KR102252333B1 - Binder compositon using limestone sludge and hardened product thereof - Google Patents

Abstract

The composition of the present invention can express characteristics comparable to that of conventional Portland cement by mixing limestone sludge, an industrial by-product, in a blast furnace slag-based binder activated by alkaline earth metal hydroxide in a specific ratio. Therefore, the cured product obtained from the composition can be widely applied to the general civil engineering field, building material, lightweight aggregate, agricultural and fishery field, where the existing Portland cement was used.

Description

Binder composition using limestone sludge and its hardened material {BINDER COMPOSITON USING LIMESTONE SLUDGE AND HARDENED PRODUCT THEREOF}

The present invention relates to a limestone sludge-containing binder composition and a cured product thereof. Specifically, the present invention relates to a technology for producing a hardened body with excellent properties that can replace the existing Portland cement by using a composition in which an additive is mixed with limestone sludge and blast furnace slag, which are industrial by-products.

Portland cement is the most important and widely used structural material for construction in the process of industrial modernization, and is a basic material in the construction of various social overhead capital (SOC) such as roads, bridges, tunnels, ports, houses, and buildings. These cements are manufactured using limestone as the main raw material and are produced at a high temperature (about 1,500°C) during the firing process, that is, clinker manufacturing, and 0.7 to 1.0 tons of carbon dioxide gas is discharged per ton of cement produced in this process.

Accordingly, although cement has played an important role in the construction industry so far, the tendency to be recognized as a negative material for nature and the global environment is increasing in recent years. Domestic cement production is about 63 million tons per year, and about 56.7 million tons of carbon dioxide are emitted. As part of a countermeasure against this, research to replace cement using industrial by-products is ongoing (refer to Korean Patent Publication No. 2002-0070527).

Limestone, the raw material of cement, is mined over 50 million tons per year in Korea. Water is sprayed into the air to remove limestone dust generated during the mining process. In this process, limestone dust and moisture in the air meet to generate limestone sludge. Limestone sludge is an industrial by-product and requires a separate cost to treat it, and most of it is buried in the ground, causing environmental pollution. In particular, if limestone sludge is not properly managed, there is also a problem of clogging of sewage pipes.

Korean Patent Application Publication No. 2002-0070527

The inventors of the present invention were researching ways to recycle limestone sludge, an industrial by-product, as a construction material, when adding limestone sludge in a specific ratio to the blast furnace slag-based binder composition activated with alkaline earth metal hydroxide, It was found that it can express similar properties.

Therefore, the present invention is to provide a blast furnace slag-based binder composition that can replace the existing Portland cement by utilizing limestone sludge. In addition, the present invention is to provide a cured product having excellent properties obtained from the binder composition and a method of manufacturing the same.

The present invention provides a composition comprising 100 parts by weight of blast furnace slag, 5 to 20 parts by weight of alkaline earth metal hydroxide, and 5 to 45 parts by weight of limestone sludge.

In addition, the present invention comprises the steps of preparing a composition comprising 100 parts by weight of blast furnace slag, 5 to 20 parts by weight of alkaline earth metal hydroxide, and 5 to 45 parts by weight of limestone sludge; Mixing water with the composition to obtain a paste; And it provides a method for producing a cured product comprising the step of curing the paste.

In addition, the present invention provides a cured product obtained from a composition comprising 100 parts by weight of blast furnace slag, 5 to 20 parts by weight of alkaline earth metal hydroxide, and 5 to 45 parts by weight of limestone sludge.

The composition of the present invention can exhibit characteristics comparable to that of conventional Portland cement by mixing limestone sludge in a specific ratio to a blast furnace slag-based binder activated by alkaline earth metal hydroxide.

In addition, the composition is eco-friendly by using limestone sludge and blast furnace slag, which are industrial by-products, as main components, compared to the existing Portland cement, and is manufactured by simply mixing materials without a large manufacturing facility, so the manufacturing cost is very low.

Accordingly, the composition of the present invention and the cured product prepared therefrom can be widely applied to the general civil engineering field, building material, lightweight aggregate, agricultural and fishery field, in which the existing Portland cement was used.

