JP2006062917A - Method of producing tile for anticorrosive-repairing wall surface of concrete structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing tile for anticorrosive-repairing the wall surface of a concrete structure which uses a raw material containing sewage sludge incineration ash in a high mixing ratio and has ≤4% water absorption. <P>SOLUTION: A powdery mixture mainly containing the sewage sludge incineration ash, clay power and ceramic powder is prepared. Water is added into the powdery mixture and kneaded to make a body, the resultant body is formed into a prescribed tile shape, the formed tile is dried, the dried tile is fired in an oven while elevating a temperature up to a temperature at which the chemical reaction of the materials is finished and further heated to exceed the chemical reaction finishing temperature to induce melting state on the surface layer of the tile and after that, the atmosphere of the oven is turned to a reducing state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a ceramic tile for anticorrosion repair of a concrete structure wall surface. The concrete structures referred to in the present invention are, for example, manholes, sewers, canals, drain pipes, etc., including various shapes such as circular, oval, rectangular, and horseshoe-shaped cross sections, but are not limited thereto. Especially, it is a large-diameter concrete structure that allows humans to enter and work. However, other concrete structures may be used.

  Hereinafter, a manhole will be described as an example. In general, manholes attached to sewers are made of concrete, and their inner walls are gradually corroded over many years due to hydrogen sulfide generated in the sewer pipes and sulfur oxides in the rainwater flowing into the sewer pipes. Then, it may progress to the collapse of the manhole, or even if it does not collapse, it may crack and cause a situation such as water leakage or water intrusion, which may lead to an increase in the amount of sewage treatment, a situation such as land subsidence . In order to prevent such a situation, it is necessary to repair the deteriorated inner wall surface of the manhole in a timely manner.

  Conventionally, as a manhole inner wall surface repair technique, for example, those described in Patent Documents 1 to 4 below have been proposed.

  In any case, first, the deteriorated surface layer portion is scraped off from the inner wall surface of the manhole. Next, a repair material is attached to the exposed undegraded inner wall surface with an adhesive.

  As for the inner wall surface of the manhole repaired by the prior art described in Patent Documents 1 to 4, the plastic repair material is exposed to the inner wall surface side.

  However, in the case of a plastic repair material, it is easily affected by temperature, and the influence is considerably great because temperature changes occur repeatedly particularly in manholes and sewer pipes. Since the plastic repair material affected by the temperature is slightly deformed, it is difficult to maintain the intended function for a long time.

  In order to deal with such a problem, the applicant has previously proposed that the inner wall surface of the manhole is repaired by bonding ceramic tiles (Japanese Patent Application No. 2003-370839). Ceramic tiles are not easily violated by acid or the like, and are resistant to heat, so that the manhole whose inner wall surface is repaired can maintain its function semipermanently.

  Ceramic tiles are generally manufactured mainly from clay and clay-like materials, but the present inventors are focusing on sewage sludge incineration ash, which is currently generated in large quantities as ceramic tile manufacturing materials and its effective use is required. did.

  The sewage sludge incinerated ash is dewatered after coagulating solid components by adding flocculants to so-called sewage sludge contained in domestic wastewater discharged from ordinary households, industrial wastewater, and rainwater containing earth and sand that has flowed into sewage pipes. , And processed by firing.

  Regarding the effective use of sewage sludge incineration ash, for example, the following Patent Document 5 and Patent Document 6 describe the manufacture of ceramic products, particularly ceramic pipes.

The literature 6, sewage sludge ash, clay powder, chamotte although manufacturing method of ceramic tubes using material mixed (ceramic tube were those pulverizing) a are described, in Fe ₂ O ₃ in the mixed material It is pointed out that foaming may occur when the iron oxide content exceeds 8% (paragraph 0014).

JP-A-8-74280 JP-A-8-27822 JP-A-9-13410 JP 2001-248177 A JP 2003-26468 A JP 2000-247730 A

  An important factor in the production of ceramic tiles for repairing concrete structure wall protection is the permeability of the manufactured tile, which can be regarded as substantially equivalent to the water absorption rate. The water absorption rate of concrete is about 4% or more. Therefore, the water absorption rate of ceramic tiles for repair must be as small as possible and less than 4% in order to fulfill the purpose of repair such as corrosion prevention. Can not.

