrete. From a micro perspective, FIG. 3 (a)
As shown in the figure, even if it is a fine molten slag particle, there will be a pool or a void due to bleeding under the particle, so that the entire circumference of the particle is completely wrapped in the solidified cement. Not be.

(D) Material cost Since molten slag particles are less expensive than good-quality sand, material costs are reduced. However, when blending molten slag grains into ordinary concrete, cement must be increased in order to increase the safety factor of compressive strength due to the problems (a) and (b) above. Become. Further, the mixing ratio of the molten slag particles is not so high.

Therefore, an object of the present invention is to establish a recycling destination of molten slag particles and to contribute to environmental problems, and to ensure sufficient strength and uniformity of a secondary product even when mixed with molten slag particles. It is an object of the present invention to provide a high-fluidity concrete and a concrete secondary product which can prevent harmful substances from being eluted in the future and can reduce material costs.

In order to achieve this object, the present inventor has made various studies. Among them, the most noticeable is a high fluidity concrete. Because the inventor first
Including water, binder, fine aggregate, coarse aggregate, cement admixture and thickener, using a specific cement admixture as a cement admixture, and using a specific thickener as a thickener, A method for producing high-fluidity concrete having a predetermined characteristic value by using an aqueous solution having a predetermined surface tension and viscosity obtained by dissolving water in water as a kneading water has been developed. (Japanese Patent Laid-Open No. 7-14949). After that, the present inventor has accumulated a lot of experience through the development and implementation of the high fluidity concrete, and as a result, has confirmed that the mixing of the molten slag particles is sufficiently permitted, and has led to the present invention.

Japanese Patent Application Laid-Open No. H11-322396 discloses that sludge melting slag powder is blended as all or a part of the fine powder of high fluidity concrete to reduce drying shrinkage and reduce the amount of blast furnace slag used. Although the technical concept of reducing the crack resistance and increasing the crack resistance has been disclosed, the present invention is a technical concept in which molten slag is blended as all or a part of the fine aggregate of the high fluidity concrete to achieve the above object. Completely different.

[0012]

Means for Solving the Problems In order to solve the above problems, the following high fluidity concretes (1), (2) and (3) and a secondary concrete product (4) have been devised.

(1) It contains water, a binder (a hydraulic component), fine aggregate, coarse aggregate and an admixture, and has a slump flow value of 50.
A high fluidity concrete having a size of not less than 80 cm and not more than 80 cm, wherein molten slag particles are blended as part or all of the fine aggregate.

By the way, the Architectural Institute of Japan specifies the following regarding high fluidity concrete. "A. The fluidity of high-fluidity concrete is represented by slump flow, and the value is 50 cm or more and 70 cm or less at the time of unloading. B. The material separation resistance of high-fluidity concrete is measured after the slump flow test at the time of unloading. It is confirmed by the condition of the concrete, and it is assumed that it is in the following conditions (1) and (2): (1) Coarse aggregate is not unevenly distributed in the central part of the spread concrete (2) The paste and free water are not unevenly distributed in the peripheral part. "
The item b is the same, but the slump flow value of the item a is 50 cm or more and 80 cm or less. This is because some concrete secondary products have a small cross-section thickness and small rebar cover, and in such cases, when the slump flow value is 65 cm or less (or 70 cm or less), a large amount of unfilled parts and entrained air bubbles are generated. May be. In this case, according to the study of the present inventors, the slump flow value is preferably from 65 cm to 80 cm, and more preferably from 70 cm to 80 cm.

The Japan Society of Civil Engineers has prescribed the following guidelines for the construction of high fluidity concrete. "A. Self-compacting concrete capable of filling without shaking and compaction work without causing material separation to all corners of a formwork or the like. B. The following levels of self-compacting property are available. 3 ranks are set: Rank 1: The minimum steel clearance is about 35 to 60 mm, and the member has a complicated cross-sectional shape and small cross-sectional dimensions, and has a self-filling property. Rank 2: The minimum steel clearance is about 60 to 200 mm. Performance of self-compacting property in reinforced concrete structures or members Rank 3: Performance of self-compacting property in members or locations with minimum steel clearance of about 200 mm or more, large cross-sectional dimensions, small amount of reinforcement, and unstripped structures The high-fluidity concrete in this specification satisfies this construction guideline, but the performance level of rank 1 of item b above To meet, as the slump flow value of the following is preferably more than 80cm 65cm, 70cm or 8
0 cm or less is more preferable.