1A and 1B show particle size distribution and XRD patterns of blast furnace slag fine powder (GGBFS) and limestone sludge (LF), respectively.
2A and 2B are results of measuring the compressive strength of cured products obtained from calcium hydroxide or barium hydroxide activated binder composition.
3A to 3C are XRD patterns of cured products obtained from a calcium hydroxide activated binder composition.
4A to 4C are XRD patterns of cured products obtained from a barium hydroxide activated binder composition.
5A to 5D are TG/DTG measurement results of cured products obtained from calcium hydroxide or barium hydroxide activated binder composition.
6A to 7D are MIP measurement results of cured products obtained from calcium hydroxide or barium hydroxide activated binder composition.
8A and 8B are photographs of brick samples obtained from calcium hydroxide or barium hydroxide activated binder compositions.

Hereinafter, the present invention will be described in more detail.

[Composition]

The composition according to the present invention includes 100 parts by weight of blast furnace slag, 5 to 20 parts by weight of alkaline earth metal hydroxide, and 5 to 45 parts by weight of limestone sludge.

Hereinafter, each component will be described in detail.

Blast Furnace Slag

_{The blast furnace slag may be formed by reacting SiO 2} and Al ₂ O ₃ in ash of a main raw material (iron ore) and an auxiliary raw material (coke, limestone) with lime at high temperature.

For example, the blast furnace slag may include CaO, SiO ₂ , Al ₂ O ₃ , MgO and SO ₃ , but is not limited thereto. Specifically, the blast furnace slag may contain 40 to 50% by weight of CaO, 30 to 36% by weight of _{SiO 2 , 10 to 15% by weight of Al 2} O ₃ , 1 to 5% by weight of MgO, and 1 to 5% by weight of _{SO 3} have.

In addition, the blast furnace slag may contain 0.1 to 1.0% by weight of each of at least one component selected from the group consisting _{of TiO 2} , Fe ₂ O ₃ , K ₂ O, MnO and Na _{2 O.}

The blast furnace slag may be in the form of a powder, and may have an average particle diameter of 1 to 100 µm, 1 to 50 µm, 3 to 25 µm, or 5 to 20 µm, for example. When it is within the range of the particle diameter, there is an advantage that the curing speed is further improved.

In addition, the blast furnace slag may have ^{a density of 2.88 to 2.94 g/cm 3} , a moisture content of 0.4 wt% or less, and a specific surface area of ^{4,000 to 6,000 cm 2 /g.}

The blast furnace slag may be included in an amount of 60 to 89% by weight based on the total weight of the composition. When it is within the above content range, the strength of the cured product can be further improved, and it is advantageous in terms of manufacturing cost. Specifically, the blast furnace slag is 60 to 79% by weight, 65 to 85% by weight, 71 to 89% by weight, 75 to 85% by weight, 70 to 80% by weight, 70 to 89% by weight based on the total weight of the composition. , Or 60 to 80% by weight may be included.

The composition contains little, and preferably no, existing Portland cement. For example, the content of Portland cement in the composition may be less than 1% by weight or less than 0.1% by weight.

Alkaline earth metal hydroxide

The alkaline earth metal hydroxide added to the composition acts as an activator and chemically reacts with the blast furnace slag during the curing process to form a cured product having excellent strength.

The alkaline earth metal hydroxide may include at least one of calcium hydroxide and barium hydroxide. Specifically, the alkaline earth metal hydroxide may include barium hydroxide.

The alkaline earth metal hydroxide may be in the form of a powder, and specifically, may have an average particle diameter of 1 to 500 µm, 1 to 100 µm, or 1 to 50 µm.

The composition includes 5 to 20 parts by weight of the alkaline earth metal hydroxide based on 100 parts by weight of the blast furnace slag. For example, the composition comprises 5 to 15 parts by weight, 5 to 10 parts by weight, 7 to 17 parts by weight, 10 to 20 parts by weight, or 10 to 15 parts by weight of the alkaline earth metal hydroxide relative to 100 parts by weight of the blast furnace slag can do. Specifically, the composition may include 12 to 15 parts by weight of the alkaline earth metal hydroxide based on 100 parts by weight of the blast furnace slag. When it is within the above content range, the strength of the cured product can be further improved, and it is advantageous in terms of manufacturing cost.

Limestone sludge

The composition comprises 5 to 45 parts by weight of the limestone sludge relative to 100 parts by weight of the blast furnace slag. For example, the composition is based on 100 parts by weight of the blast furnace slag, 5 to 20 parts by weight, 10 to 45 parts by weight, 10 to 25 parts by weight, 15 to 30 parts by weight, 20 to 40 parts by weight, or 25 to It may contain 45 parts by weight. Specifically, the composition may include 15 to 35 parts by weight of the limestone sludge relative to 100 parts by weight of the blast furnace slag.

