KR101744272B1 - Admixture composition for autoclave-cured concrete - Google Patents

Abstract

The present invention generally relates to a method for producing a slag, which comprises 25 to 75 parts by weight of Portland cement, 10 to 30 parts by weight of active silica, and 10 to 60 parts by weight of crystalline slag, 0.04% by weight. The present invention relates to a mixed material composition for an autoclave curing concrete which comprises a crystalline slag discharged as an industrial by-product, which is used for concrete production by improving the reactivity using a selective accelerator, The active use of the crystalline slag as a by-product can reduce the environmental pollution problem and reduce the manufacturing cost.

Description

[0001] The present invention relates to an admixture composition for an autoclave cured concrete,

The present invention relates to a mixed material composition for an autoclave curing concrete, and more particularly, to a mixed material composition for an autoclave curing concrete having improved reactivity of crystalline slag using an amine compound having a terminal triol containing a crystalline slag and a selective accelerator ≪ / RTI >

Generally, concrete is formed by mixing, casting, and curing with cement, aggregate, and water as main materials, adding a mixed material as necessary, and is used in various structures. The hardened concrete continues to harden after pouring (construction), and after 28 days, it reaches almost the final compressive strength. The cement chemistry continues until it is cured and exhibits sufficient strength. In this process, the curing process is performed to protect the cement from being damaged due to harmful influences such as temperature, load, impact, fouling, and breakage.

Curing is an important final task in concrete construction. The curing process is determined according to the weather conditions, the size and shape of the structure, the construction period, and the purpose of the curing. The curing is curing, wet curing, atmospheric steam curing, have. In the case of high-temperature and high-pressure curing, curing with an autoclave is used. The autoclave curing method is widely used in high-strength pile and concrete panel.

Concrete secondary products such as concrete pile, sewer pipe and pole are required to have considerable strength, so they are manufactured by mixing the high-strength and high-strength mixed materials and curing and curing at high temperature and high pressure.

The term "slag" refers generally to what is produced as a by-product of the iron and steel industry. More specifically, when a metal is smelted from a furnace, components other than the target metal are combined with the flux and separated from the metal to form an upper layer of the metal. Slag is also called slag, and most of it is composed of silicates.

The slag can be divided into blast furnace slag discharged from the blast furnace and steel slag discharged from the electric furnace or converter, and can be divided into quenched slag (amorphous slag) and slowly cooled slag (crystalline slag) according to the cooling method. In general, the quenched slag exhibits an amorphous glass structure and the slowly cooled slag exhibits crystalline. Further, if the rapid cooling the slag is present in a quenching merchant β-C ₂ S ₂ in the C S, but the cooling rate is considerably slower in the presence of the crystalline slag flow stand cold frame of the C ₂ S γ-C ₂ S phase is mainly produced. The results of XRD pattern analysis of crystalline slag and amorphous slag are shown in FIG.

In the case of amorphous slag, recycling rate is more than 95% and recycling places are various. On the other hand, in case of crystalline slag, recycling rate is lower than that of quench slag, recycling place is simple, and parts that can not be recycled are landfilled. Since recycled crystalline slag causes environmental problems, it is required to develop a method for recycling crystalline slag.

Korean Patent No. 10-0450281 (Method of Manufacturing High Strength Building Material Using Slag Generated in Steelmaking Process) relates to a method of manufacturing a building material using slag generated in a steelmaking process, wherein the average particle size of the slag is 11 탆 Crushing a smaller amount; The silica powder to adjust the mixing ratio of CaO / SiO ₂ to the pulverized steelmaking slag to (35 to 45) wt.% (55 to 65) wt.% And the hydrated reaction accelerator {Ca (OH) ₂ } Mixing together to form a mixture; Press-molding the mixture into a shaped body; And hydrothermally synthesizing the molded body in an autoclave. However, the above-mentioned patent has a disadvantage in that the steelmaking slag must be ground to a particle diameter of 11 탆 or less, and the manufacturing cost is considerably increased by using the slaked lime as a promoter of the hydration reaction.

