KR20100065989A - Additive for asphalt and it's making method of asphalt mixture - Google Patents

Abstract

PURPOSE: An additive for asphalt and a manufacturing method thereof are provided to prevent movement, abrasion and crack of pavement under bad conditions. CONSTITUTION: An additive for asphalt is manufactured as follows. An addictive is impregnated in fiber(3a) to make an impregnated mixture, wherein the fiber is produced from staple fiber(3) which is treated to become hydrophobic and the additive has affinity to straight asphalt. The impregnation mixture is taken out of the deposition container and received in a packing bag. The packing bag is hermetically sealed.

Description

Additive for asphalt and it's making method of asphalt mixture

The present invention is an additive for asphalt and a method for producing the asphalt mixture, more specifically, excellent in low temperature resistance and easy to handle additives that can be thin-layer packaging even in winter, maintaining a uniform dispersion of reinforcing fibers in asphalt and The present invention relates to an asphalt additive having a well-balanced balance of necessary properties such as wear resistance and an asphalt mixture using the asphalt additive.

In general, the asphalt used for paving the road is mixed with aggregate such as crushed stone, sand and stone powder so as to be covered on the road in a smooth state under a heated state, and then to form an asphalt road as the roller works.

In such an asphalt road, deterioration due to friction or abrasion caused by driving of the vehicle occurs at an early stage. Thus, a reinforcing material or a modifier is mixed in the asphalt to improve the mechanical strength and durability of the asphalt.

For example, Japanese Patent Laid-Open No. Hei 5-98165 discloses a packaging composition which improves durability, plasticity and shear resistance by mixing polyolefin-based reinforcing fibers on asphalt.

However, in the above technique, the strength of the paved asphalt was not uniform because the reinforcing fibers were not uniformly dispersed in the asphalt, and the polyolefin-based fibers were charged (electrically conducted) by static electricity or the like, resulting in a phenomenon of coalescence between the fibers. Since the reinforcing fiber concentration is not uniform and not solidified in the form of agglomerates, fluidization, wear, and cracks occur under adverse conditions such as high roads or high temperatures.

It is widely used as road paving material with excellent workability and water resistance by adding straight asphalt to aggregate particles composed of crushed stone, screenings, irradiated and stone powder used in asphalt mixture.

However, since the soft asphalt has a problem that the softness is easily affected by temperature, the road surface is hardened especially during winter, so it is easy to cause cracking or stone dust (blowing). Work efficiency tends to be lowered because it hardens due to temperature decrease during the paving work. For this reason, when paving in winter, the work tends to be thickly packed in order to prevent the temperature drop, and thus the work efficiency and economic efficiency are deteriorated. Moreover, when straight asphalt is used as it is, there is a problem of easy wear and bad fluid resistance.

As such, the conventional method for solving the shortcomings of the straight asphalt is to use a so-called modified asphalt in which a modifier such as a polymer material, rubber, thermoplastic elastomer, and thermoplastic resin is added to the asphalt. It has improved the low temperature resistance and at the same time the wear resistance and the fluid resistance.

On the other hand, in the modified asphalt manufacturing plant is prepared by mixing the asphalt and the modifier at a high temperature (for example 150 ~ 190 ℃), the produced modified asphalt was stored in a high temperature state of manufacture at the time of shipment. However, if the storage period of the modified asphalt is prolonged or high temperature is inevitable, the asphalt constituting the modified asphalt and the modifier may be phase separated. Thus, a method such as stirring or adding a phase separation inhibitor is used to store the modified asphalt. .

Phase separation inhibitors are disclosed, for example, asphalt compositions using mineral oil or 12-hydroxystearin acid.

However, adding a phase separation inhibitor such as mineral oil to the modified asphalt tends to cause problems such as increased penetration of the modified asphalt or lower softening point, and deterioration of necessary properties such as slip resistance, abrasion resistance, and durability. As it occurs, there is an urgent need for asphalt mixtures that can be well balanced in their properties.

The present invention has been invented in view of the problems of the conventional asphalt additives as described above, the object is to improve the low temperature resistance while preventing fluidization and wear and crack under bad conditions such as high traffic roads or high temperatures, even in winter season thin pavement It is possible to provide an additive for asphalt and a method for producing the asphalt mixture which are possible and excellent in slip resistance, wear resistance and durability.

It is another object of the present invention to provide an asphalt additive and a method for preparing the asphalt mixture, which can easily handle the asphalt mixture and the working environment, and uniformly disperse the fibers in the asphalt to balance necessary properties such as fluidity and wear resistance. Is in.

