JP2993882B2 - Ground surface structure and construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dirt course on a racetrack, a volleyball court, a tennis court, an athletic track, a general athletic field, and the like, and a construction method for constructing the same.

[0002]

2. Description of the Related Art In a dirt course of a racetrack, river sand is generally used as a roadbed layer as a cushion layer on the surface in consideration of drainage and impact mitigation.

[0003] The disadvantage of this cushion layer is that, when used for a long time, river sand is pulverized with horseshoes, which settles at the bottom of the cushion layer to form a hard plate-like layer. For this reason, the water permeability is reduced, poor drainage occurs, and the thickness of the substantial cushion layer is reduced, causing an accident such as a horseshoe kicking the above-mentioned plate-like layer and damaging a horse leg.

[0004]

SUMMARY OF THE INVENTION Therefore, chipped rubber (mainly discarded tire rubber) and plastic products used in general sports facilities such as track and field sports are mixed with river sand and the like. Therefore, it was proposed that the cushion layer be a dirt course.

[0005] However, rubber and plastic products made into chips as described above have specific gravities of 1.1 to 1.5.
When it is blended with sand, the chip floats on the surface of the cushion layer due to the difference in specific gravity from the sand, and the uniformity of the cushion layer cannot be maintained. In addition, the function of preventing the pulverization (siltation) of sand during use has not been sufficiently studied.

The present invention has been made on the basis of the above circumstances, and uses an elastic chip having a specific gravity close to the specific gravity of sand by mixing it with sand to achieve a uniform stabilization of the cushion layer, and An object of the present invention is to provide a structure of a ground surface in which foot removal is improved by elasticity, and pulverization is avoided, and a construction method thereof.

[0007]

In order to achieve the above object, according to the present invention, 7 to 0.05 m
m, preferably about 2 to 0.5 mm, and an elastic chip made of an elastic material and having a specific gravity of about 1.8 to 3.5 is used as a cushion layer by mixing with sand, and has a substantially predetermined thickness, preferably , With a thickness of 50 to 100 mm.

In the present invention, sand or soil is compacted to a predetermined thickness of 200 to 300 mm, or a predetermined thickness, preferably 50 to 70 mm, for asphalt concrete or concrete. Now, make up the subbase layer, on top of which 7 to 0.05 m
m, preferably about 2 to 0.5 mm, and an elastic chip made of an elastic material and having a specific gravity of about 1.8 to 3.5 is used as a cushion layer by mixing with sand, and has a substantially predetermined thickness, preferably , And a construction method characterized by being laid with a thickness of 50 to 100 mm.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, as shown in FIG.
As a dirt course of a racetrack, for example, cut crushed stone 1 is 250 mm thick, volcanic gravel 2 is 50 mm thick, and cinder 3 is 50 mm thick. The roadbed layer 4 is formed with a predetermined thickness, preferably 200 to 300 mm (in the drawing, 200 mm thick), and 7 to 0.05 mm, preferably 2 to 0 mm. .5
An elastic chip having a size (grain size) of about mm and a specific gravity of about 1.8 to 3.5 (in this embodiment, a specific gravity of 2.5) made of an elastic material is mixed with sand, preferably river sand. The cushion layer 5 is made to have a substantially predetermined thickness, preferably a thickness of 50 to 100 mm (in the drawing, 70 mm
Thickness), and lay it.

The shape of the elastic tip is a flake shape,
Although not specified as a granular shape, the size is set to about 2 to 0.5 mm which is close to the particle size of mountain sand or river sand in consideration of homogeneous mixing with sand. The elastic material is urethane, synthetic rubber, natural rubber, or a material selected from general-purpose synthetic resins such as vinyl chloride, vinyl acetate, polystyrene, polyethylene, and polypropylene, and a material for adjusting the specific gravity, for example, titanium oxide, It is constituted by blending an inorganic powder material (preferably having a specific gravity of 3 or more) such as barium sulfate, barium carbonate, lithofone, iron oxide, lead oxide, antimony oxide, and zinc oxide.

In this embodiment, a material having a specific gravity of 2.5, which is a mixture of 100 parts by weight of EPDM (synthetic rubber) and 400 parts by weight of barium sulfate, is used as the elastic tip.

When the cushion layer is formed by mixing the elastic tip with sand, at least 3% by weight of the elastic tip is mixed with the sand. This effectiveness will be described in detail in the following experimental examples.

[0013]

EXAMPLES The pulverization test of the cushion layer 5 was carried out in a case where the elastic chips were blended with river sand at a 3% weight ratio (97: 3), a case 1 where the elastic chips were blended at a 10% weight ratio (9: 1), and a case where river sand was mixed. Example 3 in which elastic chips were blended at a weight ratio (8: 2) of 20%, and Comparative Example (conventional) in which river sand was 100%, resulted in the results shown in Table 1.

