WO2006009386A1

WO2006009386A1 - Material in the shape of chip to improve quaility of asphalt concrete, and the manufacturing method thereof

Info

Publication number: WO2006009386A1
Application number: PCT/KR2005/002330
Authority: WO
Inventors: Ik-Hyun Hwang
Original assignee: City Of Tech Co., Ltd.
Priority date: 2004-07-19
Filing date: 2005-07-19
Publication date: 2006-01-26
Also published as: KR100492459B1; KR20040070157A

Abstract

Disclosed herein is an asphalt concrete modifier which is used to improve the quality of asphalt concrete. Particularly, provided are a method for producing asphalt concrete modifier chips and asphalt concrete modifier chips produced by the method. The method comprises the steps of: heating indirectly the waste tires crushed to a size of 5 mm or below to 100~150°C to gel the surface of the crushed waste tire particles; mixing the surface-gelled crushed waste tire particles with asphalt selected from emulsified asphalt, asphalt for road pavement, blown asphalt, natural asphalt, and cut-back asphalt; mixing a fine filler selected from carbon black, stone powder, silica flour, calcium carbonate, cement, etc. with the mixture obtained in the previous step; adding a mixture of at least one modifier selected from SBS, SIS and LDPE and at least one kind selected from emulsified asphalt, asphalt for road pavement, blown asphalt, natural asphalt and cut-back asphalt to the mixture obtained in the previous step, and mixing under heating to 150~250°C; cooling the hot mixture while discharging it in a predetermined size using an extruder; and crushing or cutting the cooled mixture to a given size to obtain chips.

Description

MATERIAL IN THE SHAPE OF CHIP TO IMPROVE QUAILITY OF ASPHALT CONCRETE, AND THE MANUFACTURING

METHOD THEREOF

Technical Field

[1] The present invention relates to materials to be used to improve the quality of asphalt concrete (hereinafter, abbreviated as "asphalt concrete modifier" or "ascon modifier"). More particularly, the present invention relates to improved asphalt concrete modifiers in the shape of chips which enable easy application of conventional asphalt concrete modifiers, such as styrene-butadiene-styrene (SBS), styrene- isoprene-styrene (SIS), low-density polyethylene (LDPE) and crushed waste tires, to asphalt concrete pavement, and a method for producing thereof.

[2] In general, asphalt concrete (hereinafter, abbreviated as "ascon") is manufactured by mixing asphalt, coarse aggregate, fine aggregate and paving fillers (limestone poweder, cement, etc.) under heating or at room temperature, and is widely used as a paving material for roads, parking lots, and the like. However, since asphalt contained in ascon is susceptible to changes in temperature, serious bending of ascon pavement takes place due to the occurrence of plastic deformation at hot weather temperatures during summer, impeding the passage of vehicles. Meanwhile, cracks are observed in ascon pavement due to cold weather and rapid temperature variations during winter, shortening the service life of the pavement.

[3] Ascon modifiers are used to improve the above problems of ascon. Ascon modifiers are bound to asphalt to vary the physical properties of the asphalt. For example, ascon modifiers serve to prevent the occurrence of plastic deformation in summer and the formation of cracks in winter. In addition, ascon modifiers function to improve the sliding resistance of pavement. Background Art

[4] Conventional ascon modifiers that have been widely used include SBS, SIS, LDPE, and the like. Figs. 1 and 2 show the concept that conventional modifier particles are dispersed in asphalt to vary the physical properties of the asphalt. Referring specifically to Figs. 1 and 2, aggregate particles 1, asphalt particles 2, filler particles 3, and modifier particles 4 are mixed to produce ascon 10. The modifier particles 4 are interposed between the asphalt particles and act as mediators to enhance the physical properties of the asphalt, leading to an overall improvement in the quality of the ascon.

[5] When modifier particles, such as SBS, SIS or LDPE particles, are bound to asphalt particles, they serve to prevent the occurrence of plastic deformation of the asphalt in summer and the formation of cracks in winter. In addition, the presence of ascon modifiers improves the sliding resistance of pavement. For these purposes, it is preferred that asphalt is used in an amount of 3.5-10 wt% based on the total amount of ascon and an ascon modifier is used in an amount of 2-10 wt% based on the amount of the asphalt. Accordingly, the ascon modifier is used in an amount of from about 0.07% to about 1% by weight, based on the total amount of the ascon.

[6] Hereinafter, conventional modifiers, including SBS, SIS and LDPE, will be described in detail.

