JP2005154265A - Water-retentive concrete member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-retentive concrete member with which the temperature of a paving road surface can be lowered and which has excellent low noise property and drainage property. <P>SOLUTION: The water-retentive concrete member 1 has a surface layer 2 comprising porous concrete 5, an intermediate layer 3 in which a water-retentive material 6 is filled in the pores of the porous concrete 5 and a lower layer 4 comprising normal concrete 7, and the porosity of the surface layer 2 is 10-25%. Further, the ratio of the thickness of the surface layer 2 to that of the intermediate layer 3 is 1:300 to 1:1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a water-retaining concrete member used as a pavement material for sidewalks, roadways, parking lots, and plazas.

  In recent years, heat island phenomenon has become a problem in urban areas, where the temperature that rises during the day does not drop at night and becomes a tropical night. This heat island phenomenon occurs when the ground covered with soil or plants is replaced with asphalt or concrete. That is, on the ground covered with concrete or the like, rainwater is discharged without being retained, and cooling due to the heat of vaporization of water does not occur.

  Therefore, in order to suppress the rise in temperature caused by concrete, etc., a method to lower the temperature of concrete pavement by spraying slurry-like water retaining material containing cement and water-absorbing resin on the existing porous concrete pavement surface is proposed. (For example, refer to Patent Document 1).

JP 2000-104214 A

  However, in the above method, since the water retaining material is filled from the surface of the porous concrete pavement, the gap in the surface layer of the pavement is blocked, and there is a problem that the low noise property and drainage of the pavement are impaired. In addition, the porous concrete pavement that is actually placed has not only continuous voids but also closed voids, and the pavement surface that has been cast in the field has gradients in the transverse and longitudinal directions. In the method, it is difficult to adjust the filling amount and filling position (depth) of the water retaining material. For this reason, the amount of water retained in the pavement becomes uneven, and there is also a problem that the temperature of the pavement road surface cannot be sufficiently reduced.

  Accordingly, the present invention is intended to solve the above-described problems, and provides a water-retaining concrete member that can reduce the temperature of a paved road surface and has excellent low noise and drainage properties. With the goal.

The present invention comprises a surface layer made of porous concrete, an intermediate layer formed by filling a void in porous concrete with a water retention material, and a lower layer made of ordinary concrete, and the porosity of the surface layer is 10 to 25%. It is a water-retaining concrete member characterized.
The thickness ratio between the surface layer and the intermediate layer is preferably 1: 300 to 1: 1.
Further, the present invention comprises a surface layer made of porous concrete and a water retention lower layer formed by filling a porous concrete void with a water retention material, wherein the porosity of the surface layer is 10 to 25%. It is a water-retaining concrete member.
In addition, in this invention, the porosity is the total porosity measured based on the porosity test method (draft) of the porous concrete by Japan Concrete Institute.

  ADVANTAGE OF THE INVENTION According to this invention, the water-retaining concrete member which can reduce the temperature of a paved road surface and has the outstanding low noise property and drainage property can be provided.

Embodiment 1 FIG.
As shown in FIG. 1, the water-retaining concrete member 1 according to the first embodiment of the present invention includes a surface layer 2 made of porous concrete 5 and an intermediate layer 3 in which a water-retaining material 6 is filled in the voids of the porous concrete 5. And a lower layer 4 made of ordinary concrete 7. Furthermore, the porosity of the surface layer is 10 to 25%.

