JP3695711B2 - Recycling method for asphalt waste - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recycling method for making it possible to use waste materials such as asphalt concrete again as a construction material, and in particular, from the aggregated state in which stone particles are adhered to each other by asphalt, The present invention relates to a method for reclaiming asphalt waste material that enables the aggregated stone particles to be crushed until substantially the same use is possible.
[0002]
[Prior art]
It is essential to use crushed stone as a paving material on asphalt paved roads. In recent years, in particular, permeable pavement roads that use good drainage of rainwater have begun to be widely used as pavement materials that use only JIS standard No. 6 crushed stone (size 5 to 13.2 mm). The current situation is that No. 6 crushed stone used here is collected only from about 17 to 19 tons from 100 tons of raw stones when it is collected from raw stones cut from mountains and the like. In other words, it is extremely inefficient to use only the necessary crushed crushed stones, and the remaining 80 tons are not used for the paving, and other uses are being searched for or discarded. Met. In other words, waste materials of road construction materials that contain the same grade of crushed stone are extremely valuable as resources, even if they are waste materials.If recycled crushed stones can be recycled, they can be used effectively and the paving materials can be used quickly and wastefully. It is possible to ensure no.
[0003]
Therefore, as a conventional technique, in order to recycle asphalt waste as a paving material, the asphalt is crushed by mechanical means such as a crusher to the level of pebbles, and the waste is immersed in warm water to melt the asphalt hot. A method for extracting crushed stone has been developed, and recycling of paving materials has been promoted.
[0004]
[Problems to be solved by the invention]
Among the methods described above, the method of mechanically crushing the waste material with a crusher has a problem of noise due to a loud crushing sound and a problem of environmental deterioration due to dust scattered around. In addition, when only mechanically crushed, many aggregates in a state where stone particles (crushed stones) are adhered to each other by asphalt were included, and it was difficult to know the exact crushed stone distribution according to the standard. Actually, some asphalt is melted and sampled according to the grade of crushed stone, the material ratio of each grade is confirmed, and the performance of the asphalt concrete when the waste material is used is predicted by calculation and used for construction. Was the current situation. The performance is only based on calculations, and the actual performance may be different from this, and there is a problem that only the crushed stone of the necessary grade cannot be selected and used.
[0005]
In the method using warm water among the above-mentioned methods, the waste material is immersed in warm water to dissolve the asphalt and crush the adhesion between the stone particles, and the stone particles are taken out. It had a very big problem of causing sewage treatment. In addition, there is a disadvantage that the production efficiency is low and the adhesion between crushed stones due to asphalt is not fully eliminated, and there is also the problem of high moisture content of the stone grains recovered as a product, so this method is almost adopted at present The fact is that it has not been done.
[0006]
[Means for Solving the Problems]
The present invention was made to solve the above-described problems. First, the asphalt waste material was crushed by a turntable while applying steam, and then put into a pipe-shaped conveyor and rolled, and hot air was fed. An object of the present invention is to provide a method for regenerating asphalt waste material that dissociates the adhesion of stone grains and prevents noise and sewage.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The asphalt waste recycling method according to the present invention recovers paving materials such as crushed stone from recycled asphalt waste such as pavement that has been crushed by excavation and cutting and peeled off from the pavement. Samachi is different. Asphalt waste lump containing a size larger than the size of the pebbles is larger than the pebbles. To crush, use a turntable that feeds steam to soften the input material and crush the waste material like a mortar. Considering the generation of noise and dust, pulverization using a turntable is preferable to crusher.
[0008]
The pipe-shaped conveyor for dissociating the waste material is for preventing the generation of noise as much as possible, and is for rolling the asphalt waste material in a substantially sealed pipe. A pipe-shaped conveyor moves a link chain connected endlessly in a pipe and travels a blade, which is a plate material attached to the chain, in the pipe to carry waste material. The waste material rolls in the pipe, the hot air sent into the pipe softens the asphalt, dissociates the adhesion between the stone particles, and the aggregate state is eliminated. The temperature of the hot air sent into the pipe is preferably about 200 to 300 ° C, and the internal material temperature is preferably controlled in the range of 60 to 140 ° C.
