JP2023153430A - Method for producing recycled asphalt mixture and testing unit - Google Patents

Abstract

To provide a method for producing a recycled asphalt mixture and a testing unit that can easily produce recycled asphalt material from asphalt waste.SOLUTION: A method for producing a recycled asphalt mixture comprises a first charging step of charging waste material of the asphalt mixture into a container, a second charging step of charging an additive into the container, a stirring and heating step in which the temperature inside the container is maintained within a predetermined temperature range and the waste material reduced to a predetermined particle size is mixed with the additive, an analysis step in which the content of effective asphalt components in the waste material is analyzed, and a determination step of determining the amount of additives required for recycling waste materials based on the content of effective asphalt components obtained in the analysis step. The analysis step comprises a test crushing step of heating and crushing at least a portion of the waste material to a predetermined particle size to obtain a crushed material, and a test body production step in which at least a part of the crushed material obtained in the test crushing step is collected and put into a test container to create a test body.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for producing recycled asphalt mixtures from waste asphalt mixtures of asphalt pavements, such as those laid on roads, and a test unit for analyzing the content of effective asphalt components in asphalt mixtures.

Many roads, both in urban and suburban areas, are paved with asphalt. Asphalt pavement uses an asphalt mixture that is a mixture of aggregates such as crushed stone or sand and petroleum asphalt.
Asphalt mixtures degrade over time. For example, the pavement layer (the surface layer of the asphalt mixture) may be cured by ultraviolet light, causing cracks on the surface of the pavement layer, ruts may be formed in the pavement layer due to contact with automobile tires, and the weight of the vehicle and the road may be affected. Fallen objects may cause depressions in the pavement layer. Therefore, for asphalt pavements that have passed a certain period of time after construction, the deteriorated pavement layer (surface layer of asphalt mixture) is peeled off from the base layer called the roadbed, and a new pavement layer made of asphalt mixture is laid in its place. In addition, even if the road has just been constructed, there is a need to repair potholes.

In recent years, unpaved roads have been replaced with asphalt-paved roads even in islands and developing countries. By the way, in such island areas and developing countries, plants for producing the asphalt mixture necessary for pavement are not necessarily located nearby. For this reason, it is difficult to prepare a new asphalt mixture at the construction site when constructing new asphalt pavement, resurfacing it, or performing repairs. Considering such cases, it is desirable to heat a solidified new asphalt mixture that has been prepared in advance at the construction site, or to regenerate and reuse degraded asphalt mixture from existing asphalt pavement.

When using a new asphalt mixture manufactured at a manufacturing plant, it is necessary to transport the manufactured asphalt mixture from the manufacturing plant to the construction site using transportation means such as trucks. Furthermore, it is necessary to transport the asphalt pavement layer (asphalt waste material) removed at the construction site from the construction site to a manufacturing plant or disposal site. On the other hand, when asphalt waste is recycled and used at the construction site as a new asphalt mixture, the time, cost, and effort required for manufacturing and transporting the new asphalt mixture can be reduced. In addition, since asphalt waste, which would normally be industrial waste, can be reused, it is in line with the goals of the SDGs (Sustainable Development Goals), and is not limited to islands or developing countries. , the benefits will be high in all countries and regions with asphalt-paved roads.

Regarding the regeneration of asphalt, Patent Document 1 below discloses that asphalt waste is introduced into a rotating drum, and while the rotating drum is rotated in an inclined state in the circumferential direction, hot air is sent into the rotating drum to regenerate the asphalt waste. An apparatus is disclosed.
In addition, in Patent Document 2 below, a trailer equipped with an asphalt regeneration device is connected to a towing vehicle and transported to a construction site, the trailer is detached from the towing vehicle and connected to the earth removal plate of a hydraulic excavator, and the trailer is transported to a construction site. While excavating the site using It is disclosed that construction will take place.

Japanese Patent Application Publication No. 2001-90018 Patent No. 4892711

By the way, in Japan, quality standards have been established for various items regarding the physical properties of asphalt for paving. For example, the JIS standard (JIS K 2207) provides guidelines for the physical properties that petroleum asphalt suitable for road paving should have. The JIS standard includes an item regarding penetration. This penetration is an indicator of the hardness of the solidified petroleum asphalt.The tip of a specified needle, about the size of a sewing machine needle with a 100g weight attached, is pressed against an asphalt sample at 25°C, and The needle penetrates the asphalt sample perpendicularly for 5 seconds, and the length of penetration of the needle into the asphalt sample is measured. Then, the penetration depth is expressed in units of 1/10 mm, and the hardness of the asphalt is determined. Asphalt for road paving is required to have a penetration value within a predetermined range, for example, more than 40 and less than 60 for use in general regions excluding cold regions. If the penetration is within this range, the asphalt's softening point, elongation, strength, viscosity, etc. tend to have values suitable for pavement.

