JPH0885905A - Water retentive pavement - Google Patents

Abstract

PURPOSE: To provide an artificial water sump part underneath pavement, and vaporize water stored therein so as to utilize latent heat of vaporization for cooling a road surface. CONSTITUTION: In pavement wherein unscreened crushed stone 2 is spread over a roadbed 1 and a plurality of water permeable asphalt layers 3, 4, 5, 6 are layered and integrated, a bottom surface and side surface at appropriate portions of the unscreened crushed stone 2 are covered with a waterproof sheet 7. In the waterproof sheet 7, nonwoven fabric 8 is provided, whose upper part is connected to the water permeable asphalt layer 3 and whose lower part is inserted into the unscreened crushed stone 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-retaining pavement provided with a portion for storing water at the bottom of the water-retaining pavement so that it can be used for evaporative cooling.

[0002]

2. Description of the Related Art A permeable pavement is made by laying cut crushed stones on a roadbed, and laying a plurality of permeable asphalt layers on top of it in order to form a layered structure. It penetrates the asphalt layer and crushed stones, penetrates the inside of the subgrade, and is returned to the underground. It secures the drainage of the street in the event of a large amount of rainfall, prevents urban flooding, and at the same time secures groundwater.

[0003]

However, in the pavement of this structure, the road surface is always in a dry state, and the surface temperature only decreases after rainfall and absorbs radiant heat on a sunny day to raise the surface temperature. If continues, the ambient temperature is raised more than necessary and the thermal environment is deteriorated.

Therefore, in this structure, heat easily accumulates on the surface of the earth, which is one of the causes of the heat island phenomenon in summer.

The present invention is intended to solve the above problems. An object of the present invention is to provide an artificial pool of water at the bottom of this kind of pavement to evaporate the water stored therein and to transfer latent heat of vaporization to the road surface. The present invention provides a water-retentive pavement that can be used for cooling.

[0006]

In order to achieve the above object, the present invention provides a pavement structure in which cut crushed stones are laid on a roadbed, and a plurality of water-permeable asphalt layers are laminated on the top of the crushed stones to form an integrated structure. The bottom surface and the side surface of the cut crushed stone are surrounded by a waterproof sheet, and in the waterproof sheet, an upper part is connected to the water-permeable asphalt layer, and a lower part is provided with a nonwoven fabric to be inserted into the cut crushed stone. And

[0007]

According to the above construction, the part surrounded by the waterproof sheet becomes an artificial pool of water, and water is stored in this part during rainfall or sprinkling. The accumulated water rises due to the capillarity of the nonwoven fabric, and the latent heat of vaporization cools the road surface.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a water-retentive pavement according to the present invention. Immediately above the roadbed 1, a crushed stone 2 having a thickness of 210 mm, which is an actual size and constitutes a lower roadbed, is laid. Is a laminated layer of 80 mm thick water-permeable modified asphalt 3 that composes the upper layer roadbed, and further 70 mm and 70 mm thick water-permeable high-viscosity modified asphalt 4 and 5 that form the base layer and intermediate layer, respectively, on top of it. Then, the pavement is completed by successively applying the laminated water-permeable high-viscosity modified asphalt 6 having a thickness of 50 mm, which constitutes the surface layer, as described above.

A container-shaped waterproof sheet 7 is arranged in a part of the crushed stone 2 and surrounds the bottom surface and the peripheral side surface of the crushed stone 2, and this portion is used as an artificial water pool portion.

Inside the waterproof sheet 7, a plurality of non-woven fabrics 8 are sewn between the crushed stones 2, and the tops thereof are connected to the water-permeable modified asphalt 3 which constitutes the upper layer roadbed.

In the above structure, when rain or the like is sprinkled on the road surface or water is sprinkled on the road surface, the water is discharged from each asphalt 6,
Infiltrate into the subgrade 1 through the crushed stone 2 at the general site, infiltrating in the order of 5, 4, and 3.

However, water collects in the water pool, that is, the area surrounded by the waterproof sheet 7. This amount of water is determined by the volume of the waterproof sheet 7 and the gap volume of the crushed stone 2, and the water that overflows the water level WL at this portion permeates into the roadbed 1 via a general portion.

Therefore, after rain or water sprinkling, the surface of the road surface is immediately dried, but the water remains at the water pool portion below the road surface. The accumulated water gradually rises due to the capillarity of the nonwoven fabric 8, and the asphalt 3, 4, 5, 6
Penetrate into the layers of. Therefore, when the road surface temperature rises due to sunshine, etc., the permeated water absorbs this heat, vaporizes, and sequentially evaporates. Conversely, asphalt 3, 4, 5, 6
By removing this latent heat of vaporization from the above, excessive temperature rise is prevented.

Although the waterproof sheet 7 may be provided on the entire lower part of the road surface, it may be provided on a part of the road surface as in the embodiment. In this case, the volume and the installation interval of the waterproof sheet 7 are the original functions of the pavement. It should be designed in consideration of the required cooling function while maintaining the underground permeability.

[0015]

As described above in detail with reference to the embodiments, in the water retentive pavement according to the present invention, the portion surrounded by the waterproof sheet becomes an artificial pool of water, and when it rains or sprinkles, water is spilled on this portion. Is stored, and this water rises due to the capillarity of the non-woven fabric, which cools the road surface by the latent heat of vaporization, so it moderately suppresses the excessive temperature rise on the road surface in the summer and improves the thermal environment of the street and reduces the cooling load. This is suitable for alleviating the heat island phenomenon in urban areas.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional perspective view showing a part of a water-retentive pavement according to the present invention by cutting out.

[Explanation of symbols] 1 Roadbed 2 Cut crushed stones 3, 4, 5, 6 Water-permeable asphalt 7 Waterproof sheet 8 Nonwoven fabric

Claims (1)

[Claims] 1. In a pavement structure in which cut crushed stones are laid on a roadbed and a plurality of water-permeable asphalt layers are laminated on the upper part of the pavement structure, and a bottom surface and a side surface of the cut crushed stones are surrounded by a waterproof sheet, and In the waterproof sheet, a water-retentive pavement is provided, in which an upper part is connected to the water-permeable asphalt layer and a lower part is provided with a nonwoven fabric to be inserted into the cut crushed stone.