[0009]
By applying steam under pressure, the waste material is crushed by the pressure, and aggregates are more eliminated. Further, the water droplets adhering to the surface of the stone grains take away the heat of the stone grains by the heat of vaporization, and the asphalt covering the surface is rapidly cooled to prevent the stone grains from reattaching.
[0010]
It is conceivable that a stone-based powder is sprayed on the dissociated stone grains so that the surface is covered with the powder so that the stone grains do not re-adhere. As the stone-based powder, cement-based fine powder after the aggregate is removed from the ready-mixed concrete by dry recovery, incinerated ash such as lime and fly ash, and the like can be used. Unlike the crushed stone that crushed the rough stone, the asphalt has a thin surface covering the surface of the collected stone, but the asphalt coating prevents moisture from penetrating the stone and suppresses the moisture content of the paving material. It will also be. In addition, asphalt powder is sprayed to form asperities on the surface together with asphalt, and asphalt can be prevented from peeling when used as a paving material.
[0011]
【Example】
Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 1 is an overall view of an apparatus for carrying out the asphalt waste recycling method according to the present invention. One pipe is formed by connecting a plurality of steel pipes in an endless manner. A part of the pipe 1 is inclined obliquely so as to increase in height in the traveling direction in order to reduce the traveling speed of the waste material. A link chain 2 connected endlessly is accommodated in the pipe 1, and the link chain 2 travels in the pipe 1 by a driving device. A plate-like blade 3 is attached to the link chain 2 at an appropriate interval and travels in the pipe 2 together with the link chain 2.
[0012]
In the figure, reference numeral 4 denotes a cylindrical drum-shaped hopper, and a turntable 5 that is rotationally driven is disposed below the hopper. A lump of waste material including a size larger than a small head put in the drum hopper 4 is ground on the rotary turntable 5 by weight from above and supplied into the pipe 1. In the figure, reference numeral 6 denotes a screen, which is arranged in two places in the embodiment. The waste material supplied from the turntable 5 into the pipe 1 is carried on the traveling blade 3, and the asphalt component is melted by the hot air sent into the pipe 1. At this stage, the first screen 6 is once taken out to collect a certain amount of stone particles, and those having a larger size are returned to the pipe 2 and carried inside the pipe 1 again to be crushed by heat. . In the apparatus of the embodiment, hot air is supplied at three points A, B, and C indicated by the pipe 1. In the embodiment, a heat source of a heating furnace using pyrolysis oil recovered from foamed polystyrene or kerosene / propane as a fuel is used as a heat source. When the heat source alone is insufficient, hot air can be supplied into the pipe 1 by a burner or the like. One of the pipes 1 is also provided with an exhaust port 7 for exhausting air.
[0013]
In the figure, reference numeral 8 denotes a steam generator, and the steam produced by this is pumped to two locations, i and b. The temperature of the supplied steam is preferably about 110 to 170 ° C. In the embodiment, the steam generator 8 uses a heat source of a heating furnace, but a boiler water heater may be used. Steam is supplied to the waste material 10 by applying a certain pressure, and the aggregated waste material 10 in which the asphalt is softened and becomes brittle is easily crushed even at a low steam pressure. In the figure, 9 is a supply device for stone-based powder, which covers the surface of the collected stone particles to prevent the reattachment of the stone particles.
[0014]
The asphalt waste material crushing operation using the above apparatus will be described. In the embodiment, aiming at a slow crushing operation in the pipe 1, 15 tons per hour are input, and the operation is performed by using the residual heat energy at night. It aims to collect products. The waste material 10 containing small-head size asphalt waste material is put into the drum-like hopper 4 fed with steam, and the waste material 10 is ground by the turntable 5 installed at the lower part. Until it becomes. In the pipe 1, the waste material 10 is pushed by the blade 3 of the traveling link chain 2, is rolled and stirred in the pipe 1, and is exposed to the supplied hot air so that the stone grains are aggregated. The portion melts and softens. Immediately before the screen 6, the pumped steam hits the waste material 10, and the waste material 10 aggregated by the pressure is crushed and the adhesion between the stone particles is dissociated. The vapor adheres to the surface of the stone grains, takes the heat of the stone grains as heat of vaporization, cools them and solidifies the asphalt covering the surface, and prevents reattachment of the stone grains. The waste material 10 that has fallen on the screen 6 is collected as a product of a certain size or less as a product, and the product of a size larger than that is put into the pipe 1 again to be crushed by heat and steam. At the same time, the impurities are removed by a grizzly bar. In the embodiment, the purpose is to recover No. 6 crushed stone, which is the most in demand, and the recovered stone surface is supplied with a stone-based powder from the supply device 9, and then reattached to each other. prevent.
