JP2003147708A - Asphalt mixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide inexpensive hard aggregate for giving wear resistance, skid resistance or the like desirable in an asphalt mixture used as a pavement material or the like. SOLUTION: In the asphalt mixture, asphalt is added to the hard aggregate which is hard slag particles 8 oxidized in an electric furnace and subjected to quenching reforming treatment. The slag particles 8 have a structure using slug components as a matrix and dispersing mineral phases in the matrix, and they have high wear resistance and skid resistance since Mohs' hardness is about 6 in the matrix and the Mohs' hardness is about 8 in the mineral phases.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an asphalt mixture used as a paving material, for example.

[0002]

2. Description of the Related Art As an asphalt mixture of this type,
Conventionally, asphalt mixed with crushed stone, crushed stone, gravel, etc. has been used. However, these aggregates have a Mohs hardness of about 6 at most, and particularly when the asphalt mixture is used as a paving material for the surface layer, they do not have sufficient performance in abrasion resistance, slip resistance, crush resistance and the like.
To improve the above performance, hard aggregate such as emery is used. Emery has a Mohs hardness of 8
It is 9 to 9 and has sufficient performance in wear resistance, slip resistance, crush resistance and the like.

[0003]

However, since the production area of emery is limited and expensive, an inexpensive hard aggregate is required.

[0004]

As a means for solving the above-mentioned conventional problems, the present invention adds asphalt to a hard aggregate which is a hard electric furnace oxidation slag granule (8) that has been subjected to a quenching reforming treatment. It provides an asphalt mixture. The asphalt mixture is a fine-grained asphalt mixture, and the asphalt contains 3 to 3 parts in the asphalt mixture.
6 wt% is mixed, or the asphalt mixture is an open particle size asphalt mixture, and 2 to 5 wt% of asphalt is mixed in the asphalt mixture.

[0005]

[Function] Although the electric furnace oxidized slag granules (8) of the present invention have a structure in which the mineral phase is dispersed in the matrix of the slag component, when the quenching reforming treatment is performed, the Mohs hardness of the matrix of the slag component is also increased. Since the mineral phase has a Mohs hardness of about 8 and has a high wear resistance and crush resistance. The mineral phase consists of iron-based minerals such as magnetite and iron chromite. In the case of water granulated slag, the mineral phase is projected on the surface to form fine irregularities, and in the case of ground slag, fine irregularities are also present on the surface because it breaks at the boundary between the matrix of the slag component and the mineral phase. It forms and imparts good slip resistance to the asphalt mixture.

As described above, according to the present invention, since fine irregularities are formed on the surface of the electric furnace oxidation slag granules (8), the asphalt as a binder is easily bited into, and even if a small amount of asphalt is used, an open grain size can be obtained. The electric furnace oxidation slag granules (8) are firmly bound, and a high-strength asphalt mixture is obtained. Also, the electric furnace oxidation slag granules
(8) has a specific gravity of 3.3 to 4.1 and a large weight,
The asphalt mixture using this has excellent vibration damping properties due to the weight effect, and also has excellent sound insulation and sound absorption properties.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below. [Electric Furnace Oxidized Slag Granules] The electric furnace oxidized slag referred to in the present invention is usually 10 to 26% by weight of CaO and 8 to _{2 of} SiO _2.
2% by weight, MnO 4 to 7% by weight, MgO 2 to 8% by weight,
Fe O 13 to 32% by weight, Fe ₂ O ₃ 9 to 45% by weight, A
l ₂ O ₃ 4 to 16 wt%, Cr ₂ O ₃ containing about 1 to 4 wt%, further Ti O ₂ from .25 to .70% by weight as a minor component, P ₂ O ₅ 0.15 to 0.50 % By weight, S0.00
It contains about 5 to 0.085% by weight and about 20 to 45% by weight of Fe for obtaining a stable mineral composition. It does not contain clay, organic impurities or salt contained in natural aggregate components at all. Free of stable free lime, free magnesia or minerals.

The electric furnace oxidation slag has a high specific gravity.
Therefore, if desired, high specific gravity metal powder or high specific gravity metal oxide
It may be added. The above-mentioned high specific gravity metal powder means iron or nickel.
Kell, cobalt, chromium, molybdenum, copper, lead, zinc,
For example, powder of alloy such as stainless steel,
Is 7 g / cm ³Above, the particle size should be less than 50μm
Good

As the high specific gravity metal oxide, there is an oxide of the high specific gravity metal. Further, as the high-specific-gravity oxide powder that can be used in the present invention, there is scale powder generated when the steel material is melt-cut. Such scale powder is substantially spherical and is ferrite, and can have the same function as that of the electric furnace oxidation slag granules. Further, other metal oxides such as calcium oxide and silicon oxide may be added to the electric furnace oxidation slag in order to adjust the basicity.

