Construction method of concrete paved road

Abstract

To provide a construction method of a concrete paved road capable of continuously constructing concrete pavement having high pavement performance and environmental performance by mechanized construction.SOLUTION: A construction method of the concrete paved road comprises a scattering step S2 for scattering granular concrete 10 in a wet state on a roadbed, and a rolling step S4 for rolling the granular concrete 10, wherein the granular concrete 10 is substantially spherical concrete formed by covering the surface of a coarse aggregate 11 with a bonding paste 12.SELECTED DRAWING: Figure 3F

Description

[Technical field]

[0001] The present invention relates to a method for constructing a concrete pavement, and more particularly to a method for constructing a concrete pavement that has high pavement performance and environmental friendliness, by means of mechanized construction in a continuous manner. [Background technology]

[0002] Pavement is the structure that makes up the road surface of a paved road, and roadways are broadly divided into asphalt pavement and concrete pavement. Asphalt pavement consists of a roadbed, a base layer, and a surface layer, which are layered on the roadbed, and asphalt mixture is used for the surface and base layers. In asphalt pavement construction, asphalt mixture heated to a high temperature is spread evenly on the roadbed by an asphalt finisher, and then compacted by a road roller to build the asphalt pavement. A concrete paved road is a paved road equipped with concrete pavement, and is constructed by carrying out each process of preparing the roadbed, setting formwork, pouring concrete, compacting the concrete, finishing the surface, setting joints, and then curing the concrete for a prescribed period of time. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-303512 A Summary of the Invention [Problem to be solved by the invention]

[0004] The asphalt pavement roads of the prior art have the following problems: <1> Heat island effect Asphalt pavement, being black in color, easily absorbs sunlight, absorbing and storing solar heat during the day and releasing it at night, causing the heat island effect. The heat island effect causes temperatures in urban areas to rise, leading to increased energy consumption due to the use of air conditioners and potentially adversely affecting people's health. <2> Large amount of carbon dioxide emissions When constructing asphalt pavement, the asphalt must be heat-treated at around 160°C to adjust the viscosity of the asphalt and improve its adhesion to the pavement surface. This heat treatment process releases a large amount of carbon dioxide, which places a heavy burden on the environment. <3> Low durability Asphalt pavement has low abrasion resistance and durability, and asphalt softens especially in high temperature environments in summer, and the pressure of wheels easily causes deflection and dents in the road surface. Asphalt is also easily affected by heat, and asphalt expands and contracts repeatedly due to temperature changes, it is prone to peeling and cracking. For this reason, it needs to be renewed roughly every 10 years, which increases maintenance and repair costs. <4> Harsh construction environment Asphalt remains hot, at around 140°C, even during construction. This creates a particularly harsh working environment in the hot summer months, placing a great physical strain on workers.

[0005] Prior art concrete pavements have the following problems: <1> Poor implementation efficiency The construction area is divided by formwork and concrete is poured, but because there is a limit to the amount of concrete that can be poured at one time, the construction span per time is shorter than that of asphalt pavement at 5 to 10 meters, making construction efficiency poor.In addition, each process, such as setting the formwork, compacting the concrete, and surface finishing, relies on manual labor, requiring a large number of workers. <2> Variation in construction quality The finished concrete pavement varies greatly depending on the skill of the worker, so there is a large variation in construction quality. <3> It will take some time before traffic opens Ordinary Portland cement requires two weeks of curing before it can develop sufficient strength to drive on, and even high-early-strength Portland cement requires more than a week of curing, so it takes a long time before the road can be opened to traffic.

[0006] The object of the present invention is to provide a method for constructing a concrete pavement that can solve the above problems and continuously build a concrete pavement having high paving performance and environmental friendliness through mechanized construction. [Means for solving the problem]

[0007] The method of constructing concrete pavement roads of the present invention comprises a spreading process for spreading wet granular concrete onto the roadbed, and a rolling process for compacting the granular concrete, and is characterized in that the granular concrete is approximately spherical in shape, with the surface of the coarse aggregate coated with a binding paste.