[7] SBS is a copolymer prepared by random polymerization of a highly elastic butadiene monomer and a hard styrene monomer. Mixing of SBS with asphalt at high temperatures sufficient to dissolve the SBS enables hardening of the asphalt. Ascon pavement using SBS may be effective in the prevention of plastic deformation due to high temperatures in summer and formation of cracks due to low temperatures in winter. Since SBS has a high melting point, however, a heater capable of heating to above 150°C and a high-shear mixer as a special-purpose mixer are required for sufficient mixing of the SBS with asphalt. However, these apparatuses are expensive and bulky, making it difficult to transport them to ascon manufacturing plants. Ac¬ cordingly, in order to utilize SBS as an ascon modifier, a heater and a high-shear mixer must be installed in an asphalt manufacturing plant where SBS is previously fed to asphalt to obtain a sufficiently uniform mixture, and then the modifier-containing mixture must be transported to construction sites. To this end, an additional asphalt tank must be installed in an ascon manufacturing plant, thus causing great in¬ convenience.

[8] Thus, conventional methods using SBS as asphalt modifier require the use of expensive apparatuses, and involve complicated procedures, requiring a great deal of time. Moreover, when a mixture of the modifier and asphalt is stored for a long period of time, separation between the asphalt and the modifier takes place and thus the addition of the modifier has little or no effect. This poses a problem that the preparation of the mixture in advance is meaningless. For these problems, SBS has not been widely used so far despite its advantages as a modifier.

[9] SIS as an elastomer and LDPE as a plastomer, which are the same kind of copolymers as SBS, are used as ascon modifiers. Like SBS, a high-temperature heater and a high-shear mixer are required to allow SIS and LDPE to be used as modifiers. In addition, when mixtures of the modifiers and asphalt are stored for a long period of time, separation between the asphalt and the modifiers takes place, which poses a problem that the preparation of the mixtures in advance is meaningless.

[10] On the other hand, since rubber, such as crushed waste tires, has low temperature sensitivity, it does not sensitively respond to changes in temperature. In addition, rubber is highly elastic. Based on these advantages of rubber, a mixture of crushed waste tires and asphalt is effective in prevention of plastic deformation in summer and formation of cracks in winter. In view of these, it can be said that crushed waste tires are to be used as one of ascon modifiers. If crushed waste tires can be used as components for road pavements, they have great usefulness from the viewpoint of resource recycling. Further, since crushed waste tires are highly elastic sufficient to impart elasticity to roads, noise is reduced and ride comfort while driving is improved.

[11] In the case where a mixture of crushed waste tires and asphalt aggregate is paved, however, the crushed waste tires and the asphalt are not integrally joined together but form a simple mixture. In the state of a mixture, the crushed waste tires act as impurities, resulting in deterioration in the durability of the pavement.

[12] In an effort to solve the problems associated with the use of crushed waste tires, the

McDonald process has been introduced. According to this process, 10-25 wt% of crushed waste tires is added to asphalt and mixed by high-speed rotation at 190~220°C for 0.5-1 hour so that the asphalt is integrally combined to the crushed waste tires. That is, asphalt and crushed waste tires are mixed at a high temperature by high-speed rotation so that the asphalt particles are firmly bound to the surface of the crushed waste tire particles, and as a result, the asphalt is integrally joined to the crushed waste tires. However, the McDonald process requires the use of expensive aging equipment, portable, large-scale asphalt tanks, and the like, thus creating an economic burden and a complicated manufacturing procedure.

[13] In another effort to integrally combine crushed waste tires to asphalt, Korean Patent

No. 394092 issued to the present inventor suggests a method for producing chips by indirectly heating crushed waste tires to gel the surface of the crushed waste tires, and adding hot asphalt at 150~300°C thereto so that the asphalt is integrally combined to the (surface-gelled) crushed waste tire particles. This method is very economically ad¬ vantageous over the McDonald process because it enables asphalt to be integrally combined to crushed waste tires.

[14] The conceptual diagrams of chips produced by the method disclosed in Korean

Patent No. 394092 are shown in Figs. 3 and 4. Referring to Fig. 3, the surface of a crushed waste tire particle 21 is gelled and then asphalt particles are bound thereto to form an integral body 20. As shown in Fig. 4, asphalt particles 23 integrally joined to crushed waste tire particles 21 are naturally bound to additional asphalt particles. According to the method disclosed in Korean Patent No. 394092, the asphalt particles and the crushed waste tire particles are firmly bound together (rather than forming a simple mixture). Fig. 4 is a conceptual diagram wherein the binding of the asphalt particles to the crushed waste tire particle shown in Fig. 3 is continuous.

