KR20150120242A - Precast aqueduct using alcali active concrete and making method thereof - Google Patents

Abstract

The present invention relates to a precast aqueduct manufactured by using alkali-activated concrete. The alkali active-activated is produced by mixing 200-350 parts by weight of a coarse aggregate, 180-300 parts by weight of a fine aggregate, 35-48 parts by weight of mixed water, and 0.3-2.0 parts by weight of a mixing agent with respect to 100 parts by weight of an alkali-activated binder. The alkali-activated binder comprises 40-65 wt% of steel slag micropowder, 10-25 wt% of high calcium ash, 3-8 wt% of desulfurized gypsum powder, 7-13 wt% of quicklime, 3-7 wt% of slaked lime, 10-15 wt% of Portland cement, 0.1-0.5 wt% of a thickening agent, and 0.1-5.0 wt% of an expansion agent.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precast concrete pipe,

More particularly, the present invention relates to a precast water pipe using alkaline active concrete and a method of manufacturing the same, and more particularly, to a method of manufacturing a precast water pipe using alkaline active concrete, The present invention relates to a precast watertube using an alkali activated concrete produced by using the same, and a method for producing the same.

Generally, a water pipe is a series of structures that send a specified amount of water from a certain point to another point in accordance with the planned and designed purpose. The water pipe is a structure for the main purpose of water supply and drainage Can be classified.

Such a pipe can be classified according to the material, besides the classification by the function of the structure, the hydraulic characteristic, etc., and can be classified into a product using a pipe made of a polymer material and concrete.

The concrete concrete conduit is divided into a direct casting method in the field and a precast channel which is produced in the form of finished products in the factory. Recently, precast products have become mainstream.

Among the applications of the precast type water pipe, the most commonly applied part is installed for drainage of the road surface. In recent years, for the snow removal due to frequent heavy snowfall, a large amount of calcium oxide is used, , The occurrence of corrosion of reinforcing bars inside the structure, the occurrence of concrete cracks, and the like.

Therefore, there is a growing need for the development of precast-shaped pipe structures, which are capable of applying highly durable bonding materials and denser internal structures.

In Korea, it is essential for sustainable economic growth to overcome the simple treatment methods such as landfilling and incineration of generated wastes due to narrow land area and resource constraints, and to recycle through recycling and recycling.

The amount of waste generated in Korea has increased from 18.5 million tons in 2009 to 28 million tons in 2014.

In some advanced countries, we are concentrating not only on active (renewable energy, energy efficiency improvement) policies but also on passive (waste reduction, energy use reduction, green construction, etc.) policy for the green growth of the country. With a significant focus on the construction industry, it is anticipated that a country dominated by green construction technology and eco-friendly certification will lead the green market.

As a part of this, the necessity of replacing cement among construction materials, which is generally used most in construction field, is increasing.

In order to produce such cement, a lot of resources and energy must be consumed.

In particular, cement production is pointed out as a major cause of global warming, and it is known that it releases about 950 g of CO ₂ gas to produce 1 kg of cement. The amount of greenhouse gas emissions generated in the manufacturing process of cement is about 1.35 million tons per year Of the world's greenhouse gas emissions.

In addition, limestone is the main raw material in the production of cement, and damage to forests and waste generated in the process of mining it is causing more burden on the environment.

Therefore, there is a growing need for development of low-cement type alkali active binders utilizing a large amount of steel and power generation by-products having effective utilization value.

The background of the present invention is disclosed in Korean Patent Registration No. 10-1323591 (published on Nov. 1, 2013, entitled "Concrete Composition Using Electric Furnace Slag and Secondary Product Manufactured Therefrom").

In general, the precast channel is difficult to reduce the consumption of cement because the cement constitutes the main composition, and it is difficult to reduce the environmental pollution caused by the manufacture of the cement.

Therefore, there is a need for improvement.

The present invention provides a precast watertube using an alkali active concrete produced using an alkali active binder in which a large amount of steel slag, high calcium ash and various alkali active materials are utilized in order to minimize the amount of Portland cement to be used, and a method for producing the same .