Even when recycling asphalt waste into an asphalt mixture at a construction site, the recycled asphalt must satisfy the predetermined penetration level described above. However, it is not easy to produce an asphalt mixture with a penetration level that meets the standards at a construction site with limited equipment.

The present invention has been made in view of the above circumstances, and is a recycled asphalt material that can be easily manufactured in compliance with standards from asphalt waste material used for existing asphalt pavement at an asphalt pavement construction site. The purpose is to provide a manufacturing method and testing unit for asphalt mixtures.

The method for producing a recycled asphalt mixture according to the present invention includes a first charging step of charging a predetermined amount of asphalt mixture waste into a container, and recycling of the waste based on the content of effective asphalt components in the waste. A second charging step of charging the required amount of additive into the container, and maintaining the temperature inside the container within a predetermined temperature range by heating, and then charging the additive into the container and reducing the particle size to a predetermined size. and a stirring and heating step of mixing the waste material and the additive. The manufacturing method includes an analysis step of analyzing the content of effective asphalt components in the waste material, and determining the amount of the additive necessary for recycling the waste material based on the content of the effective asphalt component obtained in the analysis step. The analysis step further includes a test crushing step of heating and crushing at least a part of the waste material to be recycled to a predetermined particle size to obtain a crushed material, and and a test body production step of collecting at least a part of the crushed material and placing it in a test container to produce a test body.

In the method for producing a recycled asphalt mixture according to the present invention, the additive is obtained by mixing each material constituting the additive and solidifying it into a block, and the stirring and heating step includes the solidified additive. The agent may be crushed while stirring.

In the method for producing a recycled asphalt mixture according to the present invention, the test crushing step includes stirring and heating at least a portion of the waste material in the test container under the same operating conditions as the stirring and heating step, and The particle size may be reduced.

In the method for producing a recycled asphalt mixture according to the present invention, in the analysis step, after pressing a test paper on the test specimen, the effective asphalt component in the waste material is determined based on the adhesion rate of the effective asphalt component adhering to the test paper. The content of the components may also be analyzed.

In the method for producing a recycled asphalt mixture according to the present invention, the stirring and heating step may further include a stirring speed changing step of changing the stirring speed depending on the size of the lump of waste material and the stirring state.

The method for producing a recycled asphalt mixture according to the present invention includes a discharging step of discharging the recycled asphalt mixture mixed with the waste material and the additive from the container, and discharging the recycled asphalt mixture discharged from the container. The method may further include a discharge amount adjustment step of adjusting the amount.

The test unit according to the present invention is a test unit for analyzing the content of effective asphalt components in an asphalt mixture, and the test unit includes a test container having a cylindrical shape with a bottom and a predetermined diameter; at least one test paper cut into a circle approximately equal to the inner diameter of the container; and a first test paper contained in the at least one test paper placed over the asphalt mixture loaded in the test container. and a ramming rod for tamping the asphalt mixture over the test paper.
In the test unit according to the present invention, the at least one test paper includes a first test paper and a second test paper, and the second test paper is a test paper loaded with the asphalt mixture in the test container. The first test strip may be placed on the bottom of the test vessel before being loaded with the asphalt mixture, and the first test strip may be placed over the asphalt mixture after the test vessel is loaded with the asphalt mixture.

According to the present invention, at an asphalt pavement construction site, recycled asphalt material that conforms to standards can be easily produced from asphalt waste material used in existing asphalt pavement.

FIG. 2 is a side view of a reproducing apparatus used to carry out the reproducing method according to the present invention. FIG. 2 is a schematic longitudinal cross-sectional view of the drum in FIG. 1. FIG. FIG. 3 is a sectional view taken along the line III-III of the drum in FIG. 2; FIG. 2 is a schematic diagram showing a procedure for analyzing effective asphalt components. FIG. 2 is a schematic diagram showing a procedure for analyzing effective asphalt components. FIG. 2 is a schematic diagram showing a procedure for analyzing effective asphalt components. FIG. 2 is a schematic diagram showing a procedure for analyzing effective asphalt components. FIG. 3 is a diagram showing a list used to specify the amount of additives necessary for recycling asphalt waste material.