[15] Major purposes for the use of crushed waste tires in the method of Korean Patent No. 394092 are that resources are recycled to contribute to environmental protection and elasticity is imparted to pavement to improve ride comfort. However, little con¬ sideration is given to the use of crushed waste tires as asphalt modifiers. Disclosure of Invention Technical Problem

[16] Therefore, the present invention has been made in view of the above problems of conventional ascon modifiers, and it is one object of the present invention to provide ascon modifier chips that can be easily used without the use of expensive apparatuses and complicated procedures. Specifically, the modifier chips of the present invention are produced by mixing asphalt with conventional modifiers so as to integrally join the asphalt to the conventional modifiers, and are fed to hot ascon in a simple manner before ascon paving without the need for additional expensive apparatuses and complicated procedures.

[17] It is another object of the present invention to provide a method for producing chips using crushed waste tires with or without the addition of modifiers, ensuring the chips to have ascon modification effects while maintaining the advantages of the crushed waste tires. Technical Solution

[18] The constitution of the present invention for achieving the objects will now be explained.

[19] In accordance with one aspect of the present invention, there is provided a method for producing ascon modifier chips comprising the steps of mixing crushed waste tires and emulsified asphalt under heating so that the emulsified asphalt is integrally joined to the crushed waste tires, adding a filler thereto and mixing, cooling the mixture, and crushing the cooled mixture to be chips.

[20] In accordance with another aspect of the present invention, there is provided a method for producing ascon modifier chips comprising the steps of mixing crushed waste tires and emulsified asphalt under heating so that the emulsified asphalt is integrally joined to the crushed waste tires, adding a filler thereto and mixing, adding a mixture of asphalt and at least one of the conventional ascon modifier selected from SBS, SIS and LDPE thereto, mixing under heating to bind the crushed waste tires (integrally joined with the asphalt) to the modifier, cooling the mixture, and crushing the cooled mixture to be chips.

[21] In accordance with yet another aspect of the present invention, there are provided ascon modifier chips produced by the methods. Brief Description of the Drawings

[22] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[23] Fig. 1 is a conceptual diagram showing the dispersion of modifier particles in ascon;

[24] Fig. 2 is an enlarged view showing a portion of Fig. 1 ;

[25] Fig. 3 is a conceptual diagram showing the binding of a crushed waste tire particle to asphalt particles;

[26] Fig. 4 is a conceptual diagram wherein the binding shown in Fig. 3 is continuous;

[27] Fig. 5 is a conceptual diagram of a modifier chip produced in accordance with an embodiment of the present invention; and

[28] Fig. 6 is a conceptual diagram showing the state in which constituent components of the modifier chip shown in Fig. 5 are activated. Mode for the Invention

[29] Asphalt is softened at around 60°C, whereas ascon, i.e. a mixture of asphalt, an aggregate filler and the like, is softened at above 150°C. The present invention has been achieved based on these observations. After ascon modifier chips of the present invention are fed into an ascon mixer, asphalt contained in the modifier chips of the present invention is previously softened at around 60°C (before other ascon materials are softened) and is separated from the modifier. The separated materials are activated so that the modifier particles are easily and uniformly dispersed in ascon which is then softened at around 150°C.

[30] Fig. 5 is a conceptual diagram showing the constitution of a modifier chip produced in accordance with an embodiment of the present invention. In the modifier chip 30, emulsified asphalt particles 33 are bound to the gelled surface 32 of crushed waste tire particles 31 so that the asphalt particles 33 are integrally combined to the crushed waste tire particles 31. Filler particles 34 are bound to the periphery of the asphalt particles 33 due to the adhesive force of the asphalt particles 33. The crushed waste tire units agglomerate together through a mixture of the conventional ascon modifier particles 35, e.g., SBS, SIS or LDPE particles, and asphalt particles 36.

[31] Fig. 6 shows the concept that the modifier chip shown in Fig. 5 is softened and dispersed in an ascon mixer. Once the asphalt particles 36 are activated, the asphalt particles 36, the modifier particles 35, the crushed waste tire units 31, 32 and 33 (which are composed of the crushed waste tire particles and the asphalt particles bound to the gelled surface of the crushed waste tire particles), the filler particles 34, and the like are separated from each other, and then the separated respective particles are freely dispersed in ascon. The asphalt particles 33 are strongly bound to the gelled surface 32 of the crushed waste tire particles 31, and thus the asphalt particles 33 are integrally combined to the crushed waste tire particles 31.

