JP2015045226A - Pavement structure using coal ash and construction method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pavement structure using coal ash, which has both of water permeability and water holding property, and grass-proof capability to prevent germination of plants such as weeds, capable of controlling flood and reducing thermal storage of road surface temperature by the action of evaporation heat as well; and a construction method thereof.SOLUTION: A first mixture M1 is manufactured by blending clinker ash and cement-based solidification material at a predetermined weight ratio. A second mixture M2 is manufactured by blending clinker ash shell and a resin binder at a predetermined weight ratio. The second mixture M2 is roller-compacted on a roadbed 3 to form a water holding layer 2, and the first mixture M1 is then stacked thereon to form a water permeable layer 1.

Description

  The present invention relates to a technique for reusing coal ash generated in a coal-fired power plant or the like as a raw material for a pavement, and more particularly to a pavement method having both water permeability and water retention.

  In coal-fired power plants, etc., the development of technology to recycle coal ash generated from coal incineration without creating landfill or dumping is used, and coal ash is used as road paving material. Techniques to do this have been proposed. For example, Patent Document 1 discloses a process of mixing porous coal ash (clinker ash) generated from a boiler of a thermal power plant, a cement-based solidifying material and a mixed liquid at a predetermined weight ratio, and this mixture as a roadbed. And a step of forming a pavement layer 1 by rolling it onto the surface, and a water-permeable grassproof pavement method having water permeability and surface strength that suppresses germination of plants is disclosed. In addition, Patent Document 2 discloses a pavement material having a weed growth suppression function in which clinker ash and fly ash are blended so as to have a predetermined particle size distribution.

JP 2001-90012 A JP 2007-231565 A

  However, the above prior art documents only mention water permeability (good drainage) in an asphalt pavement layer and herbicidal properties that suppress germination of plants such as weeds, and the water retention is not questioned. For example, there is no disclosure or suggestion in the prior art about pavement technology taken up to countermeasures against flood damage due to heavy rain, rise of pavement surface in summer, and countermeasures for heat island phenomenon due to it. In consideration of water permeability and water retention, not only has water-resistance and herbicidal properties to suppress germination of plants such as weeds, but can also take measures against flood damage, and heat storage of road surface temperature by the action of heat of vaporization It aims at providing the pavement structure using the coal ash which can suppress ash, and its construction method.

  In other words, by integrating the permeable pavement and the water retentive pavement, utilizing the characteristics (water retention function) of coal ash, which is essentially waste, and utilizing it as a pavement material, it is intended to recycle from waste to resources. is there.

For this reason, the pavement structure using the coal ash of the present invention is obtained by applying clinker ash having a particle diameter of 0.2 mm to 7 mm obtained by pulverization or sieving onto a roadbed made by laying granular crushed stone. ), At least one cement-based solidifying material selected from calcined gypsum, magnesia cement, hydraulic gypsum, natural cement, Portland cement or alumina cement and a water retention layer having a water retention capacity of 400 to 500 kg / m ³ solidified by kneading and water. In addition, a surface layer (water permeable layer) having a water permeability coefficient of 0.5 cm / s or more obtained by solidifying a clinker ash shell having a particle size of 2 mm to 7 mm remaining after the sieving with a resin binder on the water retaining layer is configured. Is the first feature. Further, the second feature is that the surface layer (water-permeable layer) is colored, and the construction method includes a step of producing a first mixture by mixing the clinker ash shell and the resin binder at a predetermined weight ratio. The step of producing a second mixture by mixing clinker ash, cement-based solidification material and water at a predetermined weight ratio, and after rolling the second mixture onto a roadbed covered with granular crushed stones, And a step of forming a pavement layer by laminating the first mixture, wherein the pavement layer has water permeability and water retention and has a surface strength that suppresses germination of plants.

The present invention has the following excellent effects.
(1) Since rainwater can be stored, it is effective as a flood control measure against urban sewage and river flooding that occurs during heavy rains.
(2) The heat island phenomenon can be mitigated by suppressing the increase in road surface temperature by the action of the heat of vaporization of the water retained in the water retention layer.
(3) Germination of plants such as weeds can be suppressed.
(4) The side groove is unnecessary depending on the location, and the construction cost can be reduced.
(5) Color pavement that matches the surrounding landscape.
(6) Clinker ash as waste can be used effectively and can contribute to resource recycling.
(7) Meets the national environmental standards and does not adversely affect surrounding ecosystems and groundwater.

It is a schematic sectional drawing which shows one Example of the pavement structure using the coal ash which concerns on this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a pavement structure using coal ash according to the present invention and a construction method thereof will be described based on examples shown in the drawings.