[0008] The method for constructing a concrete pavement of the present invention may further include a granulation step, prior to the spreading step, of mixing a water-absorbent granulating agent with the ready-mix concrete and stirring the mixture to produce granular concrete.

[0009] In the method for constructing a concrete pavement of the present invention, the granulation step may be carried out in a ready-mix concrete mixer or in the rotating drum of an agitator vehicle.

[0010] In the method for constructing a concrete pavement of the present invention, the ready mixed concrete may be leftover concrete.

[0011] The method for constructing a concrete pavement of the present invention may include a spreading and leveling step of spreading granular concrete evenly on the roadbed between the spreading step and the compacting step.

[0012] The method of constructing a concrete pavement road of the present invention uses an asphalt finisher comprising a vehicle body, a bucket attached to the vehicle body, a screw conveyor attached to the bucket, and a plate-shaped screed attached to the rear of the vehicle body, and in the spreading process, wet granular concrete contained in the bucket is spread onto the roadbed via the screw conveyor, and in the spreading process, the granular concrete is spread and leveled by the screed while the vehicle body is moved along the construction direction, so that the spreading process and the leveling process can be performed simultaneously.

[0013] The concrete pavement road construction method of the present invention uses a road roller equipped with a compaction roller, and in the compaction process, the road roller runs parallel to the asphalt finisher, following behind the asphalt finisher, while the compaction roller compacts the granular concrete spread and leveled by the asphalt finisher, thereby allowing the spreading process, spreading process, and compaction process to be carried out simultaneously. Effect of the Invention

[0014] Since the concrete pavement construction method of the present invention has the above-mentioned configuration, it has at least one of the following effects. <1> High workability Although it is a concrete pavement, it can be mechanized using construction equipment for asphalt pavement. This allows for efficient construction of high-quality pavement that is not dependent on the skill of the workers. In addition, the curing period is short, and traffic can be opened early, so construction can be done without affecting surrounding traffic. <2> Reducing carbon dioxide emissions Unlike asphalt pavement, heat treatment is not required, which reduces the carbon dioxide emissions that accompany heat treatment, thereby reducing the burden on the environment. <3> Carbon dioxide adsorption By contacting the surface of the granular concrete with carbon dioxide in the air, the carbon dioxide can be adsorbed into the granular concrete. In particular, the concrete pavement of the present invention is a porous pavement made by laying granular concrete, so the surface area of ​​the concrete is large and a large amount of carbon dioxide can be adsorbed. <4> Mitigating the heat island effect Granular concrete is white in color, which does not absorb sunlight well, and therefore helps prevent urban temperature rises caused by heat storage, ensuring a comfortable environment. In addition, concrete pavement has a porous structure, so rainwater is retained within the pavement and allowed to evaporate, lowering the road surface temperature and suppressing the heat island effect. <5> High durability Concrete is more resistant to friction and heat than asphalt, and is less prone to deformation, so it is less prone to deflection, peeling, or cracking on the road surface and is highly durable. This means that maintenance is less frequent, and maintenance and repair costs can be reduced. [Brief description of the drawings]

[0015] [Figure 1] Flow diagram of the construction method for concrete pavement of the present invention [Diagram 2] Diagram of granular concrete [Figure 3A] Photo of the concrete pavement construction method of the present invention (1) [Figure 3B] Photo of the construction method for concrete pavement of the present invention (2) [Figure 3C] Photo of the concrete pavement construction method of the present invention (3) [Figure 3D] Photo of the construction method for concrete pavement of the present invention (4) [Figure 3E] Photo of the construction method for concrete pavement of the present invention (5) [Figure 3F] Photo of the construction method for concrete pavement of the present invention (6) [Figure 3G] Photo of the construction method for concrete pavement of the present invention (7) [Figure 3H] Photo of the construction method for concrete pavement of the present invention (8) [Figure 4] Illustration of road surface temperature comparison test DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The method for constructing a concrete pavement road of the present invention will be described in detail below with reference to the drawings. In this invention, the term "concrete" is not limited to products that use cement as a binder, but also includes so-called "geopolymers" that use blast furnace slag, fly ash, etc. instead of cement.