In this test method, each sample was placed in a container having a diameter of 150 mm to a thickness of 70 mm (weight: 1,450).
g), its diameter is 50 mm and its weight is 4.5 kg
The iron bar is dropped naturally from a height of 425 mm.
000 times, NO. In this method, fine powder (silt) is separated with a 100-mesh sieve and the amount thereof is measured.

[0015]

[Table 1] In conclusion, micronization is halved, for example, with a mix of elastic chips of 10% or more, compared to 100% sand. That is, it can be seen that the elastic tip absorbs impact energy and greatly reduces damage to sand.

FIG. 2 shows the results obtained in the impact energy relaxation test of the cushion layer. In addition, this test
The above sample was placed in a container as shown in FIG.
Filled with thickness, rod with contact surface 40 × 40mm,
It is compressed at a speed of 5 mm / min by a strograph tester. From the graph of FIG. 2, it can be seen that the compressive displacement is significantly increased in cases 2 and 3, exhibiting high cushioning properties.

This is particularly effective when employed in a dirt course of a racetrack, and the characteristic of the elastic tip is the so-called goodness of stepping-out.

In addition, a comparison was made between the cushion layer obtained by mixing 20% elastic chips and the cushion layer obtained by using tire rubber chips (specific gravity: 1.1 to 1.5) as the elastic chips (20% mixed). The following conclusions were obtained as a result of a visual test of the homogenous stabilization of the mixed material of the cushion layer with respect to its temporal stability. That is, both were laid at a thickness of 50 mm in a busy traffic passage and left for 2 months, and when visually observed, the former according to the present invention showed no apparent change in surface, but the latter showed a considerable amount. Is emerging on the surface,
It was found that the stabilization of the cushion layer was reduced due to release from river sand. From this, it became clear that the specific gravity of the elastic tip of the present invention was adjusted.

The structure of the ground surface of the present invention and the method of constructing the same are employed in a dirt course of a racetrack in the embodiment. However, other exercise facilities such as a tennis court, a volleyball court, etc. Of course, it can be used for the construction and construction of the ground surface, such as ball games, athletics stadiums, multipurpose plazas, school playgrounds, and sports grounds.

In this case, soil may be used for the roadbed layer in addition to sand depending on the use.
A configuration having a thickness of 0 mm may be adopted.

[0021]

As described above, according to the present invention,
An elastic chip having a size of about 7 to 0.05 mm, preferably about 2 to 0.5 mm and a specific gravity of about 1.8 to 3.5 made of an elastic material is mixed on the roadbed layer by mixing with sand. As a layer, the cushion layer on the ground surface is homogeneously stabilized by laying it with a thickness of approximately a predetermined value, preferably 50 to 100 mm, and the rubber elasticity improves the foot drop, and also reduces the pulverization. Can be avoided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an embodiment of the present invention.

FIG. 2 is a graph showing test results according to the present invention.

FIG. 3 is a schematic diagram showing an outline of an apparatus adopted for a test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cut crushed stone 2 Volcanic gravel 3 Cinder 4 Roadbed layer 5 Cushion layer

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E01C 13/00 A63C 19/00

Claims (5)

(57) [Claims] 1. The method according to claim 1, wherein the base layer is 7 to 0.05 mm,
An elastic chip preferably having a size of about 2 to 0.5 mm and a specific gravity of about 1.8 to 3.5 made of an elastic material is used as a cushion layer by mixing with sand, and has a substantially predetermined thickness, preferably 50 to 50 mm. A ground surface structure characterized by being laid with a thickness of 100 to 100 mm. 2. The elastic material comprises urethane, synthetic rubber,
2. The ground surface structure according to claim 1, wherein a material for adjusting specific gravity is blended with a material selected from natural rubber and synthetic resin. 3. At least 3% by weight with respect to sand
3. The structure of the ground surface according to claim 1, wherein the elastic chips are mixed. 4. The roadbed layer according to claim 1, wherein the roadbed layer is formed by compacting sand or soil, or by asphalt, concrete or the like.
The structure of the ground surface according to any one of the above. 5. Thickness of sand or soil to a predetermined thickness, preferably 200 to 300 mm, or a predetermined thickness, preferably 50 to 70 mm thickness, for construction of asphalt concrete, concrete or the like. Now, make up the subbase layer, on top of which 7 to 0.05 m
m, preferably about 2 to 0.5 mm, and an elastic chip made of an elastic material and having a specific gravity of about 1.8 to 3.5 is used as a cushion layer by mixing with sand, and has a substantially predetermined thickness, preferably , 50 to 100 mm thick, laying the ground surface characterized by the method of construction.