JPH05301754A - Concrete composition for self packing - Google Patents

Abstract

PURPOSE:To obtain a concrete composition for self packing requiring no compaction by blending concrete with specific amounts of zeolite and a high- performance water-reducing agent and adjusting slump to >=a given slump flow value. CONSTITUTION:Concrete is blended with 2-10vol.% natural or synthetic zeolite having 0.5-10mum particle diameter and 0.6-3.0wt.% calculated as active ingredient of a high-performance water-reducing agent (e.g. condensate of naphthalenesulfonic acid or its salt and formaldehyde and/or condensate of melaminesulfonic acid or its salt or oxymethylated compound selected from a group consisting of melamine, phenol, urea and aniline and/or a condensate or cocondensate of a sulfonated substance and formaldehyde). A slump flow value is adjusted to >=50cm slump flow value to give a concrete composition for self packing requiring no compaction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-compacting concrete composition which does not require compaction, and more specifically, it enhances the fluidity of concrete used as a building material and a secondary product material to improve the flowability of aggregate, cement and water. The present invention relates to a self-compacting concrete composition which has excellent properties of separation resistance and does not require compaction due to vibration of a vibrator or the like.

[0002]

2. Description of the Related Art Conventionally, as a method of constructing a concrete composition, it has been general to put concrete into a form frame having reinforcing bars and compact it by vibrating a vibrator. However, in recent years, noise pollution caused by a vibrator when placing concrete and shortage of manpower in the concrete industry have become problems.

In order to solve these problems, research on concrete having self-filling property that does not require vibration compaction has been started, but it is the current situation that it has not yet been put into practical use technically.

[0004]

Generally, when the fluidity of concrete is increased, aggregate separation occurs, coarse aggregates are entangled with each other to deteriorate the filling property, and uniform concrete cannot be obtained. Come. In addition, in concrete mixes such as underwater concrete in which a large amount of thickener is added (for example, Japanese Patent Publication No. 62-35984), the aggregate separation is suppressed but the viscosity becomes high, and not only the filling work becomes difficult, However, it is difficult to apply it to construction and civil engineering, especially secondary products, because the initial strength is delayed to develop due to the delay of curing time, which is the property of the thickener.

Recently, the compaction-free concrete composition reported under the name of high performance concrete [Annual Report of Concrete Engineering, pages 63-68 (1989)] contains a large amount of fine powder such as blast furnace slag and fly ash. The curing time is improved compared to the above-mentioned underwater concrete, but it requires a large amount of water due to the large amount of powder, and the water / cement ratio is
Since it is 100%, it is difficult to use it for secondary products that require early demolding.

[0006]

[Means for Solving the Problems] In order to obtain a self-compacting concrete composition, the present inventors have high fluidity, large separation resistance, self-compacting property, and little influence of strength due to retardation of hardening. As a result of intensive studies, the present invention has been completed.

In the present invention, the self-compacting concrete composition is a region having a high fluidity with a slump flow value of 50 cm or more in the slump test specified in JIS-A-1101, and has a specific amount of zeolite and high performance. It is basically mixed with a water-reducing agent and does not contain a substance that causes retardation of curing, such as a thickener or a water-soluble polymer, and can satisfy the separation resistance.

The self-compacting concrete composition of the present invention contains cement, fine aggregate and coarse aggregate as the main components, as well as ordinary concrete composition, and further contains zeolite. The amount of zeolite mixed is 1 m ³ ) 2 per
~ 10% by volume.

If the content of zeolite is less than 2% by volume of concrete, the resistance to separation is lowered, and if it is more than 10% by volume, the fluidity is lowered due to thickening, which is not preferable. The cement and fine aggregate in the present invention are not particularly limited, and those used for ordinary concrete, for example, ordinary Portland cement, early strength Portland cement, blast furnace cement, cement such as fly ash cement, river sand Fine aggregates such as sea sand and crushed sand, and coarse aggregates such as river gravel and crushed stone are used. It can also be used in admixtures such as concrete containing blast furnace slag, fly ash, silica fume and the like.

The zeolite used in the present invention may be natural or synthetic, but synthetic zeolite is advantageous in terms of cost. The shape and particle size of the zeolite are not particularly limited, and it is preferable to use a commonly used zeolite having a particle size of 0.5 to 10 μm.

In the concrete composition of the present invention, in order to obtain high fluidity [slump flow value (specified in JIS-A-1101) of 50 cm or more], a high-performance water-reducing agent is added to cement in an amount of 0.6 to 3.0% by weight as an active ingredient. % Is preferably added.

As a high-performance water reducing agent, a naphthalene sulfonate formaldehyde condensate [for example, Mighty 15
0: manufactured by Kao Corporation or melamine sulfonate formaldehyde condensate [for example, Mighty 150V-2: Kao Corporation]
Manufactured] is used.