Korean Patent No. 10-1466064 (a concrete composition for ultra high strength PHC piles and a method for producing a PHC pile using the same) has a unit quantity of 105 to 135 kg / m 3; Unit bonding discretion 450 to 650 kg / m 3; Unit fine aggregate amount 600 to 800 kg / m 3; And a coarse aggregate amount of 1,000 to 1,300 kg / m 3, wherein the binder comprises 5 to 50 parts by weight of a mixed material and 1 to 5 parts by weight of a high-performance water reducing agent based on 100 parts by weight of cement, Wherein the coarse aggregate having a diameter of 10 to 13 mm is contained in an amount of 5 to 40% by weight based on the total weight of the coarse aggregate so that the coarse aggregate has a granulation ratio of 2.5 to 3.5 and a diameter of 2.5 to 3.5 Wherein the cement is at least three types of crude steel cement, wherein the mixed material comprises 40 to 80% by weight of fine silica powder, 10 to 30% by weight of limestone, and 4,000 to 7,000 of powdery material based on the total weight of the mixed material, ~ 6,000cm ² / g and a density of 2.8 ~ 2.95g / cm ³ of the blast furnace slag comprises a fine powder of 10 to 30% by weight, honhapjae silicon dioxide (SiO ₂₎ and 60 to 84% by weight of calcium oxide (CaO in the oxide ) is a 15 to 35% by weight, aluminum (Al ₂ O ₃ oxide) is from 1 to 5% by weight It relates to the characteristics of concrete compositions further comprising ultra-high strength PHC piles to that. The concrete composition for a PHC pile has an effect of producing a PHC file capable of realizing an ultra-high strength of 120 MPa or more early while minimizing the amount of unit bonding material and the use of raw materials . However, the above patent restricts usable cement to at least three kinds of crude steel cements, and thus the production cost is high, and the problem of recycling the slowly cooled crystalline slag can not be solved by using the quenched slag.

In addition, many researches have been carried out to improve the durability of the structure by imparting high durability characteristics by accelerated carbonation curing method using the physicochemical properties of γ-C ₂ S, The feasibility is low due to the size and cost of carbonation equipment.

1. Korean Patent No. 10-0450281 2. Korean Patent No. 10-1466064 3. Korean Patent No. 10-0615826 4. Korean Patent No. 10-0832755 5. Korean Patent No. 10-1034228 6. Korean Patent No. 10-1354074 7. Korean Patent Publication No. 10-2015-0023184

In order to solve the above problems, the present invention is as using crystalline slag flow which occurs, and containing a γ-C ₂ S large amount as a by-product of the steel industry producing a honhapjae for autoclave cured concrete, of γ-C ₂ S It is an object of the present invention to provide a mixed material for an autoclave curing concrete which can stabilize quality and improve quality by using a selective promoter capable of improving low reactivity and which is environmentally friendly and can reduce manufacturing cost.

In order to accomplish the above object, the present invention provides a process for producing an amine-based compound, which comprises 25 to 75 parts by weight of Portland cement, 10 to 30 parts by weight of active silica, 10 to 60 parts by weight of crystalline slag, And 0.01 to 0.04% by weight based on the weight of the crystalline slag. The present invention also provides a mixed material composition for an autoclave curing concrete.

In the mixed material composition, the crystalline slag contains γ-C ₂ S in an amount of 70 wt% or more, and the powdery degree is preferably 5000 cm ² / g or more.

In the mixed material composition, the content of the crystalline slag is more preferably 30 to 40 parts by weight.

In the mixed material composition, the amine compound having the terminal triol is preferably triethanolamine (TEA) or triisopanolamine (TIPA).

The present invention improves the reactivity of the crystalline slag discharged as an industrial by-product by using a selective promoter to reduce the amount of cement used and to use the crystalline slag, which is an industrial by-product, to reduce the environmental pollution problem and reduce the manufacturing cost .

