KR100266876B1 - Porous concrete - Google Patents

Abstract

PURPOSE: A permeable concrete is provided to conveniently evaporate water after permeating rainwater into a road while paving the road and to reduce noise caused by travelling of a vehicle. CONSTITUTION: A permeable concrete(11) is produced by injecting SBR(Styrene Butadiene Rubber) latex or VAE(Vinyl Acetate Ethylene) emulsion as mixing material after removing fine particle among sand. Then, cement, large aggregate, commit and water are mixed after mixing steel fiber, glass fiber, carbon fiber, aramid fiber and nature fiber to produce the permeable concrete. Moreover, the permeable concrete is porous concrete having sequential void to pass water and use the large aggregate over 8mesh. Amount of cement paste is 300-400kg/m3 to engage and surround the aggregates, and water-cement ratio is 30-40% to make the void by preventing dropping the cement paste.

Description

Pitcher Concrete

The present invention relates to permeable concrete, and more particularly to permeable concrete suitable for pavement of highways and heavy vehicle transit zones as well as general roads.

Normally, the road pavement adopts impermeable asphalt concrete pavement and cement concrete pavement, as shown in FIG. However, these impermeable pavements not only impede road traffic because rainwater remains on the road during rainfall, but also increases the risk of accidents due to slip resistance during braking of the vehicle. In addition, rainwater does not penetrate into the basement, causing flooding of rivers, groundwater is depleted, and microorganisms do not live in the ground, causing various problems.

To this end, permeable asphalt concrete has been developed and put into practical use in plazas, parking lots, etc., but this is not applicable to general roads as it is transformed due to the increase of road surface temperature in summer and the perforations are closed due to the viscosity of asphalt.

A permeable concrete for solving the problem of such permeable asphalt concrete is shown in FIG. It has a structure in which the wheel rim 3, the auxiliary base layer 2 and the permeable concrete layer 1 are sequentially stacked on the hearth 4. Normally, natural sand is generally used for the material of aftosis (3), and since the auxiliary base layer (2) requires supporting force and durability, an impurity having a small change in its properties due to changes in water content and freezing / thawing is used. And since the permeable concrete (1) is directly exposed to severe environmental conditions such as wheel load, meteorological action, and abrasion action, the material used should be thoroughly investigated / tested before construction, and usually cement, aggregate (grain aggregate, coarse aggregate), water, and mixed materials. Use a blended material in an appropriate ratio.

The permeable concrete layer 1 manages a slump value close to zero using less aggregate aggregate, and cement paste is filled in a part of the space part while keeping the aggregate surface thinly wrapped to maintain adhesive strength. At this time, the permeability hole without the paste is formed according to the size of the space portion, and if the fine permeation hole is made continuously, the permeation is made by securing the continuous porosity.

However, the permeable concrete layer 1 has the following problems.

First, the compressive strength is less than 300kg / ㎠ because the mixing design is made of less than about 12% of the aggregate aggregate to have a continuous porosity to secure a high permeability coefficient of about 1.0 × 10 ^-2 cm / sec.

Secondly, the use of a small amount of aggregate aggregates increases the strength of the cement, or when the fluidity of the cement paste is large, the cement paste flows into the voids between the aggregate and the aggregate to fill the pores of the lower layer. This is lowered and the concrete strength of the upper layer is lowered.

Third, because of the use of less aggregate aggregate, when there is some slump in the process of construction, the aggregate aggregate has a lower permeability and the upper layer has a significantly lower strength and only a thick aggregate remains.

Fourth, since the slump value is close to zero, it is usually used only for the pavement of bicycle roads and the like because concrete and concrete cannot be constructed and must be constructed by mechanized compaction.

Fifth, there is a problem in securing strength (particularly, durability against freezing and melting) due to excessive strength of unnecessary independent porosity not related to permeability.

Sixth, because the surface is rough and the strength is small, peeling of the surface appears, fine dust is attached to the rough pores well, the water permeability is sharply lowered, excessive maintenance costs are consumed.

Seventh, in the case of using a surface treatment reinforcing agent (acrylic agent or epoxy agent) in order to strengthen the strength of the surface, a phenomenon in which the surface permeability is sharply lowered appears.