Preferred embodiments of the present invention will be described below.
The asphalt regeneration device 1 used to carry out the method for recycling asphalt mixture waste (hereinafter referred to as asphalt waste) according to the present invention may be fixedly installed in a factory, etc. It is preferable to use it by mounting it on the loading platform of a self-propelled vehicle. In this case, by moving the cart, vehicle, etc., the regeneration device 1 can be freely moved between asphalt pavement construction sites.

The playback device 1 of this embodiment has the following structure. That is, as shown in FIGS. 1 to 3, the asphalt regeneration device 1 includes a base 2a, a tilt mechanism 2b, a frame 2, and a drum 3 for regenerating asphalt mixture waste (hereinafter referred to as asphalt waste). , drum rollers (support parts) 4 and 5 that rotatably support the drum 3, a drive part (drive unit) 6 that rotates the drum 3 around a rotation axis O that is a virtual center of rotation, and It has a burner 7 for heating. The tilt mechanism 2b and the frame 2 are arranged on the base 2a. Further, the drum 3, drum rollers 4, 5, drive section 6, and burner 7 are arranged on the frame 2. The drum 3 is supported by drum rollers 4 and 5. The drum roller 5 is not shown in FIG. 1 because it is disposed on the back side of the drum 3 (on the back side of the drum 3 in FIG. 1).

The frame 2 is composed of upper and lower frame members connected via a hinge portion, and the lower frame member is fixed to the base 2a. The base 2a is provided with a tilt mechanism 2b that tilts the frame 2 (upper frame material). When the tilt mechanism 2b is activated, the upper frame material is tilted so that the input port 11 of the drum 3 is higher than the discharge port 12. Note that the inclination angle of the upper frame material can be arbitrarily selected by changing the stroke length of the tilt mechanism. The tilt mechanism 2b is composed of, for example, a fluid cylinder.

The drum 3 is a hollow metal container for stirring and heating the asphalt waste and additives therein, and the asphalt waste is supplied into the drum 3 via a hopper 16 . The drum 3 includes a cylindrical main body 9 and a truncated conical discharge section 10. The main body 9 is surrounded by a gate-shaped frame provided on the base 2a. The main body 9 has an input port 11 (see FIG. 2) at its front end, and the asphalt waste material input into the hopper 16 is introduced into the drum 3 through the input port 11.
The discharge section 10 forms the rear part of the drum 3 and has a discharge opening 12 for discharging the recycled asphalt mixture. The discharge port 12 can be closed with a lid member 24.

A male thread is provided on the outer periphery of the rod 25 fixed to the discharge portion 10, and a female thread hole is provided in the center of the handle 26. Further, a hole slightly larger than the outer diameter of the rod 25 is provided in the center of the lid member 24, and the rod 25 is inserted into the hole. The handle 26 is screwed onto the rod 25 from the outside of the lid member 24. By operating the handle 26, the lid member 24 is moved in the axial direction of the rod 25, and the discharge port 12 and the lid member 24 are connected. Adjust the gap. By adjusting this gap, the amount of recycled asphalt mixture discharged from the discharge port 12 can be adjusted.

The drum 3 is rotatably supported by the frame 2 via a plurality of drum rollers 4 and 5. In the attitude shown in FIG. 1 (normal state), the rotation axis O of the drum 3 is oriented in the horizontal direction. The drum rollers 4 and 5 include rollers 41 and 51 that are rotatable around a roller rotation axis provided parallel to the rotation axis O, and the drum 3 is rotated by the rollers 41 and 51 coming into contact with the outer peripheral surface of the main body 9. Support freely. A total of four drum rollers 4 and 5 are provided, one each at the front and back in the longitudinal direction of the drum 3, as shown in FIG. 1, and one each at the left and right sides in the width direction of the drum 3, as shown in FIG. . The rollers 41 and 51 of each drum roller 4 and 5 support the drum 3 from below.