(1-1) The unit water amount is not particularly limited, but is preferably 150 to 200 kg / m ³ , and 160 to 1 kg / m ^3.
90 kg / m ³ is preferred. Unit water volume is 150kg / m
^If it is less than ³ , the desired fresh concrete with high fluidity cannot be obtained, and if it exceeds 190 kg / m ³ , the used material may be separated.

(1-2) The binder is not particularly limited, but preferably contains cement and blast furnace slag fine powder, and may further contain fly ash. Although not a binder, limestone fine powder can be added as a fine powder filler. The cement is not particularly limited, and examples thereof include Portland cement (normal, moderate heat, high strength) and mixed cement (blast furnace cement, etc.). The blast furnace slag fine powder is not particularly limited, but has a Blaine value of 3500 to 500.
Those having 0 cm ² / g are preferred.

The unit amount of the binder is not particularly limited.
400-700 kg / m ³ to obtain a suitable high fluidity
Is preferable, and 480 to 620 kg / m ³ is more preferable. The mixing ratio of the blast furnace slag fine powder in the binder is
Although not particularly limited, it is preferably 15 to 50% by weight, more preferably 25 to 45% by weight, in order to obtain concrete separation resistance and moderately high fluidity.

(1-3) The fine aggregate is obtained by mixing molten slag particles as part or all of the fine aggregate. As the molten slag particles, those obtained from the melting treatment of the refuse incineration ash are preferable, but part or all of them may be replaced with those obtained from the melting treatment of sewage sludge. The fine aggregate to be mixed with the molten slag particles is not particularly limited, but sand (river sand, mountain sand, sea sand, etc.) can be exemplified.

The molten slag particles may be in the form of sand having an appropriate average particle diameter as fine aggregate, and the particle diameter is not particularly limited. It is preferable that the content ratio of the particle group of 0.30 to 2.36 mm is 50% by weight or more. In addition, the content of the molten slag particles having a particle diameter of 0.15 mm or less is usually as small as less than 10% by weight (the content of fine powder is small).

The particle size of the sand is not particularly limited, but the content of particles (fine powder) having a particle size of 0.15 mm or less in the sand is preferably 10 to 30% by weight, and the particle size in the sand is 1 μm. It is more preferable that the content of the particle group having a particle size of 0.15 mm is 10 to 15% by weight. Fine aggregates containing less than 10% by weight of a particle group having a particle size of 0.15 mm or less are insufficient to beautify the concrete surface, and conversely, if it exceeds 20% by weight, desired high fluidity is obtained. Is difficult to obtain fresh concrete.

The unit amount of the fine aggregate is not particularly limited.
600 to 1000 kg / m ³ is preferable, and 700 to 90 kg / m ³ is preferable.
0 kg / m ³ is more preferred. The mixing ratio of the molten slag particles in the fine aggregate is not particularly limited, but is 5 to 80.
% By weight, more preferably from 10 to 70% by weight, and most preferably from 20 to 60% by weight. If the mixing ratio is less than 5% by weight, the recycling efficiency of the molten slag is poor,
If the content exceeds% by weight, separation is easy. It is considered that the reason for this separation is that the molten slag particles generally have a large coarse particle ratio (coarse particles) and a small amount of fine powder as compared with sand, and the particle shape is angular.

Therefore, when the mixing ratio of the molten slag particles in the fine aggregate is large, for example, when it exceeds 50% by weight,
In order to prevent separation, for example, it is preferable to perform one or both of the following. Increasing the mixing ratio of the blast furnace slag fine powder in the binder (for example, 25% by weight or more) to increase the fine powder content. Decreasing the mixing ratio of the AE water reducing agent as an admixture to the binder (for example, 1.0% by weight or less) to reduce the viscosity.