[0015]
FIG. 3 shows a sieve separating device 11 as a substitute for the screen 6, in which the pipe 1 is divided into upper and lower two stages by a net 13 and a grid in a pipe 12 that is inclined downward. The waste material that has been crushed by heat is once passed through it, and the material that has fallen off from the net 13 or the like is collected, and the rest is returned to the pipe 1 again for the crushing process.
[0016]
【The invention's effect】
The present invention has the above-described configuration and can obtain the following effects.
* Since the waste material is first ground like a stone mill with a turntable, it is far better in terms of noise and dust generation compared to conventional crushers.
* Since the crushing work is performed in a pipe-shaped conveyor that is almost sealed, the problem of environmental pollution can be overcome without scattering noise or dust around.
* Slow crushing by heat while rolling in the pipe, so noise and dust are less likely to occur, and there is no problem of wastewater treatment.
* By applying steam under pressure, the waste material is crushed by the pressure and dissociates the aggregated stone grains, and the steam takes the heat of vaporization and cools the asphalt around the stone grains, so that the stone grains reattach. To prevent it.
* The asphalt is melted to eliminate the aggregated state of the stone grains, and can be recovered in the same grain condition as the crushed crushed stone. Therefore, it is easy to predict the performance when reusing it, and its value as a product is extremely high.
* Since it can be crushed by automatic operation using a pipe-shaped conveyor, etc., almost no manual work is required, and the manufacturing cost can be reduced.
* By spraying the stone-based powder onto the collected stone particles, it is possible to prevent reattachment of the stone particles and to prevent the asphalt surface from peeling.
* The strength of the water-permeable composite material (asphalt concrete) using the collected stones (according to the Marshall stability test) is 1.7 times higher than that of the new material. It has already been used once as a paving material, and asphalt has penetrated into the stone. The asphalt bond is strong, and it is as strong as asphalt concrete modified with rubber and resin.
* Necessary particle size of stone used for water-permeable asphalt concrete cannot be obtained by mechanical crushing such as crusher. This is because the aggregated state of stone grains has not been eliminated by mechanical crushing alone, and crushed stone single grains by size cannot be recovered. The pulverization by heat and steam of the present invention can be said to be the best regeneration method for filling the gap between demand and supply, in which stone particles having a required particle size can be selected and recovered and supplied.
[Brief description of the drawings]
FIG. 1 is an overall view of an apparatus for carrying out a method for recycling asphalt waste according to the present invention.
FIG. 2 is a partially cutaway view of a pipe-shaped conveyor.
FIG. 3 is a cross-sectional view of the fluid dividing device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pipe 2 Linking chain 3 Blade 4 Drum-like hopper 5 Turntable 6 Screen 7 Exhaust port 8 Steam generator 9 Feeding device 10 Waste material 11 Fluid separating device 12 Pipe 13 Net

Claims (1)

Asphalt waste lump containing small head size or larger is crushed with a turntable while applying steam under pressure to this waste, and collapsed until it is mainly pebbles-sized. The link chain connected endlessly with blades attached at appropriate intervals is put into a pipe-shaped conveyor that runs, and the link chain moves to move the blade and roll the waste material into the pipe. Regeneration of asphalt waste material that prevents re-adhesion by dissociating the stone grains with heat and vapor adhering to the surface of the stone grains taking the heat of the stone grains as the heat of vaporization and solidifying the asphalt content Method.

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