The drive unit 6 is a drive source that rotates the drum 3. The drive unit 6 includes a motor 20, a reduction gear 22, and a pinion gear (not shown). The output of the motor 20 is reduced by a reducer 22 to rotate a pinion gear. An annular drive transmission section 21 is provided on the outer peripheral surface of the main body 9. The drive transmission section 21 is a large number of teeth (racks) that mesh with a pinion gear, and is formed in an annular shape. As the motor 20 rotates, the pinion gear and the teeth mesh with each other, and the drum 3 rolls on the rollers 41 and 51 about the rotation axis O.

The rotation speed of the drum 3 can be adjusted using an operation panel (not shown). The operation panel is provided with a switch for changing the rotation speed of the drum 3 between stop, low speed, medium speed, and high speed. By operating this switch, the operator can change the rotation speed as appropriate, depending on the size of the lump of asphalt waste material and the degree of progress of the heating and stirring process.

The burner (heating unit) 7 heats the asphalt waste loaded inside the drum 3 and recycled grains which are crushed products thereof. In the case of this embodiment, the burner 7 radiates (projects) flame into the drum 3 through the inlet 11 . Since the asphalt waste inside the drum 3 is directly heated by this flame, the asphalt waste can be quickly and efficiently softened (melting the surface layer).

The temperature control inside the drum 3 can be appropriately set by the operator using temperature input means provided on the operation panel. The burner 7 performs heating control based on the temperature set by the operator and the measurement result of a temperature measuring means provided inside the drum 3.

The burner 7 is a single-type burner that applies pressure to liquid fuel, ejects it in the form of a mist, mixes it with air, ignites it, and emits a flame, and has one flame emitting port. In this case, heating control can be performed by turning the burner 7 on and off. In addition, when using a dual burner with two flame emitting ports, one for high heat and one for low heat, it is possible to control heating by adjusting the activation timing of each burner. be. The burner 7 may be of three or more types.

In the recycling apparatus 1 having the above configuration, asphalt waste and additives are charged into the hopper 16 as shown in FIG. 1 when recycling asphalt waste. This feeding is done using a shovel car or a hopper-hanging crane. The input amount of asphalt waste material is measured in real time by a measuring unit (not shown) provided in the regeneration device 1, and the input is finished when the input amount reaches a desired amount.

While the drive unit 6 is driven to rotate the drum 3, the burner 7 heats the asphalt waste inside the drum 3. The asphalt waste loaded into the drum 3 is crushed into chunks by falling energy as the drum 3 rotates. When these crushed bodies are heated, their surface layer portions are melted, and when they are rolled inside the drum 3, they are granulated. In addition, by continuing to heat the asphalt waste material with the burner 7 for a predetermined period of time while maintaining the temperature inside the drum 3 at a predetermined temperature, the asphalt waste material can be recycled into asphalt with good yield and quality, and the recycled particles can be recycled. Obtainable. The obtained recycled grains are discharged from the drum 3 and reused for road asphalt pavement. At the time of ejection, the frame 2 is rotated around the hinge portion by driving (extending) the tilt mechanism 2b and is lifted up. As a result, the drum 3 changes to an oblique position with its rear end (lid member 24) facing downward. During this attitude change, heating by the burner 7 and driving of the drive unit 6 may be continued. When the lid member 24 is operated in the opening direction by operating the handle 26, a gap can be secured between the lid member 24 and the discharge section 10, and the recycled particles inside the drum 3 naturally fall from this gap due to its own weight.

A plurality of guide members 19 are provided on the inner peripheral wall of the discharge section 10. The guide member 19 is a plate-shaped member, and is provided at an angle with respect to a radial line extending from the center of the discharge port 12 along the inner circumferential wall. The guide member 19 is inclined so that its rear end side faces the rotational direction of the drum 3, and its rear end side is curved in an arch shape toward the opposite side to the rotational direction. The guide member 19 guides the recycled grains granulated inside the main body 9 to the discharge port 12, and can efficiently discharge the recycled grains. Also in the rear part of the main body 9, a plurality of guide members 18B are provided on the inner peripheral wall in the circumferential direction to guide the movement of recycled grains from the main body 9 to the discharge section 10.