In Embodiment 1, the surface layer 2 of the water-retaining concrete member 1 is formed of porous concrete 5 and has a porosity of 10 to 25%, preferably 15 to 20%. When the porosity of the surface layer 2 is less than 10%, the low noise property and drainage property of the water-retaining concrete member 1 are impaired.
The drainage performance of the water-retaining concrete member 1 can be evaluated by an on-site water permeability test method for water-permeable asphalt pavement (“Pavement Test Method Handbook”, edited by Japan Road Association). In this method, the average time is calculated by measuring the time required for 400 ml of water to flow down on the pavement surface three times per measurement point. Then, the amount of water that has flowed down per 15 seconds is calculated from the calculated average time, and is defined as the water permeability (ml / 15 seconds). The water permeability (water permeability measured on the surface layer side) of the water-retaining concrete member 1 calculated in this manner is preferably 1000 ml / 15 seconds or more on all surfaces, and more preferably 3000 ml / 15 seconds or more.
On the other hand, when the porosity of the surface layer 2 exceeds 25%, the strength of the water-retaining concrete member 1 is not preferable. In preparing such porous concrete 5, for example, 300 to 600 parts by mass of coarse aggregate, 0 to 500 parts by mass of fine aggregate, and 0 to 5.0 parts by mass of admixture are mixed with 100 parts by mass of cement. A cement composition is used. And, for example, the porous concrete 5 kneaded material can be prepared by mixing 15 to 35 parts by mass of water with 100 parts by mass of the cement composition and kneading with a mixer. As the cement used here, hydraulic cement such as ordinary Portland cement and early-strength Portland cement can be used without limitation. Examples of the coarse aggregate include ordinary aggregates such as gravel and crushed stone, lightweight aggregates, and the like. These coarse aggregates have a particle size of 5 mm or more, preferably 5 to 40 mm. Examples of fine aggregates include ordinary aggregates such as hill sand and crushed sand, lightweight aggregates, and the like. These fine aggregates have a particle size of 5 mm or less, preferably 0.3 mm or less. As the admixture material, known materials can be used without limitation, and examples thereof include admixtures having a water reducing effect, AE water reducing agents, high performance water reducing agents, and high performance AE water reducing agents. Among these admixtures, the strength of the porous concrete 5 can be improved by using an admixture having a water-reducing effect (for example, trade name: Poremix-10K, manufactured by Taiheiyo Cement Co., Ltd.) in the cement composition. it can.

  In the first embodiment, the intermediate layer 3 of the water-retaining concrete member 1 is formed by filling the voids of the porous concrete 5 with the water-retaining material 6. The water retention material used here may be any material that gradually releases moisture over a long period of time, and an inorganic water retention material that is not easily deteriorated by exposure to sunlight (ultraviolet rays) is particularly suitable. Examples of such inorganic water-retaining materials include clay minerals such as montmorillonite and kaolinite, blast furnace slag fine powder, fly ash, silica stone powder, limestone powder, silica fume, perlite, sepiolite, etc. Alternatively, two or more kinds can be used in combination. Inorganic water-retaining materials that can be used for such porous concrete are commercially available, and specific examples include trade name: Ryo (made by Onoda Chemico Co., Ltd.) and the like. In filling the water retaining material 6, for example, a slurry water retaining material 6 in which 60 to 100 parts by mass of water is mixed with 100 parts by mass of the inorganic water retaining material is used. By setting it as the slurry-like water retention material 6, the filling amount and filling position (depth) of a water retention material can be adjusted more correctly.

  In the first embodiment, the lower layer 4 of the water-retaining concrete member 1 is formed of ordinary concrete 7. As the ordinary concrete 7 used here, a known concrete can be used without limitation. In preparing such ordinary concrete 7, for example, 200 to 500 parts by mass of fine aggregate, 300 to 600 parts by mass of coarse aggregate, and 0 to 4.0 parts by mass of admixture are mixed with 100 parts by mass of cement. A cement composition is used. Then, for example, 40 to 55 parts by mass of water is mixed with 100 parts by mass of the cement composition, and the kneaded mixture of ordinary concrete 7 can be prepared by kneading with a mixer. As the cement, coarse aggregate, and admixture used here, the same materials as those used in the porous concrete can be used without limitation. Examples of fine aggregates include ordinary aggregates such as hill sand and crushed sand, lightweight aggregates, and the like. These fine aggregates have a particle size of 5 mm or less, preferably 0.15 to 5 mm.