(1-4) The coarse aggregate is not particularly limited, and examples thereof include river gravel, crushed stone, and lightweight aggregate. The unit amount of the coarse aggregate is not particularly limited, but is 600 to 1000 k.
g / m ³ is preferable, and 700 to 900 kg / m ³ is preferable.

(1-5) The admixture is not particularly limited, and examples thereof include an AE agent, a water reducing agent, an AE water reducing agent or a high performance AE water reducing agent, and a high performance AE water reducing agent is particularly preferable. The component of the high-performance AE water reducing agent is not particularly limited, and examples thereof include a polycarboxylic acid type, a sulfonic acid type, a polyether type, and a melanin type. The unit amount of the admixture varies depending on the components and is not particularly limited, but is preferably ³ to 10 kg / m ³ ,
4-8 kg / m ³ is more preferred. In particular, in the case of a high-performance AE water reducing agent, the mixing ratio of the high-performance AE water reducing agent to the binder is not particularly limited, but is preferably 0.5 to 2.0% by weight, and more preferably 0.8 to 1.3% by weight. preferable.

(2) 150-200 kg of water per unit amount
m^Three , Binder 400-700 kg / m^Three , Fine aggregate 60
0-1000kg / m^Three , Coarse aggregate 600-1000k
g / m ^Three And admixture 3-10 kg / m^Three Including
High flow with a pump flow value of 50 cm or more and 80 cm or less
Concrete, wherein the binder is cement and blast furnace
Rag fine powder, wherein the fine aggregate is sand and molten slag particles.
A high-fluidity concrete comprising: The above (1
The description of the items -1) to (1-5) is based on the description of this high-flow concrete.
Introduce also about the course.

(3) 160 to 190 kg of water per unit amount
m ³ , binder 480-620 kg / m ³ , fine aggregate 70
0-900 kg / m ³ , coarse aggregate 700-900 kg /
a high-fluidity concrete containing m ³ and an admixture of 4 to 8 kg / m ^{3 and} having a slump flow value of 65 cm or more and 80 cm or less, wherein the binder contains cement and blast furnace slag fine powder, and the fine aggregate is High fluidity concrete comprising sand and molten slag particles. The description of the above items (1-1) to (1-5) also applies to this high-fluidity concrete.

(4) A secondary concrete product molded from the high-fluidity concrete of (1), (2) or (3). The secondary product (precast product) is not limited to a specific product, and examples include a retaining wall block, a gutter block, a block for a waterway, a box culvert, a fishway block, a fish nest block, a building foundation block, and the like.

[0029]

EXAMPLES First, high-fluidity concrete of each composition of Comparative Examples and Examples 1 to 5 shown in Table 1 was prepared. That is, the comparative example is a high-fluidity concrete which is a standard in which only sand is blended as fine aggregate, whereas Examples 1 to 4 are examples in which sand and molten slag particles are blended as fine aggregate. Example 1
Is 10% by weight of the molten slag particles in the fine aggregate, Example 2 is 20% by weight, Example 3 is 30% by weight, and Example 4 is 33% by weight. % (Strictly, 33.3% by weight), and in Example 5, the blending ratio was 50% by weight.

[0030]

[Table 1]

The details of each material are as follows. (A) Water: tap water (b) Binder (hydraulic component) ・ Cement: Ordinary Portland cement manufactured by Ube Mitsubishi Cement Co. ・ Blast furnace slag fine powder: Blast furnace slag fine powder manufactured by Nippon Steel Chubu Esment Co. (4000 branes) (C) Fine aggregate ・ Sand: River sand from Kiso river water system (particle size in sand: 0.1
・ Molten slag particles: Molten slag particles discharged from a garbage disposal facility “Sasayuri Clean Park” (shared by 11 municipalities in the Nakano district of Gifu prefecture). (D) Coarse aggregate: River gravel from the Kiso River basin (average particle size about 1
(E) Admixture: High-performance AE water reducing agent “Tupole NV-G4 (trade name)” by Takemoto Yushi Co., Ltd. Table 2 shows the densities of these materials (a) to (e). Table 3 shows the particle size distribution of river sand and molten slag in (c).
Table 4 shows the results of component analysis of the molten slag particles.