Granules obtained by granulating the above-mentioned electric furnace oxidation slag
There are two methods for producing (8): a water granulation method and a crushing method. In the water granulation method, the melt of the electric furnace oxidation slag is poured into a high speed rotating bladed drum, the melt is crushed and granulated by the bladed drum, and the granulated melt is in a water mist atmosphere. The method of quenching reforming treatment is adopted. A plurality of bladed drums may be arranged to carry out crushing granulation in a plurality of stages. The electric furnace oxidation slag granules (8) thus obtained usually have a particle size of 5 mm or less, and particles having a particle size of 2.5 mm or less are substantially spherical, and have a high specific gravity metal powder or a high specific gravity metal oxide. When no substance is added, the specific gravity is in the range of 3.3 to 4.1, there are no defects such as cracks on the surface, and there are fine irregularities due to the mineral phase protruding on the surface and it has a hollow structure. Consisting of or including hollow structures.

In the crushing method, the electric furnace oxidation slag is cast in a molten state into a heat-resistant container to a predetermined thickness, and water is poured from above to perform a rapid reforming treatment.
In this case, if the thickness of the slag melt in the heat-resistant container is too small, it tends to solidify by natural cooling (gradual cooling) before adding water, and there is a possibility that the desired hardness cannot be obtained.
If the thickness is too large, the water will suddenly become steam when sprinkled with water, and there is a risk of steam explosion. The preferred slag melt thickness is 80 mm to 120 mm.

When sprinkling water, it is desirable to prevent water from accumulating on the surface of the slag melt of the slag melt in the heat-resistant container. Too much water should be sprinkled on the surface of the slag melt. It becomes impossible to expect a quenching effect due to the latent heat of vaporization of water that accumulates. The amount of water is 1 slag melt
About 200 to 400 liters per second is desirable per ton. The slag melt is rapidly hardened by the rapid cooling, but at this time, the slag raw mass having a diameter of about the thickness of the slag melt in the container is obtained by self-crushing.

The raw slag mass is crushed by a crusher and further crushed by a crusher. By the above pulverization, the slag mass breaks at the boundary between the matrix of the slag component and the mineral phase, and fine irregularities are formed on the surface. The crushed material is roughly classified by a coarse sieving machine or the like, and further finely classified by a crushing machine or the like to obtain 5-2.
It is divided into coarse aggregate of 5 mm, preferably 5 to 20 mm, coarse aggregate of 5 to 13 mm, preferably 5 to 10 mm, and fine aggregate of 5 mm or less.

The above-mentioned crushing and crushing may be carried out while the raw slag mass is wet with water, or the slag raw mass may be dried and subjected to the steps after the crushing, or the slag raw mass may be used. May be crushed and then dried to carry out the steps after crushing. In the classification step, it is desirable that the residue that does not pass through the sieve be returned to the crushing step. The specific gravity of the granules thus obtained is in the range of 3.3 to 4.1, like the granulated product.

[Other Aggregates] In the present invention, in addition to the hard aggregate which is the electric furnace oxidation slag granules (8),
Crushed stone, crushed stone, gravel, sand, etc. may be used.

[Asphalt] Asphalt used in the present invention includes petroleum asphalt, modified asphalt, Trinidad lake asphalt (natural asphalt), petroleum asphalt emulsion and the like. Examples of the modified asphalt include rubber and / or thermoplastic elastomer added to asphalt, and semi-blown asphalt obtained by adding a slight blowing operation to heated asphalt. When used for paving materials, modified asphalt is mainly used.

[Filler] A filler may be further added to the asphalt mixture of the present invention. Examples of the filler include stone powder, slaked lime, cement, recovered dust, fly ash and the like.

[Other Additive Materials] The asphalt mixture of the present invention may be further added with a cationic surfactant, a fibrous reinforcing material, a freeze retardant, an oil-absorbing material, an additive for regeneration, a rubber chip and the like. .

[Blending] As the asphalt mixture of the present invention, there are a dense particle size asphalt mixture and an open particle size asphalt mixture. In the dense particle size asphalt mixture, asphalt is usually added in an amount of 3 to 6% by weight. Asphalt is usually 2
~ 5 wt% is added. Further, the aggregate used in the dense particle size asphalt mixture and the open particle size asphalt mixture,
A material having a passing mass percentage (%) as shown in Table 1 is used.

