Pavement structure

Abstract

To provide a pavement structure capable of suppressing the deterioration of a freezing suppression function.SOLUTION: A pavement structure A10 includes a binder layer 10 placed on a pavement surface PS facing a first direction z, and a first aggregate 21 and a second aggregate 22 fixed to the binder layer 10. The composition of the binder layer 10 includes methyl methacrylate. The first aggregate 21 is richer in elastic deformation than the second aggregate 22. A part of each of the first aggregate 21 and the second aggregate 22 projects from the binder layer 10 in the first direction z.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pavement structure laid on the pavement surface of a road pavement. [Background technology]

[0002] Patent Document 1 discloses an example of a pavement structure capable of exhibiting anti-freezing properties. The pavement structure comprises a urethane-based resin layer placed on the pavement surface of a road pavement, and rubber and aggregate embedded in the urethane-based resin layer. The rubber has greater elastic deformation than the aggregate. The rubber and aggregate are fixed to the urethane-based resin layer. A portion of each of the rubber and aggregate protrudes from the urethane-based resin layer in the thickness direction of the road pavement. With this configuration, when the surface of the pavement structure is covered with snow and ice in a low-temperature environment, the wheels of a traveling vehicle press against the rubber and aggregate through the snow and ice, thereby breaking up the snow and ice. This makes it possible to prevent the pavement surface from freezing.

[0003] However, in the pavement structure disclosed in Patent Document 1, rubber and aggregate are fixed to a urethane-based resin layer. Although the urethane-based resin layer has relatively high durability, it has poor curing properties. This can lead to the aggregate settling in the urethane-based resin layer, and the rubber, which has a lower specific gravity than the aggregate, can fall out of the urethane-based resin layer. This can lead to a decrease in the anti-freeze function of the pavement structure. Furthermore, if the pavement structure is laid on an in-service road and then reopened to traffic earlier, there is a concern that the pavement structure could be damaged by the wheels of passing vehicles coming into contact with the pavement structure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-263997 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a pavement structure that can prevent a decline in anti-freeze function. [Means for solving the problem]

[0006] The pavement structure provided by the present invention includes a binder layer disposed on a pavement surface facing a first direction, and first and second aggregates fixed to the binder layer. The binder layer contains methyl methacrylate. The first aggregate has greater elastic deformation than the second aggregate. A portion of each of the first and second aggregates protrudes from the binder layer in the first direction.

[0007] In carrying out the present invention, preferably, the first aggregate has a core material and a coating layer covering the core material. The coating layer has a base layer covering the core material and particles contained in the base layer. The particles are harder than the core material and include portions protruding from the base layer. A first median, which is the median of the particle size of the first aggregate, and a second median, which is the median of the particle size of the second aggregate, are each 2.0 mm or more and 4.0 mm or less.

[0008] In the practice of the present invention, the first median is preferably greater than the second median.

[0009] Preferably, the present invention further comprises a top coat located on the opposite side of the pavement surface in the first direction with the binder layer interposed therebetween, the top coat covering a portion of each of the first aggregate and the second aggregate, and the composition of the top coat includes methyl methacrylate. [Effects of the Invention]

[0010] The configuration of the pavement structure according to the present invention makes it possible to prevent a decline in anti-freezing function.

[0011] Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic cross-sectional view of a pavement structure according to one embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged cross-sectional view of a first aggregate that constitutes the pavement structure shown in FIG. [Figure 3] 2 shows particle size curves of the first aggregate and the second aggregate that constitute the pavement structure shown in FIG. 1. [Figure 4] 1 shows the results of a test on the rate of ice plate breaking according to the effects of the present invention. [Figure 5] 10 shows test results of the chain aggregate scattering rate according to the effect of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the accompanying drawings.

[0014] A pavement structure A10 according to one embodiment of the present invention will be described with reference to Figures 1 to 3. The pavement structure A10 comprises a binder layer 10, first aggregates 21, second aggregates 22, and a top coat 30. The pavement structure A10 is laid on the pavement surface PS of a road pavement. Roads include both roadways and sidewalks. Road structures include all structures such as earthworks, bridges, and elevated sections. Types of road pavements include asphalt pavements and concrete pavements.

[0015] In the description of the pavement structure A10, the direction in which the pavement surface PS faces is referred to as the “first direction z.” When the type of road pavement on which the pavement structure A10 is to be laid is asphalt pavement, the pavement surface PS refers to any region of the surface of the surface layer that comes into contact with the wheels of a traveling vehicle.

