JP3074242B2 - Sintered artificial aggregate for road pavement and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sintered artificial aggregate for road pavement and a method for producing the same, and more particularly to a sintered pavement for road pavement having excellent mechanical strength, wear resistance, shear resistance and high adhesion. The present invention relates to an artificial aggregate and an advantageous production method thereof.

[0002]

BACKGROUND ART Conventionally, natural crushed stone has been generally used as an aggregate for road pavement. However, natural crushed stone is difficult to obtain stable quality, and is inferior in abrasion resistance, mechanical strength and slip resistance. Therefore, when used as an aggregate for road pavement, the following problems occur. Have been aroused.

That is, the natural crushed stones on the road surface are worn out by friction with the tires of vehicles traveling on the road, and the natural crushed stones gradually shift due to the weight of the vehicle traveling on the road. The flatness of the surface layer is impaired. On roads with a large traffic volume, such wear and displacement of crushed stones are more remarkable, so that a rut is formed on the road surface. Can cause traffic accidents. Therefore, it is necessary to repair such roads at a relatively short cycle. Particularly, on highways where vehicles pass at a high speed, such road repairs are required to ensure the safety of passing vehicles. More frequently, resulting in significant costs and labor for road safety and management.

Moreover, in snowfall areas, natural crushed stone, which is used for the surface layer of a pavement road, is scraped off by the use of tire chains, spike tires, and the like of passing vehicles in winter, and the crushed natural crushed stone is used. Dust has caused serious dust pollution.

[0005] In addition, adhesion to asphalt is also regarded as important for aggregates for road pavement. This is because if the surface of the road pavement aggregate is smooth and smooth, poor adhesion to asphalt, peeling of the aggregate occurs, not only does not serve as a road pavement aggregate, but also This is because there is a risk of causing a traffic accident due to such a rut or peeled aggregate.

[0006]

The present invention has been made in view of such circumstances, and it is an object of the present invention to have excellent mechanical strength and abrasion resistance, and to have slip resistance and high adhesion. It is an object of the present invention to provide a sintered artificial aggregate for road pavement and a manufacturing method capable of obtaining the same advantageously.

[0007]

In order to solve such a problem, the present inventors have conducted intensive studies, and as a result, by dispersing coarse particles having a predetermined particle size in a base material and projecting the coarse particles to the surface. It has been found that a sintered artificial aggregate for road pavement having excellent mechanical strength and abrasion resistance, and having slip resistance and high adhesion can be obtained.

That is, in the present invention, coarse particles having a particle size of 0.5 to 20% with respect to the diameter of the target aggregate are contained in the sintered matrix having a homogeneous structure. The gist of the present invention is a sintered artificial aggregate for road pavement characterized by being dispersed and buried and having a rough surface formed by the projection of the coarse particles from the surface.

According to an advantageous aspect of the present invention, as the material constituting the coarse particles, a material having higher fire resistance than a homogeneous base material is used, and according to another advantageous aspect. For example, the material constituting the coarse particles is a material having the same composition as the homogeneous base material and having a heat history larger than that of the base material.

Further, according to the present invention, a raw material for forming a homogeneous base material is crushed to a size of 300 μm or less so that the average particle size is 0.5 to 20% with respect to the diameter of the target aggregate. The coarse particles are mixed so as to have a ratio of 5 to 60% by weight after firing, molded and dried, and the molded product is calcined as it is or crushed at the sintering temperature of the base material. A method for producing a sintered artificial aggregate for road pavement, which is characterized by the above, is also the gist.

[0011]

Accordingly, in the present invention, in the sintered base material having a homogeneous structure, the particle size is 0.5 to 20% with respect to the diameter of the target aggregate. Coarse grains are dispersed and buried, and because of the projection of the coarse grains from the surface to form a rough surface, excellent mechanical strength, abrasion resistance, slip resistance and high adhesion, It can be demonstrated. As a base material used for such an artificial aggregate for road pavement according to the present invention (hereinafter, referred to as an aggregate), a material in which various known minerals are used alone or in combination of two or more thereof is selected. It is pulverized to a predetermined size or less, and a homogenized product is used. Specifically, alumina, silica sand, kaolin, feldspar, porcelain clay, porcelain stone, refractory clay, porcelain clay, clay for tiles, etc., are selected alone or in a combination of two or more, and crushed. Things are used.

