KR101460097B1 - Admixture for autoclave curing concrete - Google Patents

Abstract

The present invention relates to an admixture for autoclave curing concrete, which is mixed with a material for autoclave curing concrete and includes a mixture of 60 to 90 wt% of silica flour, 5 to 15 wt% of blast furnace slag powder, 2 to 12 wt% of potassium hydroxide (Ca(OH)2), and 3 to 13 wt% of anhydrous gypsum (II-CaSO4). According to the present invention, since the admixture is mixed with a material of autoclave curing concrete, the amount of cement used may be reduced while the concrete property is maintained. Thus, carbon dioxide emission may be reduced so that the admixture is environment-friendly and the cost is reduced.

Description

{Admixture for autoclave curing concrete}

The present invention relates to a mixed material for an autoclave curing concrete, and more particularly, to a mixed material for an autoclave curing concrete capable of reducing the amount of cement used while maintaining the characteristics of concrete mixed with the material of the autoclave curing concrete.

Generally, concrete is formed by mixing, casting, and curing by adding cement, aggregate, and water as main materials and adding a mixed material as needed, and is used in various structures.

When such a concrete is kneaded by adding water to the cement, after losing its plasticity characteristic after lapse of a predetermined time, it solidifies and hardens and finally hardens. In order to prevent the occurrence of defects by providing sufficient strength after the hardened concrete is applied It will be cured to protect it for a certain period of time.

The concrete curing process depends on the weather conditions, the size and shape of the structure, the construction period, and the purpose of use. The wet curing, the steam curing, the electric curing and the membrane curing are cited. ) Can be used.

In such concrete, cement is used as the main material, but it is necessary to develop eco-friendly technology to reduce the amount of cement by reducing the amount of cement, and it is necessary to make efforts to reduce manufacturing cost.

As a conventional technique for a concrete mix material, Korean Patent Laid-Open No. 10-2001-0104765 discloses a method for manufacturing a high strength concrete mixture composition for steam curing. In this method, 2 to 20 parts by weight of zeolite (dry sludge) and 2 to 15 parts by weight of anhydrous gypsum are added to 100 parts by weight of Portland cement, 110 to 230 parts by weight of sand, 150 to 280 parts by weight of coarse aggregate and 20 to 35 parts by weight of water are added, The water reducing agent is prepared by using 1.0 to 2.0 parts by weight of cement.

However, such a conventional concrete admixture is used to increase the strength in steam curing, but it is limited to be used for reducing the amount of cement used by being mixed with existing concrete material. Therefore, it is mixed with the material of the concrete for curing of autoclave It is necessary to develop a product capable of greatly reducing the amount of cement used while maintaining the characteristics of concrete.

In order to solve the problems of the prior art as described above, it is an object of the present invention to reduce the amount of cement used while maintaining the characteristics of concrete mixed with the material of the concrete for autoclave curing. Other objects of the present invention will become readily apparent from the following description of the embodiments.

According to an aspect of the present invention, there is provided a method of manufacturing a honeycomb structure including 60 to 90% by weight of a silica flour, 5 to 15% by weight of a blast furnace slag power, calcium hydroxide (Ca (OH) ) ₂ ) and 2 to 12% by weight of a heterogeneous anhydrous gypsum (II-CaSO ₄ ), and 3 to 13% by weight of a heterogeneous anhydrite (II-CaSO ₄ ) is mixed with the material of the autoclave curing concrete to provide a mixed material for an autoclave curing concrete .

The mixture may be mixed with 0.1 to 3% by weight of naphthalene powder based on the total weight.

The fine silica powder may contain silicon dioxide (SiO ₂ ) in an amount of 94 to 99% by weight, and the powdery degree may be 3,000 to 3,800 cm 2 / g.

The blast furnace slag powder may have a powder degree of 4,800 to 5,200 cm < 2 > / g.

According to the mixed material for an autoclave curing concrete according to the present invention, it is possible to reduce the amount of cement used while maintaining the characteristics of concrete while mixing with the material of the concrete for curing the autoclave, thereby reducing the amount of carbon dioxide emissions, Thereby reducing costs.

1 is a view for explaining the composition of a mixed material for an autoclave curing concrete according to an embodiment of the present invention.
FIG. 2 is a graph showing a first curing condition at the time of manufacturing concrete using a mixed material for an autoclave curing concrete according to an embodiment of the present invention. FIG.
FIG. 3 is a graph showing a second curing condition at the time of manufacturing concrete using a mixed material for an autoclave curing concrete according to an embodiment of the present invention.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in detail in the drawings. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but is to be understood to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention, And the scope of the present invention is not limited to the following examples.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant explanations thereof will be omitted.

