JP3058800B2 - Artificial light-colored aggregate for roads and construction 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 light-colored artificial aggregate for concrete used as a road pavement material or a construction material by mixing with asphalt, cement, resin or the like, and a method for producing the same. It is preferably used as a light-colored artificial aggregate with high whiteness that is effective in tunnels, at corners, at night, etc., and for artificial stones such as marble and granite using whiteness for building materials. The present invention relates to an obtained artificial light-colored aggregate and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, relatively inexpensive crushed crushed stones have been generally used as aggregates for concrete for road pavement or construction. Hard sandstone, diabolite tuff, and andesite are used as natural crushed stones, but because of their low lightness, it is difficult to use them as light-colored aggregates. Is also known to have limitations.

[0003] By the way, limestone is sometimes considered to be used especially in the field where lightness is required. However, such limestone is vulnerable to abrasion, is liable to cause a slip accident, and takes measures against acid rain. Is also an issue, and is generally not used much.

On the other hand, as the artificial aggregate, a wristen-based crystallized vitreous material mainly composed of limestone and silica sand has been used, but it is considerably modified from limestone. However, it has the same tendency as limestone, and its whiteness is just one step away at present.

[0005]

The present invention has been made in view of the above circumstances, and an object of the present invention is to mix it with asphalt, cement, or resin, which is not present in conventional artificial aggregates. Another object of the present invention is to provide a light-colored artificial aggregate having sufficient performance that can be suitably used according to the intended use and having extremely high whiteness.

[0006]

The inventors of the present invention have conducted intensive studies to solve such problems, and as a result, coarsely pulverizing crystalline kaolin or a kaolin-based main raw material, either as it is or finely pulverized, Pulverize to the extent that kaolin crystals are left, pulverize, granulate or mold, then bake, dehydrate from kaolin, and form a stable mullite-based quartz and vitreous, sufficient as aggregate By maintaining the plate-like structure of the kaolin-based crystal entirely or partially, the whiteness can be further improved by diffuse reflection at the interface of the plate-like structure, and the opacity can be increased. By increasing total reflection and the like, it was possible to obtain a good light-colored aggregate with increased lightness.

Accordingly, a feature of the present invention is an artificial sintered aggregate obtained from a raw material mainly composed of kaolin or a kaolin-based material, the main structure of which is fired to mullite. Opaque, white roads, artificial light-colored aggregates for construction, which leave the plate-like structure of kaolin-based crystals in whole or in part.

According to a preferred embodiment of the production of the artificial light-colored aggregate for roads and construction according to the present invention,
A method in which kaolin or a kaolin-based material is coarsely ground and sized to give a main mullite crystal structure, but is calcined at a temperature at which the plate-like structure of kaolin-based crystals remains wholly or partially. Will be adopted.

According to another desirable embodiment in the production of the present invention, kaolin or a kaolin-based raw material is finely ground to such an extent that kaolin crystals remain as much as possible, and the kaolin or kaolin is pulverized simply or by other methods. After performing granulation and shaping, a method is employed in which a mullite main crystal structure is provided, but calcined at a temperature at which a plate-like structure of kaolin-based crystals remains wholly or partially. It will be.

[0010]

The artificial light-colored aggregate for roads and construction according to the present invention comprises a fired material obtained by firing a coarsely pulverized ceramic material or a finely pulverized molded product thereof. However, as a ceramic raw material for providing such an artificial light-colored aggregate, a kaolin-based or kaolin-based material is mainly used, and kaolin-based kaolinite, halloysite, date kaite, and other crystalline kaolin-based materials are used. If so, any of them can be adopted.

The main structure of the raw material is changed from kaolin to mullite by firing, so that the raw material has a stable performance as an aggregate and has a plate-like form of kaolin-based crystal in whole or in part. At the sintering temperature at which sintering remains, in other words, the plate-like kaolin crystals have been changed to mullite crystals by the dehydration (loss of water of crystallization) or are in the process of progressing. Thus, it is fired with the kaolin crystal plate-like structure still remaining. In this way, the layered interface based on the plate-like form of the kaolin crystal remains in the fired product, thereby increasing whiteness and lightness due to multiple reflections between the interfaces. It became possible to obtain the material. If the firing temperature is too high, mullite crystals grow and the plate-like structure based on kaolin crystals disappears, resulting in a decrease in lightness.
A firing temperature of 500 to 1700 ° C. will be employed.

