JP4792555B2 - Porous ceramic member and manufacturing method thereof - Google Patents

Description

  The present invention relates to a porous ceramic member and a method for producing the same, and more specifically to a ceramic member having both sufficient mechanical strength as a paving material, water absorption, water permeability and water uptake, and a method for producing the same.

  As global environmental issues are addressed, roads and other pavement materials have high mechanical strength, durability, and creation of a comfortable landscape, as well as heat island phenomena and global warming caused by high road temperatures in summer. New functions such as suppression of urbanization, groundwater recharge, and suppression of urban water damage due to reduced water absorption due to high pavement are required.

  In order to realize such functions, water absorption is performed so that rainwater etc. can be retained or passed through the ground, and when the weather is clear, the road surface temperature can be lowered by the heat of vaporization of the retained water or water pumped from the ground. There is a need for a pavement material that has properties, water permeability and water pumping.

  Ceramic members such as bricks are excellent in strength and durability, have a unique texture, and have a good landscape when applied as paving materials, building materials, and the like. Therefore, brick has been used as a paving material for a long time mainly in Europe. However, conventional paving ceramic members are not sufficient in terms of water permeability, etc., and not only do not have the above new functions, but also cause problems such as water puddles and falls during walking in the rain. It sometimes occurred.

  Red bricks, earthenware tiles, and the like exhibit fairly high water absorption and pumping properties, but have low water permeability. This is thought to be due to the contribution of capillary action due to the inclusion of many pores having a small diameter and the low continuity of the pores. On the other hand, a water-permeable brick block manufactured for the purpose of increasing water permeability contains many continuous pores having a large diameter, and thus exhibits high water permeability but is poor in water absorption and pumping. As described above, there has never been a ceramic member that has all of water absorption, water permeability, and water absorption at the same time, and has sufficient mechanical strength and wear resistance as a paving material.

  The following proposals have been made as means for solving these problems.

  Japanese Patent Laid-Open No. 9-95904 (Patent Document 1) discloses an invention related to a perforated surface layer using a ceramic sintered body, which is used as a roadbed material for paving having a function of suppressing an increase in road surface temperature. .

  JP-A-8-319179 (Patent Document 2) describes glassy slag produced during metal smelting, glassy slag produced by melting municipal waste and / or sewage sludge, and amorphous glassy material. Heat is produced by using silicate coarse particles whose volume is expanded by heating consisting of coal ash, small amounts of metals, incinerated ash produced by enclosing carbon and volatile gas components, and mixtures thereof as heating. The present invention relates to a porous sintered body characterized in that it has a material structure in which a large number of through gaps are generated between skeletal particles, and is sintered-bonded with a silicate composition whose volume is shrunk by The invention is disclosed.

  Japanese Patent Application Laid-Open No. 2003-146772 (Patent Document 3) has moderate water permeability, including waste-derived ceramics, slag, sewage sludge and other waste-derived materials as part of the raw inorganic particles. In addition, an invention relating to a block excellent in water retention, water lift and strength and a method for producing the same is disclosed.

  Japanese Patent Application Laid-Open No. 2003-73181 (Patent Document 4) discloses an invention relating to a method for producing a granular, pellet-shaped, spherical, etc. inorganic porous material using pulp sludge as a pore-forming material.

JP-A-9-95904 JP-A-8-319179 Japanese Patent Laid-Open No. 2003-146772 JP 2003-73181 A

  However, in the inventions disclosed in Patent Documents 1 to 3, wastes are used as the inorganic particles, and since they form part of the sintered structure, the quality of the ceramic member obtained by sintering is high. The quality of these wastes may be affected. Further, when these ceramic members are applied as a paving material, there is a case where labor and cost are required for the construction, for example, a moisture storage layer made of crushed stone, perforated asphalt, cloth or the like is provided in the lower part thereof.

  The present inventor combines pulp sludge and other organic fibers with raw material soil and sinters them, thereby having sufficient mechanical strength as a paving material, water pumping, water permeability and water absorption, As a result, it was found that a ceramic member exhibiting a function can be produced by construction, and the present invention has been completed.