Eighth, the pavement concrete with fine-grain permeable concrete has a low strength or durability due to economic deterioration due to double laying, a decrease in strength at the adhesive surface between the thin layer and a lower layer, and an unreasonable phenomenon resulting from the difference of different permeability coefficients. The worsening phenomenon appears.

The present invention has been made to solve the above problems, has the following object.

First, when used for paving sidewalks and pavements, it is possible to evaporate water on the dryer after the rainwater is poured on the road, supply natural water to roadside trees, and thereby prevent flooding of public waters, urban rivers, etc. In addition, it is to provide an improved permeable concrete to prevent damage caused by the lowering of the groundwater level in downtown.

Second, because water does not flow on the road, it is convenient for traffic and increases the sliding resistance, which reduces the risk of car accidents, eliminates visual impairment caused by diffuse reflections, and has a sound absorption effect to significantly reduce the noise caused by traffic. To provide improved pitched concrete.

Third, it is to provide improved pitched concrete that is less affected by oil and has a small amount of pigment, so that the desired color can be obtained at a low production price.

Fourth, even if the auxiliary base is damaged can be maintained by securing the bending strength of the concrete, and to provide an improved permeable concrete to produce a concrete batching plant during production.

Fifth, the present invention provides permeable concrete with high compressive strength and flexural strength to be used for pavement in general roads, highways and heavy vehicle passing areas.

Sixthly, some slump value is acceptable, so that the quality control is easy at the time of construction, and to provide improved permeable concrete to promote quality improvement.

Seventh, to provide a permeable concrete that is improved so that the surface is not rough and less surface peeling phenomenon by securing the required fine aggregate ratio.

Eighth, it is to provide a permeable concrete with improved durability by freezing / thawing by securing the required fine aggregate ratio.

Ninth, the present invention provides permeable concrete with an extended lifetime by removing unnecessary independent porosity and minimizing continuous porosity.

Tenth, the present invention provides a pitched concrete having less dust and less maintenance costs because the surface is not rough.

Eleventh, surface treatment enhancers are unnecessary to provide more economically permeable concrete.

Twelfth, there is no need for the uneconomical double laying required for thin-walled pavement, and the unreasonable problem of different permeability coefficients is to provide the permeable concrete.

Thirteenth, to provide a permeable concrete that can be used as a soundproof wall (soundproof wall) surface landscaping material, or offshore structures because the surface is rough and beautiful.

Fourteenth, it is to provide improved permeable concrete for road pavement in areas where construction time cannot be limited due to the control of condensation time and distance.

1 is a conventional road pavement section,

2 is a cross-sectional view showing a general packaging and the packaging of the present invention,

3 is a process diagram of the present invention permeable concrete.

The present invention to achieve the above object in the permeable concrete formed by mixing cement, water, aggregate and admixture in a predetermined ratio, the fine powder particles of the aggregate, the admixture is a VAE emulsion, aramid fibers and natural fibers It is characterized by further included. In this case, the "fine powder particle" has a particle size of 2.36mm (permissible difference: average (±) 0.070mm, maximum: (+) 0.24mm) by the standard of fine aggregate mesh of standard net prescribed in KS A 5101, Nominal dimension is 2.5 mm and means the particle which passes through # 8 body, and it is called "particle which passes through # 8 body below".

According to the features of the present invention, the water-permeable concrete of the present invention has a permeability to secure the continuous porosity by removing the powder particles of the aggregate and can improve the setting time and strength by the adoption of SBR latex or VAE emulsion.

In addition, the combination of steel fibers, glass fibers, carbon fibers, aramid fibers and natural sumde, etc. to secure ultra-high strength.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the permeable concrete 11 according to the present invention, as shown in FIG. 2, the filter layer 3 and the auxiliary base layer 2 are laminated on the hearth 4 and poured on top thereof. As for the water-permeable concrete 11, cement, water, admixture, and aggregate are mixed in an appropriate ratio as usual.

Here, as a characteristic constitution of the present invention, SBR (Styrene butadiene) which removes "particles passing through # 8 body" from the aggregate, and the admixture is foamable in the polymer system to increase the strength, and can control the setting time Mullions are employed for latex or VAE (vinyl acetate ethylene).

In addition, steel fibers, glass fibers, carbon fibers, aramid fibers and natural fibers are mixed to secure ultra high strength.