Next, a method for manufacturing the water-retaining concrete member 1 according to Embodiment 1 will be described with reference to FIG. As shown in FIG. 2, the water-retaining concrete member manufacturing apparatus 8 includes a mold 9 and a pressure plate 10. First, a predetermined amount of the kneaded mixture of ordinary concrete 7 is placed in the mold 9, and is placed in advance for an initial curing time (for example, 2 hours) or more to form the lower layer 4 made of ordinary concrete 7.
After forming the lower layer 4, a predetermined amount of slurry-like water retaining material 6 is poured into the mold 9, and then a predetermined amount of porous concrete 5 kneaded material is placed, and the water retaining material 6 is placed in the voids of the porous concrete 5. The intermediate layer 3 is formed by filling. The pressurizing plate 10 is lowered and a predetermined load is applied to adjust the porosity of the intermediate layer 3. Thus, the lower layer 4 and the intermediate layer 3 can be firmly attached by interposing the water retaining material 6 at the joint between the lower layer 4 and the intermediate layer 3. After raising the pressure plate 10, the water retaining material 6 is replenished as necessary.
After forming the intermediate layer 3, a predetermined amount of the porous concrete 5 kneaded material is placed in the mold 9 to form the surface layer 2. The pressing plate 10 is lowered and a predetermined load is applied to adjust the porosity of the surface layer 2 to 10 to 25%, preferably 15 to 20%. At this time, a part of the coarse aggregate contained in the porous concrete 5 kneaded material may sink into the intermediate layer 3, but it does not matter. And after curing concrete, it can demold and the water-retaining concrete member 1 can be obtained.

  Further, when the surface layer 2 is formed, the amount of the porous concrete 5 to be placed is adjusted so that the thickness ratio between the surface layer 2 and the intermediate layer 3 is 1: 300 to 1: 1, preferably 1:10. By setting it as 1: 2, the temperature reduction effect of a paved road surface can further be improved, maintaining the outstanding low noise property and drainage property. Moreover, when using a water retaining concrete member as a pavement material of a sidewalk or a roadway, it is preferable that the thickness of the surface layer 2 shall be 5-25 mm. Within this range, the strength of the member can be improved while maintaining low noise and drainage required for sidewalks and roadways.

Embodiment 2. FIG.
As shown in FIG. 4, the water-retaining concrete member 11 according to Embodiment 2 of the present invention includes a surface layer 2 made of porous concrete 5 and a water-retaining lower layer formed by filling a space between the porous concrete 5 with a water-retaining material 6. 12. Furthermore, the porosity of the surface layer is 10 to 25%.

In the second embodiment, the surface layer 2 of the water-retaining concrete member 11 is the same as that in the first embodiment, and a description thereof will be omitted.
Further, the water retaining lower layer 12 of the water retaining concrete member 11 is formed by filling the voids of the porous concrete 5 with the water retaining material 6 in the same manner as the intermediate layer 3 of the first embodiment. The materials used here and the blending ratio of the materials are the same as those in the first embodiment, and thus the description thereof is omitted.

Next, a method for manufacturing the water-retaining concrete member 11 according to the second embodiment will be described with reference to FIG. As shown in FIG. 2, the water-retaining concrete member manufacturing apparatus 8 includes a mold 9 and a pressure plate 10. First, a predetermined amount of slurry-like water retention material 6 is poured into the mold 9, and then a predetermined amount of porous concrete 5 kneaded material is placed, and the water retention material 6 is filled in the voids of the porous concrete 5 to retain water. A lower layer 12 is formed. The pressurizing plate 10 is lowered and a predetermined load is applied to adjust the porosity of the water retaining layer 12. After raising the pressure plate 10, the water retaining material 6 is replenished as necessary.
After forming the water-retaining lower layer 12, a predetermined amount of porous concrete 5 kneaded material is placed in the mold 9 to form the surface layer 2. The pressing plate 10 is lowered and a predetermined load is applied to adjust the porosity of the surface layer 2 to 10 to 25%, preferably 15 to 20%. At this time, a part of the coarse aggregate contained in the porous concrete 5 kneaded material may sink into the water-retaining lower layer 12, but there is no problem. And after curing concrete, it can demold and the water-retaining concrete member 11 can be obtained. The water-retaining concrete member 11 is lightweight because the lower layer 4 made of ordinary concrete 7 is not formed, and is suitable as a flat plate on a sidewalk or a roof of a building. When the water-retaining concrete member 11 is used as a flat plate on a sidewalk or a roof of a building, the thickness of the surface layer 2 is preferably 5 to 30 mm. Within this range, it is possible to improve the temperature reduction effect and drainage performance of the paved road surface required for the laid flat plates on the sidewalks and buildings.