[0032]

[Table 2]

[0033]

[Table 3]

[0034]

[Table 4]

In each example, river sand containing a large amount of fine powder having a particle diameter of 0.15 mm or less was reduced, and as shown in Table 3, fine powder having a large number of coarse particles and a particle diameter of 0.15 mm or less was used as shown in Table 3. As shown in Table 1, the amount of the blast furnace slag was increased from the comparative example in order to supplement the fine powder content in order to add molten slag particles having almost no content. This increased amount was about 10% (preferably 5 to 20%) of the mass of the molten slag particles. Since the fine powder of blast furnace slag is finer than the fine powder of river sand, the resistance to concrete separation increases, but the viscosity also increases. In order to suppress this viscosity, each time the blending of the molten slag particles in the fine aggregate is increased by 10% by weight, the usage rate of the admixture (% to the binder) is set to 0.0.
It was reduced by 66% (preferably 0.03 to 0.2%). In this way, even if the molten slag particles were blended, consideration was given so that the properties of the high-fluidity concrete did not change with respect to the comparative example (reference).

The above binder (ordinary Portland cement, blast furnace slag fine powder) and fine aggregate (sand, molten slag particles)
And into a mixer placed in a constant temperature room at 20 ° C. and kneaded for 15 seconds, then kneaded water in which an admixture is dissolved in water, knead and mix for 60 seconds, and then add coarse aggregate. The mixture was kneaded for 90 seconds to prepare a highly fluid concrete.

(A) Test Category A: Evaluation of High-Fluidity Concrete in Fresh Stage For each of the high-fluidity concretes (fresh stage) of Comparative Example and Examples 1 to 5 prepared above, the slump flow value and air were determined by the following methods. The amount was measured. (A1) Slump flow value: In accordance with JIS-A1101 (Slump test method for concrete), high-fluid concrete is packed in one layer without compaction or vibration and slumped, and the maximum diameter of the expanded concrete is increased. And the length in the direction perpendicular thereto were measured, and the average value was defined as the slump flow value. (A2) Air volume: In accordance with JIS-A1128 {Test method based on pressure of air volume of concrete that has not yet solidified (air chamber pressure method)}, the degree to which high-fluid concrete slightly overflows from the container without compaction or vibration. Up to one layer and measured. Table 5 shows the test results.

(B) Test Category B: Evaluation of High-Fluidity Concrete After Hardening Each of the high-fluidity concretes prepared in Comparative Examples and Examples 1 to 5 was molded into a mold having a size conforming to each of the following test methods. It was poured without tamping or vibrating, cured and cured. The following two types of curing were used. Standard curing: After filling concrete, wait for the concrete to harden and remove the formwork. After removing the formwork, 20
A sample was obtained by keeping it wet in ± 2 ° C. water. Same curing of product: After packing concrete, 2
After curing in the air for an hour, the temperature was raised to 60 ° C. at a temperature rising rate of 20 ° C./hour in a steam curing room, and steam curing was performed at 60 ° C. for 3 hours. After that, the product that had been allowed to cool was removed from the mold to obtain a cured sample. (B1) Freeze-thaw test: Measured in accordance with JSCE-G501 (freeze-thaw test method for concrete). However,
Comparative Example and Example 4 only. (B2) Length change test: Measured by a comparator method in accordance with JIS-A1129 (mortar and concrete length change test method). However, only Comparative Example and Example 4. (B3) Compressive strength test: Measured in accordance with JIS-A1108 (test method for compressive strength of concrete). However, Examples 5, 5 ″, and 5 ′ ″ separated as described below are excluded. Table 5 also shows the results of these tests.