  In general, the content of iron oxide in the sewage sludge incineration ash is considerably large, and when the sewage sludge incineration ash is used, the above-mentioned adverse effect of iron oxide becomes a big problem.

  Therefore, the object of the present invention is that the mixing ratio of the sewage sludge incineration ash in the raw material is large, so even if the content of iron oxide is increased, the water absorption rate of the tile can be reduced to 4% or less, and further the adverse effect due to foaming. It is providing the manufacturing method of the ceramic tile for concrete structure wall surface repair which can avoid.

  As a result of repeated studies to achieve the above object, it was discovered that a large amount of metal oxides, particularly iron oxides, can be used for lowering the water absorption rate, and the invention was completed. .

That is, the invention according to claim 1 is a method for manufacturing a tile for anticorrosion repair of a concrete structure wall surface,
(A) a step of adding water to a mixed powder mainly containing sewage sludge incineration ash, clay powder, and ceramic powder and kneading the mixture;
(B) forming a kneaded material obtained by kneading into a desired tile shape;
(C) drying the resulting raw tile,
(D) a step of firing the obtained dry tile while gradually increasing the temperature to a temperature at which the chemical reaction of the material ends in the kiln,
(E) raising the temperature in the kiln further than the chemical reaction end temperature in the previous step, and at least bringing the tile surface layer into a molten state;
(F) a step of making the inside of the kiln a reducing atmosphere after the occurrence of a molten state;
It is characterized by including.

  The sewage sludge incineration ash referred to in the present invention is, as described above, a so-called sewage sludge contained in rainwater containing earth and sand flowing into a sewage pipe, domestic wastewater discharged from ordinary households, factory wastewater, etc. After the solid component is agglomerated by the above, the powder is processed and pulverized by dehydration and baking.

  The clay referred to in the present invention is mostly plastic when mixed with a certain amount of water, mainly containing silica and aluminum, and is a fine-grained material containing iron, alkali, alkaline earth, etc. It is a powder obtained by drying a fine-grained material.

  In addition, the ceramic powder referred to in the present invention is a powdery ceramic-based inorganic material including tile, cement, glass, brick, etc., and ceramic pulverized material (ceramic tube chamotte) or tile obtained by pulverizing the ceramic tube. A ceramic pulverized product (tile chamotte) obtained by pulverizing slag is suitable as the ceramic powder used in the present invention.

The sewage sludge incineration ash used in the method of the present invention is mainly composed of SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , P ₂ O ₅ , and includes TiO ₂ , CaO, MgO, Na ₂ O, G ₂ O and the like. For example, incinerated ash having the composition shown in Table 1 below can be used. Each sewage sludge incineration ash has the property that the content of Fe ₂ O ₃ is 25% by mass or more of the entire calcined ash, and the content of P ₂ O ₅ is 15% by mass or more of the entire calcined ash. ing.

  For example, clay powder having the composition shown in Table 2 below can be used.

  For example, ceramic powder having the composition shown in Table 3 below can be used.

  According to the invention described in claim 1 of the present invention, a dense crystal layer of iron is provided on the tile surface layer by the above-described steps, particularly through the reduction step (f). A significant reduction in water absorption is achieved by the action of. In addition, adverse effects due to foaming can be avoided by the action of the dense crystal layer.

  Thus, according to the present invention, a tile having a very low water absorption rate can be produced by utilizing the fact that a large amount of iron is contained in the sewage sludge incineration ash.

<Process (a)>
As for the powder mix | blended in a process (a), sewage sludge incineration ash is 20-40 mass% with respect to the whole powder (all powders to be mixed), and ceramic powder is 30-40 mass with respect to the whole powder. It is preferable that clay powder is 30-50 mass% with respect to the whole powder. The combination of the materials is preferably, for example, A + D + F, B + D + F, C + D + F, A + E + F or the like in the above table, but may be other combinations.

  The powder blended as described above and then mixed is adjusted so that the set water content is about 20%, and is further kneaded for about 5 minutes by a vacuum kneader, and is uniformly kneaded and contained. Bubbles are removed.

<Step (b)>
The clay obtained in the step (a) is charged into a mold having a predetermined shape and formed into a tile having a predetermined shape by a press.