Asphalt additives of the present invention for achieving this purpose, including the additives having affinity to the straight asphalt and the cotton fibers generated from the hydrophobized short fibers to impregnate the additives into the fiber to make the impregnated mixture and The impregnated mixture was accommodated in a synthetic plastic bag, and the copper bag was put into heated straight asphalt and used.

As it is not necessary to remove the impregnated mixture from the packaging bag when the material is added to prepare the asphalt mixture as described above, it is easy to handle and the work environment is good because the asphalt is prevented from scattering during the operation of the impregnated mixture. When the impregnated mixture is stored, it is a moisture-proof package that can be stored for a long time and prevents the outflow of additives impregnated into the fiber.In addition, since the impregnated mixture has affinity between fibers, it does not clump and has good dispersibility. Therefore, the concentration of the fiber is uniformly distributed to improve flow resistance, abrasion resistance and crack resistance.

The thickness of the packaging bag is preferably set to 0.03 ~ 0.06㎜, the thickness of this to prevent the deterioration of the quality of the contents, and also to melt the packaging bags during the manufacture of asphalt mixture, it does not interfere with the dispersion of the fiber. Do not. If the thickness of the packaging bag is less than 0.03mm, the impregnated additives will bleed out of the bag. If the packaging bag exceeds 0.06mm, it will be difficult to melt the packaging bag during mixing, and the dispersibility of the fiber on the asphalt is deteriorated.

The short fiber is made from plant fiber. The plant fiber contains cellulose and its cellulose contains many hydroxyl groups. Therefore, the cohesive force is increased by hydrogen bonding between molecules, and the smoothness between fibers is improved by impregnation of hydrophobized additive. Since it is hardly condensed and has good dispersibility, the concentration of short fibers becomes uniform, and the flow resistance, abrasion resistance, and crack resistance are improved.

Since the additive contains 40 to 70% by weight of naphthenic oil, 20 to 45% by weight of styrene-based thermoplastic elastomer, and 2 to 30% by weight of polypropylene, the naphthenic oil content of the additive is included. When the compatibility or affinity with straight asphalt improves, and the naphthenic oil content is less than 40% by weight, the straight asphalt affinity is not necessarily improved. The content rate of the components (styrene-based thermoplastic elastomer, polypropylene) is reduced, so that the balance of the overall characteristics is hardly formed. In addition, according to the content of the styrene-based elastomer, the low temperature resistance is improved, and if the content is less than 20% by weight, it is easy to be hardened at low temperatures. On the other hand, the wear resistance is improved depending on the content of polypropylene, but if the content is less than 2% by weight, the wear resistance is not necessarily improved, but if it is more than 30% by weight, the content of other components tends to decrease.

As the styrene-based thermoplastic elastomer, it is preferable to use the styrene-butadiene-styrene copolymer. The weight ratio of styrene and butadiene as the styrene-butadiene-styrene copolymer is preferably 1.6 to 3.0% by weight based on 1% by weight of styrene. If it is less than 1.6% by weight, it becomes hard and if it exceeds 3.0% by weight, it becomes too soft. More preferably, butadiene is 2.0 to 2.6% by weight with respect to 1% by weight of styrene, and still more preferably 2.1 to 2.5% by weight.

In addition, the average molecular weight of polypropylene is preferably from 1000 to 10000 in terms of favorable compatibility with asphalt or improvement of affinity, but more preferably from 1000 to 8000 and even better from 2000 to 5000.

Asphalt additives described above and straight asphalt and aggregates are mixed to produce an asphalt mixture. It is good to mix | blend in the ratio of 6.5-8.5 weight% of straight asphalt, and 0.2-0.6 weight% of asphalt additives with respect to 100 weight% of aggregates. If the straight asphalt to 100% by weight aggregate is less than 6.5% by weight, the adhesive strength is low, and if it exceeds 8.5% by weight, the manufacturing cost is likely to increase.

If the additive for asphalt is less than 0.2% by weight, the properties such as low temperature resistance and deterioration resistance are not sufficiently improved.

On the other hand, the penetration of the asphalt is preferably 60 to 80 or 80 to 100.

The aggregate described above should be one containing crushed stone, screenings, irradiated, and stone dust. The composition of each component may be 22 to 42% by weight of crushed stone, 18 to 38% by weight of screenings, 24 to 44% by weight of irradiation, and 2 to 10% by weight of stone powder. As the crushed stone, No. 7 crushed stone is most suitable, and the composition of the aggregate is as described above, and by this composition ratio, an asphalt mixture having a suitable strength, porosity, and surface roughness can be obtained.