  Further, when the surface layer 2 is formed, the amount of the porous concrete 5 to be placed is adjusted so that the thickness ratio between the surface layer 2 and the water retaining layer 12 is 1: 300 to 1: 1, preferably 1:10. By setting it to ˜1: 2, the temperature reduction effect of the paved road surface can be further improved while maintaining excellent low noise and drainage properties.

  In addition, about the water retention concrete member of this invention, the shape is not limited at all. For example, it may be a rectangular parallelepiped shape or a block shape, and may be a flat plate shape generally called a pavement flat plate.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[Example 1]
First, each raw material of ordinary concrete having a blending ratio shown in Table 1 was put into a mixer and kneaded to prepare an ordinary concrete kneaded product. This kneaded product was placed in a 2700 × 3000 × 250 mm mold and placed in front at room temperature for 2 hours to form a lower layer.

After forming the lower layer, 34 parts by mass of an inorganic water retaining material (made by Onoda Chemico Co., Ltd., trade name: Ryo) and 34 parts by mass of water are mixed, made into a slurry, poured into the mold, Each raw material of the porous concrete having the blending ratio shown in 2 was put into a mixer and kneaded, and the porous concrete kneaded material was placed in a mold to form an intermediate layer. The porosity of the intermediate layer was adjusted by applying a load of 13 to 14 kN / m ^{2 with} the pressure plate.

Immediately after forming the intermediate layer, each raw material of the porous concrete having a blending ratio shown in Table 3 was put into a mixer and kneaded, and the porous concrete kneaded material was placed in a mold to form a surface layer. The porosity of the surface layer was adjusted by applying a load of 13 to 14 kN / m ^{2 with} the pressure plate.

  After forming the surface layer, the concrete was steam-cured (for example, at 65 ° C. for 3 hours) and then demolded to obtain a water-retaining concrete member of Example 1.

The dimensions and porosity of the water-retaining concrete member obtained in Example 1 were as follows.
Vertical dimension: 2700mm
Horizontal dimension: 3000mm
Surface layer thickness: 17mm
Intermediate layer thickness: 50 mm
Lower layer thickness: 150mm
Surface layer porosity: 17%

  About each pavement which consists of the water-retaining concrete member of Example 1, the conventional asphalt, the conventional porous concrete, and the conventional ordinary concrete, Tokyo Metropolitan Government determines from 11 am to 3 pm on August 11, 2003. The change in surface temperature was measured according to “Measurement method for evaluation”. The results are shown in FIG. As can be seen from FIG. 3, the pavement made of the water-retaining concrete member of Example 1 has a maximum surface temperature of 10.8 each compared with the conventional asphalt pavement, the conventional porous concrete pavement and the conventional ordinary concrete pavement. C., 4.3.degree. C. and 3.9.degree. C. could be reduced.

  Next, after placing the water-retaining concrete member of Example 1, the conventional porous concrete and the conventional porous concrete, each pavement made of concrete filled with a water-retaining material from the upper surface is referred to as “Pavement Test Method Handbook” (corporate association) In accordance with the Japan Road Association), water permeability tests were conducted. The number of measurement points was 5, and three measurements were performed for each measurement point to determine the average water permeability. The results are shown in Table 4.

As can be seen from Table 4, the pavement composed of the water-retaining concrete member of Example 1 has a water permeability exceeding 5000 ml / 15 seconds at all points measured, and its average water permeability (average water permeability of 5 points 6286 ml). / 15 seconds) has a drainage comparable to that of conventional porous concrete pavement (average water permeability of 5 points 6355 ml / 15 seconds).
On the other hand, the concrete pavement filled with the water retaining material from the upper surface after placing the conventional porous concrete not only has a large variation in water permeability depending on the measurement point, but also has an average water permeability of 5 points at 2801 ml / 15 seconds. It can be seen that the drainage is extremely inferior.