Further, as a high-performance water-reducing agent, a formaldehyde monocondensation product or a cocondensation product of a methylol compound and / or a sulfonated compound of melamine, urea, phenol or aniline, for example, a phenolsulfonic acid formaldehyde condensate (Patent No. 1097647) is used. Compounds described in No.),
Phenol / sulfanilic acid formaldehyde co-condensate (compounds described in JP-A 1-113419), phenol / melamine methylolated sulfonic acid co-condensate (JP-A-SHO)
56-13647), urea / melamine methylolated sulfonic acid cocondensates (compounds described in JP-B-52-13991), and the like.

The concrete composition of the present invention is used for concrete moldings. The concrete molded body is not particularly limited, and a molded body compacted by a vibrator is usually targeted. Further, the concrete composition of the present invention can be used for secondary products requiring initial strength. That is, the strength after 24 hours can be 200 kg / cm ² or more by the steam curing method specified in JIS-A-5338 (4-4-2). The strength required for demolding secondary products is 10
Although it is about 0 kg / cm ² , according to the present invention, demolding for a short time of 24 hours or less is also possible.

[0015]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

The materials used in the examples are shown below.

-Cement: Chuo Cement Co., Ltd. specific gravity = 3.16-Fine aggregate: Kinokawa-produced river sand Specific gravity = 2.57-Coarse aggregate: Takarazuka crushed stone Specific gravity = 2.60-Zeolite: Kao Co., Ltd. Specific gravity = 2.60 The compounding composition of the concrete composition adjusted using the material is shown.

[0018]

[Table 1]

Next, in the composition of Table 1, as a high-performance water-reducing agent, a naphthalenesulfonic acid formaldehyde condensate [trade name: Mighty 150, manufactured by Kao Corporation] and a melamine sulfonate formaldehyde condensate [trade name: Mighty 150V] were used. -
Table 2 shows the slump flow value (cm) of the concrete and the separation resistance of the concrete measured by the method of JIS-A-1101 in the case of adding [2, manufactured by Kao Corporation].

The evaluation of the separation resistance is shown below (evaluation by visual observation): No separation of aggregate and water. Δ: Aggregate separation and water separation are slightly present. X: Aggregate separation and water separation.

[0021]

[Table 2]

From Table 2, it can be seen that the concrete composition of the present invention shows a high fluidity with a slump flow value of 50 cm or more, and has good separation resistance, while the comparative product does not contain zeolite and has a mixing ratio. It can be seen that low compositions cannot satisfy both flowability and separation resistance.

Next, Table 4 shows the results of comparison between the composition No. 1 in Table 1, the high-performance water reducing agent shown in Table 3 and the general water reducing agent. The evaluation of separation resistance is the same as above.

[0024]

[Table 3]

[0025]

[Table 4]

From the results shown in Tables 2 and 4, the high-performance water reducing agent is 0.6
% -3.0% (relative to cement solids content) is preferable for performance development.

On the other hand, in the case of the comparative product, although the separation resistance is satisfied, the slump flow value is about 40 cm even if the water reducing agent is added by 5% (relative to the cement solid content%), and the flow effect is not shown. I understand.

Next, the slump flow value, the separation resistance and the compression strength when the composition No. 1 in Table 1 and the high performance water reducing agent No. 1 in Table 3 were used with different addition amounts are shown in Table 6. Shown in.

After the concrete was kneaded, the concrete was packed into a cylindrical form having an inner diameter of 10 cm, left for 2 hours, heated at a rate of 20 ° C. for 1 hour and held at 65 ° C. for 4 hours. , Perform a steam curing method to cool, and after 24 hours, JI
The strength was measured by the SA-1108 method.

Table 5 shows an example of a mixture of low-separation concrete as a comparative product.

[0031]

[Table 5]

[0032]

[Table 6]

From the results in Table 6, it is understood that the compressive strength of the comparative product cannot be measured, whereas the compressive strength of the product of the present invention is 250 kg / cm ² or more.

[0034]

EFFECTS OF THE INVENTION According to the self-compacting concrete composition of the present invention, it becomes possible to secure high fluidity, separation resistance and initial strength. It has been improved, and especially in the production of concrete products, it has a great ripple effect on noise reduction and production rationalization.

Claims (3)

[Claims] 1. Self-filling, characterized in that it contains 2 to 10% by volume of zeolite and a high-performance water-reducing agent with respect to concrete, and has a slump flow value of 50 cm or more according to the slump test method described in JIS-A-1101. Concrete composition. 2. The self-compacting concrete composition according to claim 1, wherein the high-performance water reducing agent is a formaldehyde condensate of naphthalene sulfonic acid or a salt thereof and / or a formaldehyde condensate of melamine sulfonic acid or a salt thereof. 3. The high-performance water reducing agent is melamine, phenol,
The self-compacting concrete composition according to claim 1, which is a formaldehyde monocondensate or cocondensate of a methylol compound and / or a sulfonate compound of a compound selected from the group consisting of urea and aniline.