JPH0424484B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method and apparatus for producing asphalt mixture and ready-mixed concrete, which are road paving materials.

[Prior Art] Conventionally, asphalt mixture was produced in an asphalt plant, and ready-mixed concrete was produced in a batcher plant, each of which had its own dedicated plant. Asphalt mixture is exclusively used as road paving material, but this is because concrete pavement has various drawbacks such as a long curing period. In recent years, compacted concrete pavement has been developed to overcome the drawbacks of concrete pavement, and this compacted concrete pavement involves spreading zero slump cement concrete on the road and rolling it using vibrating rollers, etc. This is a paving method that can significantly shorten the curing period, enable early opening, and has the advantage that a paving machine for asphalt mixture can be used as is.

[Problems to be solved by the invention] However, if road paving is to be done with both asphalt concrete and cement concrete, it is necessary to have both an asphalt plant and a butcher plant. This poses a heavy economic burden. Considering this economical aspect, we believe it is desirable to construct a single plant that has both functions. Therefore, in the present invention, both asphalt concrete and cement concrete use aggregate whose particle size is controlled, and the difference is that asphalt concrete uses asphalt and stone powder, whereas cement concrete uses aggregate with controlled particle size. The purpose of this project is to propose a method and apparatus that can also produce asphalt mixture and ready-mixed concrete using an asphalt plant as a basic plant, focusing on the fact that only cement, water, and admixtures are mixed.

[Means for Solving the Problems] In view of the above-mentioned points, the present invention provides a dryer that heats aggregate, which is a raw material for asphalt mixture or ready-mixed concrete, and bone heated by the dryer, in order to solve the above-mentioned problems. It has a vertical transport device that transports the aggregate to the upper part of the plant main body, and the plant main body is equipped with an aggregate storage bin that sieves the heated aggregate and stores it by particle size. An aggregate measuring tank is installed in the area, while an asphalt measuring tank, stone powder measuring tank, cement measuring tank, and water measuring tank are installed on the side of the aggregate measuring tank, and a mixer is installed below the measuring tank. When producing asphalt mix, aggregate is heated to high temperature in a dryer, stored in aggregate storage bins for each particle size, and aggregates of various particle sizes are prepared according to the composition of asphalt mix to be shipped. A predetermined amount of aggregate is weighed and added to a mixer together with weighed stone powder and asphalt to mix and adjust.Also, when producing ready-mixed concrete, the aggregate is heated at a relatively low temperature in a dryer to evaporate only the surface water of the aggregate. The condition is that aggregates are stored in aggregate storage bins according to particle size, and a predetermined amount of aggregates of various particle sizes are weighed according to the mix of ready-mixed concrete to be shipped, and mixed and mixed by adding the weighed cement and water to a mixer. An object of the present invention is to provide a method for producing asphalt mixture and ready-mixed concrete, which are characterized by the following.

In addition, the present invention has a dryer that heats aggregate that is a material for asphalt mixture or ready-mixed concrete, and a vertical conveyance device that conveys the heated aggregate by the dryer to the upper part of the plant body. An aggregate storage bin is installed in which the materials are sieved and stored according to particle size, and an aggregate measuring tank is installed below the aggregate storage bin, while asphalt mixture is placed on the side of the aggregate measuring tank. An asphalt measuring tank and a stone powder measuring tank are installed to measure the predetermined amounts of asphalt and stone powder, which are mixed materials for fresh concrete, and a cement measuring tank and a water measuring tank are installed to measure the predetermined amounts of cement and water, which are mixed materials for fresh concrete. An object of the present invention is to provide an apparatus for producing asphalt mixture and ready-mixed concrete, characterized in that a mixer for mixing and adjusting asphalt and ready-mixed concrete is provided below the measuring tank.