<Step (c)>
Drying in this step is for removing water physically present in the tile, and is performed by natural drying such as sun drying or using a drying furnace. When using a drying furnace, for example, it is carried out at a temperature of about 60 ° C. for about 100 hours.

<Step (d)>
The dried base tile is placed in a firing kiln, and the base tile is fired by increasing the temperature in the kiln to about 900 ° C. in about 20 hours.

  The dehydrated water is dehydrated while the temperature is raised to about 120 ° C., and further the crystal water or bonded water in the tile (the water contained in the tile by chemical bonding) Water that cannot be removed by ordinary drying is dehydrated. Furthermore, chemical reaction (oxidation, thermal decomposition) is performed while the temperature rises to about 900 ° C. There are many chemical reactions in which, for example, iron changes to iron oxide, iron sulfide changes to iron oxide, and calcium carbonate changes to lime.

  The temperature rise to about 400 ° C. is preferably performed at a heating rate of about 35 to 45 ° C. per hour, particularly about 40 ° C./hour. If it is too early, voids are likely to occur between the particles of the base tile, and the water absorption rate does not decrease. Moreover, it is preferable to raise the temperature to about 900 ° C. at a heating rate of 50 to 60 ° C. per hour. If it is too early, the deformation (warp, etc.) of the substrate becomes large, the gaps between the particles are not filled, and therefore the compactness is not improved, so that the water absorption rate cannot be reduced.

<Process (e)>
After the base tile is dehydrated, oxidized and decomposed up to about 900 ° C., the base tile is subsequently sintered. The temperature in the kiln is raised to 1000-1200 ° C. or a value close to this in several hours, for example, about 5-8 hours. In such a high temperature region, the surface layer of the particles of the base tile is somewhat melted and a liquid phase is generated. The liquid phase serves to firmly bond the solid particles to each other, fills the gaps between the particles, and reduces the water absorption of the tile.

<Step (f)>
After reaching a temperature of about 1000 to 1200 ° C., the inside of the kiln is made a reducing atmosphere while maintaining the temperature as it is. A reducing atmosphere can be provided, for example, by closing the air valve with the gas burner open. The environment in the kiln is in a state of increasing carbon monoxide.

  By providing such a reduced state at a high temperature, the iron oxide in the tile moves and collects on the surface layer of the tile, and the concentration of iron oxide in the surface layer increases, resulting in an iron crystal layer. As a result, the water absorption rate of the tile surface layer is further reduced. The reduction time is preferably about 15 to 20 minutes. If the reduction time is too short, crystal formation is insufficient and a sufficient reduction in water absorption cannot be expected. On the other hand, if the reduction time is too long, the formation of the crystal layer is accompanied by large irregularities, and the surface layer property of the tile does not cause a decrease in water absorption.

  Generation of foaming in the tile surface layer can be avoided if the heating rate is selected to a preferable value in the step (d), but even if foaming occurs in the tile surface layer, formation of the molten surface layer in the step (e), The formation of a dense crystal layer of iron in the step (f) eliminates the influence of foaming.

  After the reduction, when the furnace is placed in an oxidizing atmosphere, the iron crystallized on the tile surface becomes iron oxide. As a result, an iron oxide crystal layer is formed on the tile, thus increasing the denseness of the surface layer and further reducing the water absorption rate. To do.

  As described in claim 2, the water absorption rate can be further reduced by controlling the particle size of the mixed powder. For example, in the mixed powder, 98% by mass or more of the mixed powder is occupied by particles having a particle size of 200 μm or less.

  In this case, the mixed powder contains at least 30% by mass of sewage sludge incinerated ash containing 98% or more of particles having a particle size of 200 μm or less, and at least 35% by mass of clay powder containing 98% or more of particles having a particle size of 100 μm or less. Is preferred.

  Further, in the clay powder, 98% by mass or more of the entire clay powder is occupied by particles having a particle size of 50 μm or less, and 15% by mass or more of the entire clay powder is occupied by particles having a particle size of 10 μm or more. Is particularly preferred.

  Further, in the ceramic powder, it is preferable that 98% by mass or more of the ceramic powder is occupied by particles having a particle size of 50 μm or less.