1 is a view for explaining the composition of a mixed material for an autoclave curing concrete according to an embodiment of the present invention.

Referring to FIG. 1, the mixed material for an autoclave curing concrete according to one embodiment of the present invention comprises 60 to 90% by weight of silica flour, 5 to 15% by weight of a blast furnace slag power, 2 to 12% by weight of Ca (OH) ₂ and 3 to 13% by weight of a heterogeneous anhydrous gypsum (II-CaSO ₄ ), and may be mixed with the material of an autoclave curing concrete. Also, the mixture for autoclave curing concrete according to one embodiment of the present invention can be prepared by mixing the above-mentioned mixture by dry beanbeam, mixing 0.1 to 3% by weight of naphthalene powder with respect to the total weight of the mixture .

The silica fine powder is added for the purpose of supplementing the silicate, Si component, for the formation of tobermolite of 11 Å in the final target of autoclave curing. The fine silica powder may contain silicon dioxide (SiO ₂ ) in an amount of 94 to 99% by weight, and the powdery degree may be 3,000 to 3,800 cm 2 / g. In order to maximize the reaction with calcium hydroxide (Ca (OH) ₂ ), the higher the degree of powder is, the better the powder is. However, if the degree of powder is excessively high, the water / cement ratio of concrete is increased, The powdery degree may be 3,000 to 3,800 cm 2 / g, for example 3,600 cm 2 / g.

Blast furnace slag powder contains Ca component and Si component of cement, has self-hardening property, is cheaper than cement and added for replacement with cement. The blast furnace slag powder may have a powder degree of 4,800-5,200 cm2 / g considering the water / cement ratio in consideration of the content of the mixture as a whole, for example, 5,000 cm2 / g.

When the mixed concrete is cured at a temperature of 80 ° C in the steam curing chamber of the autoclave, the compressive strength is increased. At this time, the initial strength is higher than that of ordinary concrete, , And industrial calcium oxide (CaO) in an amount of 65 to 75% by weight.

The heterogeneous anhydrite gypsum exhibits the early strength of the concrete cured in the autoclave steam curing chamber and the presence of gypsum (SO ₃ , SO ₄ ^-2 ) leads to the formation of tricalcium aluminate, 1 to produce etringing sate.

[Reaction Scheme 1]

C ₃ A + ₃ C S (-) H ₂ + ₂₆ H? C ₃ A ₃ C S (-) H ₃₂ (etringate)

In the autoclave curing, it remains in the form of a pellet so that the strength is increased.

Naphthalene powder reduces the amount of mixed water used in concrete, thereby reducing the water / cement ratio and contributing to the strength of the concrete.

The mixed material for the autoclave curing concrete according to the present invention is mixed with the concrete material for curing the autoclave to reduce the amount of the cement used. The autoclave curing may mean accelerated curing with saturated steam at 100 ° C or higher, When water is evaporated at a high temperature of 100 ° C or higher and the deterioration of concrete properties is cured by saturated steam of 100 ° C or more, moisture of the concrete is not evaporated, the hydration reaction is promoted, They have a reaction that shows a big difference. Particularly, in the case of autoclave curing, quartz-like silicate remains as an inert material at room temperature, and if water exists at high temperature, calcium silicate hydrate can be produced by rapidly reacting with lime.

A typical material produced in the autoclave curing is tobermolite, which is known to be the most important contributor to strength development in hydrates formed during autoclave curing. In the autoclave curing, silica or silicate is required in order to react with calcium hydroxide. However, silica powder is insufficient as a general formulation, and further silica fine powder is required. Therefore, a silica fine powder is used as an admixture, The substitution rate is 40% by weight in the case of the cement paste, but the powder content of the fine silica powder, the silica content of the fine silica powder, the curing temperature, the silica content of the aggregate used, the type of cement used and the chemical composition, .

In order to compare the compressive strengths of the case where the autoclave curing concrete material according to the present invention was replaced with the concrete material for autoclave curing (Examples 1 and 2) and the case where the material was not substituted (Comparative Example 1) . Example 1 is an example of replacing 30% by weight of a cement mixed material for an autoclave cured concrete according to the present invention, and Example 2 is an example of replacing 40% by weight of a cement mixed material for an autoclave cured concrete according to the present invention.