The first form of the present invention for solving the above problems is obtained by mixing 30-50 vol% pulp sludge with raw soil, forming into a predetermined shape, and firing at a temperature of 600 ° C. to 1300 ° C. is, in tissue, have a fine and irregular continuous pores derived from the pulp sludge were formulated into the raw soil material, a water absorption of 7 to 13%, was calcined after molding a length of 100mm test piece Using the measured value of the wet weight m ₁₂₀ measured after standing for 120 minutes after being immersed in distilled water kept at a depth of 10 mm for 120 minutes , and the dry weight m ₀ of the test piece , the formula (m ₁₂₀ −m _The present invention relates to a porous ceramic member characterized in that the pumping rate after 120 minutes elapses is 9% or more, which is obtained from ₀ ) / m ₀ × 100 . Here, “fine and irregular continuous pores” refers to pores having an arbitrary average pore radius, pore diameter distribution, open pore volume, etc. that can simultaneously have the above-mentioned characteristics, and are used as a material for forming pores. formulated in, it is derived from the pulp sludge to disappear in the firing process.

The second embodiment of the present invention includes a step of mixing 30-50 vol% pulp sludge with raw soil, a step of forming a mixture of the raw soil and pulp sludge into a predetermined shape, and forming a molded product. And a method of firing the molded article at a temperature of 600 ° C. or higher and 1300 ° C. or lower .

The third aspect of the present invention relates to a roadbed paving method using the ceramic member according to the first aspect of the present invention .

  According to the present invention, it is possible to provide a ceramic member having mechanical strength sufficient as a pavement material, water pumping property, water permeability and water absorbing property at a low cost and simply.

  Moreover, by using the ceramic member according to the present invention as a paving material, an increase in road surface temperature can be suppressed, and an effect of suppressing a heat island phenomenon in an urban area can be expected. Since water is quickly taken into the ceramic member, it can be expected to recharge groundwater and suppress urban water damage.

  Moreover, the creation of a comfortable cityscape can be expected by applying ceramic members such as bricks with a warm texture and high harmony with nature to the pavement.

Furthermore, by using pulp sludge , which is an industrial waste, as the organic fiber, it is possible to effectively use these wastes and contribute to the construction of a recycling society. In the present invention, pulp sludge is used as a “template” for imparting porosity, and disappears in the firing process, so that the quality of the sintered body is not influenced by the quality. .

  In addition, according to the present invention, it is possible to construct a pavement having sufficient mechanical strength, water pumping property, water permeability and water absorption property easily and inexpensively according to the conventional method without requiring a complicated process. Become.

  The porous ceramic member according to the present invention has a water absorption of 7 to 13%. The value of 13% corresponds to the maximum value of the water absorption rate required for the third type brick specified in JIS R 1250, and when the water absorption rate is less than 7%, the pumping rate is also reduced. Since the water permeability is reduced when the ratio is more than 1, a porous ceramic member having both water-uplifting property, water-permeability and water-absorbing property cannot be obtained in any case, which is not preferable.

Further, the porous ceramic member according to the present invention has a water permeability coefficient of 1 × 10 ⁻² cm / sec or more, more preferably 1 × 10 ⁻² cm / sec to ¹ × 10 ⁻¹ cm / sec. And When the water permeability coefficient is less than 1 × 10 ⁻² cm / sec, the water permeability is not sufficient, and when it exceeds 1 × 10 ⁻¹ cm / sec, the water and water absorption properties are reduced. It is not preferable because a porous ceramic member having both water permeability and water absorption cannot be obtained.

In addition, the porous ceramic member according to the present invention is a wet weight measured after allowing a test piece molded to φ2.4 mm × 100 mm and fired to stand for 120 minutes after being immersed in distilled water maintained at a depth of 10 mm until no water drops fall off. m ₁₂₀ , and using the measured value of the dry weight m ₀ of the test piece, the pumping rate after 120 minutes, which is obtained from the formula (m ₁₂₀ −m ₀ ) / m ₀ × 100, is 9% or more, When installed as a paving material, it is possible to remove the heat of vaporization by suppressing the water retained inside and the water absorbed from the ground to the upper surface and evaporating it, thereby suppressing the temperature of the road surface .

  The porous ceramic member according to the present invention is characterized in that the bending strength is 3 MPa or more and the compressive strength is 30 MPa or more. These mechanical properties are respectively the minimum value of the bending strength required for the water-permeable interlocking block specified in JASS 7M-101 and the minimum value of the compressive strength required for the fourth kind brick specified in JIS R 1250. It corresponds to the value, and below these values is not preferable because it does not have sufficient strength as a paving material.

The ceramic member according to the present invention can be manufactured by molding and firing a raw soil mixed with pulp sludge .