It is also better if the asphalt mixture has a two-layer structure in which the surface of the aggregate is covered with a straight asphalt layer and the straight asphalt layer is covered with an additive for asphalt. This makes it easy to prevent the wear of the asphalt because the thin film of the asphalt additive is supported on the straight asphalt surface, resulting in improved durability. In addition, slip resistance and elasticity at low temperatures are also improved. Accordingly, it is possible to pack the road pavement at a low temperature in a thin layer. The thickness of the asphalt mixture paved on the road should be 5 mm or more and 20 mm or less. Less than 5mm is too thin to shorten the life of the pavement, and if it exceeds 20mm, the amount of asphalt mixture used is easy to increase the cost.

In the method of manufacturing an asphalt mixture in which aggregate and straight asphalt are mixed, the aggregate and straight asphalt are mixed at 150 ° C. to 180 ° C., and then the additives for asphalt are added and mixed for 30 to 120 seconds. The heating temperature is preferably 180 ° C. or less because is so mixed that the above two-layer structure is not obtained. Although it is not necessarily said that it is less than 150 degreeC, since it does not mix enough, 150 degreeC or more is preferable. On the other hand, after the addition of asphalt additives, the mixing time of 30 to 120 seconds is difficult to form a two-layer structure after 120 seconds, but not necessarily less than 30 seconds, but not enough mixing is not achieved because the range as described above It can be said that it is preferable.

The asphalt additive of the present invention and the method of manufacturing the asphalt mixture of the present invention improves low temperature resistance while preventing fluidization, abrasion, and cracks under adverse conditions such as high roads or high traffic volume, and enables low-temperature pavement even in winter, and provides slip resistance and It has the effect of excellent wear resistance and durability, and also has the advantage of easy handling and working environment of the asphalt mixture and uniformly disperse the fibers in the asphalt to improve the flow resistance and wear resistance.

Hereinafter, an embodiment of the asphalt additive of the present invention and a method for producing the asphalt mixture will be described with reference to the drawings.

1 is a cross-sectional view showing the outline of the additive for straight asphalt of the present invention, Figure 2 (a) to (e) is a cross-sectional configuration diagram showing the manufacturing process of the above-mentioned asphalt additive, respectively, the additive for straight asphalt of the present invention ( 1) includes an additive (2) having affinity for straight asphalt and a planar fiber (3a) formed from a hydrophobic treated short fiber (3). It was deposited in the additive (2) in the inside, and the impregnated mixture (4) was formed by impregnating the additive (2) in the short fibers (3) of the fiber (3a). Thereafter, the impregnated mixture 4 is taken out of the deposition container A, and the impregnated mixture 4 is accommodated in the packaging bag 5, and the packaging bag 5 is kept closed. Prepared.

In preparing the asphalt mixture, as shown in FIG. 3, the aggregate 6 and the straight asphalt 7 are each added in an appropriate amount to the mixer M and mixed at 150 to 180 ° C., followed by the addition of the asphalt additive 1. Add and mix again for 30 to 120 seconds. Then, as shown in Figure 5, the asphalt mixture is paved to form an asphalt road (D).

With respect to the total weight of the aggregate 6, the blend of straight asphalt 7 is 6.5-8.5% by weight and the asphalt additive 1 is, for example, 0.2-0.6% by weight. As shown in Fig. 4, the asphalt mixture was formed in such a manner that the surface of the aggregate 6 was covered with a straight asphalt 7 and again covered with an additive 2 in which the short fibers 3 were uniformly dispersed.

As a result, the surface of the straight asphalt 7 is protected by a thin film of the additive 2 in which the short fibers 3 are dispersed, and the short fibers 3 are formed at the boundary between the aggregate 6 and the straight asphalt 7, Interposed on the boundary between the straight asphalt 7 and the additive (2) to perform a function as a mechanical reinforcement, it is possible to balance the characteristics such as wear resistance and durability of the pavement surface. In addition, since the particle size distribution of the aggregate 6 is as shown in Table 2 below, the strength, the positive rate, the surface roughness and the like were excellent.

If the straight asphalt 7 is less than 6.5% by weight relative to the total weight of the aggregate 6, the adhesive strength is low, and if it exceeds 8.5% by weight, the cost is likely to increase (cost up). In addition, when the additive for asphalt (1) is less than 0.2% by weight, properties such as low temperature resistance and deterioration resistance are not necessarily improved, but it is not sufficiently improved. On the other hand, the penetration of the straight asphalt 7 is preferably 60/80 or 80/100.

The aggregate 6 is composed of crushed stone, screenings, irradiated, and stone powder. The aggregate weight is 22 to 42% by weight, 18 to 38% by weight screening, 24 to 44% by weight irradiated with respect to the total weight of the aggregate 6. It is comprised by 2-10 weight%.