The inner peripheral wall of the main body 9 is also provided with a plurality of blade members 18A. Each blade member 18A is spaced apart from each other in the circumferential direction of the drum 3. In the case of a drum without the blade member 18A, even if the drum is rotated in the attitude shown in FIG. 1, the asphalt waste remains accumulated at the bottom of the drum due to its own weight. On the other hand, in the case of the drum 3 having the blade member 18A, the plurality of blade members 18A scrape up the asphalt waste material as the drum 3 rotates, so that the asphalt waste material is forcibly lifted without staying at the bottom of the drum 3, and then , falls naturally and is stirred within the drum 3.

Each blade member 18A is provided on the inner circumferential wall of the main body 9 along the direction of the rotation axis O and protrudes inward in the radial direction of the drum 3. In the case of this embodiment, each blade member 18A extends continuously in parallel to the direction of the rotation axis O.

Next, the recycling of asphalt waste using the asphalt recycling apparatus 1 having the above-described structure will be described.
When the existing asphalt pavement layer is excavated at a site where the asphalt pavement layer is to be replaced, excavated debris is created in which the asphalt pavement layers form clumps of various sizes. This is the asphalt waste material that will be used as the material for the new asphalt pavement layer.

(Analysis of effective asphalt components)
Although the particle size of asphalt waste is similar to that of aggregate in an asphalt mixture, the components of petroleum asphalt are not necessarily of a quality that can be applied to actual asphalt pavement. This is due to the fact that during excavation, pebbles and sand grains that were on the roadbed, which is the base of the previous asphalt pavement layer, are taken in with them. Since these pebbles and sand grains cannot be completely removed from asphalt waste, the asphalt waste must be recycled while still containing the pebbles and sand. Furthermore, when the asphalt pavement layer is exposed outdoors for a long period of time to rainwater, ultraviolet rays, and air, problems of aging such as hardening and oxidation of asphalt components occur. In this way, due to the inclusion of impurities and deterioration over time, if this asphalt waste is directly used in the production of recycled asphalt, it will produce low-grade asphalt with a lower content of effective petroleum asphalt components, that is, effective asphalt components compared to aggregate. Only recycled asphalt is available. That is, recycled asphalt produced from this asphalt waste material cannot be used for resurfacing because it does not meet the quality standards required for asphalt for road paving.
Therefore, when producing recycled asphalt from asphalt waste, it is necessary to know in advance how much effective asphalt component is contained in the asphalt waste obtained from the construction site.

First, as shown in FIGS. 4A to 4D, a test container 30 having a cylindrical shape with a bottom and a predetermined diameter and white filter papers (two sheets) 31 and 32 cut into a circle approximately equal to the inner diameter of the container are prepared. do. Then, the first filter paper 31 is placed on the bottom of the test container 30 (see FIG. 4A). Next, a portion 102 of the asphalt mixture as a sample taken out from asphalt waste is loaded into the test container 30 so as to cover the first filter paper 32 (see FIG. 4B). Next, the asphalt mixture 102 loaded into the test container 30 is tamped using a tool such as a tamper, and the surface is leveled. The asphalt mixture 102 loaded into the test container 30 is heated to 170 to 200° and crushed to a predetermined particle size.

After a second filter paper 32 is placed on top of the leveled asphalt mixture 102 (see FIG. 4C), the asphalt mixture 102 is further compacted using a ramming rod 33 (see FIG. 4D). As a result, effective asphalt components ooze out of the asphalt mixture 102 and adhere to the filter papers 31 and 32. The effective asphalt components adhering to the filter papers 31 and 32 appear as a black stain-like pattern.
The amount of asphalt mixture 102 loaded into the test container 30 is set so that the layer thickness of the asphalt mixture 102 in the test container 30 is approximately equal to the construction thickness (80 to 120 mm) specified in the asphalt pavement specifications. be adjusted.

Once the asphalt mixture 102 has been compacted, the filter paper 32 is peeled off from the asphalt mixture. Thereafter, the ratio of the area of the black pattern attached to the filter paper 32 to the total area of the filter paper 32 is analyzed, and based on this analysis value, the amount of effective asphalt components contained in the asphalt mixture 102 that is the sample is determined. Identify. The "pattern area" referred to here is expressed by the ratio of white background to black background to the total area of the filter paper.
By identifying the amount of effective asphalt components contained in the sample, it is possible to determine whether the asphalt waste material that was the source of the sample is
1) Does it meet the quality standards required for asphalt for road paving?
2) If the quality standards are not met, how much is the content of effective asphalt components insufficient?
can be judged. Based on the determination result of 2), it is possible to determine the amount of additive to be added to the asphalt waste material in order to supplement the missing effective asphalt component.