The limestone sludge may include fine limestone powder (solid content), and the content of the fine limestone powder may be 10 to 40 parts by weight compared to 100 parts by weight of the blast furnace slag. For example, the amount of the limestone fine powder may be 10 to 30 parts by weight, 20 to 40 parts by weight, 15 to 35 parts by weight, 25 to 40 parts by weight, or 10 to 25 parts by weight relative to 100 parts by weight of the blast furnace slag.

The limestone sludge may be obtained as an industrial by-product. For example, water is sprinkled in the air to remove limestone dust generated during the mining process. In this process, limestone dust and moisture in the air may meet to generate limestone sludge.

The moisture content of the limestone sludge is 1 to 40% by weight, 1 to 20% by weight, 20 to 40% by weight, 10 to 30% by weight, 10 to 20% by weight, 20 to 30% by weight, or 15 to 25% by weight. I can. Specifically, the limestone sludge may have a moisture content of 10 to 30% by weight.

For example, the limestone sludge may include CaO, SiO _2, Al ₂ O ₃ , Fe ₂ O ₃ , MgO and K ₂ O, but is not limited thereto. Specifically, the limestone sludge is CaO 58 to 68 wt%, SiO ₂ 15 to 25 wt% _, Al ₂ O ₃ 5 to 11 wt%, Fe ₂ O ₃ 1 to 5 wt%, MgO 1 to 5 It may contain 1 to 5% by weight and K _{2 O.}

In addition, the limestone sludge may contain 0.1 to 1.0% by weight of each of at least one component selected from the group consisting _{of TiO 2} , P ₂ O ₅ and SO _{3 O.}

In addition, the limestone sludge may contain various minerals, for example, Calcite 75-85% by weight, quartz 5-15% by weight, and 5-10% by weight of Clinochlore. %, Dolomite 1 to 5% by weight, and mica 1 to 3% by weight may be included.

Concrete composition example

As a specific example, the composition may include 100 parts by weight of the blast furnace slag, 12 to 15 parts by weight of the alkaline earth metal hydroxide, and 15 to 35 parts by weight of the limestone sludge.

As another specific example, the composition comprises 65 to 85% by weight of the blast furnace slag based on the total weight of the composition, and 12 to 15 parts by weight of the alkaline earth metal hydroxide relative to 100 parts by weight of the blast furnace slag, and the limestone sludge It may contain 15 to 35 parts by weight.

As another specific example, the composition comprises 65 to 85% by weight of the blast furnace slag based on the total weight of the composition, and 12 to 15 parts by weight of the alkaline earth metal hydroxide relative to 100 parts by weight of the blast furnace slag, and the limestone It includes 15 to 35 parts by weight of sludge, and the limestone sludge may have a moisture content of 10 to 30% by weight.

In addition, the composition may not include Portland cement, or, if included, portland cement in an amount of less than 1% by weight or less than 0.1% by weight based on the total weight of the composition.

The hydrogen ion concentration (pH) range of the composition may be 10 to 14, 10 to 12, 12 to 14, or 11 to 13. Specifically, the composition may have a pH in the range of 12 to 14. In the cementless binder, pH is closely related to the strength, and when it is dissolved in water and has the pH, the early strength during curing can be further improved. In addition, when within the above range, the metal material is not corroded, so that the corrosion of the reinforcing bar is prevented, so that the safety is high, but it can be sold in a bag in the form of a powder like Portland cement, and there is little harm to the human body, so the handling property can be high.

Characteristics after curing

In the curing process of the composition of the present invention, the blast furnace slag and limestone sludge are activated by the alkaline earth metal hydroxide to generate hydrates that exhibit excellent properties.

Accordingly, the composition may exhibit characteristic peaks of these hydrates on an X-ray diffraction (XRD) spectrum after curing.

In addition, the composition induces pore size miniaturization at the initial stage of curing and suppresses gelation over time, leading to low porosity and fine pore size, and as a result, it can be improved not only in early strength but also in long-term strength.

More specific examples of the properties (XRD peak, compressive strength, pore distribution, water absorption) of the composition after curing are described in detail in the description of the cured body to be described later.

[Method of manufacturing cured body]

The composition of the present invention is used to prepare a cured product.