The present invention relates to a steel slag, comprising 40 to 65% by weight of steel slag fine powder, 10 to 25% by weight of high calcium ash, 3 to 8% by weight of desulfurized gypsum powder, 7 to 13% by weight of quicklime, 3 to 7% 200 to 350 parts by weight of a coarse aggregate, 180 to 300 parts by weight of a fine aggregate, 35 to 48 parts by weight of a mixture of water and 100 parts by weight of an alkali active binder comprising 0.1 to 0.5% And 0.3 to 2.0 parts by weight of an admixture are mixed.

Further, the coarse aggregate of the present invention is characterized in that the coarse aggregate is composed of one or more of crushed coarse aggregate, slag coarse aggregate, waste concrete circulating coarse aggregate, and bottom ash coarse aggregate.

Further, the fine aggregate of the present invention is characterized in that it is composed of at least one of a fine slag fine aggregate, a fine fine aggregate, a heavy sand, and a bottom ash aggregate.

Further, the admixture of the present invention is characterized by being a liquid-phase admixture of polyethyl-, polycarboxylic acid- or naphthalene-series.

The present invention also provides a method for producing a steel slag comprising the steps of: (a) mixing 40 to 65 wt% of a steel slag powder, 10 to 25 wt% of a high calcium ash, 3 to 8 wt% of a desulfurized gypsum powder, 7 to 13 wt% 10 to 15% by weight of cement, 0.1 to 0.5% by weight of a thickener, and 0.1 to 5.0% by weight of an expanding agent; (b) mixing the alkali active binder with coarse aggregate, fine aggregate, mixed water and admixture to produce an alkali active concrete; (c) compressing the alkali active concrete while applying vibration to the inside of the mold by the operation of the vibration table while stepwise introducing the alkali active concrete into the mold; And (d) subjecting the alkali active concrete having been compaction to an atmospheric pressure steam curing.

In addition, the step (a) of the present invention may include: a first premixing step of pre-mixing at a speed of 10 to 60 rpm for 1.5 to 10.0 minutes by charging a steel slag fine powder, high calcium ash and Portland cement; And a second pre-mixing step of adding a desulfurized gypsum powder, quicklime, slaked lime, a thickener and an expanding agent to the binder stirred in the first pre-mixing step and mixing the mixture at a speed of 5 to 80 rpm for 2.0 to 15.0 minutes .

In the step (b) of the present invention, the coarse aggregate and the fine aggregate are mixed in a mixer at a rate of 10 to 60 rpm for 20 to 60 seconds after the mixture is introduced into a mixer; And a second mixing step of mixing the alkaline active binder, the mixed water, and the admixture into the stirrer in the first mixing step at a speed of 20 to 80 rpm for 60 to 180 seconds.

Further, in the step (c) of the present invention, the alkali active concrete is charged into the mold up to one-third of the total amount of concrete, and then subjected to vibration at 1000 to 1200 rpm using a vibration table to perform low- A low frequency compaction step; A second low-frequency compaction step of applying the alkali-active concrete to the inside of the mold up to 2/3 of the total amount of concrete and applying vibration at 2000 to 3200 rpm using a vibration table; A high frequency compaction step in which the alkali active concrete is charged into the mold up to 3/3 of the total amount of concrete and then subjected to compaction by applying a vibration of 4500 to 5500 rpm using a vibration table; And a third low-frequency compaction step of putting the alkali-active concrete into the mold and finishing the product surface by applying vibration of 2000 to 3000 rpm for 10 to 30 seconds using a vibration table.

In addition, the step (d) of the present invention may further include a low-temperature curing step in which the mold with the alkali active concrete is placed in a curing chamber, and the temperature is raised to 30 ° C for 2 hours; A middle temperature curing step in which the temperature of the curing chamber is raised to 45 캜 for 1 hour and 30 minutes after the low temperature curing step is performed; And a high-temperature curing step of raising the temperature of the curing room to 65 캜 for 1 hour and 30 minutes after the mid-temperature curing step is progressed.

The precast channel and the method of manufacturing the same using the alkali active concrete according to the present invention can reduce the amount of cement used and make use of wastes to improve the quality of the water pipe by using an alkali active binder using a large amount of high calcium ash and various alkali active materials. The amount of waste can be reduced and the amount of cement used can be reduced to reduce environmental pollution caused by cement production.