The diameter of the target aggregate is appropriately selected depending on the intended use, but is usually 2.5 to 20 mm, and the main aggregate is 13 to 20 mm.
No. 5 crushed stone and 5-13 mm No. 6 crushed stone are used. Therefore, it is desirable that it is about 5 to 20 mm on average.

The coarse particles dispersed and embedded in the sintered base material have an average particle size of 0.5 with respect to the diameter of the aggregate.
If it is up to 20%, a material used as a base material such as alumina, silica sand, kaolin, feldspar, porcelain clay, porcelain stone, or a sintered kaolin or sintered mullite obtained by sintering them
It is appropriately selected from chamotte or the like, or spinel or synthetic mullite having excellent fire resistance, and is preferably used. Preferably, fire-resistant coarse particles such as synthetic mullite are used. And when such refractory coarse particles are used, the refractory temperature must be higher than the firing temperature of the aggregate. However, if the refractory temperature of the refractory coarse particles is lower than the firing temperature of the aggregate, the refractory coarse particles are dissolved and foamed during firing of the aggregate, and deteriorate. Further, when the coarse particles are the same material as the base material, a material which has been previously baked may be used so that the coarse particles have a large thermal history. Thereby, the bondability between the base material and the coarse particles can be improved satisfactorily.

Further, as the average particle size of the coarse particles, coarse particles having a diameter of 0.5 to 20% with respect to the diameter of the aggregate are used, and preferably a coarse particle having a coarse particle diameter of about 1 to 10%. Grains are used. In consideration of the fact that the size of the aggregate is usually 5 to 20 mm, the average particle size of such coarse particles is generally about 0.1 to 5 mm. If coarse particles having an average particle size of more than 20% are used, cracks and cracks are liable to occur in the firing process, and the strength is reduced.
The effect of the present invention cannot be sufficiently exerted, and the surface of the aggregate manufactured using coarse particles having an average particle size of less than 0.5% becomes smooth. When used as an aggregate, adhesion to asphalt deteriorates because a rough surface is not formed on the surface of the aggregate.

Further, such coarse particles are not only dispersed and mixed in the base material, but also dispersed in a form protruding from the surface of the aggregate. A rough surface is formed on the surface, and various effects achieved in the present invention are exhibited.

By the way, from the above-mentioned base material and coarse particles,
In order to manufacture the aggregate according to the present invention, first, the base material such as alumina, silica sand, kaolin, feldspar, porcelain clay, porcelain stone, and the like, by a known various grinding means such as a ball mill, the average particle size is at least 300 μm And a relatively homogeneous base material. And to this,
Coarse particles having an average particle size of 0.5 to 20% with respect to the diameter of the aggregate are mixed and added, and the mixing ratio at this time is usually 5 to 60% by weight after firing. To be. However, if the mixing ratio is less than 5% by weight, the effect of adding coarse particles becomes insufficient, and the surface of the obtained aggregate becomes smooth and smooth. On the other hand, if the mixing ratio exceeds 60% by weight, the effect of improving the mechanical strength and wear resistance of the obtained aggregate is not sufficiently exhibited. It is because it is.

Next, the thus obtained aggregate raw material obtained by mixing predetermined coarse particles with a predetermined base material at an appropriate ratio is formed by a known apparatus such as an auger machine.
After being dried, such a molded product is pulverized as it is or, if necessary, by a device such as a jaw crusher to adjust the particle size. Further, thereafter, this is fired at the sintering temperature of the base material to obtain the desired aggregate. In particular, the aggregate raw material granulated as described above, by crushing and sizing, it is possible to uniform the particle size of the aggregate, and because the non-granular product can be reused as a raw material, The yield is improved, and a rough surface can be more effectively obtained on the surface of the aggregate (base material).