That is, according to the present invention, preparing a composition comprising 100 parts by weight of blast furnace slag, 5 to 20 parts by weight of alkaline earth metal hydroxide, and 5 to 45 parts by weight of limestone sludge; Mixing water with the composition to obtain a paste; And comprising the step of curing the paste, there is provided a method of manufacturing a cured body.

Hereinafter, each manufacturing step will be described in detail.

Preparation of the composition

First, a composition comprising blast furnace slag, alkaline earth metal hydroxide, and limestone sludge is prepared. For example, the composition can be prepared by simply mixing blast furnace slag, alkaline earth metal hydroxide, and limestone sludge.

The mixing ratio of the components included in the composition is as variously exemplified above. Specifically, the composition may be prepared by mixing 100 parts by weight of the blast furnace slag, 12 to 15 parts by weight of the alkaline earth metal hydroxide, and 15 to 35 parts by weight of the limestone sludge.

Paste manufacturing

Thereafter, water is mixed with the composition to obtain a paste.

The content of water contained in the paste after mixing with water may be 20 to 50 parts by weight, 20 to 40 parts by weight, 30 to 50 parts by weight, or 30 to 45 parts by weight based on 100 parts by weight of the paste solid content.

Specifically, water may be mixed with the composition so that 30 to 45 parts by weight of water based on 100 parts by weight of the solid content in the paste. When within the above mixing ratio, the composition can exhibit high compressive strength after curing.

Curing

The curing may be performed for a period of 1 day or more or 3 days or more.

For example, the curing may be performed for a period of 1 to 50 days, 3 to 40 days, 15 to 30 days, 1 to 15 days, 1 to 10 days, 3 to 15 days, or 20 to 35 days. Specifically, the paste may be cured for 3 to 7 days. Within the range of the curing period, the composition may exhibit higher compressive strength.

The temperature condition during the curing may be in the range of 20 to 50°C, in the range of 20 to 30°C, or in the range of 30 to 40°C. In addition, the relative humidity condition during curing may be in the range of 50 to 99%, or in the range of 95 to 99%.

[Hardened body]

In addition, a cured product obtained from the composition according to the present invention is provided.

That is, the cured body is obtained from a composition comprising 100 parts by weight of blast furnace slag, 5 to 20 parts by weight of alkaline earth metal hydroxide, and 5 to 45 parts by weight of limestone sludge.

The mixing ratio of the components included in the composition used as the raw material of the cured product is as variously exemplified in the description of the composition.

In addition, the curing conditions of the cured product are not particularly limited, but for example, the composition may be mixed with water at 23° C. and 95% relative humidity, and cured for 3 days, 7 days, or 28 days.

The cured body may include various hydrates and minerals generated by activation of the blast furnace slag by the alkaline earth metal hydroxide during the curing process.

For example, the cured body is CSH (calcium-silicate-hydrate), ettringite, monocarboaluminate, hemi-carboaluminate, and It may include at least one selected from the group consisting of barite, witherite, strtlingite, hydrotalcite, calcite, and calcium hydroxide.

XRD spectrum

Accordingly, the cured product may exhibit characteristic peaks on an X-ray diffraction (XRD) spectrum.

As an example, the cured product may exhibit peaks of C-S-H and calcium hydroxide on the XRD spectrum.

As another example, the cured product may exhibit peaks of ethringite, monocarboaluminate, and hemi-carboaluminate on the XRD spectrum.

As another example, the cured product may exhibit peaks of barite and witherite on the XRD spectrum.

air gap

The cured body may have micropores.

For example, the cured body may have a porosity of 10 to 50%, 20 to 40%, 10 to 30%, or 30 to 40%.

In addition, the cured body may have an average diameter of the pores of 5 to 50 nm, 10 to 40 nm, 10 to 30 nm, or 10 to 20 nm. As the porosity and the average diameter of the pores are smaller than a certain level, it may be advantageous in terms of the compressive strength of the cured product.

In particular, pores having a diameter of more than 50 nm are not preferable because they may negatively affect long-term strength due to a phenomenon in which deformation increases and shrinkage when a constant load is maintained for a long period of time. Accordingly, the cured body may include pores having a diameter of 50 nm or more in an amount of 30 vol% or less, 10 vol% or less, 5 vol% or less, or 1 vol% or less based on 100 vol% of the total pores.