FIG. 1 shows a comparison of XRD pattern analysis results between crystalline slag and amorphous slag.
Figure 2 shows the preferred conditions for the autoclave curing process.
Fig. 3 shows the results of confirming the compressive strengths after steam curing and the compressive strengths after autoclave curing in Example 1 and Comparative Example 1. Fig.
Fig. 4 shows the results of confirming the compressive strengths after steam curing and the compressive strengths after autoclave curing in Example 2 and Comparative Example 2. Fig.
5 shows XRD analysis results of the samples of Example 2 and Comparative Example 2 after autoclave curing.
6 shows SEM analysis results of the samples of Example 2 and Comparative Example 2 after autoclave curing.
7 shows the results of confirming the compressive strengths after steam curing and the compressive strengths after autoclave curing in Example 3 and Comparative Example 3. FIG.
8 shows XRD analysis results of the samples of Example 3 and Comparative Example 3 after autoclave curing.
9 shows SEM analysis results of samples of Example 3 and Comparative Example 3 after autoclave curing.

The mixed material composition for an autoclave curing concrete according to the present invention comprises 25 to 75 parts by weight of Portland cement, 10 to 30 parts by weight of active silica, and 10 to 60 parts by weight of crystalline slag, and an amine having a terminal triol Based compound to 0.01 to 0.04% by weight based on the weight of the crystalline slag.

Crystalline slag is a by-product generated in the steelmaking process, such as ladle slag, stainless steel slag, nickel slag, manganese slag, and magnesium slag, and the content of γ-C ₂ S varies depending on the process. The crystalline slag has on the quality of the final product when using the crystalline slag containing it, γ-C ₂ S is preferred to use the crystalline slag containing at least 70% by weight of γ-C ₂ S to less than 70% by weight Because it can have an adverse effect.

In addition, the crystalline slag in order to obtain the desired compression strength of the powder is also preferably used by pulverizing is at least 5000cm ² / g, it is more preferable to use the powder also pulverized so that they are at 6000cm ² / g.

The crystalline slag is preferably contained in an amount of 10 to 60 parts by weight, more preferably 30 to 40 parts by weight.

crystalline slag, which contain large amounts of γ-C ₂ S are so utilized is limited due to the low reactivity of the γ-C ₂ S, in the present invention, while promoting the reactivity of the γ-C ₂ S does not adversely affect the quality of the concrete products Use a selective accelerator.

An amine-based compound having an end-group triol is used as a selective promoter for improving the low reactivity of γ-C ₂ S. The amine-based compound having an end-group triol selectively stimulates γ-C ₂ S under a high-temperature and high-pressure process, thereby promoting the reactivity of γ-C ₂ S and without adversely affecting the quality of the concrete product. Representative examples of amine-based compounds having an end-group triol include TEA (triethanolamine, triethanolamine), TIPA (triisopanolamine, triisopanolamine) and the like. It is more preferable to use TEA. The selection accelerator is preferably incorporated in an amount of 0.01 to 0.04% by weight, more preferably 0.02 to 0.03% by weight, based on the weight of the crystalline slag.

It is more preferable that the amine compound having an end-group triol as the selective accelerator is incorporated into the crystalline slag before crushing and pulverized together.

As the pulverizer, any conventional pulverizer such as a vibrating mill, a ball mill, a roller mill, and a disc mill can be used, but it is more preferable to use a vibrating mill to obtain a mechanochemical effect.

In the preferred autoclave curing step, the product is preheated at 20 to 25 ° C. for 2 hours, heated to 80 ° C. for 3.5 hours at 17 ° C. per hour, maintained at 80 ° C. for 6 to 8 hours, Transferred to an autoclave curing unit, and then heated up to 180 ° C at 64 ° C per hour for 2.5 hours, maintained at 180 ° C for 6 hours, and allowed to cool to room temperature. A preferred autoclave curing process is shown in Fig.

The calcium silicate hydrate produced by the autoclave curing reaction is a structurally regular crystalline hydrate, of which tobermorite is the most commonly used industrially. Tobermoryite is most widely used because it is easily produced at a temperature of 180 ° C at the autoclave temperature even when relatively inexpensive raw materials or low-purity industrial by-products are used as the silicate source.

It is common to control the molar ratio of CaO / SiO ₂ , and it is usually adjusted to the range of about 0.89 to 1.1 in order to make the tobermorite the easiest to produce. Therefore, it is preferable to control the molar ratio of CaO / SiO ₂ to the range of about 0.89 to 1.1 on the basis of the values obtained from the chemical composition formula of ordinary portland cement, activated silica, and magnesium smelting slag, which are raw materials used in the present invention, It is more preferable to adjust the molar ratio of CaO / SiO ₂ to 1.