division Air volume (%) W / C (%) S / A (%) Unit material amount (Kg / m3) C The
Mixed material G S1 S2 W AD COMPARATIVE EXAMPLE 1 1.5 26 38 450 0 1,190 724 114.4 6.6 450 Example 1
30 wt% substitution 1.5 26 38 315 135 1,192 725 114.4 6.6 450 Practical Example 2
40 wt% substitution 1.5 26 38 270 180 1,192 726 114.4 6.6 450
Where W is the unit cement ratio, S / A is the fine aggregate fraction, C is the amount of cement, G is the amount of gravel, S1 and S2 are the amount of sand, W is the amount of water, It is the amount of common ingredients used. In addition, the curing conditions for Comparative Example 1 and Examples 1 and 2 are the first curing conditions by the atmospheric steam curing as shown in FIG. 2 and the second curing conditions by the autoclave curing as shown in FIG. The mixed materials for the autoclave curing concrete according to the present invention substituted in Examples 1 and 2 are as shown in Table 2 below.

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Ingredients Specification Amount of blending
(weight%) Silica Flour 96 wt% of SiO ₂
Powdery figure: 3,600 cm ² / g 75 Blast furnace slag powder
(Blast Furnace Slag Powder) Powdery: 5,000 cm ² / g 10 Calcium hydroxide (Ca (OH) ₂ ) Industrial CaO - 70% 6 Modified anhydrite (II-CaSO ₄ ) 8 Naphthalene Powder One

On the other hand, when 1㎥ of concrete is manufactured by concrete compounding, ordinary portland cement (OPC) is used at 400-450 kg / m3. Demolding concrete has required strength (primary deformation strength) of 400 kgf / The required strength (secondary final strength) of concrete is 800 kgf / ㎠. Accordingly, for the samples of Comparative Examples 1 and 2 and Comparative Examples 1 and 2 in which the mixed material for the autoclave curing concrete according to the present invention was replaced by 30% by weight and 40% by weight of cement, And the secondary ultimate strength is shown in Table 4. < tb > < TABLE >

division Specification diameter
(Cm) Inner light
(Cm) Sectional area
(㎠) Compressive strength
(Kg / cm2) Remarks COMPARATIVE EXAMPLE 1 N1 20.00 12.46 192.13 441 use
possible N2 20.00 12.44 192.52 425 N3 20.00 12.44 192.52 443 Average - - - 436 Example 1
30 wt% substitution N1 20.00 12.40 193.30 432 use
possible N2 20.00 12.40 192.52 425 N3 20.00 12.40 192.52 419 Average - - - 425 Practical Example 2
40 wt% substitution N1 20.00 12.30 195.24 401 use
possible N2 20.00 12.34 194.46 403 N3 20.00 12.34 194.46 411 Average - - - 405

division Specification diameter
(Cm) Inner light
(Cm) Sectional area
(㎠) Compressive strength
(Kg / cm2) Remarks COMPARATIVE EXAMPLE 1 N1 20.00 12.46 192.13 843 use
possible N2 20.00 12.44 192.52 845 N3 20.00 12.44 192.52 832 Average - - - 840 Example 1
30 wt% substitution N1 20.00 12.40 193.30 837 use
possible N2 20.00 12.40 192.52 842 N13 20.00 12.40 192.52 839 Average - - - 839 Practical Example 2
40 wt% substitution N1 20.00 12.30 195.24 822 use
possible N2 20.00 12.34 194.46 814 N3 20.00 12.34 194.46 825 Average - - - 820

As can be seen from Tables 3 and 4, even if the cement is replaced by 30% by weight and 40% by weight by the mixed material according to the present invention, the required strength of the above-mentioned deformation-type concrete (Secondary demolding strength) of 400 kgf / ㎠ and the required strength of final concrete (secondary final strength) of 800 kgf / ㎠, respectively.

According to the mixed material for an autoclave curing concrete according to the present invention, the amount of cement used can be reduced while maintaining the characteristics of concrete mixed with the material of the concrete for curing the autoclave, thereby reducing the amount of carbon dioxide discharged, But also to reduce costs.

Although the present invention has been described with reference to the accompanying drawings, it is to be understood that various changes and modifications may be made without departing from the spirit of the invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

Claims (4)

(II-CaSO ₄ ) 2 to 12% by weight of calcium hydroxide (Ca (OH) ₂ ), 5 to 15 wt% of blast furnace slag power, 3 to 13% by weight, and is mixed with the material for the autoclave curing concrete,
Based on the total weight of the mixture, 0.1 to 3% by weight of naphthalene powder is mixed,
The fine silica powder contains 94 to 99% by weight of silicon dioxide (SiO ₂ ), the powdery degree is 3,000 to 3,800 cm 2 / g,
Wherein the blast furnace slag powder has a powder degree of 4,800 to 5,200 cm < 2 > / g. delete delete delete

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