As a preferred example, the cured product may have a porosity of 20 to 40% and an average pore diameter in the range of 10 to 30 nm, and may contain pores having a diameter of 50 nm or more in an amount of 10% by volume or less based on the volume of the total pores.

Compressive strength

The compressive strength of the cured body may be 5 MPa or more, 10 MPa or more, 13 MPa or more, 15 MPa or more, 20 MPa or more, 25 MPa or more, 30 MPa or more, or 35 MPa or more.

For example, the compressive strength of the cured body may be 5 to 50 MPa, 5 to 30 MPa, 5 to 20 MPa, 10 to 30 MPa, 20 to 40 MPa, 30 to 50 MPa, or 15 to 45 MPa.

Specifically, the cured body may have a compressive strength of 10 MPa or more, 13 MPa or more, or 15 MPa or more, 10 to 30 MPa, 13 to 30 MPa, or 15 to 30 MPa on the third day of curing.

TG/DTG analysis

The cured product exhibits a characteristic mass reduction by temperature during thermogravimetric analysis.

For example, the cured body may have a weight reduction rate of 3% or more, 4% or more, 5% or more, 6% or more, or 7% or more in a heating period of 50 to 200°C. Specifically, the cured body may have a weight reduction rate of 3 to 10%, 4 to 9%, 5 to 8%, 3 to 9%, or 4 to 8% in the heating section of 50 to 200°C. When it is within the above range, the content of minerals such as C-S-H in the cured body is high, so that compressive strength can be improved.

Absorption rate

In addition, the absorption rate of the cured product may be 30% or less, 25% or less, 20% or less, 15% or less, or 13% or less. For example, the absorption rate of the cured body may be 5 to 30%, 5 to 25%, 5 to 20%, 10 to 30%, 10 to 20%, 5 to 15%, or 5 to 13%.

Specifically, the cured body may have an absorption rate of 13% or less and a compressive strength of 13 MPa or more. The absorption rate and compressive strength of the cured product may be measured according to KS F 4004.

[Example]

Hereinafter, the present invention will be described in more detail by examples. However, the following examples are merely illustrative of the present invention, and the contents of the present invention are not limited to the following examples.

In the following examples, two types of blast furnace slag-based binders were mixed with limestone sludge generated in a limestone mine to form a brick. As the blast furnace slag-based binder, a blast furnace slag-based binder activated with calcium hydroxide or a blast furnace slag-based binder activated with barium hydroxide was used. After replacing limestone sludge in each binder with 0% by weight, 10% by weight, and 20% by weight based on solid content, the physical properties of the binder were confirmed through various experiments, and a brick was also manufactured.

Materials used in the following examples are as follows.

-Blast furnace slag fine powder (GGBFS): a commercial product containing calcium sulfate

-Limestone sludge (LF): obtained from limestone quarry in Samcheok, Korea

-Calcium hydroxide (Ca(OH) ₂ ): Daejeong Chemical, Korea

-Barium hydroxide (Ba(OH) ₂ ): Sigma-Aldrich, USA

The measuring devices used in the following examples are as follows.

-Moisture Analyzer: KERN MLB 50-3N, Kern & Sohn GmbH, D-72336 Balingen, Germany

-X-ray fluorescence device: XRF, S8, Tiger wavelength dispersive WDXRF spectrometer, Bruker, Billerica, MA, USA

-Laser diffraction particle size analyzer: HELOS (HI199) and RODOS, Sympatec, Clausthal-Zellerfeld, Germany

-High power powder X-ray diffractometer: XRD, D/Max2500V/PC, Rigaku, Japan

-Universal testing machine: Universal testing machine, UH-F500kNX, Shimadzu, KYOTO, Japan

-Thermogravimetric Analyzer: SDT Q600, TA Instruments, New castle, DE, USA

-Porosity meter: Auto pore IV 9500, Micrometrics Instrument Co., Georgia, USA

As a result of measuring the limestone sludge using a moisture analyzer, it was found that the moisture content was about 17.95% by weight.