As permeable concrete 11 according to the present invention, as shown in Figure 3, after removing the fine particles (filter powder) that hinders the permeability of fine aggregate (sand), and mixed with SBR latex or VAE emulsion as a mixed material Steel fiber, glass fiber, carbon fiber, aramid fiber, natural fiber, etc. are mixed and then cement, coarse aggregate, finished and water are prepared in an appropriate amount.

The applicant will be described below for the experimental results on the properties of water-permeable polymer cement concrete pavement.

1. Material used

(1) cement

Cement has a specific gravity of 3.14 and a common portland cement with a powder density of 3,265 cm 2 / g. The chemical composition and physical properties are shown in the following table.

(2) aggregate

(A) Permeable cement concrete aggregate

Fine aggregates were used as the river sand and crushed sand (3mm, 5mm) .For coarse aggregates, crushed stones with the maximum dimensions of 10mm, 13mm, and 20mm were used.

(B) aggregate for permeable polymer cement

Fine aggregates were not used at all. Coarse aggregates were used for crushed stones with a maximum dimension of 10 mm. Physical properties are shown in the following table.

(3) admixture

(A) Admixtures for water-permeable cement concrete

The AE water reducing agent used 0.3% of the amount of unit cement used as calcium lignin sulfonate as a standard AE water reducing agent of M company.

(B) Admixtures for water-permeable polymer cement concrete

As the admixture, three types of polymer resins were used, and their physical properties are as shown in the following table, and the amount used was 5 and 10% of the amount of cement.

2. Experimental method

(1) porosity

The porosity of permeable concrete is calculated by the ratio of the unit volume weight in the absolute volume of the solid concrete to the unit volume weight of the solid concrete.

The unit volume weight test was performed by KS F 2409. (Unit volume weight in absolute volume is the weight of concrete filled in 1㎥ of concrete without air and voids.)

(2) continuous porosity

Continuous porosity of water-permeable concrete is measured by weighing the specimens in the state that the specimens are sufficiently caught by sealing the sides and the bottom of Φ 10 × 20cm columnar specimens with vinyl tape and injecting water from the top surface. Is specified as the ratio to the total volume of the char specimens.

(3) Permeability coefficient

Since the permeability coefficient of permeable concrete is more than 10 ⁵ larger than that of general concrete, the permeability coefficient cannot be measured by the permeability tester for general concrete. Therefore, the permeability test of permeable concrete was measured on the 7th and 28th day of specimens according to the soil permeability test method specified in KS F 2322, and the permeability coefficient was calculated according to Darcy's law.

(4) compressive strength and tensile strength

Fill the Φ 10 × 20cm columnar mold with concrete and chop them 50 times in 30cm heights in three layers with 2.5kg compaction rod, demould after 48 hours and cure in water at 20 ± 2 ℃ to test the KS F 2405 compressive strength test method. Strength was measured. The recognized strength was prepared in the same way as the specimen for compressive strength and measured by KS F 2423 at 28 days of age.

3. Experimental Results on the Characteristics of Permeable Cement Concrete Paving

(1) concrete formulation

Permeable concrete is a porous concrete that has continuous pores to allow water to pass through it. It uses only a certain size of coarse aggregates and no fine aggregates such as sand. The principle is to bond aggregates.

The amount of cement paste is about 300 ~ 400㎏ / ㎥, which is the amount that surrounds aggregate kernels and is combined with each other, and the water-cement ratio is about 30 ~ 40%, which is the amount of cement paste that can form voids without flowing down. And it depends on the porosity, it is preferable to select the optimum mixing conditions by experiment, porosity is determined according to the purpose of use about 5 ~ 30%.

Therefore, in the present application, the maximum dimension of the aggregate is 10 mm, the water-cement ratio is 30%, and the unit cement amount is 350 kg / cm 3 to determine the concrete composition.

(2) Experiment result

1) Measurement result of porosity, continuous porosity and permeability coefficient

In the experiment to determine the porosity and the continuous porosity that greatly affects the permeability in the permeable concrete, the result of measuring the feed rate, the continuous porosity and the coefficient of permeability by mixing the concrete as shown in the concrete mixing table is the following table.