The additive contains at least one polymeric material selected from petroleum asphalt, rubber, thermoplastic elastomer, and thermoplastic resin, and asphalt emulsion as main components. The "additive" used in this embodiment is a mixture of the above-mentioned components with a combustible binder added and kneaded to solidify into a block (hereinafter referred to as an additive block).

To determine the amount of additive to be added to asphalt waste, first, use samples of multiple types of asphalt waste and calculate the ratio of the area occupied by the black pattern to the amount of effective asphalt components contained in the sample. Create a first table that shows the relationships. Similarly, a second table is created that shows the relationship between the amount of effective asphalt component contained in the sample and the amount of additive required to compensate for the deficiency in the effective asphalt component. After preparing these tables in advance, at the asphalt pavement construction site, you can calculate the additions that should be added to asphalt waste based on the occupied area ratio of the black pattern of the sample obtained from asphalt waste and the first and second tables. The amount of agent is determined.

The amount of additive to be added to the asphalt waste increases as the occupied area ratio (adhesion ratio) of the black pattern of the effective asphalt component attached to the filter paper 32 to the total area of the filter paper decreases, and the more the occupied area ratio of the black pattern increases. The larger it is, the less it becomes.
To explain specifically how to determine the amount of additive from the stain on the filter paper 32, the occupied area ratio of the effective asphalt component adhering to the filter paper 32 is calculated using, for example, image analysis software running on a general-purpose computer. be able to.
First, the filter paper 32 to which the effective asphalt component has adhered is photographed, and the digital image is applied to image analysis software. The image analysis software calculates the occupied area ratio of the black pattern of the effective asphalt component to the total area of the filter paper 32 (=(total occupied area of the pattern ÷ total area of the filter paper) x 100) from the black and white shading formed on the filter paper 32. do. Then, from the relationship between the ratio of the area occupied by the pattern of the effective asphalt component calculated from the image of the filter paper 32 and the first table, the amount of the effective asphalt component contained in the asphalt mixture 102 obtained as the sample is identified. Ru.
Regarding the filter paper, in this embodiment, the occupied area ratio of the pattern of the effective asphalt component was calculated using the filter paper 32, but the occupied area ratio may be calculated in the same manner using the filter paper 31. The occupied area ratio may be calculated using two sheets of filter paper 32 and the filter paper 32, and the average value of the occupied area ratios of the two sheets may be adopted.

<Decision process>
After specifying the amount of effective asphalt component contained in the sample, the amount of additive required to make up for the deficiency in the effective asphalt component is determined from the relationship between this amount value and the second table.
Since each additive block has a constant weight, it is possible to reliably add the amount determined above without making a mistake.

When producing recycled asphalt from asphalt waste, considering the quality standards required for asphalt for road paving, the standard weight of additive blocks added to asphalt waste is 1 to 4 kg per 1000 kg of asphalt waste. , preferably 2 to 3 kg.
If the weight of the additive block added to 1000 kg of asphalt waste is less than 2 kg, the penetration into the recycled asphalt pavement layer laid using recycled asphalt may be reduced, and the quality standards may not be met. . Furthermore, if the weight of the additive block to be added is less than 1 kg, the effective asphalt component will be too small and the penetration into the recycled asphalt pavement layer will become even smaller. In addition, as the viscosity (hardness) of asphalt increases, it has poor flexibility, so the recycled asphalt pavement layer has poor followability to uneven roadbeds, making laying and construction itself difficult.

Furthermore, if the weight of the additive block added to 1000 kg of asphalt waste material is greater than 3 kg, there is a risk that the degree of penetration into the recycled asphalt pavement layer will increase, and the quality standards may not be met. Furthermore, if the weight of the additive block to be added is greater than 4 kg, the effective asphalt component will be too large and the penetration into the reclaimed asphalt pavement layer will become greater. Furthermore, since the strength of the asphalt decreases, the durability of the recycled asphalt pavement layer may decrease, and cracks and ruts may occur in a short period of time after construction.