In producing such an artificial light-colored aggregate, a crystalline raw material (raw ore) such as kaolinite, halloysite, and dateskite is coarsely pulverized and sized to an aggregate size. In addition, a method of performing calcination is adopted, and even if finely pulverized or finely pulverized, pulverization to the extent that a kaolin-based crystal having a size of about 0.3 μm or more is left, preferably 0 If the pulverization is performed to such an extent that a kaolin-based crystal having a size of 0.3 to 2.0 μm is left, the effect is somewhat reduced, but the same effect can be obtained. When such finely pulverized or finely pulverized raw materials are used, a usual granulation operation is carried out so as to obtain particles having a desired aggregate size. Mix raw materials for white ceramics, such as ceramic clay, iron feldspar, etc. in a moderate amount.Also, in a uniform base material of kaolin, coarse particles with high fire resistance, high heat history, or high hardness and high cleavage By mixing coarse particles, flow resistance, slip resistance and the like can be improved. In the mixing of other raw materials, if the content of the kaolin-based raw material is 30% by weight or more as a whole,
The diffuse reflection of the aggregate obtained can be considerably improved.

[0013] Artificial aggregates for roads and constructions having both characteristic brightness and performance as described above have high lightness and high-performance physicochemical properties. When used as asphalt mixture for roads, aggregate for rolled method, aggregate for chipping method, etc., due to its light color, visibility is increased, temperature rise of summer road is decreased, Increased visibility at night and in tunnels,
In addition, the visibility during rain can be effectively improved, and by improving the aggregate performance, the wear resistance, the flow resistance, the anti-skid properties of tires and the like can be significantly improved. . In addition, when used as aggregate for construction, it is possible to produce artificial granite etc. more effectively by mixing with artificial marble and various materials because of its excellent whiteness. It has become.

[0014]

Hereinafter, typical examples of the present invention will be described to clarify the present invention more specifically. However, the present invention imposes no restrictions on the description of such examples. It goes without saying that you don't receive anything. In addition, the present invention, in addition to the following examples, in addition to the above specific description, various modifications based on the knowledge of those skilled in the art, unless departing from the spirit of the present invention,
It should be understood that modifications, improvements and the like can be made.

Example 1 First, a kaolin raw material having a low content of iron and titanium was used as a raw material for artificial white aggregate for roads and construction. Table 1 shows the chemical composition of the raw material. In the present embodiment, kaolinite was used, but it goes without saying that kaolin-based raw materials such as date kite and halloysite can be used.

[0016]

[Table 1] * Unit: weight%

In this embodiment, the raw ore is
Coarsely pulverized as it is, and sized to a particle size of 13 to 5 mm,
This was directly baked at a predetermined temperature in a rotary kiln. The chemical composition of the obtained fired product is shown in Table 2 below. The examples of the present invention in the table were fired at a firing temperature of 1650 ° C., and the comparative examples were fired at a firing temperature of 180 ° C.
It was fired at 0 ° C. Further, the reference example shows a walsteinite-based recrystallized aggregate that is a light-colored aggregate that has been commercially available so far. This is, as shown in Table 2 below,
It is a vitreous aggregate containing silicon and lime as main components. After being melted at a firing temperature of 1450 ° C., it is rapidly cooled, and the vitrified aggregate is reheated to 1100 ° C. to be crystallized. It is crystallized vitreous.

[0018]

[Table 2] * Unit: weight%

In the present embodiment, since the raw ore is coarsely pulverized as it is and sized, the raw material is formed of kaolinite crystals containing water of crystallization. However, according to the X-ray crystal analysis after calcination, in both the present invention example and the comparative example, the kaolinite crystal disappeared and was composed of mullite, a small amount of quartz and vitreous. However, when examined by an electron microscope, in the example of the present invention, although the surface layer having a high degree of freedom at a high temperature formed large mullite, the inner layer fractured surface of the aggregate in the firing temperature range of 1650 ° C. In the above, it was found that the kaolinite was mullite, but the flake-like structure of kaolinite of about 0.3 to 2.0 μm remained as it was and had a welded structure. For this,
Kaolinite is crystallized water, becomes stable mullite, the refractive index increases from 0.62 to 1.56, the aggregate properties are stable, and the mechanical strength can be increased. In addition to having all the functions of the kaolin crystal, all or part of the morphology of the kaolin crystal remains, resulting in multi-layer reflection at the crystal interface, further increasing whiteness and opacity. Thus, the total reflection can be increased, and a remarkable increase in the brightness can advantageously obtain a good light-colored aggregate.

On the other hand, when the kaolin of the comparative example calcined at 1800 ° C., which is a high temperature, was examined by an electron microscope, it was found that very large mullite crystals were found not only in the surface layer but also in the deep part. It was found that the reflectance was relatively lowered due to this.