[Function] According to the present invention, when producing asphalt mixture, aggregate (crushed stone, crushed stone,
The aggregate is heated to around 160℃, and the heated aggregate discharged from the dryer is conveyed to the upper part of the plant using a vertical conveyance device. This aggregate is sieved and stored in aggregate storage bins according to particle size. Then, depending on the composition of the asphalt mixture to be shipped, aggregates of various particle sizes are dispensed into an aggregate measuring tank and weighed in a predetermined amount, and the asphalt measuring tank is
A predetermined amount of asphalt and stone powder are weighed in a stone powder measuring tank, and asphalt is sprayed and kneaded for a predetermined time while the weighed aggregate and stone powder are put into a lower mixer to produce an asphalt mixture.

Furthermore, when producing ready-mixed concrete, aggregates (crushed stone, sand) are supplied to a dryer for heating aggregate according to the composition of the ready-mixed concrete to be shipped. At this time, the key point in the dryer is not to heat the aggregate to raise its temperature, but to send in hot air that is sufficient to evaporate only the surface water adhering to the surface of the aggregate. In other words, it is preferable that the surface of the aggregate is free of moisture and the internal voids are filled with water, a so-called surface dry condition. The surface-dried aggregate discharged from the dryer is conveyed to the upper part of the plant by a vertical conveyance device in the same manner as described above, and is stored in aggregate storage bins according to particle size. Then, depending on the mix of ready-mixed concrete to be shipped, aggregates of various particle sizes are dispensed into an aggregate measuring tank and weighed in a predetermined amount, and cement and water are weighed in predetermined amounts in a cement measuring tank and a water measuring tank. Fresh concrete is produced by putting the materials into a mixer and kneading them for a predetermined period of time.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

Reference numeral 1 denotes a dryer for heating and drying aggregates, in which a cylindrical drum 2 having a number of raking blades (not shown) arranged around its inner periphery is rotatably and tiltably supported by a support roller 3. , and is rotated at a predetermined speed by a drive device (not shown). Reference numeral 4 denotes a burner for heating aggregates disposed in a hot hopper 5 at one end of the drum 2. Hot air is sent from the burner 4 into the drum 2, and aggregates (crushed stone, sand) are stored according to various particle sizes. A predetermined amount of aggregate is cut out from the aggregate hoppers 6a to 6d by variable speed feeders 7a to 7d, and is supplied to the input port of the cold hopper 10 of the drum 2 via belt conveyors 8 and 9, and is fed to the input port of the cold hopper 10 of the drum 2. The aggregate is heated and dried while being rolled down in the drum while being scraped up by the drum, and is discharged from the discharge chute 11. The heated aggregate is lifted to the upper part of the plant body by a bucket elevator, which is a vertical conveyance device, and is sieved by a vibrating sieve 14 according to particle size, and stored by particle size in an aggregate storage bin 15 with internal compartments. be done. 16 is an aggregate measuring tank provided below the aggregate storage bin 15;
Aggregates of various particle sizes discharged from the site are cumulatively weighed. Although this aggregate measuring tank 16 measures aggregate in a similar manner, a plurality of aggregate measuring tanks may be provided so that crushed stone and sand can be measured individually. Reference numeral 17 denotes an asphalt measuring tank, which measures a predetermined amount of molten asphalt that is circulated and supplied from an asphalt tank (not shown). Reference numeral 18 is a stone crushing measuring tank in which stone powder taken out from a stone powder storage silo (not shown) is transported to the upper part of the plant main body 13 by a stone powder elevator 19, and is temporarily stored in a stone powder storage bin 20 arranged in the plant main body 13. Weigh a predetermined amount of stored stone powder. 2
Reference numeral 1 denotes a water measuring tank for measuring water used in producing fresh concrete, and a predetermined amount of water is supplied from a water tank (not shown) disposed above. Additionally, an admixture measuring tank (not shown) is located above the water measuring tank 21.
A predetermined amount of admixture is placed in the water measuring tank 21.
and mix it with water. Reference numeral 22 is a cement measuring tank, in which cement taken out from a cement storage silo (not shown) is transported by a cement elevator 23 to a cement storage bin 24 disposed above the plant main body 13 and temporarily stored therein. The cement stored in the bin 24 is taken out and measured in a predetermined amount. 25 is asphalt composite material,
This is a two-shaft mixer capable of kneading both materials of fresh concrete, and the two kneading shafts 26 arranged parallel to each other between the opposing side walls of the mixing tank are rotated in opposite directions. Attached kneading blade 27
The kneading material is kneaded by moving it along the axial direction while scraping up the kneaded material. This type of twin-shaft mixer is also used in asphalt plants and batcher plants, and although there are slight differences in the shaft seal, arrangement of mixing blades, shape, etc., the two-shaft mixer is capable of mixing both asphalt mixture and ready-mixed concrete. It is possible to construct a shaft mixer, and a mixer capable of kneading both materials is employed.