Hereinafter, the present invention will be described in detail with reference to examples. The following examples illustrate the present invention and the scope of the present invention is not limited to these examples.

[ Example ]

Test Methods

1. Mixing of materials

After the chemical composition of the materials was determined, the molar ratio of CaO / SiO ₂ was calculated and the materials were dry-mixed. Each material was dry mixed and then mixed using a mortar mixer under the conditions of water / powder ratio = 48.5% and powder / sand ratio = 2.45. The mixed mortar was molded using a 5 cm x 5 cm x 5 cm cube-shaped mold to prepare a molded article.

2. Curing

The autoclave curing was cured under the conditions shown in Fig.

3. Measurement of compressive strength

The compressive strength was measured at two places using a compressive strength tester. That is, the steam curing strength after holding at 80 ° C for 6 hours and demolding and the autoclave curing strength after holding at 180 ° C for 6 hours were measured.

< Example  1>

Magnesium smelting slag  Comparison of Compressive Strength According to Amount of Powder Replacement

The magnesium smelting slag was prepared by pulverizing using a pulverizer to a powder degree of 4000 cm ² / g. At this time, a laboratory ball mill was used.

In order to easily produce tobermorite, the molar ratio of CaO / SiO ₂ is calculated as 1 based on the values obtained from the chemical composition formula of ordinary portland cement, activated silica, and magnesium smelting slag, which are raw materials used in this embodiment . The blending ratios are shown in Table 1 below, and the blending ratio is in parts by weight.

Usually Portland Cement Active silica Magnesium smelting slag Example 1-1 61.6 28.4 10 Examples 1-2 54.8 25.2 20 Example 1-3 48.0 22.0 30 Comparative Example 1 68.4 31.6 -

The results of measuring the compressive strength immediately after steam curing and the compressive strength after autoclave curing are shown in Table 2 and FIG. 3 for the samples.

Strength after steam curing Strength after autoclave Example 1-1 18.5 45.4 Examples 1-2 15.1 44.2 Example 1-3 12.4 42.4 Comparative Example 1 23.1 48.4

The magnesium smelting slag was pulverized to 4000 cm ² / g and then substituted by 10 to 30 parts by weight. As a result, the compression strength after steam curing was about 53.7% as compared with that of Comparative Example 1, The compressive strength after curing was 87.6%. Also, as the amount of magnesium smelting slag increased, the compressive strength tended to decrease. This is because the reactivity of γ-C ₂ S, which accounts for most of the constituents of magnesium slag, is very low, and thus the hydrothermal reaction is not properly exhibited even under high temperature and high-temperature curing conditions.

< Example  2>

Of magnesium smelting slag Powder aid  Comparison of Compressive Strength According to Use of Selective Accelerator

The magnesium smelting slag was prepared by using a pulverizer to improve the powder viscosity from 4000 cm ² / g to 6000 cm ² / g. In this case, a pulverizer was intended to obtain a mechanochemical effect on the magnesium smelting slag particles pulverized by using a batch type vibration mill in place of the batch ball mill of Example 1.

In addition, TIPA and TEA were mixed with 0.02% of the magnesium smelting slag weight as a selective promoter. The mixing ratio is shown in Table 3 below, and the mixing ratio is in parts by weight.

Usually Portland Cement Active silica Magnesium smelting slag TIPA TEA Example 2-1 48.0 22.0 30 - - Example 2-2 48.0 22.0 30 0.02 - Example 2-3 48.0 22.0 30 - 0.02 Comparative Example 2 68.4 31.6 - - - * TIPA and TEA are mixed with 0.02% by weight of magnesium smelting slag weight.

The results of measuring the compressive strength immediately after steam curing and the compressive strength after autoclave curing are shown in Table 4 and FIG. 4, respectively.

Strength after steam curing Strength after autoclave Example 2-1 12.0 54.2 Example 2-2 14.0 55.8 Example 2-3 13.7 65.8 Comparative Example 2 18.2 44.6

(1) Comparison of compressive strength with increase of powderiness

With the magnesium Slag fineness compared to 6000cm ² / g in Example 2-1 and the fineness is 4000cm ² / g in Example 1-3, if raising the fineness of the magnesium slag refining to increase the compressive strength Respectively.