[Example 2]
First, 34 parts by mass of an inorganic water retention material (made by Onoda Chemico Co., Ltd., trade name: Ryo) and 34 parts by mass of water are mixed, made into a slurry, poured into a 300 × 300 × 60 mm mold, and continued. Then, each raw material of the porous concrete having the blending ratio shown in Table 2 was put into a mixer and kneaded, and the porous concrete kneaded material was placed in a mold to form a water retention lower layer. The porosity of the water retaining layer was adjusted by applying a load of 15 to 25 kN / m ^{2 with} the pressure plate.
Immediately after forming the water-retaining lower layer, each raw material of the porous concrete having the blending ratio shown in Table 3 was put into a mixer and kneaded, and the porous concrete kneaded material was placed in a mold to form a surface layer. . The porosity of the surface layer was adjusted by applying a load of 15 to 25 kN / m ^{2 with} the pressure plate.
After forming the surface layer, the concrete was steam-cured (for example, at 65 ° C. for 3 hours) and then demolded to obtain a water-retaining concrete member of Example 2.

The dimensions and porosity of the water-retaining concrete member obtained in Example 2 were as follows.
Vertical dimension: 300mm
Horizontal dimension: 300mm
Surface layer thickness: 10mm
Water retention layer thickness: 40mm
Surface porosity: 20%

  In the same manner as in Example 1, for each pavement made of the water-retaining concrete member of Example 2, conventional asphalt, conventional porous concrete, and conventional ordinary concrete, from 10:00 am to 3:00 pm on August 20, 2004 During this time, the change in surface temperature was measured. The results are shown in FIG. As can be seen from FIG. 5, the pavement made of the water-retaining concrete member of Example 2 has a maximum surface temperature of 12.1 compared to the conventional asphalt pavement, the conventional porous concrete pavement and the conventional ordinary concrete pavement, respectively. C., 3.8.degree. C. and 3.6.degree. C. could be reduced.

  When the water permeability test was conducted in the same manner as in Example 1, the water permeability exceeded 5000 ml / 15 seconds at all points measured, and the average water permeability was 5306 ml / 15 seconds.

  As described above, the water-retaining concrete member of the present invention can accurately adjust the filling amount and filling position (depth) of the water-retaining material by making it into a secondary product, thereby achieving excellent low noise. , Drainage and pavement surface temperature reduction effect can be achieved.

It is sectional drawing of the water retention concrete member by Embodiment 1 of this invention. It is the schematic of the manufacturing apparatus of the water-retaining concrete member used by one Embodiment of this invention. It is a figure which shows the change of the surface temperature in the pavement which consists of a water-retaining concrete member by Example 1, the conventional asphalt, the conventional porous concrete, and the conventional ordinary concrete. It is sectional drawing of the water retention concrete member by Embodiment 2 of this invention. It is a figure which shows the change of the surface temperature in the pavement which consists of a water retention concrete member by Example 2, the conventional asphalt, the conventional porous concrete, and the conventional ordinary concrete.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,11 Water-retaining concrete member, 2 Surface layer, 3 Intermediate layer, 4 Lower layer, 5 Porous concrete, 6 Water-retaining material, 7 Normal concrete, 8 Water-retaining concrete member manufacturing apparatus, 9 Formwork, 10 Pressing plate, 12 Water retention Sexual lower layer.

Claims (6)

  It comprises a surface layer made of porous concrete, an intermediate layer in which a porous concrete void is filled with a water retention material, and a lower layer made of ordinary concrete, and the porosity of the surface layer is 10 to 25%, A water-retaining concrete member.   2. The water-retaining concrete member according to claim 1, wherein a thickness ratio between the surface layer and the intermediate layer is 1: 300 to 1: 1.   A water-retaining concrete member comprising a surface layer made of porous concrete and a water-retaining lower layer formed by filling a void in porous concrete with a water-retaining material, wherein the surface layer has a porosity of 10 to 25%.   The water-retaining concrete member according to claim 3, wherein the thickness ratio between the surface layer and the water-retaining lower layer is 1: 300 to 1: 1.   The water retention concrete member according to any one of claims 1 to 4, wherein the water retention material is an inorganic water retention material.   The water-retaining concrete member according to any one of claims 1 to 5, wherein the water permeability is 1000 ml / 15 seconds or more on all surfaces.

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