[0020]

[Table 1]

Example 1 (Production of Granulated Electric Furnace Slag Granules) FIG. 1 shows an apparatus for producing granulated electric furnace slag granules (hereinafter abbreviated as slag granules) (8) of the present invention. That is 1500
The electric furnace oxidation slag melt (1) at around ℃ is transferred from the ladle (2) to the shooter (3) and poured from the shooter (3) to the high speed rotating bladed drums (4,5). The steelmaking slag melt (1) is crushed and granulated by the bladed drums (4,5), and the granulated product (1A) of the electric furnace oxidation slag melt is sprayed into a quenching chamber (6) ( 7) Quenched by water mist sprayed from. The slag granules (8) thus obtained are stored in the storage container (9). The slag granules (8) are substantially spherical hollow bodies, have no defects such as cracks on the surface, have fine irregularities, and have high hardness (Mohs hardness is about 6 in the matrix and about 8 in the mineral phase). It has excellent wear resistance and has a true specific gravity of 3.84,
Absolute dry specific gravity of 3.52, fire resistance of 1100 ℃, magnetic permeability,
It has excellent dielectric properties, acid resistance, and alkali resistance. The particle size of the slag granules (8) is 5 mm or less.

[Example 2] (Production of crushed electric furnace slag granules) Iron powder, calcium oxide, and silicon oxide are post-added to the molten slag discharged from the electric furnace to adjust the composition to the following. CaO 24.92% by weight SiO ₂ 15.24% by weight Al ₂ O ₃ 6.72% by weight MnO 5.66% by weight MgO 4.25% by weight Cr ₂ O ₃ 1.97% by weight Total Fe 41.24% by weight CaO / SiO ₂ = 1.64 The above slag melt is heated to about 1350 ° C.,
It is poured into a heat-resistant container (dish-shaped steel) to a thickness of about 80 mm and immediately sprayed with 300 liters per second of slag melt per second by spraying.

In this way, a raw slag mass having a diameter of about 80 mm was obtained, and the Mohs hardness of the raw slag mass was 6 in matrix.
The mineral phase was 8. The raw slag mass is roughly crushed by a crusher, dried by a dryer and then crushed by a crusher. The crushed slag raw mass is then roughly classified by a coarse sieving machine, and further finely classified by a fine sieving machine to obtain coarse aggregate having a particle size of 5 to 20 mm, or 5 to 1
It is divided into coarse aggregate of 3 mm (or 5 to 10 mm) grain size and fine aggregate of 5 mm or less.

[Example 3] A dense particle size asphalt mixture was prepared according to the formulation shown in Table 2 below. As the coarse aggregate, an electric furnace oxidation slag granular material having a particle size of 5 to 13 mm obtained in Example 2 was used.
(8) As the fine aggregate, the electric furnace oxidation slag granules (8) having a particle size of 5 mm or less obtained in Example 1 were used, and asphalt was straight asphalt. Comparative Example 1
As crushed stone with a particle size of 5 to 13 mm is used as coarse aggregate,
River sand having a particle size of 5 mm or less was used as fine aggregate, and the volume% was set to be equal to that in Example 3. The results of the Marshall stability test conducted on the asphalt mixture are shown in Table 2 in the physical properties column.

[0025]

[Table 2]

Example 4 An open particle size asphalt mixture was prepared according to the formulation shown in Table 3 below. As coarse aggregate, electric furnace oxidation slag granules (8) having a particle size of 5 to 10 mm obtained in Example 2
The semi-blown asphalt was used as the asphalt. In Comparative Example 2, crushed stone having a particle size of 5 to 10 mm was used as coarse aggregate, and the volume% was set to be equal to that in Example 4. The results of performance tests conducted on the asphalt mixture are shown in Table 3 in the physical properties column.

[0027]

[Table 3]

[0028]

EFFECT OF THE INVENTION The electric furnace oxidation slag granules of the present invention are hard aggregates that can be obtained at a very low cost, and an asphalt mixture containing such hard aggregates has extremely good wear resistance and slip resistance. It is extremely useful for paving materials and the like.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an electric furnace slag granular material manufacturing apparatus.

[Explanation of symbols]

8 Electric furnace slag granules

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Keiichi Tsuruyama             Aichi Prefecture, Kabu-gun, 14 Yamamura Large-scale horseback ground Nitta             Tame 62 Hoshino Sansho Co., Ltd. F-term (reference) 2D051 AA08 AD07 AF01 AF02 AF04                       AF05 AF14 AG01 AG03 AG11                       AH02 AH03 EA06 EB04 EB06

Claims (3)

[Claims] 1. An asphalt mixture, characterized in that asphalt is added to a hard aggregate which is a hard electric furnace oxidized slag granular material that has been subjected to a quenching reforming treatment. 2. The asphalt mixture according to claim 1, wherein the asphalt mixture is a dense particle size asphalt mixture, and 3 to 6% by weight of asphalt is mixed in the asphalt mixture. 3. The asphalt mixture according to claim 1, wherein the asphalt mixture is an open particle size asphalt mixture, and 2 to 5% by weight of asphalt is mixed in the asphalt mixture.