[0039]

[Table 5]

The comparative example is a high-flowable concrete serving as a reference and has a desired performance. That is, as described above, the slump flow value is 65c suitable for the production of a concrete secondary product having a small cross-sectional thickness and a small cover of a reinforcing bar.
It is in the range of m to 80 cm, and there is no problem in the results of the air volume, freeze-thaw test and length change test. The compressive strength (14 days) is 67.42 N / mm ² with the same curing of the product,
There 72.20N / mm ² in the standard curing, design strength of L-type retaining wall blocks or boxes culverts is 30 N / mm
^Since it is ² , it has twice or more the strength.

On the other hand, in Examples 1 to 5, the slump flow value was in the range of 65 cm or more and 80 cm or less, and each of the results of the air amount, freeze-thaw test and length change test had no problem at all. The compressive strength (14 days) is 64.2 with the same curing of the product
8 to 66.84 N / mm ² , 66.47 to ⁷ with standard curing
1.95 N / mm ² , 3-6 N /
Although it tends to decrease by about mm ² , there is no problem because the safety factor is higher than the design standard strength of the L-shaped retaining wall block and box culvert as described above.

However, in Example 5 in which the blending ratio of the molten slag particles in the fine aggregate was 50% by weight, as a result of the slump flow test, there was a tendency to separate. As described above, it is presumed that the molten slag particles have more coarse particles (higher coarse particle ratio) than river sand and less fine particles having a particle diameter of 0.15 mm or less and that the particle shape is angular. Was.
Then, in order to confirm this presumption, the following Examples 5 ′, 5 ″, 5 ′ ″ were carried out for the same blending ratio of 50% by weight.

In Example 5 ', the blending amount of blast furnace slag was reduced compared to Example 5, and the usage rate of the admixture (% based on the binder).
However, the tendency of separation was stronger than that of Example 5. Example 5 ″ is an example in which the blending amount of the blast furnace slag was reduced and the usage rate of the admixture was slightly reduced as compared with Example 5, but the separation tendency was almost the same as in Example 5. Example 5 ′ ″ is an example in which the blending amount of the blast furnace slag was increased and the use rate of the admixture was significantly reduced as compared with Example 59, but no separation was observed and the condition was good. Therefore, the above guess is correct,
When the mixing ratio of the molten slag particles is large: a: Increase the fine powder content. This increase is preferably 5 to 20% of the mass of the molten slag particles as described above. b: The use rate of the admixture (AE water reducing agent) is reduced. This weight loss is preferably 0.03 to 0.2% every time the blending of the molten slag particles in the fine aggregate is increased by 10% by weight, and particularly when the blending is 30% by weight or more, 10% by weight is used. It is preferable to set the amount to 0.08 to 0.15% each time the amount is increased.

However, in the case of mass production on a daily basis, if the composition of the molten slag particles is large, excessive care must be taken to control the molten slag particles, the sand particle size, and the measurement accuracy of each material. 33% by weight which seems to be manageable here
(Example 4) was determined as a standard, and the following secondary products were manufactured.

As shown in FIG. 1 (b), the high-fluidity concrete 2 of Example 4 was poured into a mold 1 and cured and hardened.
An L-shaped retaining wall block 10 shown in FIG. 2A and FIG. 2B
And the box culvert 11 shown in FIG. At the time of the driving, it can be carried out without tamping or vibration, and since there is no need to mount a vibrator as in the prior art, no labor and labor are required, and neither vibration nor noise is generated.

With respect to the manufactured L-shaped retaining wall block 10 and box culvert 11, the unfilled portion and the surface condition were visually checked. As a result, although there was no unfilled portion, it was found that spots of about 2 to 3 cm square appeared on the entire product surface. Therefore, the high-fluidity concrete 2 of Example 4 was mounted on a transparent acrylic U-shaped test form.
And the occurrence of spots was tested. No abnormalities were observed up to 4 hours, but then spots occurred. When the U-shaped top was pressed down from above, the spots disappeared, indicating that the spots were shallow surface dents.