  By using the powder with the particle size as described above, the homogeneity of the obtained ceramic tile is increased, leading to an improvement in the strength of the ceramic tile and a decrease in the water absorption rate, and also the water absorption rate even if the firing temperature is relatively low. Since ceramic tiles with small size can be obtained, it can contribute to energy saving.

If the content of Fe ₂ O ₃ in the sewage sludge incineration ash is at least 20% or more as described in claim 3, almost all sewage sludge incineration ash that is generally available can be used.

  If the content of the sewage sludge incineration ash in the mixed powder is at least 25% or more as described in claim 4, a large amount of sewage sludge incineration ash is consumed.

  Hereinafter, the present invention will be described in more detail by way of examples.

  1 to 6 show examples of tiles for repairing the inner wall surface of a manhole. FIGS. 1 to 3 show a first tile, and FIGS. 4 to 6 show a second tile.

  1 is a view of the first tile 1 as seen from the back side, that is, the side in contact with the inner wall of the manhole, FIG. 2 is a sectional view taken along line II-II in FIG. 1, and FIG. 3 is a bottom view of the tile shown in FIG. It is the figure seen from the side.

  4 is a view of the second tile 2 as seen from the back side as in FIG. 1, FIG. 5 is a cross-sectional view taken along line VV in FIG. 4, and FIG. 6 is a view of the tile shown in FIG. FIG.

  The tile dimensions of both tiles 1 and 2 are length (L) 312 mm, width (W) 168 mm, and thickness (T) 20 mm.

  The tile 1 has a recessed portion 12a having a depth of 8 mm formed on the back side by 20 mm-wide ribs 11 a to 11 d provided on each edge of the peripheral edge portion and a 20 mm-wide rib 11 e provided in the center portion in the tile width direction. 12b. The front side of the tile 1 is a curved smooth surface.

  On the other hand, the tile 2 has a depth of 8 mm formed on the back side by two intersecting ribs 21a and 21b each having a width of 10 mm extending in the diagonal direction of the tile and ribs 22a to 22d having a width of 15 mm provided on each edge of the peripheral edge. The concave portions 23a to 23d are provided. The front side of the tile 2 is also a curved smooth surface.

  The following examples all relate to the production of tile 1 having the above-mentioned dimensions, and the materials include incinerated ash (AC), clay powder (D, E), ceramic powder (shown in Tables 1 to 3 above). F) was used in combination.

<Example 1a>
The above incinerated ash A, clay powder D, and ceramic powder F were used, and each powder was used without particularly controlling the particle size. A: D: F was blended at a ratio of 25% by mass: 50% by mass: 25% by mass, mixed, and then adjusted to have a water content of 21% by water, and further 0.03 kgf by a vacuum kneader. A kneaded material was obtained by kneading at a pressure of / cm ² for 5 minutes (step a).

  The obtained clay was left as it was overnight, and then this clay was placed in a mold and press-molded to produce a raw green tile (step b).

  This base tile was dried under natural conditions for 5 days (step c).

  Next, this dry operation tile is put in a firing kiln, and the firing temperature is increased from 100 ° C. to 180 ° C. in the first 2 hours, to 320 ° C. in the next 5 hours, and 440 in the next 1 hour and a half by burning propane gas. Up to 600 ° C in the next 4 hours, up to 740 ° C in the next 2 hours, up to 880 ° C in the next 4 hours, up to 1060 ° C in the next 4 hours, up to 1200 ° C in the next 4 hours Increased (step d-step e).

  When the temperature reached 1200 ° C., the supply of air into the kiln was stopped and raw gas was injected to convert the raw gas into carbon monoxide, whereby the kiln was made a reducing atmosphere. The raw gas was injected for 15 minutes (step f).

<Example 1b>
In the step (a), control was performed so that 98% by mass or more of the mixed powder was occupied by particles having a particle diameter of 200 μm or less. Except for this particle size control, substantially the same operation as in Example 1a was performed up to step (f).

<Comparative Example 1a>
Steps (a) to (e) were performed substantially in the same manner as in Example 1a, and step (f) was not performed.

<Comparative Example 1b>
In the step (a), control was performed so that 98% by mass or more of the mixed powder was occupied by particles having a particle size of 200 μm or less, and the other operations were substantially the same as those in Comparative Example 1a.