[0016] As shown in Figure 1, the binder layer 10 is placed on the pavement surface PS. The binder layer 10 bonds the first aggregate 21 and the second aggregate 22 to the pavement surface PS. The binder layer 10 has a composition containing methyl methacrylate. The binder layer 10 is made of a material containing, for example, an acrylic resin.

[0017] As shown in Fig. 1, the first aggregates 21 are fixed to the binder layer 10. A portion of the first aggregates 21 protrudes from the binder layer 10 in the first direction z. The first aggregates 21 are more elastically deformable than the second aggregates 22. The maximum particle size of the first aggregates 21 is 5.0 mm or less.

[0018] As shown in Fig. 2, the first aggregate 21 has a core material 211 and a covering layer 212. The core material 211 is made of an elastomer. The elastomer is made of any rubber material such as natural rubber, isoprene rubber, butadiene rubber, or chloroprene rubber. The covering layer 212 covers the core material 211.

[0019] As shown in FIG. 2, the coating layer 212 has a base layer 212A and particles 212B. The base layer 212A covers the core material 211. The base layer 212A bonds the particles 212B to the core material 211. The base layer 212A is an adhesive containing, for example, urethane or modified silicone. The particles 212B are harder than the core material 211 and include portions protruding from the base layer 212A. The particles 212B are an inorganic compound. The inorganic compound is, for example, calcium carbonate, silicon dioxide, or ceramics, or a mixture thereof. The maximum particle size of the particles 212B is 100 μm or less.

[0020] As shown in FIG. 1, the second aggregate 22 is fixed to the binder layer 10. A portion of the second aggregate 22 protrudes from the binder layer 10 in the first direction z. The maximum particle size of the second aggregate 22 is 5.0 mm or less. The second aggregate 22 is made of a material containing any of blast furnace slag, water-cooled oxidizing electric furnace slag, molten slag, ceramics, river sand, and the like.

[0021] As shown in Fig. 3, a first median M1, which is the median of the particle size of the first aggregate 21, and a second median M2, which is the median of the particle size of the second aggregate 22, are each 2.0 mm or more and 4.0 mm or less. Here, the median particle size of each of the first aggregate 21 and the second aggregate 22 is the size (inner dimension) of the sieve opening where the passing weight percentage of the sieve corresponds to 50% in the particle size curves of each of the first aggregate 21 and the second aggregate 22 shown in Fig. 3. As shown in Fig. 3, the first median M1 is larger than the second median M2.

[0022] In the pavement structure A10, the weight of each of the first aggregate 21 and the second aggregate 22 per unit area is greater than that of the first aggregate 21. The weight ratio of the first aggregate 21 to the second aggregate 22 per unit area in the pavement structure A10 is, for example, 3:7.

[0023] As shown in FIG. 1 , the top coat 30 is located on the opposite side of the pavement surface PS in the first direction z, with the binder layer 10 sandwiched therebetween. The top coat 30 covers a portion of each of the first aggregates 21 and the second aggregates 22, and is in contact with the binder layer 10. The top coat 30 prevents the first aggregates 21 and the second aggregates 22 from scattering when the pavement structure A10 is in service. The top coat 30 has a composition containing methyl methacrylate. The top coat 30 is made of a material containing, for example, an acrylic resin.

[0024] Next, an example of a construction procedure for the pavement structure A10 will be described. The construction of the pavement structure A10 is carried out manually.

[0025] First, the pavement surface PS is cleaned and otherwise cured, and then the binder layer 10 is applied to the pavement surface PS. A rake or the like is used to apply the binder layer 10. The amount of binder layer 10 applied is 1.0 kg / m or more and 2.0 kg / m or less per unit area of ​​the pavement structure A10.

[0026] Next, before the binder layer 10 applied to the pavement surface PS hardens, the first aggregate 21 and the second aggregate 22 are scattered on the binder layer 10. The amount of the first aggregate 21 scattered per unit area of ​​the pavement structure A10 is 1.7 kg / m2 or more and 2.1 kg / m2 or less. The amount of the second aggregate 22 scattered per unit area of ​​the pavement structure A10 is 4.8 kg / m2 or more and 5.9 kg / m2 or less. In this case, the amount of the second aggregate 22 scattered per unit area of ​​the pavement structure A10 is set to be greater than the amount of the first aggregate 21.