As can be seen from the table below, the porosity of permeable concrete according to the formulation ranged from 6.83% to 29.12%, and the continuous porosity ranged from 4.24% to 24.01%. It can also be seen that the permeability coefficient was from 1 × 10 ⁻² cm / sec to 1.1 cm / sec. And when the maximum dimension of aggregate is 13mm, it is determined by changing the aggregate aggregate rate.When the unit cement amount 380㎏ / ㎥ does not include fine aggregate, the permeability coefficient is 0.92cm / sec and 0.01cm / when the fine aggregate ratio is 30%. As sec, the difference is also largely affected by the change of the aggregate aggregate.

In addition, as a result of changing the unit cement amount, the permeability coefficient decreased as the unit cement amount increased in the maximum dimensions of 5mm, 10mm and 13mm.

(2) Strength measurement of permeable concrete

The compressive, flexural and tensile strengths of permeable concrete were measured and the results are summarized in the table below. The compressive strength is the result measured at 7 and 28 days of age, and the flexural and tensile strengths are measured at 28 days of age.

(3) Characteristics of Permeable Cement Concrete Pavement

In this experiment, as a part of the study to obtain the data of the basic stage for the practical use of permeable concrete pavement, the concrete manufactured by varying the unit cement amount, aggregate maximum dimension, and aggregate aggregate ratio to determine permeability and strength The experiment result was as follows.

① The results of experiments in which the maximum dimensions of aggregates were changed to 5 types from 3mm to 20mm among the factors affecting permeability and strength in permeable concrete pavement were examined. Although the permeability coefficient and the steelmaking degree were significantly different according to the change of the rate, in general, the larger the maximum dimension of the aggregate, the larger the permeability coefficient, but the opposite result.

② Permeability coefficient, porosity, and compressive strength of 9 composite concrete were changed to 0, 10 and 20% of aggregate aggregate, 320, 380 and 420㎏ / ㎥ As a result of the comparison, the larger the aggregate aggregate and the amount of cement, the smaller the permeability coefficient was. In particular, the residual aggregate ratio was significantly higher at zero aggregate aggregate. On the other hand, the steelmaking strength was greater as the aggregate aggregate rate increased.

③ Among the factors affecting the permeability and strength of permeable concrete pavement, the maximum size and aggregate aggregate rate of aggregate are fixed equally, and the unit cement amount is 320, 380 and 420㎏ / ㎥, and the maximum size of aggregate is 5, 10 and 13mm. In comparison of the permeability and strength of 9 blends with the maximum 9mm of aggregate and 13mm of aggregates and 0, 10 and 20% of aggregates, the permeability increased while the maximum size of aggregates increased and the permeability decreased with larger aggregates. The degree was less correlated with the maximum size of aggregates, and the larger the aggregate aggregates, the better.

④ The porosity, continuous porosity, and steel strength of the permeable concrete pavement differed according to the change of the maximum size, aggregate aggregate, and unit cement amount. In other words, the porosity was found to be 6.8 ~ 29.1%, and the continuous porosity was 4.2 ~ 24.0%, which was about 20% less than that. The compressive strength was 117 ~ 356㎏ / ㎠, flexural strength 21 ~ 65㎏ / ㎠ and tensile strength 12 ~ It appeared to be about 38㎏ / ㎠. In addition, the flexural strength was about 1/5 ~ 1/6 of the compressive strength, which is similar to that of 1/5 ~ 1/8 of general concrete.

⑤ Permeable concrete rarely uses fine aggregates, so if the maximum size of aggregate is large, permeability coefficient is increased. However, when used for paving concrete, the surface of pavement is curved, so it is not usable and pop-out phenomenon of aggregate is likely to occur. There are many. Therefore, in order to enhance permeability, strength and usability, aggregates having a small maximum size and good formation of voids are preferable. Based on the above experimental results, the road paving design guideline established by the Ministry of Construction and Transportation stated that the permeability of the permeable asphalt mixture had a high permeability coefficient if the permeability of the permeable asphalt mixture was about 10 ^-2 cm 2 / sec.

