JPH0118204B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for producing a heat exchange heated asphalt mixture (hereinafter referred to as recycled mixture) using asphalt pavement waste.

The reuse of asphalt pavement waste materials generated from repair work on existing asphalt pavements has been affected by the dramatic rise in oil prices and unstable oil supplies since oil shocks, so it is important to effectively use limited resources. In addition, asphalt pavement waste has been designated as industrial waste under the "Waste Disposal and Public Cleansing Act," and the use of recycled composite materials has also rapidly developed from the standpoint of disposal site management. It has entered the practical stage.

The uses of this recycled composite material include: (1) recycled roadbed material by on-road mixing method for light pavement, (2) recycled roadbed material by plant mixing, (3) heat recycled composite material by plant mixing, etc. There are many uses for asphalt mixtures as alternative materials when using them only for the surface layer of simple pavements, and at present they are the mainstream.

In addition, as for the manufacturing method of the recycled composite material, a drum dryer mixing method is generally adopted, in which asphalt pavement waste accounts for a high proportion of 80 to 100% by weight as aggregate in the heated recycled composite material. This requires the introduction of a drum dryer/mixing method and other large equipment costs, and the asphalt in the asphalt pavement waste has aged considerably, so if it is used at a high rate,
As asphalt pavement waste is reheated, a softening agent is required to correct the penetration due to issues such as compaction characteristics, and the quality of supplied asphalt pavement waste varies depending on time and location, making it difficult to recycle. The quality of the composite material is also unstable due to these effects, so its use is limited to the top layer of road surfaces.

The present invention solves these problems and provides recycled composite materials of stable quality with small equipment costs and without the use of softeners, and the scope of use thereof is equivalent to that of new composite materials. The purpose is to provide a device that can obtain something.

The basic concept of the recycled composite material manufacturing device according to the present invention is to use recycled materials from asphalt pavement waste in 100%
% of asphalt pavement waste is mixed in at room temperature during mixing during the process of producing new composite material at an asphalt plant, and the heat dissipation of the heated new composite material is achieved. This is a heat exchange type that attempts to reuse asphalt pavement waste materials by indirectly heating them.

That is, in the present invention, asphalt pavement waste is crushed into recycled material, heated new aggregate and recycled material are subjected to primary heat exchange in the measuring tank 4b and mixer 3, and then filled with stone powder etc. and heated. The new asphalts were added to mixer 3 in the order in which they were mixed and kneaded.
A dryer 2 in an asphalt plant 1 that heats new aggregate in a heat exchange heated asphalt mixture manufacturing device that performs secondary heat exchange during that time.
is a cylindrical body that extends from the aggregate input port 2g to the discharge port 2f with an inclination that allows the aggregate to rotate and slide down;
On the cylindrical inner wall of the flame part 2h of the burner 2d,
The auxiliary vane 18 has a shape that allows the aggregate to move along the entire circumference inside the cylinder without inhibiting the progress of the flame, and the inner wall of the cylinder beyond the flame part 2h of the burner 2d has aggregates distributed uniformly in the cross section of the cylinder. a distributable scraper blade 19;
It is characterized in that an aggregate backflow prevention blade 20 is installed on the inner wall of the cylinder near the aggregate input port 2g.

According to the above configuration, a certain percentage of the asphalt pavement waste is mixed in at room temperature during mixing, and is heated indirectly by the heat dissipation of the new aggregate, so there is no need to introduce a drum dryer mixing method. By simply installing a device that automatically feeds asphalt pavement waste into a mixer at room temperature into a conventional asphalt plant, recycled composite material can be manufactured, reducing capital investment and reducing the mixing ratio of asphalt pavement waste. Since the amount is 10 to 45 parts by weight, no softener is required to correct the penetration, and since the mixing rate of asphalt pavement waste is low, the recycled composite material can be used even against fluctuations in the quality of supplied asphalt pavement waste. It has a number of excellent effects, including an extremely small impact.

Embodiments of the present invention will be described below based on the drawings.
FIG. 1 is a schematic diagram of the plant.

The asphalt plant 1 has a dryer 2 for new aggregate and a mixer 3 for mixed materials in its main parts, and above the mixer 3, measuring tanks 4a, 4b, and 4c are arranged. The measuring tank is divided into a stone powder 4a, an aggregate 4b, and an asphalt 4c.The stone powder measuring tank 4a is equipped with a stone powder bin 6 for storing stone powder via a stone powder elevator 5. A waste material bin 8 for storing asphalt pavement waste material via a waste material hopper 7 and a hot bin 9 for storing aggregate heated by the dryer 2 while keeping it warm are disposed in the tank 4b.