The additive (2) is 40 to 70% by weight of naphthenic oil, 20 to 45% by weight of styrene thermoplastic thermoplastic elastomer, and 2 to 30% by weight of polypropylene, based on the total weight of the additive (2). It is.

 The styrene-based thermoplastic elastomer is a styrene-butadiene-styrene copolymer, and in particular, the weight ratio of styrene and butadiene is 1.6 to 3.0% by weight of butadiene with respect to 1% by weight of styrene. In addition, the average molecular weight of polypropylene is preferably 1000 to 10,000 in terms of compatibility with a straight asphalt (7) or improved affinity, more preferably 1000 to 8000, and even better 2000 to 5000. In addition, the additive 2 is preferably mixed with 0.05 to 5.0% by weight relative to the total weight of the straight asphalt 7, more preferably 0.1 to 1.0% by weight. If less than 0.05% by weight, the effect of the flow resistance and wear resistance of the paved asphalt is not obtained, even if the weight exceeds 5.0% by weight does not change.

In the fiber 3a, the short fiber 3 is a tree composed mainly of cellulose, a fiber or old paper obtained from crops, a recycled fiber obtained from food waste, and the like. Cellulose content is about 80%, ash content is 10% or less, moisture content is 7% or less, acidity (pH) is 6-8, volume density is 32g / L, longest fiber length is about 5mm, average fiber length is 1.1mm It can be mentioned. Further, the fiber material 3a is mixed at 0.05 to 5.0% by weight relative to the total weight of the straight asphalt 7. Good is 0.1 to 1.0% by weight, when less than 0.05% by weight of the cellulose content is too small to achieve the effect of the flow resistance and wear resistance of the paved asphalt. Even if it exceeds 5.0 weight%, the effect of electricity does not change. In addition, hydrophobization of the fiber material 3a is performed using a silicone resin, a fluororesin-based water repellent, or the like.

The packaging bag 5 is made of synthetic resin, and examples thereof include vinyl chloride, polyethylene, and polystyrene, and the thickness thereof is set to 0.03 to 0.06 mm. This thickness prevents the deterioration of the contents and on the other hand, during the manufacture of the asphalt mixture, the dissolution of the packaging bags 5 is good and the dispersibility of the short fibers 3 in the fibers 3a is not impeded. . If the thickness of the packaging bag 5 is less than 0.03, the impregnated additive 2 will leak out of the packaging bag 5, and if it exceeds 0.06 mm, the packaging bag 5 will not melt during mixing, resulting in short fibers of asphalt. Dispersibility of (3) deteriorates.

In the method of manufacturing the asphalt mixture, for example, the mixture is mixed at a high temperature of about 150 to 180 ° C. The reason for this is that the additive for asphalt (1) and the straight asphalt (7) are overmixed when the temperature exceeds 180 ° C. This is because it does not have a two-layer structure. In addition, it is not fully mixed below 150 degreeC. On the other hand, the mixing time after the addition of the asphalt additive 1 is 30 seconds to 120 seconds because it is difficult to form a two-layered structure after 120 seconds. More preferably, the mixing time is 30 to 100 seconds, and more preferably 40 to 60 seconds.

<Examples>

Hereinafter, a description will be given of the experiment performed to confirm the effect of the present invention.

First, in order to obtain an additive (2) for use in the additive for asphalt (1), naphthenic oil, styrene thermoplastic elastomer, and polypropylene were blended as shown in Table 1 below.

Content rate (% by weight) Naphthenic oil 54 SBS 32 Polyflofilene 14

The component of Table 1 used the following.

SBS: Styrene-butadiene-styrene copolymer, the product made by Ukwa Chemical Co., Ltd., Asaprene T437, Styrene / butadiene ratio 30/70.

Polypropylene: Samyang Chemical Co., Ltd., Biscol 660.

In order to obtain the additive 1 for asphalt, the impregnated mixture 4 in which the additive 2 was impregnated into the short fibers 3 of the fibers 3a was housed in a packaging bag 5 made of vinyl chloride having a thickness of 0.05 mm. . As the additive 2, <trade name: Mino Coat, manufactured by Minodoro Co., Ltd.> was used, and the fiber 3a used <trade name: Topcell, manufactured by MI Tech Co., Ltd.>. The total weight of the additive 1 for asphalt was blended so that the additive 2 contained 75% by weight, the fiber 3a contained 25% by weight, and the packaging bag 5 contained 0.001 parts by weight.