1 is a flowchart showing a method of manufacturing a precast water pipe using an alkali active concrete according to an embodiment of the present invention.
FIG. 2 is a view illustrating a first stirrer used in a method of manufacturing a precast water pipe using an alkali active concrete according to an embodiment of the present invention. Referring to FIG.
3 is a view showing a second agitator used in a method of manufacturing a precast water pipe using an alkali active concrete according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, one embodiment of a precast water pipe using alkaline activated concrete according to the present invention and a method of manufacturing the same will be described with reference to the accompanying drawings.

In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation.

In addition, the terms described below are terms defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator.

Therefore, definitions of these terms should be made based on the contents throughout this specification.

FIG. 1 is a flowchart showing a method of manufacturing a precast water pipe using an alkali active concrete according to an embodiment of the present invention, FIG. 2 is a view showing a method of manufacturing a precast water pipe using an alkali active concrete according to an embodiment of the present invention FIG. 3 is a view showing a second stirrer used in a method of manufacturing a precast water pipe using an alkali active concrete according to an embodiment of the present invention. Referring to FIG.

1 to 3, a precast channel using an alkali active concrete according to an embodiment of the present invention comprises 40 to 65% by weight of steel slag fine powder, 10 to 25% by weight of high calcium ash, 3 to 8 By weight based on 100 parts by weight of an alkali active binder, wherein the binder contains 3 to 7% by weight of calcium oxide, 7 to 13% by weight of calcium oxide, 3 to 7% by weight of calcium hydroxide, 10 to 15% by weight of Portland cement, 0.1 to 0.5% by weight of a thickener, 200 to 350 parts by weight of coarse aggregate, 180 to 300 parts by weight of fine aggregate, 35 to 48 parts by weight of mixed water and 0.3 to 2.0 parts by weight of admixture.

As described above, the present embodiment utilizes a large amount of steel slag, high calcium ash and various alkali active materials in order to minimize the amount of commonly used Portland cement, so that the engineering performance such as strength and durability is excellent .

In addition, the present embodiment can reduce the amount of existing Portland cement to 15% or less by utilizing a large amount of high-calcium ash generated in a steel slag as a steelmaking by-product and a fluidized bed bilayer in a bath-in-the-bath type system to produce a low-carbon environmentally friendly binder .

The coarse aggregate is composed of one or more of crushed coarse aggregate, slag coarse aggregate, waste concrete circulating coarse aggregate, and bottom ash coarse aggregate, and the fine aggregate is selected from the group consisting of fine slag fine aggregate, crushed fine aggregate, One or two or more.

Since the admixture is made of a polyethyl-, polycarbonate- or naphthalene-based liquid admixture, the workability of the concrete can be ensured and the anti-freezing property of the concrete can be improved.

A method of manufacturing a precast water pipe using the alkali active concrete according to an embodiment of the present invention will now be described.

A method of manufacturing a hydrographic tunnel using an alkali active concrete according to an embodiment of the present invention comprises the steps of: preparing 40 to 65 wt% of steel slag powder, 10 to 25 wt% of high calcium ash, 3 to 8 wt% of desulfurized gypsum powder, By weight of an alkali activated binder, 3 to 7% by weight of calcium hydroxide, 10 to 15% by weight of Portland cement, 0.1 to 0.5% by weight of a thickener, and 0.1 to 5.0% by weight of an expanding agent, Mixing the alkali active concrete with the fine aggregate, mixed water, and an admixture to produce an alkali active concrete; subjecting the alkali active concrete to compaction while applying vibration by operation of the vibration table while gradually introducing the alkali active concrete into the mold; And atmospheric vapor curing the active concrete.

The alkaline active binder to be mixed at the composition ratio described above is mixed with the coarse aggregate, the fine aggregate, the mixed water and the admixture, cured in the mold, and cured, thereby manufacturing the water pipe according to the present embodiment.

The step of producing an alkali active binder includes a first premixing step of introducing a fine powder of steel slag, high calcium ash and Portland cement and pre-mixing at a speed of 10 to 60 rpm for 1.5 to 10.0 minutes, And a second pre-mixing step of adding a desulfurized gypsum powder, quicklime, slaked lime, a thickener, and an expanding agent to the agitated binder at a speed of 5 to 80 rpm for 2.0 to 15.0 minutes.