When producing asphalt mixture, the operation method is the same as that of a conventional asphalt plant, and depending on the composition of the asphalt mixture to be shipped, a predetermined aggregate (crushed stone, sand, etc.) is ) is dispensed in a predetermined amount by variable speed feeders 7a to 7d, fed into dryer 1 via belt conveyors 8 and 9, and heated and dried with hot air from burner 4. The temperature of the aggregate used for asphalt mixture is usually around 160°C, so the burner 4 is adjusted so that the temperature of the aggregate discharged from the dryer 1 is at the above temperature.
combustion control is performed. The aggregate heated and heated by the dryer 1 is transported to the upper part of the plant body 13 by a bucket elevator 12, is sieved by a vibrating sieve 14 according to particle size, and is stored in an aggregate storage bin 15 according to particle size. Then, a predetermined amount of aggregate of various particle sizes is cumulatively weighed in the aggregate measuring tank 16 according to the composition of the asphalt mixture to be shipped, and is fed into the mixer 25. At the same time, a predetermined amount of stone powder is weighed in the stone powder measuring tank 18 and mixed. 25, and while mixing, asphalt measured in an asphalt measuring tank 17 is sprayed onto the mixture, and mixed for a predetermined time to produce an asphalt mixture.

In addition, when producing ready-mixed concrete, a predetermined amount of aggregate is fed from the aggregate hoppers 6a to 6d to the variable speed feeder 7a according to the mix of the ready-mixed concrete to be shipped.
~ Cut out a predetermined amount with 7b, and convey it to belt conveyors 8 and 9.
Although the aggregate is supplied into the dryer 1 through the burner 4 and heated with hot air from the burner 4, the aggregate is not heated to a high temperature as in the production of the asphalt mixture described above. The water/cement ratio is an important factor in concrete, and since this water/cement ratio greatly affects the strength and slump value of concrete, it is said that the moisture management of aggregate is the most important factor when producing ready-mixed concrete. It is no exaggeration to say so. Therefore, unless you always measure the surface water percentage of the aggregate, calculate the amount of surface water adhering to the surface of the aggregate, and use the amount of water obtained by subtracting the amount of surface water from the amount of water designed for mixing, the desired amount of water cannot be obtained. It is a matter of course that the water/cement ratio is not the same. However, by constantly sampling the surface water content of aggregates,
It is impossible to feed back this surface water rate and reflect it in water measurement value correction.

Therefore, we changed our thinking and evaporated the surface water of the aggregate, creating a state where there is no moisture on the surface of the aggregate and only the internal voids are filled with water, a so-called surface dry state. There is no need to constantly sample the moisture content, and we think that subsequent moisture management will be easier. Therefore, when heating the aggregates in the dryer 1, the burner 4 is designed to evaporate only the water adhering to the surface of the aggregates, and send relatively low-temperature hot air so that the aggregates are surface-dry. It is necessary to control the amount of combustion. It is thought that this combustion amount control can be controlled if information such as the amount of aggregate supplied, the surface water rate, and the temperature of aggregate discharged from the dryer can be obtained. However, in continuous operation, it may not be possible to maintain the surface dry condition at all times, but if it is possible to maintain the aggregate near the surface dry condition, it is possible to periodically measure the surface water content by sampling and watering the aggregate. This method allows for more severe moisture management than the method that feeds back to the measured value.