Aggregate (6) consisting of crushed stone, screenings, and irradiated is mixed at 150 ° C., and then added to a straight asphalt (7) having a penetration of 60/80, so that the surface of the aggregate (6) is a thin film of straight asphalt (7). A mixture covered in was obtained. After adding the asphalt additive (1) to the mixture, the mixture was stirred for about 40 seconds. Thus, a sample of asphalt mixture belonging to the present invention was prepared.

Further, as the blending ratio of each component, 32 wt% of No. 7 crushed stone, 25 wt% of screenings, 34 wt% of irradiation, 6 wt% of stone powder, 7.5 wt% of straight asphalt 60/80, and additives for asphalt (1) 0.4 weight%. In addition, the particle size and percentage pass through aggregate (6) is shown in Table 2 below.

Mesh scale (mm) 13.2 4.75 2.36 0.6 0.3 0.15 0.075 Pass-through percentage 100 90-100 65-85 25-55 15-35 10-23 5-12

Properties of the asphalt mixture are shown in Table 3 below. In this way, it was confirmed that the characteristics required for the asphalt were excellent and the altitude was well balanced. Among these properties, in particular, it was found that the flexural strength and fracture torsion are large.

Test Items My appearance Marshall test  O.A.C 9.0%, Porosity 3.2%, Safety 1100㎏, Flock 30 Bending test Flexural Strength 130kgf / ㎠, Breaking Torsion 12x10 ^-3 Slip resistance test  BPN 58 (at 20 ℃ equivalent) Labering test  Wear amount 2.5㎠ cross chain Foil tracking test DS 140 times / mm (earth pressure 6.4㎏ / ㎠)
225 (5.5㎏ / ㎠)

1 is a cross-sectional view showing the outline of the additive for straight asphalt of the present invention,

2 (a) to (e) is a cross-sectional view showing a manufacturing process of the additive for asphalt, respectively;

Figure 3 (a) to (c) cross-sectional view showing the manufacturing process of the asphalt mixture of the present invention,

Figure 4 is an enlarged cross-sectional view showing an overview of the asphalt mixture of the present invention,

Figure 5 (a) and (b) is a cross-sectional view showing a state in which the asphalt mixture of the present invention is paved.

<Description of the symbols for the main parts of the drawings>

1: additive for straight asphalt

2: additive

3: short fiber

3a: fiber

4: impregnation mixture

5: packing bag

6: aggregate

7: straight asphalt

Claims (10)

Forming the impregnated mixture impregnated with the additives, including the additives having affinity to the straight asphalt and the cotton fibers formed on the hydrophobized short fibers, the impregnated mixture is contained in a packaging bag made of synthetic resin, Asphalt additive, characterized in that the packaging bag is used to put into straight asphalt. The additive for asphalt according to claim 1, wherein the thickness of the pouch is 0.03 to 0.06 mm. The additive for asphalt according to claim 1, wherein the short fibers are obtained from plant fibers. The method of claim 1, wherein the additive contains 40 to 70% by weight of naphthenic oil, 20 to 45% by weight of styrene-based thermoplastic elastomer, and 2 to 30% by weight of polypropylene, based on the total weight of the additive. Asphalt type additive. The additive for asphalt according to claim 4, wherein the styrene-based thermoplastic elastomer is a styrene-butadiene-styrene copolymer, and a weight ratio of styrene and butadiene is 1.6 to 3.0 wt% of butadiene based on 1 wt% of styrene. Asphalt additive used for road paving Asphalt, characterized in that the asphalt containing 6.5 to 8.5% by weight of the asphalt, 0.2 to 0.6% by weight of the asphalt additive to 100% by weight of the aggregate including the asphalt additive and the straight asphalt and aggregate Method for preparing the mixture. According to claim 6, wherein the aggregate is composed of crushed stone, screenings, irradiation, stone powder, the composition for the total weight of the aggregate is 22 to 42% by weight crushed stone, 18 to 38% by weight screening, irradiation 24 to 44 Method for producing an asphalt mixture, characterized in that 2% by weight to 10% by weight of stone powder. 8. The method of claim 6 or 7, wherein the surface of the aggregate is covered with a straight asphalt layer and the straight asphalt layer is covered with an asphalt additive layer. The method for producing an asphalt mixture according to claim 6, wherein the mixture of the additive for asphalt, the mixture of straight asphalt and aggregate is packed on the road with a thickness of 5 mm or more and 20 mm or less. 7. The asphalt mixture according to claim 6, wherein when the aggregate is mixed with the straight asphalt, the asphalt mixture is heated and mixed with the asphalt at 150 to 180 DEG C, and then the additive is added to the asphalt to mix again for 30 to 120 seconds. Manufacturing method.

Images