(Recycling of asphalt waste)
<Feeding process>
First, asphalt waste and additive blocks are put into the hopper 16 of the asphalt regeneration apparatus 1 that has been moved to the site, and the asphalt waste and additive blocks are loaded into the drum 3. The amount of additive block added is determined based on the above-mentioned analysis results.
The tilt mechanism 2b is operated to tilt the frame 2 together with the drum 3 so that the input port 11 of the drum 3 is slightly higher than the discharge port 12. By making the input port 11 higher than the discharge port 12, the asphalt waste treated in the drum 3 is moved from the input port 11 toward the discharge port 12 due to its own weight.

<Stirring and heating process>
Next, the drive unit 6 is operated to rotate the drum 3, and the asphalt waste material and additive block are crushed to a predetermined particle size. In parallel with this crushing process, the burner 7 is ignited to heat the inside of the drum 3 to a temperature range of 170°C to 200°C.

The asphalt waste material and additive blocks fed into the drum 3 are initially lumps of various sizes, but as the drum 3 rotates, they are repeatedly scraped up and dropped by the blade member 18A, and gradually crushed ( smaller diameter). At the same time, the crushed pieces of asphalt waste and the additive block are heated by the burner 7, and the petroleum asphalt contained in the asphalt waste and the additive block is softened and increases in viscosity.

The asphalt waste material and additive block that have been crushed in the drum 3 and increased in viscosity by heating reach a predetermined temperature range, that is, a temperature range of 170°C to 200°C, while being continuously stirred and heated, and have a predetermined particle size. The particles are stirred and heated until they reach a particle size (medium gravel, particle size: 4.75 to 19.00 mm) that can be used as aggregate for asphalt pavement.
Through this heat treatment, the asphalt waste material and additive block are crushed and heated. As a result, the surface layer portions of both crushed bodies are melted and stirred, so that both crushed bodies are mixed together to produce homogeneous recycled asphalt material (recycled granules).

The recycled asphalt material generated within the drum 3 is discharged from the drum 3 at an arbitrary timing. At this time, by driving (extending) the tilt mechanism 2b, the frame 2 is rotated around the hinge portion, and the front end side (the left side in FIG. 1) of the drum 3 is lifted up. As a result, the drum 3 changes to an oblique position with its rear end side (lid member 24 side) facing downward. During this attitude change, the heating by the burner 7 and the rotation of the drum 3 by the drive unit 6 may be continued.
As the attitude of the drum 3 changes, the regenerated particles inside the drum 3 are drawn toward the rear end of the drum 3 due to its own weight, and are gathered toward the center of the drum 3 by the guide members 18B and 19. Thereafter, when the lid member 24 is operated in the opening direction by operating the handle 26, a gap can be secured between the discharge port 12 and the lid member 24, and the recycled grains inside the drum 3 naturally fall from this gap due to their own weight. . The discharged recycled particles are spread on the roadbed from which the asphalt pavement layer has been removed, and used as recycled asphalt material for asphalt pavement.

As explained above, according to the recycling method of this embodiment, asphalt waste used in existing asphalt pavement is analyzed, the amount of additives to be added to the asphalt waste is determined, and the asphalt waste and additives are By heating and stirring the agents together, recycled asphalt material that meets standards can be easily produced from asphalt waste. As a result, high-quality recycled asphalt material that meets quality standards can be easily produced at the construction site from the waste material of the asphalt pavement layer used for existing asphalt pavement.

In the above explanation, a general-purpose computer was used to determine the amount of additive from the pattern of the effective asphalt components attached to the filter papers 31 and 32, but it is assumed that there may be an environment in which such electronic equipment cannot be used at the site. . Therefore, a method for determining the amount of additive without using electronic equipment will be explained.

First, from among the past cases included in the first table, several representative cases are selected in stages according to the exclusive area ratio of the pattern of effective asphalt components formed on the filter paper. For example, case (1) obtained by performing the above analysis using an asphalt mixture suitable for paving as a sample, and case (2) obtained by conducting the above analysis using asphalt waste material approximately 3 years after installation. ), similarly select cases (3) obtained from asphalt waste material that has been installed for about 7 years, and case (4) that was obtained from asphalt waste materials that have been installed for more than 10 years. Then, for those cases, the amount (kg/ton) of additive required in each case is specified with reference to the second table. Then, as shown in FIG. 5, a list is created in which the digital image of the filter paper in each case is associated with the value of the amount of additive required in each case. The amount referred to here is the amount of additive added per ton of asphalt waste material.