The chemical composition of the blast furnace slag fine powder and limestone sludge was measured by an XRF instrument. As a result, as shown in the following table, it was confirmed that _{most of the blast furnace slag powder and limestone sludge were composed of CaO and SiO 2.}

Blast furnace slag fine powder (GGBFS) Limestone sludge (LF) ingredient Solid content wt% ingredient Solid content wt% CaO 46.38 CaO 63.00 SiO ₂ 32.54 SiO ₂ 19.60 Al ₂ O ₃ 12.82 Al ₂ O ₃ 8.10 MgO 3.54 Fe ₂ O ₃ 2.90 SO ₃ 2.27 MgO 2.80 TiO ₂ 0.68 K ₂ O 2.30 K ₂ O 0.40 TiO ₂ 0.50 Na ₂ O 0.31 P ₂ O ₅ 0.20 Fe ₂ O ₃ 0.54 SO ₃ 0.10 MnO 0.24 Etc 0.50

In addition, the particle size distribution of the blast furnace slag fine powder and limestone sludge was measured using a laser diffraction particle size analyzer. As a result, as shown in Fig. 1a, the average particle diameter of the blast furnace slag fine powder and limestone sludge was confirmed to be about 15 ~ 20 ㎛, respectively.

In addition, the XRD patterns of the blast furnace slag fine powder and limestone sludge were measured using a Cu-Kα light source and an XRD device. As a result, as shown in FIG. 1B, the blast furnace slag fine powder was mostly composed of vitreous, but in the case of limestone sludge, vitreous was not confirmed.

In addition, the composition of the crystal phase of limestone sludge was measured by a standardized RIR (reference intensity ratio) method. As a result, as shown in the table below, it was confirmed that most of the limestone sludge was composed of calcite.

Limestone sludge (LF) ingredient Solid content wt% Calcite 79 Quartz 9 Clinochlore 7 Dolomite 3 Mica 2

Example 1. Preparation of binder composition and cured body

Blast furnace slag fine powder, alkaline earth metal hydroxide and limestone sludge were mixed in various ratios (parts by weight) as shown in the table below to obtain respective binder compositions. A paste was prepared by mixing water to 40 parts by weight relative to 100 parts by weight of solid content (based on dry powder) to each of the prepared binder compositions. The paste was placed in a cube-shaped frame with a side of 5 cm and cured for up to 28 days while maintaining conditions of 23° C. and 95% relative humidity to obtain a cured product.

Table 3 below shows the ratio of each component in parts by weight when the amount of solid content of the binder composition is 100 parts by weight, and Table 4 below shows the ratio of each component in parts by weight when the amount of blast furnace slag powder is 100 parts by weight. .

Sample name Binder composition (parts by weight)* Water formulation
(Parts by weight)* Blast Furnace Slag
Fine powder Hydration
calcium Hydration
barium Limestone sludge
(Solid + moisture) 0LF-CH 90 10 - 0 (0+0) 40 10LF-CH 80 10 - 12.19 (10.00 + 2.19) 37.81 20LF-CH 70 10 - 24.38 (20.00 + 4.38) 35.62 0LF-BA 90 - 10 0 (0+0) 40 10LF-BA 80 - 10 12.19 (10.00 + 2.19) 37.81 20LF-BA 70 - 10 24.38 (20.00 + 4.38) 35.62 * Parts by weight for each component based on 100 parts by weight of solid content of the binder composition

Sample name Binder composition (parts by weight)* Water formulation
(Parts by weight)* Blast Furnace Slag
Fine powder Hydration
calcium Hydration
barium Limestone sludge
(Solid + moisture) 0LF-CH 100 11.11 - 0 (0+0) 44.44 10LF-CH 100 12.50 - 15.24 (12.50 + 2.74) 50.00 20LF-CH 100 14.29 - 34.83 (28.57 + 6.25) 57.14 0LF-BA 100 - 11.11 0 (0+0) 44.44 10LF-BA 100 - 12.50 15.24 (12.50 + 2.74) 50.00 20LF-BA 100 - 14.29 34.83 (28.57 + 6.25) 57.14 * Parts by weight for each component compared to 100 parts by weight of blast furnace slag fine powder

Test Example 1. Compressive strength

The compressive strength of the hardened bodies obtained in Example 1 was measured at a rate of 0.4 mm/min using a universal testing machine according to ASTM C109.

As shown in Figure 2a, when activated with calcium hydroxide, the sample to which LF was added had a generally higher strength than the sample to which LF was not added, and in particular, in the case of the early strength, about twice as high strength was measured, and the substitution amount of LF Regardless, similar levels of strength are measured, and it is expected that up to 20% of LF can be recycled.