<Example 2a>
In the step (a), the incinerated ash B, clay powder D, and ceramic powder F were used, and each powder was used without particularly controlling the particle size. Other than that, the substantially same operation as in Example 1a was performed until step (f).

<Example 2b>
In step (a), substantially the same operation as in Example 2a is performed up to step (f) except that control is performed so that 98% by mass or more of the mixed powder is occupied by particles having a particle size of 200 μm or less. It was.

<Comparative Example 2a>
Steps (a) to (e) were performed substantially in the same manner as in Example 2a, and step (f) was not performed.

<Comparative Example 2b>
In the step (a), substantially the same operation as in the case of Comparative Example 2a was performed except that control was performed so that 98% by mass or more of the mixed powder was occupied by particles having a particle size of 200 μm or less.

<Example 3a>
In the step (a), the incinerated ash C, clay powder D, and ceramic powder F were used, and each powder was used without particularly controlling the particle size. Other than that, the substantially same operation as in Example 1a was performed until step (f).

<Example 3b>
In step (a), substantially the same operation as in Example 3a is performed up to step (f) except that control is performed so that 98% by mass or more of the mixed powder is occupied by particles having a particle size of 200 μm or less. It was.

<Comparative Example 3a>
Steps (a) to (e) were performed substantially in the same manner as in Example 3a, and step (f) was not performed.

<Comparative Example 3b>
In the step (a), substantially the same operation as in the case of Comparative Example 2a was performed except that control was performed so that 98% by mass or more of the mixed powder was occupied by particles having a particle size of 200 μm or less.

<Example 4a>
In the step (a), the incinerated ash A, clay powder E, and ceramic powder F were used, and each powder was used without particularly controlling the particle size. Other than that, the substantially same operation as in Example 1a was performed until step (f).

<Example 4b>
In step (a), substantially the same operation as in Example 4a is performed up to step (f) except that control is performed so that 98% by mass or more of the mixed powder is occupied by particles having a particle size of 200 μm or less. It was.

<Comparative Example 4a>
Steps (a) to (e) were performed substantially in the same manner as in Example 4a, and step (f) was not performed.

<Comparative Example 4b>
In the step (a), substantially the same operation as in the case of Comparative Example 4a was performed except that 98% by mass or more of the mixed powder was controlled by particles having a particle size of 200 μm or less.

The chemical composition of each mixed powder in the above Examples and Comparative Examples was as shown in Table 4 below. A characteristic of these mixed powders is that the content of Fe ₂ O ₃ in the mixed powder is about 11 to 17%, indicating a high content.

  The results of measuring the water absorption rate for the tiles obtained in Examples 1a to 4b and Comparative Examples 1a to 4b are as shown in Table 5.

<Example 5, Comparative Example 5>
The same material as in Example 1a was used, but the mixing ratio of the material was changed (A: 30%, D: 40%, F: 30%) and manufactured by performing substantially the same operation as Example 1a. The water absorption rates of the tiles manufactured and the tiles manufactured by performing substantially the same operation as Comparative Example 1a were compared. The results were as shown in Table 6 below.

  As apparent from the comparison between Example 1a and Comparative Example 1a in Table 5 above, the tile of Example 1a has a significantly reduced water absorption (8.67% → 2) compared to the tile of Comparative Example 1a without reduction. The water absorption rate (2.33%) achieved by Example 1a is a perfect value for a concrete structure wall repair tile. Furthermore, when the particle size is controlled, the water absorption rate tends to decrease dramatically. However, in the case of Example 1b with particle size control, the water absorption rate is further reduced as compared with the case of Comparative Example 1b. It is clear (3.21% → 0.68%).

  Similarly, Example 2a: Comparative Example 2a, Example 2b: Comparative Example 2b, Example 3a: Comparative Example 3a, Example 3b: Comparative Example 3b, Example 4a even when the proportions of the components in the mixed powder are different. : Comparative Example 4a, Example 4b: As is clear from the comparison of Comparative Example 4b, the water absorption of the tile according to the present invention is reduced, and this water absorption is further reduced by controlling the particle size.

In any of the above examples, despite the relatively high content of Fe ₂ O ₃ in the mixed powder (see Table 4), a satisfactory water absorption rate is provided as a concrete structure wall repair tile. ing.

