Paving method and pavement structure

Abstract

To provide a paving method and a pavement structure that can prevent ruts and large-scale unevenness by preventing scouring.SOLUTION: A paving method includes a roadbed reinforcement material laying process to lay a roadbed reinforcement material with a large number of partitioned storage parts on the upper surface of the subgrade, a roadbed formation process to fill the large number of storage parts of the roadbed reinforcement material with a filler containing hydraulic steel slag to form the roadbed, a first asphalt emulsion layer formation process to apply a first asphalt emulsion to the top of the roadbed formed in the roadbed formation process to form a first asphalt emulsion layer, a roadbed unevenness leveling layer formation process to lay a granular material on the top of the first asphalt emulsion layer to form a roadbed unevenness leveling layer, a second asphalt emulsion layer formation process to apply a second asphalt emulsion on the top of the roadbed unevenness leveling layer to form a second asphalt emulsion layer, and a seal coating process to dispose crushed stones on the top of the second asphalt emulsion layer and roll-compact them to form a seal coat layer.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention mainly relates to a paving method and a paving structure used for forest roads, parking lots, etc.

Background Art

[0002] Conventionally, on roads, forest roads, and parking lots with a gradient finished with crushed stones, crushed stones such as gravel are usually used. Such crushed stones generally have a specific gravity of about 1.7 t / m3. Due to local heavy rain, spring water from mountains, or water seepage, etc., the surface layer is washed out, resulting in "puddles" and large-scale unevenness, which has the drawback of hindering vehicle passage. In addition, the roadbed reinforcement material is exposed due to the washing out, which has been an obstacle to vehicle passage.

[0003] In the case of concrete paving, the strength is high and washing out can be prevented. However, at a construction site far from a fresh concrete manufacturing plant such as a forest road, it takes time to transport fresh concrete, and there is a risk of quality deterioration and poor construction. Also, when the seal coat is sand or crushed stone, there is a concern about dust due to peeling.

[0004] By the way, conventionally, as a technique for avoiding the occurrence of puddles, etc. in paving provided with a crushed stone layer, "a road strengthening method characterized by providing a non-woven fabric layer with a fiber density of 10 to 2000 m / cm3 on a roadbed soil leveled to a substantially flat surface, and further providing a crushed stone layer on the non-woven fabric layer" (Patent Document 1) is known. However, the crushed stone used for the crushed stone layer is a crusher run with a general specific gravity, and it has not been effective in preventing washing out, etc.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In view of the above-described conventional drawbacks, an object of the present invention is to provide a paving method and a paving structure that can prevent the occurrence of undulations and large-scale unevenness by preventing washout.

Means for Solving the Problems

[0007] In order to achieve the above object, the paving method according to claim 1 of the present invention includes a roadbed reinforcing material laying step of laying a roadbed reinforcing material having a large number of storage portions partitioned on the upper surface of the roadbed, a roadbed forming step of filling the large number of storage portions of the roadbed reinforcing material with a filler containing hydraulic steel slag to form a roadbed, a first asphalt emulsion layer forming step of applying a first asphalt emulsion to the upper portion of the roadbed formed in the roadbed forming step to form a first asphalt emulsion layer, a roadbed unevenness rectifying layer forming step of laying granular materials on the upper portion of the first asphalt emulsion layer to form a roadbed unevenness rectifying layer, a second asphalt emulsion layer forming step of applying a second asphalt emulsion to the upper portion of the roadbed unevenness rectifying layer to form a second asphalt emulsion layer, and a seal coat step of arranging crushed stones on the upper portion of the second asphalt emulsion layer and compressing them to form a seal coat layer.

[0008] The roadbed reinforcing material of the paving method according to claim 2 is characterized in that it is formed in a substantially honeycomb shape.

[0009] The crushed stone used in the seal coat step of the paving method according to claim 3 is characterized in that it is a granular material having a particle size of 10 mm or less or barite crushed stone.