The first preliminary mixing step is performed by the operation of the first agitator 10. The first agitator 10 includes a main body 10 having a long left and right direction and formed with a charging port 12a and a discharge port 12b, A screw 32 and a stirring rod 32 which are rotatably installed inside the main body 10 and are mixed while moving the fine powder of steel slag, high calcium ash and portland cement flowing through the inlet 12a to the outlet 12b side, And a motor 50 for transmitting power to the drive shaft 30. The drive shaft 30 includes a drive shaft 30,

The second preliminary mixing step is performed by the operation of the second stirrer 110. The second stirrer 110 includes a main body 112 having an opening 112a formed on an upper surface thereof and a circular space formed therein, A driving shaft 130 coupled to the main body 112 so as to protrude upward from the bottom of the main body 112 and equipped with a stirring vane 132 and a motor 150 for providing power to the driving shaft 130.

The step of preparing the alkali active concrete according to the present embodiment includes a first mixing step of mixing the coarse aggregate and the fine aggregate into a mixer at a speed of 10 to 60 rpm for 20 to 60 seconds after the mixing, Mixing the active binder, mixed water and an admixture at a speed of 20 to 80 rpm for 60 to 180 seconds.

The first mixing step and the second mixing step are performed by the operation of the first agitator or the second agitator and the homogeneity of the concrete can be ensured through the first mixing step and the second mixing step as described above .

The alkali active concrete is produced by the process as described above, the workability of the concrete is secured by the admixture to be added, and the freezing resistance of the concrete is improved.

The step of compaction according to the present embodiment is a method of compressing a first low-frequency compaction member which applies low-frequency compaction by applying a vibration of 1000 to 1200 rpm using a vibration table after putting alkali active concrete in a mold up to 1/3 of the total amount of concrete, A second low-frequency compaction step in which the alkali active concrete is charged into the mold up to 2/3 of the total amount of concrete and then subjected to compaction by applying a vibration of 2000 to 3200 rpm using a vibration table; A high frequency compaction step in which vibration is applied by applying a vibration of 4500 to 5500 rpm by using a vibration table and a high frequency compaction step in which alkali active concrete is put into the mold and the vibration table is operated at 2000 to 3000 rpm And a third low-frequency compaction step of finishing the product surface by applying a vibration of 10 to 30 seconds.

The step of compaction stepwise progresses according to the magnitude of vibration is to maximize the degree of confinement of precast channel by using alkali active concrete with a relatively small amount of cement, And the problems such as reduction in durability and reduction in durability caused by defective forming and molding are alleviated.

The curing step of this embodiment is a curing step in which a mold with an alkali active concrete is placed in a curing chamber and then the temperature is raised to 30 DEG C for 2 hours and the curing room temperature is reduced to 45 And a high-temperature curing step in which the temperature of the curing room is raised to 65 ° C after the middle-temperature curing step is performed, and then the curing curing is performed for 1 hour and 30 minutes.

In the curing step of this embodiment, atmospheric pressure steam curing is carried out in order to secure the initial strength of the precast pipe product and to secure the strength and durability of the concrete pipe, and the steam pressure is adjusted to 5 to 50 kgf / Cm < 2 >.

Since the step-by-step steam curing step as described above promotes the hydration and curing reaction of the alkali active concrete having a relatively small content of cement, the durability and common use of the conduit pipe by securing the early strength of the precast channel and improving the compactness of the matrix structure inside the concrete The effect of improving the performance is shown.

Thus, it is possible to provide a precast watertube using an alkali active concrete produced by using an alkali active binder in which a large amount of steel slag, high calcium ash and various alkali active materials are utilized in order to minimize the amount of Portland cement used, and a method for manufacturing the same .

≪ Example 1 >

An alkali activity comprising 45% by weight of a steel slag powder, 10% by weight of high calcium ash, 5% by weight of desulfurized gypsum powder, 13% by weight of lime, 7% by weight of calcium hydroxide, 15% by weight of Portland cement, 0.5% by weight of a thickener, 300 parts by weight of coarse aggregate, 200 parts by weight of fine aggregate, 40 parts by weight of mixed water and 2.0 parts by weight of admixture are mixed with 100 parts by weight of binder to prepare a water pipe.