Subsequently, in order to determine whether the surface dent is due to concrete shrinkage or gas generation, an expanding agent is blended with the high-fluidity concrete 2 of Example 4 to strike the L-shaped retaining wall block. When I set it up, the shading of the spots became slightly lighter. Further, from the component analysis of the molten slag particles shown in Table 4, the components in the oxide form and the components in the element form were examined,
It was presumed that the reaction was caused by the reaction of the Al element with the alkali to generate hydrogen gas. It is considered that the foamed material before the hardening spreads in an amoeba-like manner on the surface of the mold because of the start of the setting.

For a secondary product (for example, a box culvert) whose appearance does not matter much, spots are not so much a problem, but a secondary product (for example, L
(Retaining wall block), it is preferable to make the surface a design uneven pattern so that the spots are not conspicuous, or to make the surface design in consideration of the spots as the design pattern. Alternatively, since the spots are evidence that the molten slag particles are contained, it is one way to make them visible and declare that they are recycled.

As shown in FIG. 2, the L-shaped retaining wall block 10 and the box culvert 11 were subjected to a load test by applying a tensile force or a compressive force with a hydraulic jack 12, but they had a desired strength. There was no problem at all.

According to the high-fluidity concrete and the concrete secondary product of the present embodiment, the following operational effects can be obtained. (B) Strength of secondary products As described above, high-fluidity concrete has a 14-day compressive strength of 70 days.
It reaches about N / mm ² . Since the design standard strength of the L-shaped retaining wall block and the box culvert is 30 N / mm ² , the strength is twice or more. 1-2 N / mm assuming high fluidity concrete with molten slag
² Strength tends to decrease, but has no effect at all because of high safety factor. Similarly, in the freeze-thaw test and the length change test regarding the durability, since high-fluidity concrete has high durability, the mixing of the molten slag particles is not affected at all.

(B) Uniformity of secondary product as a structure Since high-fluidity concrete can be vibrated without using a vibrator, there is no concern that molten slag particles are separated.
Even if the product is cracked and confirmed, the molten slag grains are distributed evenly and form a uniform structure. Also, no vibration
Since there is no noise, there is no need to worry about people in the surrounding area, and it can be said that this is an environmentally friendly manufacturing method that meets the environmental purpose of recycling molten slag.

(C) Elution of harmful substances Unlike high-density concrete, bleeding hardly occurs in high-fluid concrete. Therefore, microscopically, as shown in FIG. The entire circumference will be wrapped in solidified cement, ensuring safety. To verify this, for each of the high-fluidity concrete of the comparative example and the high-fluidity concrete of Example 4, the hardened concrete was crushed, and 500 g of a sample passed through a 2.0 mm sieve was prepared. Dissolution test of harmful substances was conducted at Center. Table 6 shows the test results.

[0053]

[Table 6]

From the test results, the cadmium, total cyanide, lead, abrasive, and total mercury were the same in Comparative Example and Example 4, but hexavalent chromium was more in Example 4 than in Comparative Example. Turned out to be significantly less. In any case, there is no problem in safety at all.

(D) Material cost Even if the molten slag particles are blended, there is no problem in strength as described in (a) above, and it is not necessary to increase the amount of expensive cement. Also, since molten slag grains are cheaper than good quality sand,
By blending the molten slag particles, the overall material cost is reduced. As described above, the material cost of the blast furnace slag is increased by increasing the amount of the blast furnace slag to make up for the fine powder, but the influence of the molten slag particles is greater, and the use of an admixture (AE water reducing agent) is also required. Smaller volumes also reduce material costs.

It should be noted that the present invention is not limited to the above embodiments, but may be embodied with appropriate modifications without departing from the spirit of the present invention.

[0057]

As described in detail above, according to the high-fluidity concrete and the secondary concrete product of the present invention, it is possible to establish a recycling destination of the molten slag particles and to contribute to environmental problems, and to mix the molten slag particles. Even though the secondary product has sufficient strength and uniformity, it is possible to prevent harmful substances from being eluted in the future, and it is possible to reduce material costs. To play.