  As the raw material soil, any material usually used for the production of ceramic members can be used. Used refractories, or at least aluminum oxide, silicon oxide and iron oxide, known to improve the water absorption and compressive strength of bricks obtained by firing when mixed with the brick soil It is also possible to mix and use a granular material containing.

The raw soil organic fibrous Ru earthenware pots are added to a pore-forming material, pulp, pulp sludge, cotton, silk, natural fiber wool, nylon, synthetic fibers and regenerated fibers of rayon or the like of the polyester And those selected from the group consisting of chemical fiber, grass, rice husk and sawdust. Regarding natural fibers and chemical fibers, yarns made of these may be cut and used, but fiber waste generated in a textile factory or the like may be used. These may be used alone or it may also be used in any combination of two or more bur, pulp sludge is used in the present invention. The amount of pulp sludge added is 30 to 50 vol% , most preferably 30 vol% with respect to the raw soil. If the amount of organic fiber added is less than 30 vol%, for example, about 10 vol% , pore formation is not sufficient, so that a sufficient value for water absorption cannot be obtained, and if it exceeds 50 vol%, the mechanical strength decreases, Since moldability also deteriorates, both are not preferable.

Mixing of raw material soil and pulp sludge can be performed by a stirrer equipped with a stirrer, a mixer, a mortar mixer or the like. Further, an appropriate amount of water may be added and hydromixed.

Molding of the mixture of raw material soil and pulp sludge is carried out by any method such as press molding using a vibration press machine, high pressure press machine, etc., extrusion molding machine, extrusion molding using a clay kneader, etc., if necessary. It can be carried out.

  The molded body can be fired using a tunnel kiln, a roller hearth kiln, an electric furnace, or the like, if necessary. By firing, the organic fiber is lost by receiving carbonization, air oxidation, etc. by heat, and desired pores can be obtained. The firing temperature is 600 to 1300 ° C, preferably 700 to 1200 ° C, and most preferably 1000 to 1100 ° C. When the firing temperature is lower than 600 ° C., sufficient mechanical properties are not exhibited, and when it is higher than 1300 ° C., the formation of open pores is inhibited, resulting in a decrease in water absorption and water permeability.

  In order to improve water permeability, the porous ceramic member may be provided with a through hole penetrating the upper surface and the lower surface. The number of the through holes is preferably set to a number that does not impair the mechanical strength while ensuring sufficient water permeability. Further, in order to prevent a decrease in water permeability due to clogging, a taper may be provided so as to increase in diameter toward the lower surface, and the upper surface side may be closed to prevent intrusion of dust.

  The porous ceramic member according to the present invention can be suitably used as a pavement material for roads such as roadways and sidewalks, open spaces and parks. Construction can be done in the same way as when using normal ceramic members, but when the water retention of the ground is poor, supply an appropriate amount of moisture to the ground and keep the back of the paving material always moist. In order to maintain the road surface temperature rise suppression effect due to latent heat of vaporization, a water supply system may be installed as appropriate.

  Hereinafter, in order to further clarify the features of the present invention, a detailed description will be given based on examples. The present invention is not limited to these examples.

  The porous ceramic member according to the present invention was manufactured by the following method.

The red clay was crushed and classified with a sieve having an opening of 0.5 mm. To this, a predetermined amount of classified pulp sludge and water were added, kneaded with water, and cured for a predetermined time. The raw material soil-organic fiber mixture thus obtained was extruded by a kneader. After molding, the weight was measured and measured, dried at 110 ° C. for 24 hours, and then fired at a predetermined temperature (600 ° C., 800 ° C., or 1000 ° C .: see FIG. 1) .

The water absorption is measured by the dry weight of the test piece (dried at 110 ° C. for 24 hours) m ₀ (g) and the wet weight m (g) measured after being gently taken out of the water after being immersed in water for 24 hours. From this, the following equation was used.

Water absorption (%) = (m−m ₀ ) / m ₀ × 100

The pumping rate is a test piece of φ 24 mm × 100 mm, and the test piece was immersed in distilled water in a container to a height of 10 mm in the length direction (during the test, it was always immersed to a height of 10 mm. It was measured by weight change after elapse of a predetermined time. From (24 hours at 110 ° C. drying) the dry weight of the test piece m 0 _(g) and after t minutes passed gently removed from the water, the wet weight was measured after leaving until the water droplets can not drop m _{t (g),} t minutes elapsed The subsequent pumping rate was calculated by the following equation.