[0017] [Concrete road construction method] <1> Overall configuration (Figure 1) The method for constructing a concrete pavement includes at least a spreading step S2 and a compaction step S4. In this example, the method further includes a granulation step S1 before the spreading step S2 and a spreading and leveling step S3 after the spreading step S2. The concrete pavement 1 is formed by stacking concrete pavement 1a on a roadbed. Note that the roadbed construction and roadbed construction prior to the spreading process S2 are well-known techniques, so a description thereof will be omitted here. One feature of the method for constructing a concrete pavement is that the concrete pavement 1a is made up of a plurality of granular concrete 10 laid on the roadbed.

[0018] <1.1> Construction equipment One of the features of the concrete pavement construction method is that, although it is a concrete pavement, it can be constructed using asphalt pavement construction equipment. Examples of asphalt pavement construction equipment include wheel loaders, motor graders, asphalt finishers, vibratory rollers, tire rollers, etc. By using these construction equipment, it is possible to continuously construct the concrete pavement 1a while running multiple construction equipment side by side in the construction direction. In this example, an asphalt finisher is used in the spreading process S2 and the leveling process S3, and a road roller is used in the compaction process S4. An asphalt finisher is a construction device that is originally used for spreading, heating, and spreading asphalt, and is equipped with a self-propelled vehicle body, a hopper installed at the front of the vehicle body, a belt conveyor installed inside the hopper, a screw conveyor installed at the bottom of the hopper, and a plate-shaped screed installed at the rear of the vehicle body.

[0019] <2> Granulation process The granulation step S1 is a step of granulating the ready-mix concrete A to produce the granulated concrete 10. Specifically, the granulation step S1 is performed, for example, in the following manner. A specified amount of water-absorbent granulating agent B is poured into the drum of an agitator truck loaded with ready-mix concrete A. The water-absorbent granulating agent B is an agent for absorbing and granulating the water in the fresh concrete A. In this example, a powdered highly absorbent polymer is used as the water-absorbent granulating agent B. Powdered superabsorbent polymers are available, for example, under the trade name "Ydan (trademark)" from Nagaoka Ready-Mixed Concrete Co., Ltd., or under the trade name "Re-Con Zero Evo (trademark)" from MAPEI S.p.A. (Italy). The drum of the agitator vehicle is rotated to thoroughly mix and mix the fresh concrete A and the water-absorbent granulating agent B, dispersing the water-absorbent granulating agent B evenly within the fresh concrete A. As the water in the fresh concrete A is absorbed by the water-absorbing granulating agent B and the concrete is rotated and stirred in a drum, the outer periphery of the coarse aggregate 11 in the fresh concrete A is coated with a layer of binding paste 12, producing approximately spherical granular concrete 10 (Figure 3A). In this embodiment, the granular concrete 10 can be produced in the drum of an agitator vehicle, so that transportation and production of the paving material can be carried out in parallel, improving the efficiency of construction. The granulation step S1 may be performed in a ready-mix concrete mixer, not limited to the drum of an agitator vehicle. Also, the method is not limited to mixing a highly water-absorbent polymer, and may be performed by agitating and aerating the ready-mix concrete A.

[0020] <2.1> Granular concrete (Fig. 2) The granular concrete 10 is concrete obtained by granulating the ready-mix concrete A. The granular concrete 10 has a roughly spherical structure with a core of coarse aggregate 11, the periphery of which is covered with binding paste 12. Here, "covered" includes cases where the entire surface of the coarse aggregate 11 is completely covered with binding paste 12, as well as cases where more than half of the surface of the coarse aggregate 11 is covered. The binding paste 12 is made of a mixture of a binding material 12a, fine aggregate 12b, and water 12c. In this embodiment, ordinary Portland cement is used as the binder 12a, but it is not limited to this and may be blast furnace cement, fly ash cement, or the like. The granular concrete 10 is ready-mixed concrete, but is not liquid, so it is easy to handle and can be rolled and spread on the roadbed in a wet state, making construction easy. In addition, since the unit water content is small, the hardening time is shorter than that of ordinary ready-mixed concrete. As the granular concrete 10 dries, the binding paste 12 hardens and bonds the particles together, forming a concrete pavement 1a having a porous structure with voids.