[0010] The paving structure according to claim 4 is composed of a roadbed formed on the upper surface of the subgrade, a first asphalt emulsion layer formed on the upper part of the roadbed, a roadbed unevenness rectifying layer laid on the upper part of the first asphalt emulsion layer, a second asphalt emulsion layer formed on the upper part of the roadbed unevenness rectifying layer, and a seal coat layer laid on the upper part of the second asphalt emulsion layer. The roadbed is composed of a roadbed reinforcing material having a large number of partitioned storage parts and a filler containing hydraulic steel slag filled in each of the large number of storage parts of the roadbed reinforcing material, which is characterized in that.

[0011] The roadbed reinforcing material of the paving structure according to claim 5 is characterized in that it is formed in a substantially honeycomb shape.

[0012] The crushed stone forming the seal coat layer of the paving structure according to claim 6 is characterized in that it is barite crushed stone.

Advantages of the Invention

[0013] As is clear from the above description, the following advantages can be obtained in the present invention. (1) In each of the inventions described in claim 1 and claim 4, since a roadbed reinforcing material filled with a filler containing hydraulic steel slag in a large number of partitioned storage parts is used, the roadbed reinforcing material becomes a high-strength (tough) structure and can support crushed stone. (2) Also, since quality deterioration due to transportation such as fresh concrete does not occur, construction can be carried out while maintaining quality even at a remote site. (3) By providing a roadbed unevenness rectifying layer, flatness can be ensured even when there are irregularities on the upper surface of the roadbed. (4) Since such a roadbed, roadbed unevenness rectifying layer, and crushed stone are laid on the upper part of the roadbed unevenness rectifying layer, erosion by rainwater runoff is suppressed, and the occurrence of "puddles" and large-scale unevenness can be prevented. (5) In each of the inventions described in claim 2 and claim 5, the same effects as those in (1) to (4) above can be obtained, and the strength of the roadbed reinforcing material can be improved by using a substantially honeycomb-shaped roadbed reinforcing material. In each of the inventions described in claim 3 and claim 6, the same effects as those of the above (1) to (5) can be obtained, and by using barite crushed stones that are more than twice as heavy as ordinary sand or dust, erosion by surface runoff caused by rainwater or spring water can be further suppressed.

Brief Description of the Drawings

[0014] Figs. 1 to 9 are explanatory diagrams showing a first embodiment of the present invention.

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Embodiments for Carrying Out the Invention

[0015] Hereinafter, the present invention will be described in detail according to the embodiments for carrying out the present invention shown in the drawings.

[0016] In the first embodiment for carrying out the present invention shown in Figs. 1 to 9, 1 is a paving method used for paving roads, forest roads, parking lots, etc.

[0017] This paving method 1 includes, as shown in FIG. 1, a subgrade reinforcement material laying step 4 of laying a subgrade reinforcement material 3 having a large number of storage portions 3a partitioned on the upper surface of the subgrade 2, preferably a substantially honeycomb-shaped subgrade reinforcement material 3; a subgrade forming step 7 of filling the large number of storage portions 3a of the subgrade reinforcement material 3 with a filler 5 containing hydraulic steel slag to form a subgrade 6; a first asphalt emulsion layer forming step 10 of applying a first asphalt emulsion 8 to the upper portion of the subgrade 6 formed in the subgrade forming step 7 to form a first asphalt emulsion layer 9; a subgrade unevenness leveling layer forming step 13 of laying granular materials 11 on the upper portion of the first asphalt emulsion layer 9 to form a subgrade unevenness leveling layer 12; a second asphalt emulsion layer forming step 16 of applying a second asphalt emulsion 14 to the upper portion of the subgrade unevenness leveling layer 12 to form a second asphalt emulsion layer 15; and a seal coat step 19 of arranging crushed stones 17 on the upper portion of the second asphalt emulsion layer 15 and compacting them to form a seal coat layer 18.