As shown in FIG. 2B, when activated with barium hydroxide, a somewhat complicated compressive strength result was measured according to the substitution amount of LF. Specifically, when LF was substituted by 10%, the compressive strength was slightly higher until the 7th day of curing compared to the sample in which the LF was not substituted, but almost the same compressive strength was expressed on the 28th. When LF was substituted by 20%, about 4 times higher compressive strength was measured compared to the sample in which LF was not substituted, but no further development of strength was observed.

Therefore, when comparing the compressive strength, it was confirmed that 20LF-BA and 20LF-CH have almost the same strength, and although 20LF-BA was activated as barium hydroxide, Ca(OH) ₂ acts as a practical activator through the following chemical reaction. Seems to be.

Ba(OH) ₂ + CaCO ₃ → Ca(OH) ₂ + BaCO ₃

Test Example 2. XRD analysis

The XRD patterns of the cured products obtained in Example 1 were obtained using an XRD apparatus using a Cu-Kα light source (k = 1.5418 Å).

As shown in FIGS. 3A to 4C, C-S-H (calcium-silicate-hydrate) and calcium hydroxide were found in all samples regardless of the amount of substitution of LF and the type of activator.

As shown in FIGS. 3A to 3C, when activated with calcium hydroxide, ettringite, monocarboaluminate, and hemi-carboaluminate were confirmed regardless of the substitution amount of LF.

In addition, as shown in Figs. 4a to 4c, when activated with barium hydroxide, unlike the case of activation with calcium hydroxide, ethringite, monocarboaluminate, etc. were not generated, but barium ions were SO ₄ ^2- and CO ₃ ^2- It appears to be because it reacted first with BaSO _{4 to produce barite.} In addition, in the LF-substituted sample, _{witherite of BaCO 3} component was additionally confirmed. _{Ba(OH) 2} ㆍ8H ₂ O was confirmed in the XRD pattern of 0LF-BA on the 3rd day of curing, but not in the LF-substituted samples (10LF-BA, 20LF-BA). It seems that the substitution of LF prevented the formation of _{Ba(OH) 2} ㆍ8H _{2 O and produced BaCO 3} , thereby affecting the early strength. Further, in the sample of LF is a substituted _{Ba (OH) 2 + CaCO 3} → Ca (OH) 2 + a Ca (OH) generated by the chemical reaction of BaCO _{3 2} is increasing the pH of the binder to cure the beginning of more GGBFS It is believed that it contributed to the development of strength by melting glass matter.

The XRD pattern of CSH shown for reference in FIGS. 3A to 4C is a CSH pattern of a 23-year-old fully hydrated β-C ₂ S paste from which the Ca(OH) ₂ peak was removed.

Test Example 3. TG/DTG analysis

The cured products obtained in Example 1 were subjected to thermogravimetric analysis (TG) and differential thermogravimetric analysis (DTG).

5A and 5B, when activated with calcium hydroxide, C-S-H, ethringite, calcium hydroxide, and calcite were identified as reaction products as a result of TG/DTG, and were consistent with the XRD results. The more LF was added, the greater the amount of C-S-H and etringite were identified, which appeared to have an effect on the strength development (consistent with the tendency of compressive strength).

As shown in Figs. 5c and 5d, when activated with barium hydroxide, 10LF-BA was found to have a greater mass reduction below 200°C than 0LF-BA, which means that a greater amount of CSH was produced, and compressive strength It matches the result. In addition, the TG/DTG result of 20LF-BA was measured very similar to that of 20LF-CH, which seems to be because it had similar compressive strength. Therefore, 20LF-BA was activated with barium hydroxide, but it is believed that this phenomenon occurred because calcium hydroxide played a role in the actual activation.

Test Example 4. MIP analysis

The porosity distributions of the cured bodies obtained in Example 1 on the 3rd and 28th days of curing were obtained using a porosity meter by mercury intrusion porosimetry (MIP).

As shown in Figs. 6a to 6d, when activated with calcium hydroxide, it was confirmed that a smaller amount of total voids and a smaller size of voids occur as a larger amount of LF is substituted, and because of this phenomenon, in the sample in which LF is substituted It appears that a higher compressive strength was measured. In addition, the same trend was observed on the 28th, and it was confirmed that most of the voids were formed below 50 nm, and it was confirmed that the void distribution structure and the compressive strength result were consistent.