As shown in FIG. 1, the ground constructed by the pavement method of the present invention has a water retaining layer 2 formed on a roadbed 3 in which granular crushed stones are laid, and further laminated on the water retaining layer 2 for water permeability. Layer 1 is provided. The thickness _{t 1} of the permeable layer 1, generally about 10mm, the thickness _{t 2} of the water retaining layer 2 is generally about 40mm, the thickness _{t 3} of roadbed 3 is set to about 100 mm.

Next, the material and construction method of the present invention will be described.
First, porous clinker ash, which is coal ash generated from a boiler of a thermal power plant, etc., a cement-based solidifying material, and an admixture (water in which a cement-based reinforcing agent is appropriately mixed) are mixed at a predetermined weight ratio. In the present invention, clinker ash refers to ash that has been collected and dehydrated and crushed from coal ash that has fallen to the bottom of the boiler among coal ash generated when coal is burned at a thermal power plant or the like. Say. As the coal ash, one obtained by pulverizing or sieving clinker ash to a particle size of about 0.2 mm to 7.0 mm is preferably used. As for the weight ratio, 200 kg of cement-based solidified material and 120 to 140 liters of the mixed solution are kneaded with a mixer with respect to 1 m ^{3 of} clinker ash, and the second mixture M2 that becomes the material of the water retention layer 2 is generated. In this example, as a cement-based solidifying material, tough rock (trade name: manufactured by Sumitomo Osaka Cement Co., Ltd.) was used. The cement-based solidifying material refers to a powder that hardens over time when kneaded with a liquid mixture such as water. Examples of the cement-based solidifying material include calcined gypsum, magnesia cement, hydraulic gypsum, and natural cement. Portland cement, alumina cement and the like can be used.

[Water retention layer material kneading process]
(1) Put coal ash into the mixer.
(2) Input cement-based solidifying material. (For example, 100 × 0.001 × 200 = 20 kg of cement-based solidified material is added to 100 liters of clinker ash.)
(3) Knead for 1-2 minutes and mix well.
(4) Add the mixture. (For example, 100 × 0.001 × 120 (140) = 12 (14) liters of mixed liquid is added to 100 liters of clinker ash.)
(5) Mix thoroughly for 2 to 3 minutes.

  Here, the amount of the admixture to be added is preferably the same as that described above, but the clinker ash brought into the field does not necessarily have a constant water content, and therefore is appropriately mixed according to the water content. In other words, it is preferable that the admixture is gradually added while confirming the physical properties by hand, and the water squeezes out a little while holding it lightly. Note that if the mixed solution is insufficient, there is a possibility that the water retention layer may not have sufficient strength.

[Construction of water retaining layer] (t ₂ = 40 mm)
(1) Small transport of the second mixture M2 to the construction site by a unicycle or the like.
(2) The second mixture M2 is put on the crushed stone spread on the roadbed 3, and spread with a dragonfly, a rake or the like.
(3) Then, the roadbed 3 is firmly bitten so as to be pushed in with a gold iron (rolling with a roller or the like as necessary).
(4) Ensure that the curing is more than one day.
The water retention layer 2 after construction exhibits a water retention capacity of 400 to 500 kg / m ^3, and surplus water exceeding the absorption capacity penetrates into the ground.

Next, a clinker ash shell having a particle size of 2 mm to 7 mm and a resin binder are mixed at a predetermined weight ratio. As for the weight ratio, 100 kg or more of a resin binder is blended with 1 m ^{3 of} clinker ash shell and kneaded with a mixer to produce a first mixture M1 that becomes a material of the water permeable layer (surface layer) 1. In the present embodiment, Sanyu Road R-145 (trade name: manufactured by Sun Elec Co., Ltd.), which is an epoxy resin, was used as the resin binder. Moreover, you may add suitably the colored powder of the color according to the surrounding landscape to construct.

[Surface material kneading process]
(1) Put the clinker ash shell into the mixer.
(2) Add epoxy resin. (For example, 100 × 0.001 × 100 = 10 kg of a resin binder is added to 100 liters of clinker ash shell.)
(3) Stir well for 2 to 3 minutes.

[Construction of surface layer] (t ₁ = 10 mm)
(1) Transport the first mixture M1 to a construction site by a unicycle or the like.
(2) Put the first mixture M1 on the water retaining layer 2 and spread it with a dragonfly, a rake or the like.
(3) Press it with a gold iron and finish it with eyes closed so that there is no variation (roll with a roller or the like if necessary).
(4) From kneading to finishing, aim for 20 minutes in summer and 30 minutes in winter.
(5) Curing for about 6 hours after construction.
The water permeable layer 1 after construction exhibits a water permeability coefficient of 0.5 cm / s.