As shown in Table 2, the clay powder E used in Examples 4a and 4b and Comparative Examples 4a and 4b has an Al ₂ O ₃ content of 23% by mass or less of the entire clay powder, as shown in Table 2, and Fe ₂ O The content of ₃ is 4.5% by mass or less of the entire clay powder. In clay, SiO ₂ and Al ₂ O ₃ are actually present as hydrous aluminum silicate, and clay having a high content of Al ₂ O ₃ is kaolin-based clay (kaolinite, nacrite, dickite, halloysite, hydrous halloysite, etc. 1 or more clays). Therefore, kaolin clay is suitable as a material. It is clear from Table 5 that when such a kaolin clay is used, a dense ceramic tile having a low water absorption rate can be obtained even when using a sewage sludge calcined ash having a high Fe ₂ O ₃ content. is there.

Further, in the clay powder E used in Examples 4a and 4b and Comparative Examples 4a and 4b, 98% by mass or more of the entire clay powder is occupied by particles having a particle size of 50 μm or less, and a 90% particle size d ₉₀ Has a characteristic that the ratio of to 50% particle size d ₅₀ is about 3. This means that a clay powder composed of fine particles and having a wide particle size distribution was used. The reason why the water absorption rate of the tiles according to Examples 4a and 4b shows extremely favorable results is considered to be due to the use of such clay powder having a wide particle size distribution. That is, when fine clay powder is dispersed in the clay and the clay is molded into a predetermined shape, the clay powder is densely packed between the sewage sludge calcined ash particles having a relatively wide particle size distribution. It is considered that the density of the molded body increases.

  As is apparent from Table 6 above, even when the blending ratio of the materials is changed, a tile having a low water absorption rate can be manufactured by carrying out the method of the present invention.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of invention. For example, the materials A to G can be variously combined in addition to the above, and materials other than those listed above may be used. Alternatively, the top surface of the tile obtained as described above, particularly the surface exposed to the space in the manhole, may be applied to the surface of the tile and fired in a kiln to be fused to the surface. Furthermore, the tiles can be produced not only in a curved shape as shown in FIGS. 3 and 6 of the above embodiment, but also in a flat or flat shape if necessary.

It is the figure which looked at one example of the ceramic tile for manhole inner wall surface manufacture manufactured by the method of this invention from the adhesion surface side with the manhole inner wall surface. It is sectional drawing which follows the II-II line | wire in FIG. It is the figure which looked at the tile of FIG. 1 from the bottom face side. It is the figure which looked at the other example of the ceramic tile for manhole inner wall surface repair manufactured by the method of this invention from the adhesion surface side with the manhole inner wall surface. It is sectional drawing which follows the VV line in FIG. It is the figure which looked at the tile of FIG. 4 from the bottom face side.

Claims (5)

A method for manufacturing a concrete structure wall anticorrosion repair tile,
(A) a step of adding water to a mixed powder mainly containing sewage sludge incineration ash, clay powder, and ceramic powder and kneading the mixture;
(B) forming a kneaded material obtained by kneading into a desired tile shape;
(C) drying the resulting raw tile,
(D) a step of firing the obtained dry tile while gradually increasing the temperature to a temperature at which the chemical reaction of the material ends in the kiln,
(E) raising the temperature in the kiln further than the chemical reaction end temperature in the previous step, and at least bringing the tile surface layer into a molten state;
(F) a step of making the inside of the kiln a reducing atmosphere after the occurrence of a molten state;
A method for manufacturing a tile for anti-corrosion repair of a wall surface of a concrete structure, characterized by comprising:   The manufacturing method according to claim 1, wherein a particle size of the mixed powder is controlled to a maximum particle size of 200 μm or less. The production method according to claim 1 or 2, wherein the content of Fe ₂ O ₃ in the sewage sludge incineration ash is at least 20% or more.   Content of the sewage sludge incineration ash in the said mixed powder is at least 25% or more, The manufacturing method as described in any one of Claims 1-3 characterized by the above-mentioned. 5. The method according to claim 1, wherein in step (d), the temperature is raised to about 900 ° C. at a heating rate of 50 to 60 ° C. per hour.

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