In addition to the reflectance (whiteness) of each of these aggregates, the reflectance (whiteness) of French cobblestone, cold water stone, limestone, and hard sandstone as typical natural aggregates having high whiteness is measured. The results obtained are shown in Table 3 below. According to this, the reflectance of the example of the present invention is as high as 81.5%, but the comparative example of high temperature firing is 7%.
It is relatively reduced to 6.1%. In addition, the reflectance of natural aggregates is 69.1-even for high-white French cobblestone and cold water stone.
Although it is as low as 64.7%, this is presumably because the white and transparent material has less diffuse reflection and does not have an aggregate structure as in the present invention. And hard sandstone and limestone had very low reflectance.

[0022]

[Table 3] * Reflectivity (%)

Measurement method of reflectance The reflectance measurement for examining the whiteness is shown in FIG. 1 by using a luminance meter (Topcon color luminance meter; BM-5), a halogen spotlight and a standard white plate. As described above, the measurement was performed by setting the spotlight in the direction perpendicular to the sample and the luminance meter in the direction at 45 ° to the sample. In the measurement method, first, as C ₁ (Candilla), a sample is placed at a measurement point with a halogen lamp turned on, and a luminance meter is adjusted to the measurement point to measure the luminance of the sample. Next, the sample is removed as C ₂ (Candilla), and a standard white plate is placed on the measurement point to measure the luminance. Incidentally, reflectance, and thus obtained by reflectance _{(whiteness) = C 1 / C 2 (} % indication) becomes equation.

The physical properties of the aggregate in this embodiment are shown in Table 4 below. According to this, it is clear that the examples of the present invention have sufficient physical properties as an aggregate.

[0025]

[Table 4] * Water absorption: Performed in accordance with JIS A1110. * Apparent specific gravity: Performed in accordance with JIS A1110. * Loss loss in Los Angeles: Performed according to JIS A1121. * Aggregate crushing test (crushing value): Performed in accordance with S812. * Asphalt peeling test (peeling area ratio): It was carried out in accordance with “Asphalt Pavement Outline” Appendix 4-6.

Example 2 In Example 1, kaolin-based ore was coarsely crushed and calcined so that a plate-like structure based on kaolinite crystals remained as it was, whereby aggregate having high whiteness was obtained. Although it could be obtained, in this case, the range of application is very limited. Then, as a result of examining a method that can be applied more widely, the following method could be found.

First, kaolin-based raw ore is pulverized to the extent that the smallest unit of flaky crystals (having a size of about 0.3 μm) remains, and after simple or composite with other raw materials, Then, granulation is performed to produce particles that give the desired aggregate size, and then the particles are fired. Then, the flaky crystals are laminated and fused, and as in Example 1, the kaolin raw ore is calcined as it is.
Although not clear, it was possible to obtain a highly white aggregate having a similar reflection structure. In this case, a base material (kaolin crushed material) and a coarse-grained material (synthetic mullite) were mixed at a weight ratio of 85:15, and a white aggregate having a rough surface was examined. Raw kaolin,
Table 5 below shows the chemical composition of the synthetic mullite.

[0028]

[Table 5] * Unit: weight%

Then, the raw material kaolin was put into a ball mill, and water was further added thereto.
The slurry was pulverized by stopping it at 0 μm or less and keeping the lower limit to the extent that kaolin crystals remain (approximately 0.3 μm) to obtain a slurry. Next, into this slurry, a coarse granular material of synthetic mullite (average particle size: 0.6 mm) having a higher fire resistance than the base material was mixed so as to have a weight ratio after firing of 15% by weight, and was subsequently obtained. After the obtained slurry was dehydrated with a filter press, it was molded using an auger machine.

Then, the molded article thus obtained was pulverized in a dry or semi-dry state and sized to obtain a granulated product. This was fired at a firing temperature of 1600 ° C. using a rotary kiln to obtain a white sintered aggregate having a rough surface. The chemical composition in this case is shown in Table 6 below. Similarly, the physical properties of such aggregates are shown in Table 7 below, and it was found that the aggregates had sufficient physical properties as road and construction aggregates.

[0031]

[Table 6] * Unit: weight%

[0032]

[Table 7] * Water absorption: Performed in accordance with JIS A1110. * Apparent specific gravity: Performed in accordance with JIS A1110. * Loss loss in Los Angeles: Performed according to JIS A1121. * Aggregate crushing test (crushing value): Performed in accordance with S812. * Asphalt peeling test (peeling area ratio): It was carried out in accordance with “Asphalt Pavement Outline” Appendix 4-6.