[0018] The three-dimensional shape of the subgrade reinforcement material 3 may be a continuous shape of a polygon such as a triangle, rhombus, quadrilateral, rectangle, square, or a circular shape such as an ellipse or a perfect circle, which is continuous horizontally without gaps as a large number of partitioned storage portions 3a, but is preferably substantially honeycomb-shaped.

[0019] Further, as shown in FIG. 2, the paving structure 20 of the present invention includes a subgrade 6 formed on the upper surface of the subgrade 2, a first asphalt emulsion layer 9 formed on the upper portion of the subgrade 6, a subgrade unevenness leveling layer 12 formed on the upper portion of the first asphalt emulsion layer 9, a second asphalt emulsion layer 15 formed on the upper portion of the subgrade unevenness leveling layer 12, and a seal coat layer 18 laid on the upper portion of the second asphalt emulsion layer 15.

[0020] In the subgrade reinforcement material laying step 4, preferably as shown in FIG. 3, a substantially honeycomb-shaped subgrade reinforcement material 3, so-called geocell, is laid on the upper surface of the roadbed 2. This subgrade reinforcement material 3 is a honeycomb-shaped subgrade reinforcement material 3 having a large number of storage portions 3a (cells) formed by adhesively bonding a sheet material made of a resin such as high-density polyethylene in a staggered pattern by ultrasonic waves or the like. This subgrade reinforcement material 3 uses a commonly used geocell, and its dimensions can be appropriately selected according to the construction site and used. Note that the substantially honeycomb shape refers to not only a three-dimensional object with a hexagonal shape in plan view arranged in the present invention, but also a three-dimensional figure including an arc-shaped portion such as a geocell, or a three-dimensional figure arranged without gaps. Further, one cell and another cell do not necessarily have the same shape, and as long as it has a plurality of storage portions 3a that can be filled with the filler 5 even if it is not formed in a substantially honeycomb shape, it may be used as the subgrade reinforcement material 3.

[0021] In the subgrade forming step 7, as shown in FIG. 4, it is a step of filling the storage portion 3a (cell) of the subgrade reinforcement material 3 with a filler 5 containing hydraulic steel slag to form the subgrade 6. As the filler 5 filled in this subgrade reinforcement material 3, by using hydraulic steel slag, a subgrade with good compaction properties, excellent workability, and strong durability can be formed.

[0022] After this subgrade forming step 7, in this embodiment, a first asphalt emulsion layer forming step 10 of applying the first asphalt emulsion 8 to form the first asphalt emulsion layer 9 is performed. As shown in FIG. 5, in the first asphalt emulsion layer forming step 10, the asphalt emulsion 8 such as PE-1, PE-2, PK-1, PK-2 is sprayed at 200 to 240 liters per 100 m2 with a sprayer or a distributor to form the first asphalt emulsion layer 9.

[0023] After this first asphalt emulsion layer forming step 10, the roadbed unevenness rectification layer forming step 13 is carried out without delay. In the roadbed unevenness rectification layer forming step 13, as shown in FIG. 6, granular materials 11 such as crushed stones with a particle size of 10 mm or less are spread by a spreader to a thickness of about 3 cm, and then compacted about 4 to 8 times by a rolling machine to ensure flatness and form the roadbed unevenness rectification layer 12.

[0024] By forming such a roadbed unevenness rectification layer 12, even if the upper surface of the roadbed 6 has irregularities, the upper surface can be made flat, and the erosion of the roadbed 6 can also be prevented. In addition, this unevenness rectification step can be omitted when the upper surface of the roadbed 6 is substantially flat.

[0025] After the roadbed unevenness rectification layer forming step 13, a second asphalt emulsion layer forming step 16 is carried out in which a second asphalt emulsion 14 is applied to form a second asphalt emulsion layer 15. As shown in FIG. 7, in the second asphalt emulsion layer forming step 16, the second asphalt emulsion 14 is applied to the upper surface of the roadbed unevenness rectification layer 12 to form the second asphalt emulsion layer 15. As the second asphalt emulsion 14, a known asphalt emulsion is used. In this embodiment, the same one as the first asphalt emulsion 8 is used. For its application, known coating devices such as sprayers and distributors are used, and 200 to 240 liters of the second asphalt emulsion 14 are applied per 100 m2.