In the present invention, the pavement configuration can be changed to a preferred form depending on the application location. For example, people and bicycles pass (roadbed + roadbed (granulated crushed stone 100 mm) + water retention layer (coal ash 40 mm) + (surface layer coal galley 10 mm), and parked management vehicles pass (roadbed + roadbed (granulated crushed stone) 150mm) + water retention layer (coal ash 50mm) + (surface coal galley 15mm), and only the water retention layer 2 has a compressive strength of about 3 N / mm ² or more, so that weed roots cannot penetrate, so weed prevention The purpose (roadbed + water retention layer 50mm) is good.

The results and considerations of various strength tests conducted according to the on-site test method for asphalt pavement stipulated by the Japan Road Association or JIS are shown below.
[Water retention function test]
Check the water retention capacity of the stable layer. Measure with a moisture content meter. The maximum water retention rate was 47%, and the reference value was 40%, so it was confirmed that it was acceptable.
[Constant water level permeability test]
Make sure that the hydraulic conductivity is above the standard value. Measure with a simple permeability tester. Since the average value of 3 times was 0.535 and the reference value was 0.5, it was confirmed that it passed.
[Uniaxial compressive strength test (surface layer)]
Check that the compressive strength is above the reference value. It was measured according to JIS 1108 2006, the average intensity was 6.84N, and the reference value was 3N.
[Uniaxial compressive strength test (stable layer)]
Check that the compressive strength is above the reference value. Measured according to JIS 1108 2006, the average intensity was 14.8N, and the reference value was 3N.
[Acute toxicity test]
Make sure it is safe for animals. Confirmed with Himedaka. The survival rate after 72 hours was 100%, which was confirmed to be acceptable.
[Heavy metal test]
Check if the coal ash is within the national environmental standards. It was confirmed that all items were within the standard value and passed by the specified measurement.
[Road surface temperature test]
The difference in surface temperature difference between asphalt and the pavement of the present invention was verified. The pavement of the present invention was 7.7 ° C. lower than the asphalt pavement.

The present invention can be applied to a pavement method for forming a pavement layer on a roadbed. Applicable places are places where people pass such as parks, promenades, plazas, and promenades. Heat island countermeasure construction, grass prevention countermeasure construction. In addition, when aiming at heat island countermeasures, increasing the thickness of the water retaining layer increases the amount of stored water, which increases the effect of suppressing the road surface temperature. In addition, when aiming at herbicidal measures, only 50 mm of the water retaining layer is constructed. Such crushed stone pavement and concrete pavement prevent the germination as a result of confining seeds to hard soil with a uniaxial compressive strength of about 3N / mm ² or more, in addition to blocking the sunlight necessary for seed growth. As a result of maintaining the seeds in a dry state with excellent water permeability, the ground surface has a weed growth inhibiting function of inhibiting germination or growth.

1 Water permeable layer (surface layer: first mixture layer)
2 Water retention layer (stable layer: second mixture layer)
3 roadbed (granular crushed stone)
M1 first mixture M2 second mixture

Claims (3)

Clinker ash with a particle size of 0.2 mm to 7 mm obtained by pulverization or sieving on a roadbed made by laying granular crushed stone, tough rock (registered trademark), calcined gypsum, magnesia cement, hydraulic gypsum, natural cement , At least one cement-based solidifying material selected from Portland cement or alumina cement and a water retention layer having a water retention capacity of 400 to 500 kg / m ³ solidified by kneading and water, the particle size remaining in the water retention layer after the sieving is A pavement structure using coal ash, characterized by laminating a surface layer (water permeable layer) having a water permeability coefficient of 0.5 m / s or more obtained by solidifying a clinker ash shell of 2 mm to 7 mm with a resin binder. The pavement structure using coal ash according to claim 1, wherein the surface layer (water-permeable layer) is colored. Mixing the clinker ash shell and the resin binder at a predetermined weight ratio to produce the first mixture, and mixing the clinker ash, the cement-based solidified material and water at the predetermined weight ratio to form the second mixture. And a step of rolling the second mixture onto a roadbed covered with granular crushed stone, and then laminating the first mixture to form a pavement layer, wherein the pavement layer is water permeable. 3. A method for constructing a pavement structure using coal ash according to claim 1 or 2, wherein the construction method has a water retaining property and a surface strength that suppresses germination of plants.

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