[0027] Next, the binder layer 10, the first aggregates 21, and the second aggregates 22 are subjected to rolling compaction. As a result, when the binder layer 10 hardens, the first aggregates 21 and the second aggregates 22 are fixed to the binder layer 10 so that a portion of each of the first aggregates 21 and the second aggregates 22 protrudes from the binder layer 10 in the first direction z. A hand roller or the like is used for the rolling compaction. At this time, the first aggregates 21 and the second aggregates 22 that are not fixed to the binder layer 10 are collected.

[0028] Finally, a top coat 30 is applied to cover the first aggregates 21 and the second aggregates 22. A spray is used to apply the top coat 30. The amount of top coat 30 applied per unit area of ​​the pavement structure A10 is 0.1 kg / m2 or more and 0.5 kg / m2 or less. Thereafter, the binder layer 10 and the top coat 30 each harden, completing the construction of the pavement structure A10.

[0029] Next, based on FIG. 4, the ice plate breaking rate test and the results thereof for the pavement structure A10 as an example and the comparative example will be described.

[0030] The ice plate breakage rate test was conducted based on the "Ice Plate Cracking Test Method" in "C056T Ice Plate Breakdown Test Method Using Wheel Tracking Test for Anti-freeze Pavement" in the "Pavement Survey and Test Method Handbook" published by the Japan Road Association. The test procedure is as follows:

[0031] First, the pavement structure A10 and the comparative example are constructed as specimens on a base specimen made of dense-graded asphalt concrete (13). The comparative example differs from the pavement structure A10 in the median particle size of each of the first aggregate 21 and the second aggregate 22. The median particle size of each of the first aggregate 21 and the second aggregate 22 in the comparative example is 1.0 mm or more and 2.0 mm or less.

[0032] Next, the surface texture depth of the pavement structure A10 and the comparative example is measured by the sand patching method.

[0033] Next, the amount of water on the ice plate covering each of the pavement structure A10 and the comparative example is calculated using the following formula.

[0034]

number

[0035] Next, ice plates covering each of the pavement structure A10 and the comparative example were made based on the calculated water volume. The ice plates were made at a temperature of -5°C and cured for 2 hours.

[0036] Next, a wheel load was applied to the ice plate to conduct a wheel tracking test for one hour.

[0037] Finally, the destruction rate of the ice plates covering each of the pavement structure A10 and the comparative example was calculated using the following formula. The target area for setting the total number of cells was 230 mm x 50 mm, which is the wheel travel range in the wheel tracking test. Each cell was a 5 mm mesh. Therefore, the total number of cells was set to 460.

[0038]

number

[0039] As shown in Figure 4, the ice plate destruction rate for pavement structure A10 was 10.1%, while the ice plate destruction rate for the comparative example was 8.0%. Therefore, it was confirmed that pavement structure A10 has better anti-freeze function than the comparative example.

[0040] Next, based on FIG. 5, the chain aggregate scattering rate test and the results thereof for the pavement structure A10 as an example and the comparative example will be described.

[0041] The chain aggregate scattering rate test was conducted based on "C054T Method for measuring resistance to peeling of heat shielding materials on road surfaces by impact method" described in the "Pavement Survey and Test Method Handbook" published by the Japan Road Association. The test procedure is as follows:

[0042] First, the pavement structure A10 and the comparative example are constructed as specimens on a base specimen made of dense-graded asphalt concrete (13). The comparative example differs from the pavement structure A10 in the median particle size of each of the first aggregate 21 and the second aggregate 22. The median particle size of each of the first aggregate 21 and the second aggregate 22 in the comparative example is 1.0 mm or more and 2.0 mm or less.

[0043] Next, the test was carried out using a labeling tester for 30 minutes.

[0044] Finally, the chain aggregate scattering rate for each of the pavement structure A10 and the comparative example is calculated using the following formula.

[0045]

number

[0046] As shown in Figure 5, the chain-aggregate scattering rate for pavement structure A10 was 6.4%, while the chain-aggregate scattering rate for the comparative example was 14.1%. Therefore, it was confirmed that pavement structure A10 has improved abrasion resistance compared to the comparative example.

[0047] Next, the effects of the pavement structure A10 will be explained.