In firing the formed and dried aggregate material as described above, any of various kilns such as a rotary kiln, a tunnel kiln, and a shuttle kiln are used, but an angular aggregate is obtained. However, it is desirable to use a rotary kiln.

[0019]

EXAMPLES Next, the present invention will be described in further detail with reference to examples of the present invention. However, the present invention is not limited to the following examples, and further includes the above specific description. In addition, it should be understood that various changes, modifications, improvements, and the like can be made based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

In Examples of the present invention and Comparative Examples, a commercially available kaolin mineral used as a base material for a target aggregate,
Mullite (MMS
1 mmF: manufactured by Naigai Ceramic Co., Ltd.), the respective chemical compositions were analyzed, and the results are shown in Table 1 below.

[0021]

[Table 1]

Next, a kaolin mineral, which is a base material of the artificial aggregate, is charged into a ball mill, and water is added thereto. Then, a wet process is performed so that the average particle diameter of the kaolin mineral is 300 μm or less. Was sufficiently crushed to obtain a slurry. With respect to the slurry thus obtained, synthesis of refractory coarse particles having an average particle size and a particle size range as shown in Table 2 below and having higher fire resistance than kaolin mineral as a base material material Mullite was added at a mixing ratio (weight ratio) shown in Table 2 below. Then, the thus-prepared slurry was dewatered using a filter press device, and then extruded using an auger machine.

[0023]

[Table 2]

Next, after drying such a molded product, it was crushed using a jaw crusher to obtain a granulated material as an aggregate raw material. Further, after the granulated product was sized, it was baked in a rotary kiln at a temperature of 1600 ° C. to obtain an intended aggregate.

Next, the physical properties of the sintered aggregate thus obtained were measured, and the results are shown in Tables 3 and 4 below. Also, for reference, as for Comparative Example 4, physical properties were measured for 5 to 13 mm of natural crushed bony sandstone conventionally used, and the results are shown in Tables 3 and 4 below. . The measurements of the water absorption, the surface specific gravity, the apparent specific gravity, and the apparent porosity shown here were all measured by JI.
Performed in accordance with SA1110. In addition, the Loss Loss Loss Loss was measured according to JIS A1121. S. 812. Further, the asphalt peeling test was performed in accordance with Asphalt Pavement Outline Appendix 4-6.

[0026]

[Table 3]

[0027]

[Table 4]

From the results of the physical test, in Invention Example 1,
While excellent in durability and abrasion resistance, as in Comparative Example 1,
If the average grain size of the coarse grains used is large, the loss of abrasion loss in Los Angeles increases, the results of the aggregate crushing test are poor, and the abrasion resistance and aggregate strength of the aggregate are insufficient,
It becomes difficult to use. In the case where the average particle size of the coarse particles used is small as in Comparative Example 2, the effect on the surface of the coarse particles is small, and the mechanical strength of the aggregate is good.
The results of the asphalt peeling test were comparable to those of Comparative Example 3 in which no coarse particles were blended, and no improvement effect was observed.

As described above, the coarse particles to be mixed in the base material having a homogeneous structure have an average particle size of 0.5 to 20% with respect to the diameter of the target aggregate. It is understood that the mechanical strength, abrasion resistance, and adhesion are effectively enhanced by using these materials and projecting the coarse particles on the surface of the aggregate. And, the mixing ratio of such coarse particles is desirably 5 to 60% by weight in the ratio after firing.

The aggregate obtained in Invention Example 1 and Comparative Example 3
The following property comparison test was performed on the asphalt mixture prepared using the aggregate consisting of only the base material obtained in the above and the natural crushed hard stone sandstone 5-13 mm prepared as Comparative Example 4.

Marshall Test A marshall test was performed on dense-grained asphalt concrete (grain size 13 mm). The test method is
According to Asphalt Pavement Outline Appendix 4-8. And
The results are shown in Table 5 below. From these results, the stability of the aggregate of Inventive Example 1 was higher than that of Comparative Examples 3 and 4.
Good stability and low flow value. This is presumably because the rough surface formed on the surface of the aggregate increases the adhesive force between the aggregate and the asphalt and lowers the fluidity.