[0021] <2.2> Utilization of leftover concrete For ready mixed concrete A, leftover concrete can be used. Here, "remaining concrete" includes so-called "remaining concrete" (concrete that remains in the agitator truck after unloading at the work site) and so-called "returned concrete" (concrete that is not unloaded from the agitator truck and is returned to the ready-mix concrete plant). By using leftover concrete as a raw material for the granular concrete 10, it is possible to eliminate the cost of disposing of leftover concrete as industrial waste and the waste of resources.

[0022] <3> Spraying process The spreading step S2 is a step of spreading unhardened granular concrete 10 onto the roadbed. The spreading step S2 is performed, for example, in the following manner. Granular concrete 10 is discharged from the drum of the agitator vehicle into the bucket of a wheel loader (Figure 3B), and the granular concrete 10 is dumped from the bucket into the hopper of an asphalt finisher (Figure 3C). While the asphalt finisher is traveling in the construction direction, the granular concrete 10 is delivered to the discharge outlet at the rear of the hopper by a belt conveyor installed at the bottom of the hopper. A screw conveyor extending in the width direction of the vehicle body is provided below the discharge port, and as the screw conveyor rotates, the granular concrete 10 that falls from the discharge port is spread out in the width direction and scattered onto the roadbed.

[0023] <4> Laying process The spreading and leveling step S3 is a step of spreading and leveling the granular concrete 10 on the roadbed. The spreading and leveling step S3 is performed, for example, in the following procedure. When the asphalt finisher is running, the granular concrete 10 spread onto the roadbed is blocked by a plate-shaped screed (Figure 3D) and passes through the gap below the vibrating screed, spreading the granular concrete 10 on the roadbed to the specified thickness (Figure 3E). The granular concrete 10 of the present invention has a generally spherical shape that makes it easy to roll, so even if the granular concrete 10 piles up in chunks in the spreading step S2, it can be easily spread evenly by a screed. The leveling step S3 may be performed using a bulldozer or a backhoe equipped with a leveling bucket.

[0024] <5> Rolling process The rolling step S4 is a step of rolling compacting the granular concrete 10. The rolling step S4 is performed, for example, in the following procedure. The layered granular concrete 1 is initially compacted with a road roller (Figure 3F), and then the second compaction is performed with a tire roller. Tire marks caused by compaction are corrected with a plate compactor, etc. By compacting the layers of granular concrete 10, they are pressed together at the binding paste 12, forming a porous concrete pavement 1a with voids between the layers (FIG. 3G). After the compaction step S4, the granular concrete 10 of the concrete pavement 1a is hardened by curing for a predetermined period of time, and the concrete pavement 1 is constructed (FIG. 3H). The curing period depends on the mix proportions of the ready-mix concrete A and the temperature, etc., but pedestrians are permitted to enter the area immediately after the compaction step S4, and vehicles are generally permitted to enter the area from the day after the compaction step S4. EXAMPLES

[0025] [Road surface temperature comparison test] A comparative test was carried out on the road surface temperatures of the concrete pavement 1a of the present invention and the asphalt pavement of the prior art. Test date: August 5, 2023 (noon) Test location: Izu Nagaoka City, Shizuoka Prefecture Weather: Sunny Outside temperature: 33°C Test method: Measuring road surface temperature using a non-contact infrared thermometer The measurement results are shown in Table 1 below and FIG.