[32] The reason for the use of asphalt as a main material for the ascon modifier chips of the present invention is that asphalt can be readily melted by heating and is the main material of ascon, enabling the modifier particles contained in the modifier chip to be rapidly and easily dispersed in ascon. Examples of asphalt that can be used in the present invention include asphalt for road pavements, blown asphalt, cut-back asphalt, natural asphalt, tar, and the like. It is preferred that blown asphalt, natural asphalt, or asphalt having a penetration index of 40 or less is used in order to reduce the temperature sensitivity of the asphalt to some degree.

[33] The method for producing ascon modifier chips by mixing crushed waste tires and asphalt according to the present invention consists of the following six steps.

[34] . First step: waste tires are crushed to a size of 5 mm or below, and indirectly heated to 100~150°C to gel the surface of the crushed waste tire particles.

[35] . Second step: one part by weight of the surface-gelled crushed waste tire particles is mixed with 0.05-0.5 parts by weight of asphalt selected from emulsified asphalt, asphalt for road pavement, blown asphalt, natural asphalt, and cut-back asphalt.

[36] . Third step: 0.02-0.3 parts by weight of a fine filler selected from carbon black, stone powder, silica flour, calcium carbonate, cement, etc., is mixed with the mixture obtained in the second step.

[37] . Fourth step: a mixture of asphalt and the conventional modifier, such as SBS, SIS or LDPE, is added to the mixture obtained in the third step, followed by mixing under heating to 150~250°C.

[38] . Fifth step: the mixture obtained in the fourth step is air-cooled or water-cooled while it is discharged in a predetermined size using an extruder.

[39] . Sixth step: the cooled mixture is crushed or cut to a given size to obtain chips.

[40] In the first step, the reason why crushed waste tires are heated to 100~150°C is to gel the surface of the crushed waste tires while preventing excessive expansion of the crushed waste tire particles. When the heating is carried out at a temperature lower than 100°C, the surface of the crushed waste tires is not readily gelled. Meanwhile, when the heating is carried out at a temperature exceeding 150°C, there exists a danger of excessive expansion of the crushed waste tire particles. The restriction in the size of the crushed waste tire particles to 5 mm or below serves to limit the size of the final chips to 10 mm or less. The reason why the modifier chips of the present invention are crushed as small as possible is to reduce the time necessary to soften the modifier chips in an ascon mixer. In conclusion, it is desirable that the size of the crushed waste tires is limited to 3 mm or less and the size of the final modifier chips is limited to 5 mm or less.

[41] In the second step, the amount of asphalt used is limited to 0.05-0.5 parts by weight based on one part by weight of the crushed waste tires so that the asphalt is integrally combined to the crushed waste tires. When the amount of the asphalt used is less than 0.05 parts by weight, (i.e. the amount of the asphalt coated on the crushed waste tires is insufficient), there is a danger that the asphalt is not integrally combined to the crushed waste tires. Meanwhile, when the amount of the asphalt used exceeds 0.5 parts by weight, the final modifier chips is too bulky, causing inconvenience in use.

[42] In the third step, the reason why a fine filler selected from carbon black, stone powder, silica flour, calcium carbonate, cement, etc., is mixed with the mixture of the crushed waste tires and the asphalt is to prevent the aggregation of the crushed waste tire particles when the crushed waste tires are expanded at temperatures as high as 150°C. When the fine filler is used in an amount of less than 0.02 parts by weight, ag¬ gregation of the crushed waste tire particles cannot be prevented. On the other hand, when the fine filler is used in an amount exceeding 0.3 parts by weight, the addition effects of the fine filler are few and the final modifier chips is too bulky, causing in¬ convenience in use. Accordingly, it is preferred that the amount of the fine filler used be limited to the range of 0.02-0.3 parts by weight.

