JP3082861B2 - Hydraulic composition for high-strength concrete and method for producing high-strength mortar or concrete - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic composition for mortar and concrete used in the fields of construction and civil engineering, and a method for producing high-strength mortar and high-strength concrete using the same.

[0002]

2. Description of the Related Art Blast furnace slag fine powder has inherently hydraulic potential, and has been conventionally produced as blast furnace cement by mixing with cement, masonry and the like, and is commercially available. In addition, cement, blast furnace slag fine powder, other admixtures, aggregates, and the like are separately measured, mixed, and kneaded in a batcher plant, and concretes adapted to various uses are also manufactured. The blast furnace slag fine powder used in these powders generally has a Blaine specific surface area of about 4,000 to 4,500 cm ² / g. More recently, slag fine powder has been atomized by a classifier or the like to obtain ultrafine powder with a Blaine specific surface area of about 8,000 cm ² / g, which is used instead of conventional slag fine powder for the purpose of obtaining high strength. ("The 8th Annual Meeting of Concrete Engineering", 1986, pp.289-292).

[0003] Examples of hydraulic compositions containing fine particles include inorganic solid particles A having a particle size of 50 ° to 0.5 µm and a particle size of 0.5 µm.
A hydraulic composite material comprising solid particles B having a size of m to 100 μm and one order of magnitude larger than the particles A and a surface active dispersant is known (Japanese Patent Publication No. 60-59182). The solid particles A are, for example, silica fume, and the solid particles B are, for example, Portland cement.

[0004]

[Problems to be Solved by the Invention] Normal Blaine value of 4,50
Although slag fine powder of about 0 cm ² / g has hydraulic properties, it has the disadvantage that the strength at the initial age is lower than that of ordinary Portland cement, and it is difficult to obtain high strength. Further, the fine powder having a Blaine value of about 8,000 cm ² / g obtained by classifying the above-mentioned granulated blast furnace slag fine powder has a high strength, but still has a low initial strength at 3 days old strength.

[0005] This is an example of concrete using silica fume as an admixture, for which research results have recently been published. In this case, the water / binder ratio must be 0.30 or less.
The problem is that the concrete is not sticky and has poor workability because it does not have an ultra-high strength exceeding 1,000 kgf / cm ² and contains a large amount of a high-performance water reducing agent. An object of the present invention is to obtain a hydraulic composition capable of obtaining high strength more easily than in the past by effectively utilizing the hydraulic properties of blast furnace slag itself.

[0006]

SUMMARY OF THE INVENTION The above-mentioned object is to achieve a particle size of 10%.
90% by weight or more of fine blast furnace slag powder
m is not less than 50% by weight and not more than 80% by weight, and 1 μm
The problem is solved by a hydraulic composition comprising a vitreous blast furnace slag fine powder having a m-passage of 10% by weight or more and 20% by weight or less and cement.

The vitreous blast furnace slag fine powder used in the hydraulic composition of the present invention has a particle size of 10 μm passing through 90 wt% or more, 5 μm passing through 50 wt% to 80 wt%, and 1 μm passing through. Is 10% by weight or more and 20% by weight or less. The range of the particle size distribution is shown by oblique lines in FIG. Such a fine powder may be obtained by finely pulverizing a vitreous blast furnace slag such as a granulated blast furnace slag using a known pulverizer, or a pulverized blast furnace slag having a Blaine value of 4,000 to 4 which has already been pulverized for cement or the like. , About 500 cm ² / g.

[0008] The cement itself forms a hydrated structure and has an alkaline stimulating action on the slag powder, and is specifically Portland cement or a mixed cement containing at least 30% Portland cement.

The ratio between the vitreous blast furnace slag fine powder and the cement is 20 to 80% by weight, preferably 40 to 80% by weight.
60% by weight, so the cement is 80-20% by weight, preferably
60 to 40% by weight. If the amount is less than 20% by weight, the effect of the slag is not exhibited. If the amount is more than 80% by weight, the amount of the cement which is a reaction stimulating material of the slag is too small.

The above-mentioned hydraulic composition has a lower SO ₃ content than ordinary Portland cement. Therefore, higher strength can be obtained by adding SO ₃ in the form of powdered stone. This stone can be used in dihydrate, hemihydrate or anhydrous. The amount of added stone blast is 15 parts by weight or less, preferably about 2 to 8 parts by weight of powdered stone as SO _{3 with} respect to 100 parts by weight of blast furnace slag fine powder and cement in total. S
The reason why the maximum value of the O ₃ amount is set to 15 parts by weight is that if it is added more than that, there is a risk of abnormal expansion of the hardened body, and furthermore, there is a possibility that the steel material in the hardened body is corroded.