[0026] [Table 1] <1> When dry When dry, the road surface temperature of the concrete pavement of the present invention was 8.7 degrees lower than that of the asphalt pavement. This is thought to be due to the difference in the solar absorption rate caused by the difference in color between the granular concrete and the asphalt mixture. <2> Immediately after sprinkling water Water was sprinkled on the concrete pavement and asphalt pavement of the present invention. Immediately after sprinkling the water, the surface temperature of the concrete pavement of the present invention dropped to 42.7 degrees, and the surface temperature of the asphalt pavement dropped to 45.5 degrees. The difference in road surface temperature narrowed to 2.8 degrees. <3> 15 minutes after sprinkling water The temperature of the asphalt pavement rose by about 7°C immediately after the water was sprinkled, whereas the temperature of the concrete pavement of the present invention dropped by about 3°C ​​immediately after the water was sprinkled. This is thought to be because the cooling effect caused by the evaporation of the water trapped in the gaps in the porous structure exceeded the heat generated by the absorption of sunlight. It is also assumed that concrete pavement made of roughly spherical granular concrete has larger voids between the substrates than asphalt pavement made of gravel-like asphalt mixture, and therefore has higher water retention. The difference in road surface temperature widened to 12.8 degrees. <4> 30 minutes after sprinkling water The temperature of the asphalt pavement rose by about 5°C further 15 minutes after the water was sprinkled, whereas the temperature of the concrete pavement of the present invention remained almost unchanged 15 minutes after the water was sprinkled. This is thought to be because the cooling effect of evaporation from the water sprinkled on concrete pavement continues. The difference in road surface temperature was significant at 17.7 degrees. <5> conclusion It was observed that the concrete pavement of the present invention, which is made of white granular concrete, has a lower solar absorption rate and a relatively lower road surface temperature than black asphalt pavement. It was also observed that the concrete pavement of the present invention has excellent water retention properties against rainfall and water sprinkling, and can maintain the cooling effect of the road surface for a long period of time compared to asphalt pavement. [Explanation of symbols]

[0027] 1. Concrete paved roads 1a Concrete pavement 10 Granular concrete 11 Coarse aggregate 12 Bonding Paste 12a Binding material 12b Fine aggregate 12c water S1 Granulation process S2 Spraying process S3 Laying and leveling process S4 Rolling process A Ready-mix concrete B. Water-absorbent granulating agent

Claims

1. A method for constructing a concrete pavement, which is capable of continuously constructing a concrete pavement along a construction direction, comprising the steps of: A spreading process of spreading wet granular concrete on the roadbed; A rolling process for rolling the granular concrete. The granular concrete is a roughly spherical concrete having a surface of coarse aggregate coated with a binding paste. How to construct concrete paved roads.

2. The method further comprises a granulation step of mixing a water-absorbent granulating agent with fresh concrete and stirring the mixture to produce the granular concrete, prior to the spreading step. A method for constructing a concrete pavement according to claim 1.

3. The granulation process is carried out in a ready-mix concrete mixer or in a rotating drum of an agitator vehicle. A method for constructing a concrete pavement according to claim 2.

4. The ready-mix concrete is a residual concrete. A method for constructing a concrete pavement according to claim 2.

5. The method further comprises a spreading step of spreading the granular concrete on the roadbed between the spreading step and the rolling step. A method for constructing a concrete pavement according to any one of claims 1 to 4.

6. An asphalt finisher is used, the asphalt finisher comprising a vehicle body, a bucket provided on the vehicle body, a screw conveyor attached to the bucket, and a plate-shaped screed attached to the rear of the vehicle body; In the spreading step, the wet granular concrete contained in the bucket is spread onto a roadbed via the screw conveyor, In the spreading process, the granular concrete is spread evenly by the screed while moving the vehicle body along the construction direction, The spreading process and the leveling process are carried out simultaneously in parallel, A method for constructing a concrete pavement according to claim 5.

7. Use a road roller equipped with a rolling roller, In the rolling process, the road roller follows the asphalt finisher and runs parallel to it, and the granular concrete spread by the asphalt finisher is rolled by the rolling roller, The spreading process, the leveling process, and the rolling process are carried out simultaneously in parallel. A method for constructing a concrete pavement according to claim 6.

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