As a result of permeable concrete, the continuous porosity satisfying the permeability coefficient of 10 ^-2 ㎠ / sec is about 8%, the porosity is about 12%, and the compressive strength is about 250㎏ / ㎠. However, considering the general conditions of the site and the fact that permeable pavement is mainly applied to light traffic roads such as parking lots, sidewalks and bicycle paths, the compressive strength of 200 kg / ㎠ is sufficient to satisfy the required strength of permeable concrete pavement. The permeability coefficient of permeable concrete corresponding to the compressive strength of 200 kg / ㎠ was about 0.38 cm / sec, and the continuous porosity and the porosity were about 15% and 19%, respectively. Permeable concrete has a strong variation in strength and permeability depending on the type of compounding, and considering that water is permeated into the concrete, it is difficult to secure durability against freezing and thawing.

3. Experimental Results of Permeable Polymer Cement Concrete

(1) concrete formulation

Permeable concrete is a porous concrete that has continuous pores to allow water to pass through. It is made of coarse aggregates of a certain size and no fine aggregates such as sand. The principle is to bond aggregates.

The amount of cement paste is about 300 ~ 400㎏ / ㎥, which is the amount that surrounds the aggregate kernels and is combined with each other.The water-cement ratio is about 30 ~ 40%, which is the amount of cement paste that can form voids without flowing down. And it depends on the porosity, it is preferable to select the optimum mixing conditions by experiment, porosity is determined according to the purpose of use about 5 ~ 30%.

Therefore, in this experiment, the maximum size of aggregate was 10nm, water-cement ratio was unified to 30%, and the unit cement amount was 350㎏ / ㎥ and the concrete mixture was determined.

(2) Measurement of porosity, continuous porosity and permeability coefficient

The results of measuring the porosity, continuous porosity, and permeability coefficient at 28 days of age by mixing concrete are the results of the permeability coefficient specific result table. As can be seen from this table, the porosity of permeable concrete according to the formulation ranged from 15.8% to 25.9%, and the continuous porosity ranged from 13.0% to 23.8%. In addition, the coefficient of permeability can be seen that appeared from 0.25cm / sec to 0.68cm / sec.

(3) Result of strength measurement of permeable polymer cement concrete

The compressive and tensile strengths of water-permeable polymer cement concrete are measured and shown in the following table. The compressive strength of each polymer was measured at 7, 14 and 28 days of age, and the tensile strength was summarized at 14 and 28 days of age.

(4) Experimental Study of Permeable Polymer Cement Concrete

1) Effect of Porosity and Continuous Porosity on Permeability

In order to secure the permeability of permeable concrete, a certain amount of continuous voids is required. Therefore, the presence of voids in permeable concrete is inevitable. As the amount of voids in concrete increases, the strength decreases, so that the strength of permeable concrete is significantly lower than that of ordinary concrete. Therefore, the most ideal permeable concrete is high permeability and strength, which means that the continuous porosity is large and the porosity is small. In order to do this, if a large number of continuous voids are generated, the permeability coefficient increases, and reducing the air trapped inside the concrete increases the compressive strength by minimizing the voids.

Compared to ordinary concrete without polymers by type of polymer and incorporation amount, 5 and 10% of polymers were used by type. In most cases, continuous porosity was higher at 10% than when 5% was used. Regardless of the age, the permeability coefficient tends to decrease as the age increases.

In addition, when the polymer content is 5% compared to ordinary concrete without polymer, the permeability coefficient of the polymer is less than that of ordinary concrete. However, the value of permeability was much higher than the permeability coefficient of 1 × 10 ^-2 cm / sec suggested by the road pavement design guideline of the Ministry of Construction and Transportation.

In the case of normal permeable concrete without polymer, the permeability coefficient is 0.71cm / sec when the continuous porosity is 21.7%, which is about 12% more than the continuous porosity and permeability coefficient 19% and 0.38cm / sec when 5% SBR latex is incorporated. It was found to be 46% higher and VAE emulsion and acrylic solution both showed less than the permeable concrete, but the road pavement design guidelines were satisfactory.

(2) Effect of Porosity and Continuous Porosity on Strength

Strength is as important as water permeability in permeable concrete, but it is difficult to express high strength because porous concrete has more voids than dense general concrete. In general, in order to increase the strength of the concrete, such as a method for manufacturing a precast or prestressed member, centrifugal molding of a low water-cement ratio concrete, followed by steam curing (65-75 ° C.), and a high temperature and high pressure curing method. In some cases, fine powder penetrating method is used to fill pores in concrete by mixing polymer polymer or slag. The manufacturing principles and methods are summarized in the following table.