In order to obtain high strength by using the hydraulic composition of the present invention as a binder for concrete and mortar, water / water
It is necessary that the binder ratio be about 0.5 to 0.3 by weight. 0.
If it is larger than 5, the cured product is inferior in compactness, and if it is smaller than 0.3, the concrete becomes highly viscous and poor in workability like concrete mixed with silica fume, and the amount of water becomes too small from the reaction surface of the slag. Sand, as aggregate for ready-mixed concrete and mortar
It goes without saying that gravel and the like are blended, but the blending amount may be the same as in the case where conventional cement is used for the binder.

The hardening of the raw mortar and the raw concrete may be carried out at room temperature, but by carrying out steam curing at 40 ° C. to 80 ° C., the strength can be obtained in a short period of time. This steam curing is carried out at the above-mentioned temperature in the presence of saturated steam. Specifically, the steam-cured composition molded to keep the saturated steam is placed in a closed room or wrapped in vinyl to saturate the steam. The condition is maintained during curing. The curing time is suitably 2 hours to 24 hours, and optimally about 4 to 12 hours is suitable from the viewpoint of strength and economy.

[0013]

[Function] Since vitreous blast furnace slag is not crystallized,
There is no change in the composition due to the size of the particles even when crushed. Therefore, atomizing the slag increases the surface area per unit weight, and increases the reactivity of the slag in the initial age.
Therefore, in order to increase the strength at an early age (particularly about 3 to 7 days), it is necessary to secure a highly reactive fine particle. In the hydraulic composition of the present invention, not only the strength at the initial age but also the final strength of the cured product is increased by pulverizing blast furnace slag fine powder and combining it with cement.

By the way, if all the particles are composed of ultrafine particles of 1 μm or less, there will be no long-term reaction, and the long-term strength will deteriorate. Therefore, the particles of 1 μm or less, which are the fine particles of the vitreous blast furnace slag fine powder, are reduced to 10 to 20% by weight, and the particles of 1 to 5 μm and
By adjusting the particle size of 10 μm to the above ratio, both the improvement of the initial strength and the elongation of the long-term strength can be satisfied.

[0015]

EXAMPLE 1 Granulated blast-furnace slag having a particle size range according to the present invention was prepared by the following procedure. The granulated slag of the raw material having an average particle size of 1.2 mm is classified into powder having an average particle size of 13.5 μm by a ball mill to obtain an average particle size of about 3 μm, and the fine particles collected in the bag filter are added. A vitreous blast furnace slag fine powder indicated by a solid line was obtained. Its brane specific surface area is
12,300 cm ² / g. As a comparison, the particle size distribution of the granulated blast furnace slag powder Blaine specific surface area of 4,500cm ² / g by the one-dot chain line in the figure, and Blaine specific surface area of the particle size distribution of the granulated blast furnace slag powder 8,000cm ² / g FIG.

[0016] 200 kg of ordinary Portland cement (a product of Daiichi Cement Co., Ltd.) is added to 200 kg of the above blast furnace slag fine powder.
g was mixed to obtain a hydraulic composition.

160 kg of water and gravel (hard
1026 kg of sandstone, 807 kg of sand (river sand) and high-performance water reducing agent
Opild 8N, Bozoris product) 6.00kg mixed with ready-mix
Cleats were made. For comparison, the blast furnace slag fine
200 kg (400 kg total) of the same ordinary Portra instead of powder
Cement (Comparative Example 1), Blaine specific surface area 4,500cm ^Two
/ g blast furnace granulated slag powder (Comparative Example 2) or Blaine ratio table
Area 8,000cm^Two/ g blast furnace granulated slag powder (Comparative Example 3)
Then, a ready-mixed concrete of a comparative example was produced. cement,
Water, gravel and sand were the same as in the example, but the high performance water reducing agent was
Comparative example according to the difference in adsorption capacity of cement and slag
Sample No. 1 weighed 4.96 kg, Comparative Examples 2 and 3 each had 4.40 kg.
kg. Further, in Comparative Example 1 in which no slag was used,
To increase the cement from 400 kg to 533 kg and increase the gravel to 1026 kg.
To 1020 kg and sand from 807 kg to 719 kg
Make ready-mixed concrete with the water reducing agent increased to 9.38 kg,
This was designated as Comparative Example 4. Example 2 is the cement of Comparative Example 4.
Of the present invention, sand, gravel and water reducing agent were used in Comparative Example 4
Adjusted to obtain a slump of almost the same level as
It is. Table 1 shows the mixing ratio of each ready-mixed concrete. each
Inject concrete into 10cmφ × 20cm formwork
After curing in a curing room at 20 ° C and 80% RH for 1 day, remove
And then cured and cured in water at 20 ° C to determine the change in compressive strength over time.
Table 2 shows the measured results.