[0026] In the seal coat step 19, as shown in FIG. 8, granular materials such as crushed stones 17 with a particle size of 10 mm or less finely crushed or high specific gravity crushed stones 17 such as barite crushed stones, preferably high specific gravity crushed stones 17, are spread and arranged on the upper surface of the second asphalt emulsion layer 15 by a spreader or the like, and then rolled 4 to 6 times by a rolling machine to form the seal coat layer 18. Incidentally, the high specific gravity crushed stone 17 in this embodiment refers to a granular material or powder with a unit volume weight of γt = 4 t / m3 or more, and preferably barite crushed stone is used. In addition to barite crushed stone, granular or powdered iron, lead, etc. can also be used.

[0027] The particle size of the high specific gravity crushed stone 17 is preferably 5 mm or less, more preferably 1 mm or less. Also, the thickness of the seal coat layer 18 is preferably 1 mm or less, more preferably 0.3 mm or less.

[0028] In this embodiment, the high specific gravity crushed stone 17 is scattered so as to be 0.6 m3 per 100 m2.

[0029] Note that as the crushed stone 17, the granular material 11 forming the roadbed unevenness rectifying layer 12 can also be used. When using such a granular material 11, those with a particle size of 10 mm or less are used, and the granular material 11 is scattered and rolled so as to be 1 m3 to 3 m3 per 100 m2.

[0030] The seal coat layer 18 laid in this way can prevent scouring by the high specific gravity crushed stone 17 or the like, and can also ensure flatness. Therefore, it is possible to perform high-quality paving of the road surface of forest roads or the like that have a gradient, such as forest roads, and where it is difficult to place fresh concrete.

[0031] Here, the results of a comparative experiment between the paving structure 20 of the present invention and other paving structures are shown. In this comparative experiment, the roadbeds etc. of the following case1 to case5 were formed, and an experiment was conducted in which a dump truck with a total load of 20 tons passed 1,000 times at a speed of 9 km / hour on this road surface.

[0032] The structures of the roadbeds etc. used in the comparative experiment are as follows, case1 to case5. case1: Only the roadbed 6 similar to the present invention was formed case2: The paving structure 20 of the present invention case3: The roadbed reinforcing material 3 was filled with recycled crusher run having a particle size of 0 to 40 mm and rolled, and on the upper part thereof, the first asphalt emulsion layer 9, the roadbed unevenness rectifying layer 12, the second asphalt emulsion layer 15, and the seal coat layer 18 similar to the present invention were formed. case4: The roadbed reinforcing material 3 was filled with recycled crusher run having a particle size of 0 to 40 mm and rolled. Case 5: The roadbed was filled with recycled crusher run with a particle size of 0 to 40 mm and compacted without using the roadbed reinforcement material 3. The results of the comparative experiments using these roadbed structures are shown in Fig. 9 and below.

[0033] In the structure of Case 5, at the time when 49 passes were completed, the road surface level had a 9 cm depression and a 21 cm bulge, resulting in undulations and potholes on the road surface. The unevenness of the road surface exceeded the height of the countermeasure structure, and it was judged that the structure had collapsed. At the time when 49 passes were completed, repair work (levelling work and base material filling work) was carried out.

[0034] In the structure of Case 4, at the time when 112 passes were completed, the road surface level had a 5.0 cm depression and a 7.5 cm bulge, resulting in undulations and potholes on the road surface. The unevenness of the road surface exceeded half of the height of the countermeasure structure, and it was judged that the structure had collapsed. At the time when 49 passes were completed, repair work was carried out.