When constructing asphalt pavement, workers should bring the above list to the site. This list may be printed on paper or stored as a digital image on a commercially available general-purpose computer, a mobile terminal with a display, or the like. Then, an asphalt mixture 102 as a sample is obtained from asphalt waste material from the site, and the asphalt mixture 102 is put into a test container 30 and compacted, and the effective asphalt component is impregnated into the filter paper 32. Thereafter, the filter paper 32 is removed from the test container 30.

The worker compares the appearance of the filter paper 32 acquired at the site with the image of the filter paper of each case included in the above list, and identifies the case that is closest to the exclusive state of the pattern of the filter paper 32 acquired at the site. Then, the amount of additive required in that case is identified as the amount of additive to be added to the asphalt waste material obtained at the site. If there is no case where the pattern of the filter paper 32 obtained in the field is close to exclusive, for example, it has less black background than the image of case (2), and more black background than the image of case (3). Then, the average value (2.25 kg/ton) of the amount of additive in case (2) (2.0 kg/ton) and the amount of additive in case (3) (2.5 kg/ton) is Identified as the amount of additive that should be added to asphalt waste on site.

In this way, even if the construction site is not in an environment where general-purpose computers can be operated, the amount of additive can be easily determined without imposing an undue burden on the workers. For example, this point is even more advantageous if the construction site is located in a harsh environment such as extremely cold or scorching heat, or if the site is located in a developing country.

The present invention relates to a method for regenerating an asphalt mixture, and is a method that can be applied at an asphalt pavement construction site to regenerate recycled asphalt that conforms to standards from asphalt waste material used in existing asphalt pavement.

Claims (8)

a first charging step of charging a predetermined amount of asphalt mixture waste into a container;
a second charging step of charging an amount of additive necessary for recycling the waste material into the container based on the content rate of effective asphalt components in the waste material;
Recycled asphalt comprising: maintaining the temperature inside the container within a predetermined temperature range by heating, and mixing and heating the waste material, which has been introduced into the container and has been reduced to a predetermined particle size, and the additive. A method for producing a mixture, the method comprising:
The manufacturing method includes:
an analysis step of analyzing the content of effective asphalt components in the waste material;
a determination step of determining the amount of the additive necessary for recycling the waste material based on the content of effective asphalt components obtained in the analysis step;
further including;
The analysis step includes:
a test crushing step of heating and crushing at least a portion of the waste material to be recycled to obtain a crushed material;
A method for producing a recycled asphalt mixture, comprising a test body production step of collecting at least a part of the crushed material obtained in the test crushing step and placing it in a test container to produce a test body. The additive is a mixture of materials constituting the additive and solidified into a block,
The method for producing a recycled asphalt mixture according to claim 1, wherein in the stirring and heating step, the solidified additive is crushed while stirring. 1 or 2 , wherein the test crushing step stirs and heats at least a portion of the waste material in the test container under the same operating conditions as the stirring and heating step, and reduces the waste material to the predetermined particle size. 2. The method for producing a recycled asphalt mixture according to 2. In the analysis step, after pressing a test paper on the test specimen, the content of the effective asphalt component in the waste material is analyzed based on the adhesion rate of the effective asphalt component on the test paper. 4. A method for producing a recycled asphalt mixture according to claim 3. The regeneration according to any one of claims 1 to 4, wherein the stirring and heating step further includes a stirring speed changing step of changing the stirring speed depending on the size of the lump of waste material and the stirring state. Method of manufacturing asphalt mixture. The manufacturing method includes:
a discharge step of discharging a recycled asphalt mixture mixed with the waste material and the additive from the container;
a discharge amount adjustment step of adjusting the discharge amount of the recycled asphalt mixture discharged from the container;
The method for producing a recycled asphalt mixture according to any one of claims 1 to 5, further comprising: A test unit for analyzing the content of effective asphalt components in an asphalt mixture, the test unit comprising:
The test unit is
a test container having a cylindrical shape with a bottom and a predetermined diameter;
at least one test paper cut into a circle approximately equal to the inner diameter of the test container;
and a ramming rod for tamping the asphalt mixture from above a first test paper included in the at least one test paper, which is placed over the asphalt mixture loaded in the test container. test unit. The at least one test paper includes a first test paper and a second test paper,
a second test strip is placed on the bottom of the test container before the asphalt mixture is loaded into the test container;
8. The test unit of claim 7, wherein the first test strip is placed over the asphalt mixture after the test container is loaded with the asphalt mixture.

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