[43] In the fourth step, a mixture of asphalt and a modifier, such as SBS, SIS or LDPE, is added to the mixture obtained in the third step, followed by mixing under heating to 150~250°C. Such heating enables the modifier, such as SBS, SIS or LDPE, to be suf¬ ficiently and uniformly mixed with the asphalt so that the modifier can be easily and rapidly dispersed throughout hot ascon in an ascon manufacturing plant. At this time, the asphalt and the modifier is mixed under continuous heating while maintaining at a temperature of 150~250°C. In this temperature range, the crushed waste tire particles coated with the fine filler, e.g., stone powder, are additionally aged, resulting in strong adhesion of the crushed waste tire particles to the asphalt. When the temperature is less than 150°C, the mixing of the asphalt with the modifier may be insufficient. Meanwhile, when the temperature exceeds 250°C, the quality of the asphalt may be de¬ teriorated as well as fuel is unnecessarily consumed, which is economically disad¬ vantageous.

[44] In the method of the present invention, the ratio between the amount of the modifier, such as SBS, SIS or LDPE, and that of the asphalt is determined considering the amount of the asphalt used to manufacture ascon to be paved. For example, the optimal amount of the modifier, such as SBS, SIS or LDPE, added is 2-10 wt%, based on the total amount of the asphalt contained in the ascon. In addition, the amount of the asphalt contained in the ascon is optimally 3.5-10 wt, based on the amount of the ascon. Accordingly, in the case where ascon paving is performed using the ascon modifier chips of the present invention, the amount of the modifier chips must be controlled. For example, when the content of the conventional ascon modifier, SBS, SIS or LDPE, in the modifier chips contain is relatively high, the ascon modifier chips of the present invention must be added in a relatively low amount. Meanwhile, when the content of the conventional ascon modifier in the modifier chips is relatively low, the ascon modifier chips of the present invention must be added in a relatively high amount.

[45] When the modifier chips are produced by mixing crushed waste tires and a con¬ ventional modifier, such as SBS, SIS or LDPE, in accordance with the method of the present invention, the mixing ratio between the crushed waste tires and the con¬ ventional modifier must be determined according to the applications of ascon pavement. In the case of pavements for sidewalks and small car traveling which require water permeability and/or elasticity, it is preferred that the amount of the crushed waste tires used be increased. On the other hand, in the case of pavements for high traffic areas, such as general car roads and highways, it is preferred that the amount of the crushed waste tires used be lowered.

[46] In the present invention, the reason why the modifier chips are crushed into granules and packaged in bags is to prevent the modifier chips from being deteriorated during storage, to facilitate the transportation of the modifier chips to a manufacturing plant, and to add the modifier chips to hot ascon in a simple and easy manner.

[47] Alternatively, the modifier chips of the present invention may be directly produced from the mixture of the crushed waste tires obtained in the third step. Although the modifier chips have poor asphalt modification effects when compared to those containing the conventional modifier, such as SBS, SIS or LDPE, they prevent the occurrence of plastic deformation and the formation of cracks to a sufficient extent when they are used to manufacture ascon for water permeable sidewalks and small car traveling road.

[48] According to the method of the present invention, sulfur, paraffin, glue, rosin, etc., can be further mixed. If necessary, reinforcing fibers, such as optical fibers, cellulose fibers and polymer fibers, are further added. The use of these materials can maximize the quality of ascon.

[49] Hereinafter, the present invention will be explained with reference to the following example.

[50] (Example)

[51] A 300 m long road for vehicle passage was paved using ascon. At this time, 100 m was paved using general ascon (hereinafter, referred to as a "pavement A"), 100 m was paved using ascon manufactured using the modifier chips of the present invention containing no conventional modifier, such as SBS, SIS or LDPE (hereinafter, referred to as a "pavement B"), and 100 m was paved using ascon manufactured using the modifier chips of the present invention containing a conventional modifier, such as SBS, SIS or LDPE (hereinafter, referred to as a "pavement C").

[52] The modifier chips used in pavement B in this example were produced in accordance with the following procedure. First, 100 kg of crushed waste tires having a size of 1.2 mm or below was heated to about 120°C using a heating mixer equipped with a gas burner to gel the surface of the crushed waste tires. 30 kg of emulsified asphalt was added to the crushed waste tires so that the emulsified asphalt was integrally combined to the gelled surface of the crushed waste tires. Then, 20 kg of CaCO as a filler was added to the mixture and heated to 150~250°C. The hot mixture

3 was extruded using a screw extruder, allowed to cool to room temperature, crushed to a size of 3 mm, divided into 10 kg samples, and packaged in PE bags for storage.