[0035] In the structure of Case 3, at the time when 112 passes were completed, the road surface level had a 2.5 cm depression and a 0.5 cm bulge, and there were somewhat undulations on the road surface, but the unevenness of the road surface was less than half of the height of the countermeasure structure, and it was judged that the structure had not collapsed. However, in some parts, the rutting of the outer front wheel part was prominent, and the roadbed reinforcement material 3 was slightly visible. Repair work was carried out before 100 passes were completed.

[0036] At the time when 112 passes were completed, the road surface level of the Case 1 structure had a 6.0 cm depression and a 7.0 cm bulge, resulting in undulations and potholes on the road surface. The unevenness of the road surface exceeded half of the height of the countermeasure structure, and it was judged that the structure had collapsed. The repair work was carried out at the time when 112 passes were completed. It should be noted that ruts have occurred at the positions of the inner front wheel and the inner rear wheel. This is mainly considered to be due to the fact that water pools were formed only inside CASE1 due to the rain the previous day, and the strength of the adjacent hydraulic steel slag decreased due to the influence.

[0037] In contrast, in the pavement structure 20 (case 2) of the present invention, when the number of passages reaches 112 times, the road surface level of the Case 2 structure is recessed by about 1.0 cm, and almost no undulation or pitting occurs on the road surface. It was determined that the structure was in a sound state.

[0038] Also, when the number of passages reaches 1000 times, the road surface level is recessed by 2.5 cm and bulges by about 0.4 cm. There is little undulation or pitting on the road surface, and the structure remains in a sound state. Although the position of the rear wheel passage after 1000 passages is recessed by about 0.5 cm to 1.0 cm, no undulation or pitting has occurred, and the structure remains in a sound state.

Industrial Applicability

[0039] The present invention is used in the industry of pavement construction.

Explanation of Reference Numerals

[0040] 1: Pavement method, 2: Roadbed 3: Subgrade reinforcement material, 4: Subgrade reinforcement material laying process 5: Filling material, 6: Subgrade 7: Subgrade formation process, 8: First asphalt emulsion 9: First asphalt emulsion layer 10: First asphalt emulsion layer formation process 11: Granular material, 12: Subgrade unevenness correction layer 13: Subgrade unevenness correction layer formation process, 14: Second asphalt emulsion 15: Second asphalt emulsion layer 16: Second asphalt emulsion layer formation process 17: Crushed stone, 18: Seal coat layer 19: Seal coat process, 20: Pavement structure

Claims

1. a first asphalt emulsion layer forming step of forming a first asphalt emulsion layer by applying a first asphalt emulsion to the top of the roadbed formed in the roadbed formation step; a second asphalt emulsion layer forming step of forming a roadbed unevenness leveling layer by laying a granular material on the top of the first asphalt emulsion layer; a second asphalt emulsion layer forming step of applying a second asphalt emulsion to the top of the roadbed unevenness leveling layer to form a second asphalt emulsion layer; and a seal coat step of arranging crushed stone on top of the second asphalt emulsion layer and compacting it to form a seal coat layer.

2. 2. A paving method according to claim 1, wherein said roadbed reinforcement material is formed into a substantially honeycomb shape.

3. 3. A paving method according to claim 1, wherein the crushed stone used in the seal coat step is granular material having a particle size of 10 mm or less or barytic crushed stone.

4. A pavement structure comprising a roadbed formed on the upper surface of a roadbed, a first asphalt emulsion layer formed on top of the roadbed, a roadbed unevenness leveling layer laid on top of the first asphalt emulsion layer, a second asphalt emulsion layer formed on top of the roadbed unevenness leveling layer, and a seal coat layer laid on top of the second asphalt emulsion layer, wherein the roadbed is composed of a roadbed reinforcement material having a number of partitioned storage sections, and a filler containing hydraulic steel slag filled in each of the many storage sections of the roadbed reinforcement material.

5. 5. A pavement structure according to claim 4, wherein the roadbed reinforcement material is formed in a substantially honeycomb shape.

6. 6. A pavement structure according to claim 4, wherein the crushed stone constituting the seal coat layer is barite crushed stone.

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