(2) Comparison of compressive strength with use of selective accelerator

Compared with Example 2-1 in which the selection accelerator was not used, it can be seen that the compressive strength of Examples 2-2 and 2-3 using the selective accelerator was increased. This suggests that amine-based selective accelerators with an end-group triol stimulated the low-reactivity γ-C ₂ S and increased the reactivity under high-temperature and high-pressure conditions, thus favoring the formation of tobermorite during autoclave curing.

(3) Comparison of compressive strengths according to the type of selective promoter

Among the amine-based selective accelerators, Example 2-3 using TEA showed excellent compressive strength compared to Example 2-2 using TIPA.

In order to confirm the reason, the hydration product phase was observed by XRD-Rietveld analysis, and the result was shown in FIG. 5. The FE-SEM analysis was performed to observe the formation phase and the structure according to hydration The results are shown in Fig.

Generally, the strength development of concrete products for autoclave curing is known to be realized by tobermorite. As a result of the XRD analysis of FIG. 5 and the SEM analysis of FIG. 6, in the case of Example 2-3 using TEA as the selective promoter, the size of the tobermorite produced was smaller than that of Example 2-2 using TIPA, It was confirmed that the strength was the best in the compressive strength test.

< Example  3>

Of magnesium smelting slag  Comparison of compressive strength according to substitution amount

The effect of substituting amount of magnesium smelting slag with 6000cm ² / g powder by using TEA as a selective accelerator and batch type vibration mill on the mixed material for autoclave curing concrete was investigated. The compounding ratio is shown in Table 5 below, and the unit of the compounding ratio is parts by weight.

Usually Portland Cement Active silica Magnesium smelting slag TEA Example 3-1 61.6 28.4 10 0.02 Example 3-2 48.0 22.0 30 0.02 Example 3-3 27.4 12.6 60 0.02 Comparative Example 3 68.4 31.6 - - * TEA is mixed with 0.02% by weight of magnesium smelting slag weight.

The results of measuring the compressive strength immediately after steam curing and the compressive strength after autoclave curing are shown in Table 6 and FIG. 7, respectively.

Strength after steam curing Strength after autoclave Example 3-1 14.7 48.9 Example 3-2 13.7 65.8 Example 3-3 9.8 44.6 Comparative Example 3 17.6 41.4

From the results of Table 6 and FIG. 7, it can be seen from the results of Table 7 that when the magnesium smelting slag of 6000 cm ² / g was replaced by 10 parts by weight, 30 parts by weight and 60 parts by weight, The compressive strength after autoclave curing is superior.

In addition, the hydration product phase was observed through XRD-Rietfeld analysis, and the results are shown in FIG. 8, and FE-SEM analysis was performed to observe the formation phase and texture of the product by hydration.

From the results of Figs. 8 and 9, the amount of tobermorite produced in the autoclave curing began to remarkably start from 10 parts by weight, but the amount of tobermorite produced remarkably increased at 30 parts by weight, SEM analysis showed that the addition of 30 to 40 parts by weight of the composition in terms of the density of the tissue and the size of the tobermorite layer would provide the best quality.

Claims (4)

25 to 75 parts by weight of ordinary Portland cement, 10 to 30 parts by weight of active silica, and 10 to 60 parts by weight of crystalline slag containing γ-C ₂ S,
0.01 to 0.04 parts by weight, based on 100 parts by weight of the crystalline slag, of an amine compound having an end-group triol as a selective promoter,
Wherein the selection accelerator is mixed with the crystalline slag and pulverized together with a vibrating mill. The method according to claim 1,
Wherein the crystalline slag contains γ-C ₂ S in an amount of 70% by weight or more, and the powdery degree is 5000 cm ² / g or more. 3. The method according to claim 1 or 2,
And the crystalline slag is contained in an amount of 30 to 40 parts by weight. The method according to claim 1,
Wherein the amine-based compound having an end-group triol is triethanolamine (TEA) or triisopanolamine (TIPA).

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