Pumping rate after elapse of t minutes (%) = (m _t −m ₀ ) / m ₀ × 100

  The water permeability and bending strength were measured according to JASS 7M-101, and the compressive strength was measured according to JIS R 1250.

  The relationship between the added amount of pulp sludge and the water absorption and bending strength is shown in the table below.

The amount of compressive strength and hydraulic conductivity of pulp sludge added to the raw material soil is 30 vol% (corresponding to 12.5 parts by weight of pulp sludge with respect to 100 parts by weight of raw material soil), respectively, 37.8 MPa and 1.68 × 10 ⁻² cm / sec. Both satisfy the standards of JIS R 1250 and JASS 7M-101. In addition, the water absorption rate was remarkably increased as compared with the addition amount of 0 vol% (brick produced by a normal method), and it was confirmed that the water absorption rate was sufficient as a water-permeable pavement material.

  The relationship between the pumping rate and the immersion time is shown in FIG. In the figure, “ordinary brick” refers to a brick manufactured by a normal method without adding pulp sludge, and “lifted brick” refers to the same raw material soil as “ordinary brick” and 30 vol% pulp sludge. Each of the bricks according to the present invention produced by adding It can be seen that at any firing temperature, the addition of pulp sludge markedly increases the pumping capacity of the resulting porous brick.

  Also, a 90 × 60 × 200 mm rectangular parallelepiped test piece (sample a: pulp sludge addition amount 0 vol%, sample b: pulp sludge addition amount 10 vol%, sample c: pulp sludge addition amount 30 vol%, sample d: pulp sludge addition amount The following table shows the change over time of the height of the tip of the pumped water from the water surface, measured under the same conditions as in the above-described pumping test.

By adding pulp sludge and firing, it is possible to maintain high pumping capacity without saturation of pumping height even after 120 minutes , and the effect of improving pumping capacity is particularly remarkable in sample c. I know that there is.

  The test pavement for verifying the effect of suppressing the increase in the road surface temperature was constructed by a normal construction method using a 60 mm thick brick. FIG. 2 shows the results of field tests (maximum road surface temperature on each measurement day) carried out at the Yamada Exhibition Hall, Araki Ceramics Co., Ltd. from April 1, 2005 to April 29, 2005. For comparison, the measured values on the asphalt road surface and the pavement surface using ordinary permeable brick are also shown.

  It turns out that the maximum road surface temperature of the pavement surface using the water-lifting brick which concerns on this invention is remarkably low compared with others. On April 22, the difference from the maximum road surface temperature on the pavement surface using ordinary permeable bricks was 11.7 ° C, which was the maximum value. This was because there was rain from April 19th to 20th. It is considered that the effect of suppressing the temperature rise due to the heat of vaporization was most noticeable when sufficient moisture was supplied to the brick and the soil and then it became clear.

It is a figure which shows the relationship between immersion time and the pumping rate in the normal brick and the water-lifting brick which concerns on this invention. It is a figure which shows the temperature rise inhibitory effect in the paved road surface using the water-lifting brick which concerns on this invention.

Claims (5)

It is obtained by mixing 30-50 vol% pulp sludge in the raw soil, molding it into a predetermined shape, and firing it at a temperature of 600 ° C or higher and 1300 ° C or lower,
Within the structure, it has fine and irregular continuous pores derived from the pulp sludge blended in the raw soil ,
Water absorption rate is 7 to 13%
Measurement of wet weight m ₁₂₀ measured after standing a test piece molded to 100 mm length and baked in distilled water kept at a depth of 10 mm for 120 minutes until no water droplets dropped , and dry weight m ₀ of the test piece using the values obtained from the formula _{(m 120 -m 0) / m} 0 × 100, wherein the pumping rate after 120 minutes is less than 9%, the porous ceramic member.   The porous ceramic member according to claim 1, wherein the ceramic member is a brick. Mixing 30-50 vol% pulp sludge with raw soil;
Forming a mixture of the raw soil and the pulp sludge into a predetermined shape, and forming a molded product;
And a step of firing the molded product at a temperature of 600 ° C. or higher and 1300 ° C. or lower . The method for manufacturing a porous ceramic member according to claim 3 , wherein the ceramic member is a brick. Using the ceramic member according to claim 1 or 2, pavement method of roadbed.

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