≪ Example 2 >

An alkali activity comprising 55 wt% of steel slag powder, 10 wt% of high calcium ash, 5 wt% of desulfurized gypsum powder, 10 wt% of burnt lime, 5 wt% of slaked lime, 10 wt% of Portland cement, 0.5 wt% of a thickener, 300 parts by weight of coarse aggregate, 200 parts by weight of fine aggregate, 40 parts by weight of mixed water and 2.0 parts by weight of admixture are mixed with 100 parts by weight of binder to prepare a water pipe.

≪ Example 3 >

An alkali activity comprising 65% by weight of steel slag fine powder, 10% by weight of high calcium ash, 3% by weight of desulfurized gypsum powder, 7% by weight of lime, 3% by weight of calcium hydroxide, 10% by weight of Portland cement, 0.1% by weight of a thickener, 300 parts by weight of coarse aggregate, 200 parts by weight of fine aggregate, 40 parts by weight of mixed water and 2.0 parts by weight of admixture are mixed with 100 parts by weight of binder to prepare a water pipe.

≪ Comparative Example 1 &

An alkali activity comprising 35% by weight of a steel slag powder, 20% by weight of high calcium ash, 5% by weight of desulfurized gypsum powder, 13% by weight of lime, 7% by weight of calcium hydroxide, 15% by weight of Portland cement, 0.5% by weight of a thickener, 300 parts by weight of coarse aggregate, 200 parts by weight of fine aggregate, 40 parts by weight of mixed water and 2.0 parts by weight of admixture are mixed with 100 parts by weight of binder to prepare a water pipe.

≪ Comparative Example 2 &

, An alkali activity comprising 75% by weight of fine steel slag powder, 8% by weight of high calcium ash, 3% by weight of desulfurized gypsum powder, 5% by weight of quicklime, 3% by weight of calcium hydroxide, 5% by weight of Portland cement, 0.1% by weight of a thickener, 300 parts by weight of coarse aggregate, 200 parts by weight of fine aggregate, 40 parts by weight of mixed water and 2.0 parts by weight of admixture are mixed with 100 parts by weight of binder to prepare a water pipe.

As shown in Table 1, the results of the measurement of the compressive strength and the coagulation time ratio of the 28 days old concrete according to the weight ratio of the steel slag powder are shown in Table 1. The coagulation time ratio is 100% of the 55% weight ratio of the steel slag fine powder of Example 2 Means the ratio between the time for condensation of each of the comparative examples and the examples.

division Weight ratio of steel slag fine powder (%) Compressive strength at 28 days (MPa) Condensation time ratio (%) ⁽¹⁾ Remarks Comparative Example 1 35 24.3 76 Example 1 45 30.7 88 Example 2 55 33.4 100 Example 3 65 36.1 110 Comparative Example 2 75 36.3 131

In Comparative Example 1, which is less than 45% by weight of the steel slag fine powder, it is difficult to secure a pot life for work such as molding and compacting of the concrete because the setting time is excessively shortened, The coagulation time is relatively excessively delayed and it is difficult to secure the initial strength.

In addition, when the amount of the steel slag powder is less than 45% by weight, the compressive strength of the concrete at 28 days, which is the typical concrete strength of the concrete, is drastically lowered due to the lack of the hydraulic material capable of reacting with the alkali active material in the composite.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. .

In addition, although the precast channel using alkali active concrete and the manufacturing method thereof have been described as an example, the present invention is merely an example, and the precast channel using alkali active concrete and other products other than the method of manufacturing the same, A manufacturing method can be used.

Accordingly, the true scope of the present invention should be determined by the following claims.