As shown in Figures 7a to 7d, when activated with barium hydroxide, 0LF-BA and 10LF-BA had similar total voids, but 10LF-BA had a smaller pore size and thus a relatively higher compressive strength was measured. Is judged to be. 20LF-BA had a significantly smaller total void volume than other samples, and this trend was consistent with the compressive strength results. On day 28, similar levels of total void volume and void size were found in 0LF-BA and 10LF-BA. On the other hand, in the case of 20LF-BA, the average pore size decreased compared to the 3-day MIP result, but the total pore amount increased, indicating the possibility that nanometer-sized microcracks occurred, but most of the pores existed below 50 nm So, there seems to be no significant impact.

Example 2. Manufacture of brick

Using 20LF-CH and 20LF-BA of the binder composition of Example 1, a paste was prepared according to the procedure of Example 1 above, placed in a frame of 190 mm x 90 mm x 57 mm, and cured to obtain brick samples, respectively.

The 3-day compressive strength and water absorption of the 20LF-CH brick were measured to be 15 MPa and 15.6%, and the 3-day compressive strength and water absorption of the 20LF-BA brick were measured to be 20 MPa and 12.2%.

According to KS F 4004, the criterion of class 2 bricks should exceed the compressive strength of 13 MPa and the water absorption rate should be less than 13%. Therefore, in the case of 20LF-BA brick, it was possible to use it as a type 2 brick by satisfying the standards of KS F 4004.

Test Example 5. Dissolution test

The dissolution test of the brick sample obtained in Example 2 was performed according to the TCLP (toxicity characteristic leaching procedure) of the US Environmental Protection Agency (EPA).

ingredient Measurement concentration (mg/L) TCLP standard
(mg/L) 20LFCH brick 20LFBA brick As 0.002 0.004 5.0 Ba 0.002 10.200 100.0 CD 0.000 0.001 1.0 Cr 0.001 0.000 5.0 Pd 0.002 0.000 5.0

As shown in the table above, as a result of the elution test of bricks, heavy metals and the like were not eluted, so it is judged that no problem in use occurs.

Claims (15)

100 parts by weight of blast furnace slag,
12 to 15 parts by weight of an alkaline earth metal hydroxide containing barium hydroxide, and
As a composition containing 25 to 45 parts by weight of limestone sludge,
A composition having a compressive strength of 15 MPa or more, a porosity of 20-40%, and an absorption rate of 13% or less on the third day of curing when cured by mixing with water.
The method of claim 1,
The limestone sludge contains limestone fine powder,
The composition of the composition in which the content of the limestone fine powder is 10 to 40 parts by weight based on 100 parts by weight of the blast furnace slag.
The method of claim 1,
The composition of the limestone sludge having a moisture content of 10 to 30% by weight.
The method of claim 1,
The limestone sludge is CaO 58 to 68 wt%, SiO ₂ 15 to 25 wt% _, Al ₂ O ₃ 5 to 11 wt%, Fe ₂ O ₃ 1 to 5 wt%, MgO 1 to 5 wt% and A composition comprising 1 to 5% by weight of _{K 2 O.}
delete delete delete delete The method of claim 1,
The composition comprises the blast furnace slag in an amount of 60 to 89% by weight based on the total weight of the composition.
The method of claim 1,
The composition, wherein the composition has a pH in the range of 12 to 14.
Preparing a composition comprising 100 parts by weight of blast furnace slag, 12 to 15 parts by weight of alkaline earth metal hydroxide including barium hydroxide, and 25 to 45 parts by weight of limestone sludge;
Mixing water with the composition to obtain a paste; And
As a method for producing a cured product comprising the step of curing the paste,
On the third day of curing, the compressive strength is 15 MPa or more, the porosity is 20 to 40%, and the water absorption rate is 13% or less.
The method of claim 11,
In the step of mixing water with the composition, water is mixed with the composition so that 30 to 45 parts by weight of water relative to 100 parts by weight of the solid content in the paste,
Curing the paste for 3 to 7 days in the curing step, a method for producing a cured body.
100 parts by weight of blast furnace slag,
12 to 15 parts by weight of an alkaline earth metal hydroxide containing barium hydroxide, and
As a cured product obtained by curing from a composition containing 25 to 45 parts by weight of limestone sludge,
A cured product with a compressive strength of 15 MPa or more, a porosity of 20-40%, and a water absorption of 13% or less on the 3rd day of curing.
delete The method of claim 13,
The cured product has an average pore diameter in the range of 10 to 30 nm, and contains pores having a diameter of 50 nm or more in an amount of 10% by volume or less based on the volume of the total pores.

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