A screen 10 is disposed above the hot pin 9, and a hot elevator 1 transports the aggregate between the screen 10 and the discharge port of the dryer 2.
1 is arranged. A dry cyclone 13, a wet cyclone 14, and an exhaust fan 15 are sequentially arranged between the dryer 2 and the smoke cylinder 12, and the dry cyclone 13 has a hot air pipe 13a connected to the hot elevator 11 for heating. It consists of

Further, the waste material hopper 7 discharges a predetermined amount of asphalt pavement waste material by a belt feeder (not shown),
A belt conveyor (not shown) is used to transport and stock the waste material into the waste material bin 8. When a command is issued from the operation room of the plant main body (not shown), a screw conveyor (not shown) of the waste material bin 8 is activated, and the waste material is cumulatively weighed into the measuring tank 4b of the plant main body together with the heated aggregate in the hot bin 9, and then fed into the mixer 3. After dry mixing, asphalt measuring tank 4
Asphalt is added from c and wet mixed to produce a recycled composite material. The dryer 2 is installed on a support 17, and a rotating body 2c is rotatably installed around an axis via a drive mechanism (not shown) between a base end structure 2a and an upper end structure 2b. In the drawing, 2d is a burner, 2e is a flame, 2
f is an outlet, and 2g is an inlet.

The rotating body 2c is a cylindrical body, and is divided into a flame part 2h, an inner wall part 2i, and an inlet part 2j from the base end, and the flame part 2h has a generally L-shaped cross section as shown in FIG. Auxiliary blades 18 are arranged on the circumferential surface of the inner wall of the cylinder in a radial arrangement with respect to the cylinder center P. Said inner wall part 2
As shown in FIG. 4, raking blades 19 are arranged radially around the cylindrical center P on the circumferential surface of the inner wall of the cylinder. As shown in FIG. 6, the raking blade 19 is formed into a substantially U-shaped cross section by arranging shelf boards 19b, 19b on a base portion 19a having a substantially L-shaped cross section. Code 19 in the figure
c is a fixing material for the shelf board.

As shown in FIGS. 5 and 7, in the inlet portion 2j, plate-shaped backflow prevention blades 20 are provided on the inner wall surface of the cylinder radially with respect to the cylinder center P and with respect to the axis passing through the cylinder center P. They are arranged in an inclined manner. The flame 2e is adjusted to keep the atmosphere inside the cylinder at a temperature of 200 to 250°C, and the new aggregate 16 is introduced from the input port 2g to rotate the rotating body 2c. In this process, the backflow prevention blade 20 prevents the aggregate from flowing back toward the upper end structure 2b and transports the aggregate to the center of the dryer. The scraping blades 9 scrape up the aggregates falling on the bottom of the inner wall of the rotating body 2c upward along the peripheral wall, and drop the aggregates 16 from between the shelf boards 19b as they reach the top, as shown in FIG. As shown in the figure, the particles are allowed to fall evenly like hail into the cylinder of the rotating body 2c, thereby promoting heat absorption in the aggregates evenly. This means that as the percentage of recycled materials increases from, for example, 10% to 45% by weight, the amount of new aggregate decreases, so the more new aggregate there is, the more it falls like a hailstorm, and the more new aggregate A shelf board 19b is installed so that if there is less aggregate, it can fall like hail.

Next, in the flame section 2h, the auxiliary blades 18 scoop up the aggregate 16 along the peripheral wall of the rotating body 2c.
By dropping the aggregate 16 only at the side of the cylinder without dropping the aggregate 16 at the top of the cylinder,
It is configured so that the progress of the flame 2e is not inhibited by the aggregate, and the coarse aggregate and fine aggregate are mixed on the side of the cylinder, and during this time heat exchange is performed between the aggregates to reach the desired temperature. can be easily reached. With the above configuration, the aggregate 16 is arbitrarily heated to a temperature in the range of 200 to 250°C in the dryer 2 and
f and is temporarily stored in the hot bin 9 via the screen 10 by the hot elevator 11. The hot elevator 11 is the dryer 2
Since the waste heat is sent through the dry cyclone 13 and kept warm, the new aggregate heated by the dryer 2 does not cool down in the hot elevator 11, and the hot bin 9 is also kept sufficiently warm.

The waste material bin 8 stores asphalt pavement waste material obtained by cutting an asphalt pavement slab in advance with a cutting machine, or asphalt pavement waste material obtained by crushing with a crusher. Then, a mixture of stone powder, aggregate, asphalt pavement waste, and asphalt are each weighed from each of the measuring tanks 4a, 4b, and 4c, and are charged into the mixer 3 and mixed. The amount of asphalt in the composite material is usually 5 to 7% by weight, but in the case of recycled composite material, new asphalt is added in an amount equal to the value obtained by subtracting the value obtained by multiplying the amount of asphalt extracted from the asphalt pavement waste material by the mixing rate. A recycled material of asphalt pavement waste is appropriately mixed in a range of 10 to 45 parts by weight in 100 parts by weight of a heat-regenerated composite material such as asphalt, aggregate, and stone powder. These mixing ratios are determined by taking into account the quality of the asphalt pavement waste, the particle size of the new aggregate, the purpose of use, temperature fluctuations, etc.

During the mixing process by mixer 3, asphalt pavement waste, asphalt, stone powder, etc. are heated to a temperature of 200 to 250.
Heat is exchanged and mixed by the new aggregate, which has been heated to 160°C, and the temperature approaches the target temperature of recycled composite material, 160°C.