[53] The modifier chips used in pavement C in this example were produced in accordance with the following procedure. First, 100 kg of waste tires were crushed to a size of 0.6 mm or below in a primary double- walled mixer and heated to about 120°C. 15 kg of blown asphalt was added to the waste tires and mixed. 5 minutes after the mixing, 5 kg of cement was added to the mixture and heated to loosen the crushed waste tire particles. 30 kg of SBS and 30 kg of blown asphalt were added to the cement mixture and mixed under heating to 150~250°C. The resulting mixture was fed into an extruder hopper, extruded to a diameter of 10 mm, cooled in a water bath, and crushed to a size of 3 mm. 3 kg samples were weighed, and packaged in a PP vinyl bag for storage.

[54] Pavement A is a general ascon pavement containing no ascon modifier. Pavements B and C were substantially identical to pavement A except for the use of ascon modifiers. In this example, each of pavements A, B and C was paved on top of pre¬ existing conventional concrete pavement in an overlay manner. The kind of materials used in pavements A, B and C, and mixing ratios therebetween are shown in Table 1.

[55] Table 1

[56] [57] The distribution of particle size of aggregates and particle size of the composed materials (containing 3% of CaCO as the filler) used in this example are shown in Table 2.

[58] Table 2

[59]

[60] In this example, the materials were mixed under heating to 160~185°C, transported to a construction site using a dump truck, and paved. The ascon modifier of pavement B was fed into an ascon mixer in a manufacturing plant, mixed, and transported to a construction site using a dump truck. The pavements were paved using a finisher by a common method at the construction site, and then compacted using a macadam roller, a tandem roller and a tire roller.

[61] In this example, pavements A, B and C were tested for dynamic stability, resilient modulus and wear amount, which are major quality defining characteristics of ascon pavements using modifiers, and the obtained results are shown in Table 3.

[62] Table 3

[63] [64] As can be seen from the data shown in Table 3, the dynamic stability, which is a criterion for the occurrence of plastic deformation, of pavements B and C was greatly improved when compared to pavement A containing no ascon modifier. The resilient modulus, which is a criterion for the formation of low-temperature cracks, of pavements B and C was stabilized to about 1/3 that of pavement A. The wear amount of pavements B and C was reduced to about 1/4 that of pavement A. Industrial Applicability

[65] As apparent from the above description, the present invention provides improved ascon modifier chips which enable easy application of conventional ascon modifiers to ascon pavement and a method for producing the ascon modifier chips. The ascon modifier chips of the present invention are easy to use. In addition, the ascon modifier chips of the present invention are very useful because they can greatly improve the quality of ascon, for example, the ascon modifier chips can prevent the occurrence of plastic deformation in summer and the formation of cracks in winter, and the ascon modifier chips can improve the sliding resistance of pavement.

Claims

[1] A method for producing asphalt concrete modifier chips, comprising the steps of: heating indirectly the waste tires crushed to a size of 5 mm or below to 100~150°C to gel the surface of the crushed waste tire particles; mixing one part by weight of the surface-gelled crushed waste tire particles with 0.05-0.5 parts by weight of at least one kind selected from emulsified asphalt, asphalt for road pavement, blown asphalt, natural asphalt, and cut-back asphalt; and mixing 0.02-0.3 parts by weight of a fine filler with the mixture obtained in the previous step.

[2] A method for producing asphalt concrete modifier chips, comprising the steps of: heating indirectly the waste tires crushed to a size of 5 mm or below to 100~150°C to gel the surface of the crushed waste tire particles; mixing one part by weight of the surface-gelled crushed waste tire particles with 0.05-0.5 parts by weight of at least one kind selected from emulsified asphalt, asphalt for road pavement, blown asphalt, natural asphalt, and cut-back asphalt; mixing 0.02-0.3 parts by weight of a fine filler with the mixture obtained in the previous step; and adding a mixture of at least one modifier selected from SBS, SIS and LDPE and at least one kind selected from emulsified asphalt, asphalt for road pavement, blown asphalt, natural asphalt and cut-back asphalt to the mixture obtained in the previous step, and mixing under heating to 150~250°C.

[3] The method according to claim 1 or 2, further comprising the steps of cooling the hot mixture while discharging it in a predetermined size using an extruder, and crushing or cutting the cooled mixture to a given size to obtain chips.

[4] The method according to claim 1 or 2, wherein the asphalt mixed with the modifier has a penetration index of 40 or less.

[5] The method according to claim 1, wherein the modifier chips have a size of 10 mm or less.

[6] The method according to claim 1 or 2, wherein the fine filler is at least one filler selected from carbon black, stone powder, silica flour, calcium carbonate, and cement.

[7] An asphalt concrete modifier chip produced by the method according to any one of claims 1 to 6.