[0048] The pavement structure A10 comprises a binder layer 10 disposed on a pavement surface PS facing the first direction z, and first and second aggregates 21 and 22 adhered to the binder layer 10. The first aggregates 21 are more elastically deformable than the second aggregates 22. Portions of the first and second aggregates 21 and 22 protrude from the binder layer 10 in the first direction z. This configuration allows the wheels of a traveling vehicle to press against the protruding portions of the first and second aggregates 21 and 22 through the snow and ice when the surface of the pavement structure A10 is covered with snow and ice. Furthermore, because the first aggregates 21 have greater deformation capacity under load than the second aggregates 22, the load transmitted from the wheels to the snow and ice is more widely distributed. This allows the snow and ice to be efficiently crushed, enabling the pavement structure A10 to effectively exert its anti-freeze function.

[0049] Furthermore, in the pavement structure A10, the binder layer 10 contains methyl methacrylate. This configuration allows the binder layer 10 to harden faster than binder layers 10 containing either epoxy resin or urethane resin. This suppresses settling of the first aggregate 21 and the second aggregate 22 in the binder layer 10 and allows the first aggregate 21 and the second aggregate 22 to be fixed to the binder layer 10 more quickly. This more reliably stabilizes the state in which a portion of each of the first aggregate 21 and the second aggregate 22 protrudes from the binder layer 10 in the first direction z. Therefore, with the above configuration, it is possible to suppress a decrease in the anti-freeze function of the pavement structure A10.

[0050] The first aggregate 21 has a core material 211 and a coating layer 212. The coating layer 212 has a base layer 212A that covers the core material 211, and particles 212B contained in the base layer 212A. The particles 212B are harder than the core material 211 and include portions that protrude from the base layer 212A. This configuration causes the binder layer 10 to exhibit an anchoring effect on the first aggregate 21. This allows the first aggregate 21 to be more firmly fixed to the binder layer 10.

[0051] The first median M1, which is the median of the particle size of the first aggregate 21, and the second median M2, which is the median of the particle size of the second aggregate 22, are each 2.0 mm or more and 4.0 mm or less. By adopting this configuration, the ice plate crushing rate shown in Figure 4 is increased compared to the comparative example. This means that the anti-freezing function of the pavement structure A10 is improved. Furthermore, the chain aggregate scattering rate shown in Figure 5 is reduced compared to the comparative example. This means that the wear resistance of the pavement structure A10 is improved. Therefore, by adopting this configuration, the anti-freezing function and wear resistance of the pavement structure A10 can be improved.

[0052] In the above case, as shown in FIG. 3, if the first median value M1 is set to be larger than the second median value M2, it is possible to further improve the anti-freezing function and the wear resistance.

[0053] The pavement structure A10 further includes a top coat 30. The top coat 30 covers a portion of each of the first aggregates 21 and the second aggregates 22. This configuration effectively prevents the first aggregates 21 and the second aggregates 22 from falling off from the binder layer 10 while protecting the surfaces of the first aggregates 21 and the second aggregates 22. Furthermore, the composition of the top coat 30 includes methyl methacrylate. This configuration increases the affinity between the binder layer 10 and the top coat 30, effectively preventing the top coat 30 from peeling off from the binder layer 10.

[0054] The present invention is not limited to the above-described embodiment, and the specific configuration of each part of the present invention can be freely designed and modified in various ways. [Explanation of symbols]

[0055] A10: Pavement structure 10: Binder layer 21: 1st aggregate 211: Heartwood 212: Covering layer 212A: Base layer 212B: Particle 22:Second aggregate 30: Top coat PS: Paved surface M1, M2: First median, second median

Claims

1. a binder layer disposed on the pavement surface facing in the first direction; a first aggregate and a second aggregate fixed to the binder layer; The composition of the binder layer includes methyl methacrylate, The first aggregate has greater elastic deformation than the second aggregate, A pavement structure, wherein a portion of each of the first aggregate and the second aggregate protrudes from the binder layer in the first direction.

2. The first aggregate has a core material and a coating layer covering the core material, The coating layer has a base layer covering the core material and particles contained in the base layer, the particles are harder than the core material and include portions protruding from the base layer; The pavement structure described in claim 1, wherein a first median, which is the median of the particle size of the first aggregate, and a second median, which is the median of the particle size of the second aggregate, are each 2.0 mm or more and 4.0 mm or less.

3. The pavement structure of claim 2 , wherein the first median value is greater than the second median value.

4. a top coat positioned on the opposite side of the pavement surface with the binder layer interposed therebetween in the first direction; the top coat covers a portion of each of the first aggregate and the second aggregate; 4. The pavement structure of claim 1, wherein the top coat composition includes methyl methacrylate.

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