The aggregate, which has been surface-dried in the dryer 1, is conveyed to the upper part of the plant body 13 by a bucket elevator 12, and is introduced into a vibrating sieve 14. Since the aggregate is in a surface dry state, it is sieved by particle size without clogging the sieve and stored in the aggregate storage bin 15 according to particle size. Then, aggregates of various particle sizes are discharged into an aggregate measuring tank 16 according to the mix of ready-mixed concrete to be shipped, cumulatively weighed in a predetermined amount, and fed into a mixer 25. Cement is put into the mixer 25, and the amount of water according to the mixing design is measured in the measuring tank 21 (although it is not necessary to correct the surface water ratio, if necessary, the aggregate in the aggregate storage bin 15 is sampled to The water content may be measured and fed back to correct the surface water content), and then put into the mixer 25 and kneaded for a predetermined period of time to produce ready-mixed concrete.

Although it is most preferable to heat the aggregate in the dryer 1 so that it is surface dry, it is possible to heat the aggregate in a vibrating sieve by heating the aggregate in a wet state to the extent that the temperature does not rise too much and make the sand smooth. Since the desired objective can be achieved to a certain extent without clogging in the combustion chamber 14, the present invention includes combustion management within a range that does not overdo the objective of the present invention.

[Effects of the invention] As described above, in the present invention, both asphalt mixture and ready-mixed concrete can be produced in a single plant, so the initial cost of the plant is low and the economic benefits are large. It is something.

In addition, when producing ready-mixed concrete, the wet aggregate is heated in a dryer to bring it close to a surface-dry state in which the surface water evaporates, so the water/cement ratio, which is an important factor in concrete, becomes more severe. It is something that can be managed.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of an embodiment of the apparatus of the present invention. 1...Dryer, 4...Burner, 6a-6d...
...Aggregate hopper, 7a to 7d...Variable speed feeder,
12... bucket elevator, 13... plant main body, 14... vibrating sieve, 15... aggregate storage bin,
16... Aggregate measuring tank, 17... Asphalt measuring tank, 18... Stone powder measuring tank, 21... Water measuring tank, 2
2... Cement measuring tank, 25... Mixer.

Claims (1)

[Claims] 1. It has a dryer that heats the aggregate that is the raw material for asphalt mixture or ready-mixed concrete, and a vertical conveyance device that conveys the heated aggregate in the dryer to the upper part of the plant body. An aggregate storage bin is installed to sieve and store aggregates according to particle size, and an aggregate measuring tank is installed below the aggregate storage bin, while asphalt is placed on the side of the aggregate measuring tank. A measuring tank, a stone powder measuring tank, a cement measuring tank, and a water measuring tank are installed, and a mixer is installed below the measuring tank, and when producing asphalt mixture, the aggregate is heated to a high temperature in a dryer. , store each particle size in aggregate storage bins, and measure a predetermined amount of aggregate of various particle sizes according to the composition of the asphalt mixture to be shipped.
The aggregate is mixed and mixed by putting it into a mixer together with weighed stone powder and asphalt, and when producing ready-mixed concrete, the aggregate is heated at a relatively low temperature in a dryer, and only the surface water of the aggregate is evaporated to form a surface-dry state. The asphalt is stored in an aggregate storage bin, and is made by weighing a predetermined amount of aggregate of various particle sizes according to the mix of ready-mixed concrete to be shipped, and adding it to a mixer together with the weighed cement and water for mixing and adjustment. Mixture material and ready-mixed concrete manufacturing method. 2. It has a dryer that heats the aggregate that is the raw material for asphalt mixture or ready-mixed concrete, and a vertical conveyance device that transports the heated aggregate by the dryer to the upper part of the plant body.The plant body also has a sieve for the heated aggregate. An aggregate storage bin is installed to store each particle size according to particle size, and an aggregate measuring tank is installed below the aggregate storage bin, while a mixed material of asphalt mixture is placed on the side of the aggregate measuring tank. Naru Asphalt,
An asphalt measuring tank and a stone powder measuring tank are installed to measure a predetermined amount of stone powder, and a cement measuring tank and a water measuring tank are installed to measure a predetermined amount of cement and water to be mixed into fresh concrete. Asphalt mixture and ready-mixed concrete production equipment characterized by a mixer installed at the bottom for mixing and adjusting asphalt and ready-mixed concrete.