Further, in Example 2, the luminance reflectance in a dry state and a wet state were measured in order to examine whiteness characteristics by using the same method as in Example 1. The result is
Table 8 below shows the results together with the case of the first embodiment.

[0034]

[Table 8]

According to the result, the luminance reflectance of the aggregate obtained in Example 2 was slightly lower than that of Example 1, but was still high, and even if it was fired after pulverized kaolin, As long as the flake crystal structure remains, it is found that the layer is welded by lamination to form a diffusely reflecting surface, and thus has high reflectance and functions as an excellent light-colored aggregate.

It should also be noted that the reflectance of the aggregate obtained in Examples 1 and 2 is high in the rainy weather, which is important for the performance of the light-colored aggregate for roads. It can be said that the aggregate according to the invention has a special diffuse reflection structure. Furthermore, the aggregate according to the present invention has a characteristic that the wet-dry ratio of the reflectance is 95% or more. In particular, in Example 2, a favorable aggregate could be obtained as the wet-dry ratio reached 99.4% due to the combination of the special diffuse reflection structure and the diffuse reflection due to the protruding rough surface. It is.

[0037]

As is apparent from the above description, the artificial light-colored aggregate for roads and construction according to the present invention is fired until the main structure becomes mullite, but is entirely or partially fired. Since the plate-like form of the kaolin-based crystal remains, not only does it have sufficient performance as an aggregate, but the whiteness is further improved by diffuse reflection at the interface of the plate-like structure, and The increase in opacity increases total reflection, which advantageously increases brightness. And when such artificial light-colored aggregates are used as road aggregates such as road asphalt mix, rolled aggregates, and chipping aggregates, due to their excellent lightness, It is possible to effectively improve visibility, suppress a rise in the temperature of a summer road, improve visibility at night and in a tunnel, and improve visibility during rainfall.

In addition, when used as an aggregate for construction, it is possible to produce artificial granite more effectively by mixing with artificial marble or various materials because of its excellent whiteness. It becomes.

Further, in the method for producing an artificial light-colored aggregate for roads and construction according to the present invention, the kaolin or kaolin-based raw material is roughly pulverized, sized, and then fired at the firing temperature. As the main crystal structure of mullite is given, but the temperature is adopted such that the kaolin-based crystal has a plate-like structure in whole or in part, and has various excellent characteristics as described above. An artificial light-colored aggregate can be manufactured.

Further, in the above-mentioned manufacturing method, before firing, coarse particles having high fire resistance and high heat history, or coarse particles having high hardness and high cleavage are mixed in a uniform base material of kaolin. Thereby, it is possible to effectively improve the aggregate performance, and it is possible to advantageously produce an artificial aggregate having significantly improved abrasion resistance, flow resistance, anti-slip effect of tires and the like. It was.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a road surface reflectance measuring device used for checking whiteness.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toyohiko Tsukada 11-4 Shiogusacho, Seto City, Aichi Prefecture Inside and outside Ceramics Co., Ltd. (56) References JP-A-6-172022 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C04B 14/36 Patent file (PATOLIS) Practical file (PATOLIS)

Claims (3)

(57) [Claims] 1. A raw material mainly composed of kaolin or a kaolin-based material is used at 1500 to 1700 ° C. (however, 1500 ° C.
) , And the main structure of the artificial sintered aggregate obtained by firing at a temperature of 0.3 to 2.0 , although the main structure is fired to mullite.
Co When leaving the plate-like morphology of kaolin crystals μm
An artificial light-colored aggregate for roads and constructions, wherein the wet-dry ratio of the reflectance is 95% or more . 2. A method for producing kaolin or kaolin-based raw material,
After being coarsely pulverized to a particle size of 5 to 13 mm and sized, a mullite main crystal structure is given, but calcined at a temperature at which the plate-like structure of kaolin-based crystals remains wholly or partially. The road according to claim 1, wherein
A method for producing artificial light-colored aggregate for construction. 3. A method for producing kaolin or a kaolin-based raw material,
Pulverize finely until kaolin crystals with a size of 0.3 to 2.0 μm remain, and then simply or mix with other raw materials, granulate, and then form a main mullite crystal structure. although giving a plate-like morphology of whole or partially kaolin crystals Ru residue, 1500
The method for producing an artificial light-colored aggregate for roads and construction according to claim 1, wherein the firing is performed at a temperature of 1700 ° C (excluding the case of 1500 ° C) .