10: first stirrer 12, 112: main body
12a: Inlet port 12b: Outlet port
30, 130: drive shaft 32: screw
34: stirring rod 50, 150: motor
110: second stirrer 112a: opening
132: stirring blade

Claims (9)

A steel slag powder of 40 to 65 wt%, a high calcium ash of 10 to 25 wt%, a desulfurized gypsum powder of 3 to 8 wt%, a burnt lime of 7 to 13 wt%, a slaked lime of 3 to 7 wt%, a Portland cement of 10 to 15 wt% To 0.5% by weight, and an expansion agent in an amount of 0.1 to 5.0% by weight, based on 100 parts by weight of the alkali-
A precast waterway pipe using alkaline active concrete, comprising 200 to 350 parts by weight of coarse aggregate, 180 to 300 parts by weight of fine aggregate, 35 to 48 parts by weight of mixed water, and 0.3 to 2.0 parts by weight of admixture.
The method according to claim 1,
Wherein the coarse aggregate comprises one or more of crushed coarse aggregate, slag coarse aggregate, waste concrete circulating coarse aggregate, and bottom ash coarse aggregate.
The method according to claim 1,
Wherein the fine aggregate comprises at least one of a fine aggregate of slag, a fine aggregate of crushed stone, a fine aggregate of sand, and a fine aggregate of bottom ash.
The method according to claim 1,
Wherein the admixture is a polyethyl-, polycarbonate- or naphthalene-based liquid admixture. ≪ RTI ID = 0.0 > 11. < / RTI >
(a) 40 to 65 wt% of steel slag powder, 10 to 25 wt% of high calcium ash, 3 to 8 wt% of desulfurized gypsum powder, 7 to 13 wt% of burnt lime, 3 to 7 wt% of slaked lime, 10 to 15 wt% 0.1 to 0.5% by weight of a thickener, and 0.1 to 5.0% by weight of an expanding agent;
(b) mixing the alkali active binder with coarse aggregate, fine aggregate, mixed water and admixture to produce an alkali active concrete;
(c) compressing the alkali active concrete while applying vibration to the inside of the mold by the operation of the vibration table while stepwise introducing the alkali active concrete into the mold; And
and (d) curing the alkaline activated concrete having undergone compaction by atmospheric vapor curing. 6. The method of claim 5, wherein the step (a)
A first pre-mixing step of introducing fine powder of steel slag, high calcium ash, and Portland cement into a mixer at a speed of 10 to 60 rpm for 1.5 to 10.0 minutes; And
Mixing a desulfurized gypsum powder, quicklime, slaked lime, a thickener, and an expanding agent into the binder stirred in the first pre-mixing step at a rate of 5 to 80 rpm for 2.0 to 15.0 minutes; A method of manufacturing a precast channel using active concrete.
6. The method of claim 5, wherein step (b)
Mixing the coarse aggregate and the fine aggregate into a mixer at a speed of 10 to 60 rpm for 20 to 60 seconds; And
Mixing the alkaline active binder, the mixed water, and the admixture into the stirrer in the first mixing step and mixing the mixture at a speed of 20 to 80 rpm for 60 to 180 seconds. A method of manufacturing a precast channel.
6. The method of claim 5, wherein step (c)
A first low-frequency compaction step of applying low-frequency compaction by applying vibration of 1000 to 1200 rpm using a vibration table after putting the alkali-active concrete up to 1/3 of the total amount of concrete in the mold;
A second low-frequency compaction step of applying the alkali-active concrete to the inside of the mold up to 2/3 of the total amount of concrete and applying vibration at 2000 to 3200 rpm using a vibration table;
A high frequency compaction step in which the alkali active concrete is charged into the mold up to 3/3 of the total amount of concrete and then subjected to compaction by applying a vibration of 4500 to 5500 rpm using a vibration table; And
And a third low-frequency compaction step of applying the alkali-active concrete to the inside of the mold and applying a vibration of 2000 to 3000 rpm for 10 to 30 seconds using a vibration table to finish the product surface. A method of manufacturing a precast channel.
6. The method of claim 5, wherein step (d)
A low-temperature curing step in which the mold with the alkali-activated concrete placed therein is placed in a curing chamber, the temperature is raised to 30 ° C and then the curing is performed for 2 hours;
A middle temperature curing step in which the temperature of the curing chamber is raised to 45 캜 for 1 hour and 30 minutes after the low temperature curing step is performed;
And a high-temperature curing step in which the temperature of the curing room is raised to 65 캜 for 1 hour and 30 minutes after the mid-temperature curing step is performed.

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