[0018]

[Table 1]

[0019]

[Table 2]

The product of the present invention has almost the same strength as Comparative Example 1 containing almost no slag by the age of 3 days, and after 7 days, the strength sharply exceeds the comparative example. 00
More than 0kgf / cm ^2. On the other hand, Comparative Example 2 is an example in which ordinary slag fine powder is used. However, as compared with Comparative Example 1, the strength of Comparative Example 1 cannot be exceeded even with a 91-day material age. Comparative Example 3
Is a slag with a brane specific surface area of 8,000 cm ² / g, but the results obtained according to the conventional knowledge of overcoming the strength of Comparative Example 1 after 28 days were obtained, but the strength of the present invention was much higher than that . Comparative Example 4 was a compound containing no slag having a water-cement ratio of 0.30, which is considered to be the limit of the current practical level.
Even in the day timber order, it did not reach 1,000 kgf / cm ² , indicating the superiority of the product of the present invention. Example 2 shows the result of the water-cement ratio (the cement in this case is the product of the present invention) of 0.30. The advantage of is obvious.

Example 2 A ready-mixed concrete was prepared by adding the anhydrous stone of 7% in SO ₃ amount to the product of Example 1, and the strength development was examined.

[0022]

[Table 3] As described above, the strength development effect in the early age is large.

Example 3 The product of Example 1 was cast and left in the air at 20 ° C. for 2 hours, followed by steam curing at 60 ° C. for 8 hours. It was allowed to cool and a strength test was performed 7 days after the material age. As a result, a strength of 1,070 kgf / cm ² was obtained, and the result of steam curing was recognized.

[0024]

As described above, according to the present invention, the effect of increasing the initial strength and the long-term strength of the hydraulic composition can be obtained by adjusting the viscosity of the granulated blast furnace slag powder. By limiting the proportion of the cement, the reactivity of the slag could be effectively utilized. Improvement of the initial strength was observed by the addition of stone. For example, a hydraulic composition of the present invention is a hydraulic composition for high-strength concrete and mortar, as concrete having a water / binder ratio of 0.4 and a concrete exceeding 1,000 kgf / cm ² was obtained by a 28-day material age. As effective. In addition, steam curing is an economically effective method for producing concrete because 28 days strength can be obtained by 7 days old material in order to increase the reactivity of slag.

[Brief description of the drawings]

FIG. 1 is a graph showing the particle size distribution of blast furnace slag fine powder used in the hydraulic composition of the present invention.

[Explanation of symbols]

1 ... conventional slag powder conventional slag powder 3 ... Blaine specific surface area of 8,000cm ² / g of the slag powder 2 ... Blaine specific surface area of 4,500cm ² / g used in Example

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazuyoshi Sato 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (56) References JP-A-63-74943 (JP, A) JP-A-2 −289453 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 28/04 C04B 18/14 C04B 20/00 C04B 22/14

Claims (6)

(57) [Claims] 1. A particle having a particle diameter of 10 μm passes through 90% by weight or more of the blast furnace slag fine powder and a particle diameter of 5 μm passing through 50% by weight or more
0% by weight or less, and 1 μm passing amount is 10% by weight or more 2
Hydraulic composition comprising glassy blast furnace slag fine powder of 0% by weight or less and cement 2. The blast-furnace slag fine powder is composed of 20 hydraulic compositions.
2. The hydraulic composition according to claim 1, wherein the content of the cement is from about 80% by weight to about 80% by weight. 3. A hydraulic composition comprising 100 parts by weight of the hydraulic composition according to claim 2 and 15 parts by weight or less of SO ₃ as SO ₃ amount. 4. A water / binder ratio by weight of a hydraulic composition comprising a vitreous blast furnace slag fine powder having a particle diameter of 10 μm or more of 90% by weight or more of the blast furnace slag fine powder and cement as a binder. Mortar or ready-mixed concrete with 0.3 to 0.5 5. The water / binder ratio of the hydraulic composition according to claim 1, 2, or 3 as a binder, in a weight ratio of 0.3 to 0.1.
Fresh mortar or ready-mixed concrete 6. A method for producing mortar or concrete, comprising subjecting the raw mortar or concrete according to claim 4 or 5 to hardening and curing at 40 to 80 ° C. under saturated steam.