Setting the heating temperature for new aggregates takes into consideration the outside temperature, the time required for transportation, etc. When the temperature is 19 to 20℃, the heating temperature of new aggregate is 200℃ when the asphalt pavement waste mixture rate is 10%, 220℃ when it is 20%, and 30℃.
% is 235℃, and 45% is 250℃, which will be close to the target temperature of 160℃ for heat-regenerated composite material.

The recycled composite material thus produced is used in the same manner as conventional composite materials. Marshall tests and wheel tracking tests (test temperature 60℃, ground pressure
6.4Kg/cm ² ) and repeated bending tests (specimen dimensions 3 x 3 x 40 cm, span 30 cm, 2-point loading method, frequency 5 Hz) are shown in Figures 10, 11, and 12. According to this, asphalt pavement waste 20
The dynamic stability of the recycled composite material containing ~45% is about 1.5 times higher than that of the new mixture, and the dynamic stability after one year of construction is also higher. It can be said that it is very stable even with respect to kneading. As for the number of repeated failures of recycled composite material at low temperatures, the higher the asphalt pavement waste mixture rate, the higher the number of failures.
Furthermore, according to the results one year after construction, this correlation shows that the recycled composite material has a greater number of fractures than the new composite material, and it can be said that it has superior durability at low temperatures.

Although one embodiment has been described above, the present invention is not limited to this, and various modifications can be made.

The effects of the present invention can be summarized as follows.

(1) Since some of the asphalt pavement waste is mixed in at room temperature during mixing and heated indirectly by heat radiation from the heated new aggregate, it is necessary to introduce a drum dryer mixing method. First, recycled composite material can be manufactured by simply installing a device that automatically feeds asphalt pavement waste into a mixer at room temperature into a conventional asphalt plant, reducing capital investment.

(2) Since the amount of asphalt pavement waste used is low compared to the quality fluctuation of asphalt pavement waste, recycled composite material with little quality fluctuation can be obtained.

(3) Although it is a simple device, continuous mass production is possible.

(4) In primary heat exchange, the heating temperature of new aggregate can be easily controlled according to the amount of asphalt pavement waste added.

[Brief explanation of drawings]

The drawings relate to embodiments of the present invention, and FIG. 1 is a schematic diagram of an asphalt plant, FIG. 2 is a sectional view of a dryer, FIG. 3 is a sectional view taken along line A-A in FIG. 2, and FIG. 5 is a sectional view taken along C-C in FIG. 2, FIG. 6 is a perspective view of the scraping blade, FIG. 7 is a perspective view of the backflow prevention blade, and FIG. BB sectional view in Fig. 2 showing the rotating body, and Fig. 9 A in Fig. 2 showing the rotating body rotating.
-A sectional view, FIG. 10 is a marshal stability test result table, FIG. 11 is a deformation rate table for cut specimens, and FIG. 12 is a fracture bending test result table. 1... Asphalt plant, 2... Dryer, 2a... Base end structure, 2b... Upper end structure,
2c... Rotating body, 2d... Burner, 2e... Flame, 2f... Outlet, 2g... Inlet, 2h...
Flame part, 2i... Inner wall part, 2j... Inlet part, 3
...Mixer, 4a...Measuring tank for stone powder, 4b...Measuring tank for aggregate, 4c...Measuring tank for asphalt, 5
... Stone powder elevator, 6... Stone powder bin, 7... Waste material hopper, 8... Waste material bin, 9... Hot bin,
10... Screen, 11... Hot elevator, 12... Smoke tube, 13... Dry cyclone, 1
4... Wet cyclone, 15... Exhaust fan, 16...
... Aggregate, 17... Support column, 18... Auxiliary blade, 19
... Raking blade, 19a... Base portion, 19b... Shelf board, 19c... Fixing material, 20... Backflow prevention blade.

Claims (1)

[Claims] 1 Asphalt pavement waste is crushed with a crusher to obtain recycled material, heated new aggregate and recycled material are mixed in the measuring tank 4b and mixer 3 to perform heat exchange, and then a filler such as stone powder and heated In an apparatus for producing a heat exchange heated asphalt mixture in which new asphalt is sequentially introduced into a mixer 3 and kneaded, a dryer 2 in an asphalt plant 1 that heats new aggregate is used to rotate aggregate from an aggregate input port 2g. Due to the slope that allows for dynamic fall, the discharge port 2f
The inner wall of the cylinder in the flame section 2h of the burner 2d is provided with auxiliary blades 18 shaped so that the aggregate can move along the entire circumference inside the cylinder without inhibiting the progress of the flame, and the burner 2d. The inner wall of the cylinder beyond the flame part 2h is equipped with scraper blades 19 that can distribute aggregate uniformly in the cross section of the cylinder, and the inner wall of the cylinder near the aggregate input port 2g is equipped with blades 20 to prevent backflow of aggregate. A heat exchange type heated asphalt mixture production device using asphalt pavement waste material, characterized by: