JP2021179142A - Manufacturing method and manufacturing device of asphalt mixture - Google Patents

Abstract

To ensure the quality of foamed asphalt in manufacturing an asphalt mixture.SOLUTION: A manufacturing method of asphalt mixture includes a process of putting heated asphalt from an asphalt tank 300 to an asphalt measuring tank 320, a process of adding water to heated asphalt that has been put into the asphalt measuring tank 320 to make foamed asphalt, a process of putting aggregates from an aggregate storage bin into an aggregate measuring tank and a process of putting fillers from a filler storage bin into a filler measuring tank. In addition to the above processes, the manufacturing method of asphalt mixture further includes a process of supplying a mixer with foamed asphalt of the asphalt measuring tank 320, aggregates of the aggregate measuring tank, and fillers of the filler measuring tank and mixing them.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for producing an asphalt mixture in which an aggregate, a filler (stone powder, etc.) and asphalt are mixed, and an apparatus for producing the same.

As asphalt with improved workability, foamed asphalt foamed by adding water to heated asphalt is known. As a method for producing foamed asphalt, as described in Japanese Patent Application Laid-Open No. 2019-44367 (Patent Document 1), a so-called piping method in which water is added to a pipe for transporting heated asphalt from an asphalt measuring tank to a mixer is used. It has been put to practical use.

Japanese Unexamined Patent Publication No. 2019-44367

By the way, when the foamed asphalt is manufactured by the piping method, the heated asphalt in the piping cannot be confirmed from the outside, so water is added after a predetermined time has passed from the start of transporting the heated asphalt from the asphalt measuring tank to the mixer. The time method was adopted. In this case, if the viscosity of the heated asphalt changes according to the outside air temperature or the like and the transport speed of the heated asphalt flowing in the pipe changes, water cannot always be added at an appropriate timing. If water cannot be added at an appropriate timing, for example, the degree of foaming of the foamed asphalt becomes uneven, and it becomes difficult to ensure the quality of the foamed asphalt.

Therefore, an object of the present invention is to provide a method and an apparatus for producing an asphalt mixture, which can ensure the quality of foamed asphalt.

According to one aspect of the present invention, the method for producing an asphalt mixture is a step of charging heated asphalt from an asphalt tank into an asphalt measuring tank and adding water to the heated asphalt charged in the asphalt measuring tank to form a foamed asphalt. A step of charging the aggregate from the aggregate storage bin into the aggregate measuring tank, and a step of charging the filler from the filler storage bin into the filler measuring tank are provided. Further, the method for producing an asphalt mixture further includes, in addition to the above steps, a step of supplying the foamed asphalt of the asphalt measuring tank, the aggregate of the aggregate measuring tank, and the filler of the filler measuring tank to the mixer and mixing them. ing.

According to another aspect of the present invention, the asphalt mixture manufacturing apparatus includes an asphalt tank, an asphalt measuring tank, a water addition device, an aggregate storage bin, an aggregate measuring tank, a filler storage bin, and a filler weighing. It is equipped with a tank and a mixer. The asphalt tank stores heated asphalt. The asphalt measuring tank measures the heated asphalt supplied from the asphalt tank. The water addition device adds water to the heated asphalt supplied to the asphalt measuring tank to make foamed asphalt. The aggregate storage bottle stores the aggregate. The aggregate measuring tank measures the aggregate supplied from the aggregate storage bottle. The filler storage bottle stores the filler. The filler measuring tank measures the filler supplied from the filler storage bottle. The mixer mixes the foamed asphalt weighed by the asphalt metering tank, the aggregate weighed by the aggregate metering tank, and the filler weighed by the filler metering tank.

According to the present invention, the quality of foamed asphalt can be ensured in the method and apparatus for producing an asphalt mixture.

It is a schematic diagram which shows an example of the asphalt mixture manufacturing apparatus. It is a schematic diagram which shows an example of the mechanism which supplies heated asphalt and water to an asphalt measuring tank. It is explanatory drawing which shows an example of the method of adding water to heated asphalt. It is explanatory drawing which shows an example of the 1st method of adding an additive to water. It is explanatory drawing which shows an example of the 2nd method of adding an additive to water. It is a flowchart which shows an example of the process of manufacturing an asphalt mixture.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an example of an asphalt mixture manufacturing apparatus (hereinafter abbreviated as “asphalt manufacturing apparatus”) 100.

The asphalt manufacturing apparatus 100 is installed in, for example, an asphalt manufacturing factory (asphalt mixing plant). The asphalt manufacturing apparatus 100 includes a cold hopper 120, a dryer 140, a bag filter 160, a blower 180, a chimney 200, a hot elevator 220, a screen 240, a hot bin 260, an aggregate measuring tank 280, and asphalt. It includes a tank 300, an asphalt measuring tank 320, a filler storage bin 340, a filler measuring tank 360, a mixer 380, and a water tank 400. Here, the hot bin 260 is given as an example of an aggregate storage bin.

The cold hopper 120 is a device for temporarily storing aggregates for supplying aggregates (coarse aggregates, fine aggregates, sand, etc.) to a production line, for example, an inverted conical shape having an open upper surface or an inverted cone shape. A plurality of hoppers 122 having an inverted quadrangular pyramid are connected in one direction. Further, an opening (not shown) is formed in the lower portion of each hopper 122 of the cold hopper 120, and a shutter for opening and closing this opening with a remotely controllable actuator is attached. Here, as the actuator, for example, a hydraulic cylinder, an air cylinder, an electric motor, a hydraulic motor, an air motor, or the like can be used (the same applies hereinafter). Therefore, for example, by controlling the actuator with an electronic control unit having a built-in microprocessor to open the opening, the aggregate of the hopper 122 can be discharged downward from the opening. Further, below the cold hopper 120, a belt conveyor 124 for receiving the aggregate discharged from the opening of each hopper 122 and transporting the aggregate to the dryer 140 is installed.

The dryer 140 is a device that heats and dries the aggregate with a burner that uses heavy oil, gas, or the like as fuel, and includes, for example, a cylindrical casing that is rotated by an actuator with respect to the gantry. Further, the dryer 140 is provided with a belt conveyor 142 that receives the aggregate conveyed from the cold hopper 120 by the belt conveyor 124 and inputs the aggregate into the internal space from the aggregate input port. Then, the aggregate dried by the dryer 140 is supplied to the hot elevator 220 from the aggregate discharge port.

The bag filter 160 is a device that receives the exhaust gas discharged from the dryer 140 and collects and removes dust such as fine dust and soot contained in the exhaust gas. For example, a glass fiber is put inside the bag filter 160. It has a built-in filter formed in a shape. The exhaust gas from which the dust has been removed by the bag filter 160 is sent to the chimney 200 by the blower 180, and is discharged into the atmosphere through the upper end opening thereof.

The hot elevator 220 is a device that receives the aggregate dried by the dryer 140 and conveys it to the screen 240, and is composed of, for example, a member capable of conveying the aggregate heated by the dryer 140. The high-temperature aggregate carried by the hot elevator 220 slides down the chute 222 installed on the upper part and is thrown into the screen 240 from the tip thereof.

The screen 240 is a device for classifying the aggregate charged from the hot elevator 220 into a predetermined particle size classification, and for example, a sieve having an opening corresponding to the particle size classification is incorporated in a slanted state. There is. The aggregate charged into the screen 240 rolls on the upper surface of the sieve and is classified by an opening according to a predetermined particle size classification. Then, the aggregate classified into a predetermined particle size classification by the screen 240 is supplied to the hot bin 260 arranged below the aggregate.

The hot bin 260 is a device for temporarily storing the aggregate classified by the screen 240 while keeping it warm according to the particle size, and is composed of, for example, a container having an inverted conical lower portion. Further, an opening is formed in the lower portion of the hot bin 260 for individually discharging the aggregates stored according to the particle size, and a shutter for opening and closing each opening with a remotely controllable actuator is attached. Therefore, by individually controlling the actuator that opens and closes each opening of the hot bin 260, the aggregates of different particle sizes can be mixed at a predetermined ratio and charged into the aggregate measuring tank 280 arranged below the aggregates. ..

The aggregate measuring tank 280 is a device for measuring the aggregate input from the hot bin 260, and is, for example, a measuring tank mounted so as to be movable in the vertical direction with respect to the gantry via a load cell for measuring the weight. It is composed of including. Further, an opening for discharging the aggregate is formed in the lower part of the aggregate measuring tank 280, and a shutter for opening and closing this opening with an actuator that can be remotely controlled is attached. Therefore, by opening the opening of the aggregate measuring tank 280, the aggregate can be charged into the mixer 380 arranged below the opening.

The asphalt tank 300 is a device for temporarily storing liquid heated asphalt, and is provided with a heat retaining function such as a heater that keeps the temperature of the heated asphalt constant, for example. Further, although three asphalt tanks 300 are installed in the illustrated example, at least one asphalt tank 300 may be installed in consideration of the amount of heated asphalt used and the like. Then, as shown in FIG. 2, the heated asphalt stored in the asphalt tank 300 operates the first pump P1 arranged in the first asphalt pipe L1 connecting the asphalt tank 300 and the asphalt measuring tank 320. By letting it, it is put into the asphalt measuring tank 320. Here, the first pump P1 may be, for example, a remotely controllable electric pump, a hydraulic pump, an air pump, or the like (the same applies hereinafter).

The asphalt measuring tank 320 is a device for measuring the heated asphalt charged from the asphalt tank 300, and is, for example, a measuring tank mounted so as to be movable in the vertical direction with respect to the gantry via a load cell for measuring the weight. It is composed of including. Further, an opening for discharging heated asphalt is formed in the lower part of the asphalt measuring tank 320, and as shown in FIG. 2, it is arranged in a second asphalt pipe L2 connecting the asphalt measuring tank 320 and the mixer 380. By operating the second pump P2, the asphalt is charged into the mixer 380.

The filler storage bottle 340 is a device for temporarily storing the filler in order to feed the filler into the filler measuring tank 360, and is composed of, for example, a columnar or prismatic container. Further, an opening for discharging the filler is formed in the lower portion of the filler storage bottle 340, and a shutter for opening and closing this opening with an actuator that can be remotely controlled is attached. Therefore, by opening the opening of the filler storage bottle 340, the filler can be charged into the filler measuring tank 360 arranged below the filler storage bottle 340.

The filler measuring tank 360 is a device for measuring the filler charged from the filler storage bottle 340, and is, for example, a measuring tank mounted so as to be movable in the vertical direction with respect to the gantry via a load cell for measuring the weight. It is configured to include. Further, an opening for discharging the filler is formed in the lower portion of the filler measuring tank 360, and a shutter for opening and closing this opening with an actuator that can be remotely controlled is attached. Therefore, by opening the opening of the filler measuring tank 360, the filler can be charged into the mixer 380 arranged below the filler measuring tank 360.

The mixer 380 is a device that uniformly mixes the aggregate charged from the aggregate measuring tank 280, the asphalt charged from the asphalt measuring tank 320, and the filler charged from the filler measuring tank 360 to form an asphalt mixture. For example, it is equipped with a 2-axis bag mill mixer. Further, an opening for discharging the asphalt mixture is formed in the lower part of the mixer 380, and a shutter for opening and closing this opening with a remotely controllable actuator is attached. Therefore, by opening the opening of the mixer 380, the asphalt mixture can be loaded into the dump truck 500 stopped below the mixer 380.

The water tank 400 is a device for temporarily storing water to be added to the heated asphalt charged into the asphalt measuring tank 320, and is composed of, for example, a hollow cylindrical tank. Further, an opening for discharging water is formed in the lower portion of the water tank 400, and as shown in FIG. 2, a third water pipe L3 is arranged in the water pipe L3 connecting the water tank 400 and the asphalt measuring tank 320. By operating the pump P3 of the above, water is added to the heated asphalt charged into the asphalt measuring tank 320.

When water is added to the heated asphalt, the heated asphalt foams and the volume expands momentarily to become foamed asphalt. At this time, even if the timing of adding water to the heated asphalt is not strictly controlled, the time for foaming the heated asphalt in the asphalt measuring tank 320 can be secured, and the quality of the foamed asphalt can be ensured.

The foamed asphalt foamed in the asphalt measuring tank 320 is charged into the mixer 380 by operating the second pump P2 arranged in the second asphalt pipe L2. At this time, by appropriately controlling the second pump P2, the flow rate of the foamed asphalt charged from the asphalt measuring tank 320 to the mixer 380 can be arbitrarily changed.

As shown in FIG. 3, it is preferable to add water to the heated asphalt by injecting water from the tip opening of the first asphalt pipe L1 toward the heated asphalt charged into the asphalt measuring tank 320. That is, it is preferable to set the direction of the nozzle formed at the tip of the water pipe L3 so that the water directly hits the heated asphalt introduced from the tip opening of the first asphalt pipe L1. By doing so, since the heated asphalt and water are mixed and charged into the asphalt measuring tank 320, foaming of the heated asphalt in the asphalt measuring tank 320 can be promoted.

Additives such as a foaming agent, a foaming enhancer, a workability improving agent, and a regeneration additive may be added in advance to the water to be added to the heated asphalt. Here, the foaming agent is a chemical that assists the foaming of asphalt, the foaming enhancer is a chemical that prolongs the foaming effect of asphalt, the workability improving agent is a chemical that reduces the viscosity of the asphalt mixture to improve the workability, and the regeneration additive. Is a drug that restores the properties of asphalt that adheres to recycled aggregate produced from asphalt waste. As the additive, a plurality of types selected in consideration of a required purpose from among a foaming agent, a foaming strengthening agent, a workability improving agent, a regenerating additive, and the like may be mixed.

FIG. 4 shows an example of the first method of adding an additive to water.
An additive tank 420 for temporarily storing the additive is arranged in the vicinity of the water tank 400. The additive stored in the additive tank 420 is added to the water tank 400 by operating the fourth pump P4 arranged in the additive pipe L4 connecting the additive tank 420 and the water tank 400. NS. The additive added to the water tank 400 is added to the asphalt measuring tank 320 by operating the third pump P3 arranged in the water pipe L3 in a state of being uniformly mixed with water. Therefore, an effect can be expected depending on the type of additive.

FIG. 5 shows an example of a second method of adding an additive to water.
In the vicinity of the asphalt measuring tank 320, an additive tank 440 for temporarily storing the additive is arranged. The additive stored in the additive tank 440 is stored in the asphalt measuring tank 320 by operating the fifth pump P5 arranged in the additive pipe L5 connecting the additive tank 440 and the asphalt measuring tank 320. Is added. In the asphalt measuring tank 320, the heated asphalt charged from the asphalt tank 300, the water added from the water tank 400, and the additive added from the additive tank 440 are mixed, and the effect according to the type of the additive is expected. can.

Next, the operation of the asphalt manufacturing apparatus 100 will be described.
The aggregate charged in the cold hopper 120 is conveyed by the belt conveyors 124 and 142, and is charged into the internal space from the aggregate charging port of the dryer 140. The aggregate thrown into the internal space of the dryer 140 is exposed to the flame of a burner and heated, and the moisture evaporates and is dried. The aggregate dried by the dryer 140 is conveyed by the hot elevator 220 and charged into the screen 240. Further, the exhaust gas of the dryer 140 is discharged from the chimney 200 into the atmosphere by the blower 180 after the dust is removed by the bag filter 160. The aggregate put into the screen 240 is classified into a predetermined particle size classification and supplied to the hot bin 260 for temporary storage. Then, the aggregates of each particle size temporarily stored in the hot bin 260 are put into the aggregate measuring tank 280 arranged below the shutter by opening the shutter at the lower part of the hot bin 260.

The filler temporarily stored in the filler storage bottle 340 is charged into the filler measuring tank 360 arranged below the shutter by opening the shutter at the bottom of the filler storage bottle 340. Further, the heated asphalt temporarily stored in the asphalt tank 300 is charged into the asphalt measuring tank 320 by operating the first pump P1 arranged in the first asphalt pipe L1. Further, the water temporarily stored in the water tank 400 is collected from the heated asphalt charged from the asphalt tank 300 into the asphalt measuring tank 320 by operating the third pump P3 arranged in the water pipe L3. Is added. When water is added to the heated asphalt, the heated asphalt foams and rapidly expands in volume to become foamed asphalt.

Then, the aggregate measured by the aggregate measuring tank 280, the foamed asphalt measured by the asphalt measuring tank 320, and the filler measured by the filler measuring tank 360 are charged into the mixer 380, and the aggregate, the foamed asphalt and the filler are charged. The filler is uniformly mixed to produce an asphalt mixture. The asphalt mixture produced in the mixer 380 is loaded onto a dump truck 500 parked below the shutter by opening the shutter at the bottom of the mixer 380, and is transported to, for example, a construction site of asphalt pavement.

The mechanism (water addition device) for adding water to the heated asphalt charged in the asphalt measuring tank 320 is a compact one including a water tank 400, a water pipe L3, and a third pump P3. Therefore, if these are unitized, the asphalt manufacturing apparatus according to the present embodiment can be easily realized by adding a water addition device to the existing asphalt manufacturing apparatus.

FIG. 6 shows an example of a process for producing an asphalt mixture.
In step 1 (abbreviated as "S1" in FIG. 6; the same applies hereinafter), the first pump P1 arranged in the first asphalt pipe L1 is operated to heat the asphalt tank 300 to the asphalt measuring tank 320. Add asphalt. At this time, by appropriately controlling the first pump P1 according to the output signal of the load cell of the asphalt measuring tank 320, the heated asphalt of a predetermined weight of the asphalt measuring tank 320 can be charged.

In step 2, the third pump P3 arranged in the water pipe L3 is operated to add water to the heated asphalt charged in the asphalt measuring tank 320. When water is added to the heated asphalt, the heated asphalt foams and momentarily expands in volume to become foamed asphalt.

In step 3, the shutter at the bottom of the hot bin 260 is opened, and the aggregate is charged from the hot bin 260 into the aggregate measuring tank 280. At this time, by appropriately controlling the shutter of the hot bin 260 according to the output signal of the load cell of the asphalt measuring tank 320, a predetermined weight of aggregate can be charged into the aggregate measuring tank 280.

In step 4, the shutter of the filler storage bottle 340 is opened, and the filler is charged from the filler storage bottle 340 into the filler measuring tank 360. At this time, by appropriately controlling the shutter of the filler storage bin 340 according to the output signal of the load cell of the asphalt measuring tank 320, a filler having a predetermined weight can be charged into the filler measuring tank 360.

In step 5, the foam door asphalt, the aggregate and the shutter are appropriately controlled by appropriately controlling the second pump P2 arranged in the second asphalt pipe L2, the shutter of the aggregate measuring tank 280, and the shutter of the filler measuring tank 360. The filler is added to the mixer 380 and mixed. Then, the asphalt mixture is produced by uniformly mixing the foamed asphalt, the aggregate and the filler in the mixer 380.

It should be noted that those skilled in the art may omit some of the technical ideas of the various embodiments described above, combine some of them as appropriate, replace some of them with well-known techniques, and further use well-known techniques. It will be easy to understand that the combination can create new embodiments.

As an example, the asphalt production apparatus 100 may further include a trolley that conveys the asphalt mixture discharged from the mixer 380, and a hot silo that keeps and stores the asphalt mixture conveyed by the trolley.

100 Asphalt manufacturing equipment (asphalt mixture manufacturing equipment)
260 hot bottles (aggregate storage bottles)
280 Aggregate measuring tank 300 Asphalt tank 320 Asphalt measuring tank 340 Filler storage bottle 360 Filler measuring tank 380 Mixer 400 Water tank (water addition device)
420 Additive tank 440 Additive tank L3 Water piping (water addition device)
L4 additive piping L5 additive piping P3 3rd pump (water addition device)
P4 4th pump P5 5th pump

Claims (5)

The process of charging heated asphalt from the asphalt tank to the asphalt measuring tank,
The process of adding water to the heated asphalt put into the asphalt measuring tank to make foamed asphalt, and
The process of loading aggregate from the aggregate storage bottle into the aggregate measuring tank,
The process of filling the filler from the filler storage bottle into the filler measuring tank, and
A step of supplying the foamed asphalt of the asphalt measuring tank, the aggregate of the aggregate measuring tank, and the filler of the filler measuring tank to a mixer and mixing them.
A method for producing an asphalt mixture. A step of adding an additive to the water before adding the water to the heated asphalt is further provided.
The method for producing an asphalt mixture according to claim 1. Further provided with a step of adding an additive to the heated asphalt put into the asphalt measuring tank.
The method for producing an asphalt mixture according to claim 1. In the step of adding water to the heated asphalt charged in the asphalt measuring tank to make foamed asphalt, water is jetted from the asphalt tank toward the heated asphalt charged in the asphalt measuring tank and added.
The method for producing an asphalt mixture according to any one of claims 1 to 3. Asphalt tanks for storing heated asphalt and
An asphalt measuring tank that measures the heated asphalt supplied from the asphalt tank, and
A water addition device that adds water to the heated asphalt supplied to the asphalt measuring tank to make foamed asphalt, and
An aggregate storage bottle for storing aggregate and
An aggregate measuring tank for measuring the aggregate supplied from the aggregate storage bottle, and an aggregate measuring tank.
Filler storage bottles for storing fillers and
A filler measuring tank for measuring the filler supplied from the filler storage bottle, and a filler measuring tank.
A mixer that mixes the foamed asphalt weighed by the asphalt measuring tank, the aggregate weighed by the aggregate measuring tank, and the filler weighed by the filler measuring tank.
Asphalt mixture manufacturing equipment.

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