Wheel Tracking Test A wheel tracking test was performed on dense-grained asphalt concrete (grain size 13 mm) in the same manner as the Marshall test described above. The test method was carried out in accordance with Asphalt Pavement Outline Appendix 4-12, and the measurement conditions were a temperature of 60 ° C.
And the load was 70 kg. The results are shown in Table 5 below. And from this result, the asphalt using the aggregate of Invention Example 1 has a dynamic stability of 250 as compared with the asphalt using the aggregate of Comparative Examples 3 and 4.
It can be seen that the number of times / mm has been improved. This is also considered to be due to the improvement in the adhesion between the aggregate and asphalt due to the rough surface formed on the surface of the aggregate, as in the Marshall test.

Labeling Test The amount of labeling abrasion at -10 ° C. for 1.5 hours was measured using a Clothene. The method was based on Asphalt Pavement Outline Appendix 4-13. The amount of the labeling abrasion mainly depends on the durability of the aggregate, and the higher the durability of the aggregate, the smaller the amount of the labeling abrasion. That is, as shown in Table 5 below, it is understood that the aggregate of Inventive Example 1 has improved durability as compared with the aggregate of Comparative Example 4 made of conventionally used crushed natural bone sandstone. It is done.

[0034]

[Table 5]

In the above-mentioned invention examples, various properties such as stability, dynamic stability and durability are measured for dense-grained asphalt concrete, but when aggregate is used for drainage pavement, Since the improvement of flow resistance, slip resistance and bondability is a more important factor compared to ordinary pavement, the aggregate according to the present invention has a very large effect on the maintenance of drainage pavement. It is easy to see that it will work.

By the way, in the invention example 1, an example is shown in which a material having a higher refractory degree than the base material is used as the coarse particles. In the invention example 2, the coarse particles are the same material as the base material. An example using coarse particles having a larger heat history than the base material will be described below.

A commercially available kaolin mineral was used as a base material of the aggregate in the same manner as that used in Invention Example 1, and coarse particles obtained by sintering and pulverizing commercially available kaolin were used as coarse particles. Table 6 shows the chemical compositions of the base material and the coarse particles used here.

[0038]

[Table 6]

As the kaolin of the base material, a commercially available kaolin mineral which has been pulverized so as to be 300 μm or less in the same manner as in Invention Example 1 is used. Sintered kaolin obtained by sintering under temperature conditions and then pulverizing was used. Table 7 shows the particle size of the coarse-grained material of Invention Example 2 and the mixing ratio between the base material and the coarse particles.

[0040]

[Table 7]

First, the base material prepared as described above and the coarse particles are mixed at the mixing ratio shown in Table 7 and then molded using an auger machine, and the molded product is dried or semi-dried. The obtained granulated product is directly or crushed and sized, and then is 1600 ° C. using a rotary kiln.
Firing under the following temperature conditions.

The physical properties of the thus obtained aggregate of Inventive Example 2 were measured in the same manner as in the above Examples and Comparative Examples, and the results are shown in Tables 8 and 9 below. The results of Comparative Examples 3 and 4 are also shown for reference.
The measured aggregate particle size was 13 mm.

[0043]

[Table 8]

[0044]

[Table 9]

As can be seen from Table 9, in the physical properties, there is no significant difference between the aggregate of the present invention and the aggregate of the comparative example in Los Angeles abrasion loss and aggregate crushing test. As for the test, it is understood that the aggregate of the present invention example shows very good results as compared with the aggregate of Comparative Example 3 (aggregate containing only the base material).

Next, from among the above-mentioned aggregates,
Using an aggregate of 13 mm, an asphalt mixture was prepared, and a property comparison test was performed. The results are shown in Table 10.