[Brief description of the drawings]

FIG. 1A is a schematic view showing a state of a conventional high-fluidity concrete casting, and FIG. 1B is a schematic view showing a state of a high-performance concrete placing example.

FIG. 2A is a schematic diagram of an L-shaped retaining wall block according to an embodiment, and FIG. 2B is a schematic diagram of a box culvert according to the embodiment.

FIG. 3 (a) is a schematic diagram illustrating the periphery of a conventional molten slag particle, and FIG. 3 (b) is a schematic diagram illustrating the periphery of a molten slag particle of an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Formwork 2 High fluidity concrete 10 L type retaining wall block 11 Box culvert

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C04B 18:14 C04B 18:10 Z 18:10 18:04 18:04 24:26 E 24:26 14:06) Z 14:06) 103: 32 103: 32 B09B 3/00 ZAB (72) Inventor Hiroshi Yamaoka 10-600-3, Nagasumicho, Gifu City Showa Concrete Industries Co., Ltd. (72) Inventor Hiromi Shimizu 10 Nagasumicho, Gifu City Chome 600-3 Showa Concrete Industry Co., Ltd. (72) Inventor Akinori Miura 10-chome, Nagasumi-cho, Gifu City Showa Concrete Industry Co., Ltd. F-term (reference) 4D004 AA43 BA02 CA15 CA45 CC03 CC13 CC15 DA02 DA03 DA10 DA20 4G012 PA26 PA29 PB31 PC02 PC03 PC12 PD01

Claims (11)

[Claims] 1. A high-fluidity concrete containing water, a binder, a fine aggregate, a coarse aggregate and an admixture and having a slump flow value of 50 cm or more and 80 cm or less, wherein at least a part of the fine aggregate is included. High-fluidity concrete containing molten slag particles. 2. The high fluidity concrete according to claim 1, wherein the binder comprises cement and blast furnace slag fine powder. 3. The high fluidity concrete according to claim 2, wherein the mixing ratio of the blast furnace slag fine powder in the binder is 15 to 50% by weight. 4. The molten slag particle according to claim 1, wherein a content ratio of a particle group having a particle diameter of 0.30 mm to 2.36 mm in the molten slag particle is 50% by weight or more. High fluidity concrete. 5. The high fluidity concrete according to claim 1, wherein the fine aggregate contains sand and molten slag particles. 6. The high fluidity concrete according to claim 5, wherein the mixing ratio of the molten slag particles in the fine aggregate is 5 to 80% by weight. 7. The high fluidity concrete according to claim 1, wherein the admixture is an AE agent, a water reducing agent, an AE water reducing agent or a high-performance AE water reducing agent. 8. The blending ratio of the AE water reducing agent as an admixture to the binder is 0.8 to 1.3% by weight.
7. The high fluidity concrete according to any one of 6. 9. 150 to 200 kg of water expressed in unit amount
/ M ³ , binder 400-700 kg / m ³ , fine aggregate 6
00-1000 kg / m ³ , coarse aggregate 600-1000
comprises kg / m ³ and admixtures 3~10kg / m ^3, a high fluidity concrete slump flow value is 50cm or 80cm or less, wherein the binder comprises a cement and blast furnace slag, the fine bone High fluidity concrete characterized in that the material contains sand and molten slag grains. 10. 160 to 190 k of water expressed in unit amount
g / m ³ , binder 480-620 kg / m ³ , fine aggregate 700-900 kg / m ³ , coarse aggregate 700-900 k
g / m ³ and an admixture of 4 to 8 kg / m ³ , wherein the slump flow value is 65 cm or more and 80 cm or less, wherein the binder comprises cement and blast furnace slag fine powder, High fluidity concrete characterized in that the material contains sand and molten slag grains. 11. A secondary concrete product molded from the high-fluidity concrete according to any one of claims 1 to 10.