Therefore, in the case of high-strength concrete, it is common to require a relatively larger amount of unit cement than ordinary strength. In this study, the unit cement amount of 350㎏ / ㎥ was used, and the polymer was used to increase the strength of permeable concrete. 5% and 10% of incorporation was performed to increase the strength. 4 and 5 show the compressive strength and the tensile strength of each polymer according to the age as compared to the normal permeable concrete, the strength is generally increased by using the polymer as compared to the normal permeable concrete.

In order to find out the permeability coefficient and compressive strength of permeable concrete pavement, we investigated the continuous porosity, porosity, permeability coefficient, compressive strength and tensile strength of permeable concrete prepared by mixing 5% and 10% of polymers. The results are as follows.

(1) Permeability Performance of Permeable Polymer Cement Concrete As a result, the continuous porosity was generally lower than the permeable concrete without polymer, so the permeability coefficient was low.

Regardless of the polymer type, the continuous porosity was unexpectedly increased or the permeability coefficient was almost similar to that of 5% at 10%.

(2) At 5% polymer content, the permeability coefficient was reduced from 25% to 60% than without the polymer, but the permeability coefficient suggested in the high guidelines when designing road pavement by the Ministry of Construction and Transportation was 25 rather than 1 × 10 ^-2 ㎝ / sec. It is more than 50 times.

(3) Comparison of three permeability coefficient sizes in water-permeable polymer cement concrete with 5% polymer content showed water-soluble acrylic and SBR latex VAE emulsion in order, and the compressive strength of VAE emulsion was opposite to that of water-permeable coefficient. , SBR latex, and water-soluble acrylic.

(4) Permeable Polymer As a result of examining the strength-improving effect when the polymer of cement concrete is mixed, the compressive strength is 20 ~ 25% and tensile strength is about 10 ~ 20% than the polymer.

The permeable concrete according to the present invention is to remove the "particles passing through the # 8 body" of the aggregate to secure a continuous porosity is secured permeability and by mixing SBR latex or VAE emulsion to increase permeability and high strength, steel fiber, Incorporating glass fiber, carbon fiber, aramid fiber and natural fiber, such as to ensure ultra-high strength and has the following advantages.

First, when used for paving sidewalks and pavements, it is possible to evaporate water on the dryer after the rainwater is poured on the road, and to supply natural water to roadside trees, thereby preventing flooding of public waters, urban rivers, etc. The damage caused by the drop in the groundwater can be prevented.

Second, because water does not flow on the road, traffic is convenient and the sliding resistance can be increased to reduce the risk of car accidents, to eliminate visual impairment caused by diffuse reflections, and the sound absorption effect can eliminate the noise caused by traffic. .

Third, because the concrete is less affected by the oil and the original color of the concrete is off-white, the desired color can be obtained at a low cost by a small amount of pigment.

Fourth, even if the auxiliary base is damaged can be maintained somewhat by securing the bending strength of the concrete, can be produced in the concrete batch plant during production.

Fifth, because of the high compressive strength and flexural strength, it can be used for pavement of highways and heavy vehicle passing areas as well as general roads.

Sixth, because it allows some slump, it is easy to control quality during construction, and excellent quality can be secured.

Seventh, the surface roughness and less surface peeling phenomenon occurs by securing the required fine aggregate ratio.

Eighth, durability by freeze-thawing is excellent by securing required aggregate aggregate rate.

Ninth, service life is extended by eliminating unnecessary independent porosities and minimizing continuous porosities.

Tenth, because the surface is not rough, there is less dust and maintenance costs are reduced.

Eleventh, the surface treatment enhancer becomes unnecessary and becomes more economical.

Twelfth, the uneconomic double laying required for thin-grained pavement is eliminated, and the irrationality resulting from the difference of different permeability coefficients is eliminated.

Thirteenth, because the surface is not rough and beautiful, it can be used as a soundproof wall (soundproof wall) rough landscaping material, or marine structures.

Fourteenth, the condensation time can be adjusted, which can be used for pavement in areas where construction is not possible due to restrictions on transport time and distance.

Claims (1)

In the permeable concrete formed by mixing cement, water, aggregate, and admixture in a predetermined ratio, the aggregate lacks "particles passing through # 8", and the admixture is a VAE emulsion, and further includes aramid fibers and natural fibers. Pitched concrete characterized in that.

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