[0047]

[Table 10]

From these results, the asphalt mixture using the aggregate of Invention Example 2 was subjected to a marshall test, and as can be seen from the comparison with the comparative example, the stability was improved and the flow value was reduced. They are hurried. This is because the rough surface is formed on the surface of the aggregate, thereby increasing the adhesive force between the aggregate and the asphalt.
It is considered that the displacement between the aggregates is reduced, and the flowability of the asphalt mixture is reduced.

In the results of the wheel tracking test, the one using the aggregate of the invention example was improved in dynamic stability by nearly 300 times / mm as compared with the one using the aggregate of the comparative example. ing. Furthermore, similarly in the labeling test, the asphalt mixture using the aggregate of the invention example showed good results. In other words, when the aggregate according to the present invention is used, the rough surface is formed, so that the adhesiveness with the asphalt is improved, the displacement between the aggregates is reduced, and the wear resistance is reduced. The nature is also improved. By improving these physical properties, when such an aggregate is used as an asphalt mixture, great effects such as prevention of the separation of the aggregate, reduction of fluidity, and reduction of rutting are expected.

In the above-mentioned invention example 2, a pulverized kaolin mineral is used as a base material, and a kaolin fired product is used as a coarse particle. However, the present invention is not limited to this. Various combinations of clay and its fired product, mullite raw material and mullite sintered product, alumina pre-sintered or pulverized aluminum hydroxide and alumina sintered material are considered. Even if used, a similar effect can be achieved. It is also possible to mix the base material and the sintered product by coloring.

[0051]

As is apparent from the above description, in the sintered artificial aggregate for road pavement according to the present invention, coarse particles having a predetermined average particle size are dispersed and embedded in a homogeneous base material. By such coarse particles protruding from the surface, from the place where the rough surface is formed, the adhesiveness is improved by the effect of burying the binder such as asphalt, cement, etc. in the concave and convex, and the peeling of the aggregate also It will decrease. Also, as the connectivity between aggregates also increases, asphalt,
Both cement concrete can be made of high strength, high elasticity, and high fire resistance.

When such an aggregate is used for asphalt concrete, the flowability is reduced and the connection between the aggregates is improved, so that the rut digging which is a major problem on the asphalt road is effectively prevented. In addition, the reduction of the peeling of the aggregate can ensure the safety of the passing vehicle sufficiently, and can exert effects in various aspects such as prolonging the interval of road maintenance.

Further, when the aggregate according to the present invention is used for drainage pavement, the flow resistance, the shear resistance, and the bondability are improved, so that the drainage pavement has a very large effect. Can be raised.

Furthermore, according to the method for producing an artificial aggregate for road pavement of the present invention, it is possible to advantageously produce an aggregate capable of exhibiting various excellent effects as described above. That is, the coarse particles can be made to protrude advantageously on the surface of the aggregate, so that the rough surface can be advantageously formed.

Continuation of the front page (72) Inventor Toyohiko Tsukada 11-4 Shiogusa-cho, Seto-shi, Aichi, Japan Inside and outside Ceramics Co., Ltd. (56) References Real-life 1979-116737 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) C04B 14/02 C04B 14/04 C04B 20/00

Claims (2)

(57) [Claims] 1. A sintered base material having a homogeneous structure, wherein coarse particles having a particle size of 0.5 to 20% with respect to the diameter of a target aggregate are dispersed and embedded. , The coarse particles are
A material with the same composition as the homogeneous base material, but larger than the base material.
A sintered artificial aggregate for road pavement comprising a material having a high heat history and a roughened surface formed by the projection of the coarse particles from the surface. 2. A raw material for forming a homogeneous base material is 300 μm.
Then, pulverize the mixture into a mixture having the same composition as the homogeneous base material.
A material having a heat history larger than that of the base material
And coarse particles having an average particle size of 0.5 to 20% with respect to the diameter of the target aggregate are mixed so that the ratio after firing is 5 to 60% by weight, A method for producing a sintered artificial aggregate for road pavement, which comprises, after forming and drying, sintering or crushing the formed product at a sintering temperature of a base material.