Medium-low temperature asphalt modifier having deodorization function, asphalt mixture prepared using the same, and construction method thereof

Abstract

To provide an asphalt mixture that can reduce the production temperature of asphalt mixtures and remove hydrogen sulfide, which is the main cause of odor.SOLUTION: There are provided a high-strength medium-low temperature asphalt modifier including: i) a styrenic thermoplastic elastomer powder which is frozen ground to 0.1 to 1 mm at a low temperature, wherein the styrenic thermoplastic elastomer is selected from a polystyrene-polybutadiene-polystyrene block copolymer (SBS), a styrene-butadiene rubber (SBR), a styrene-isoprene-styrene block copolymer (SIS), a styrene-ethylene-butylene-styrene block copolymer (SEBS), and a styrenic thermoplastic elastomer (STE), ii) a high-boiling point process oil, iii) a rosin resin tackifier modified by an aliphatic hydrocarbon, iv) a polymer-silica nanocomposite, and v) an asphalt deodorant; an asphalt mixture prepared using the same; and a construction method thereof.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure can be produced at a medium - low temperature of 140°C or lower, preferably 120°C or lower, more preferably 100°C or lower, which is lower than the production temperature of conventional asphalt mixtures that can be produced at a temperature of 160°C or higher or 180°C or higher. The produced asphalt mixture has high strength and deodorizing properties. Provided is a medium - low temperature asphalt modifier having a deodorizing function and imparting high - strength characteristics. Also provided is an asphalt mixture produced using the asphalt modifier and a construction method thereof.

[0002] Specifically, by lowering the production temperature of conventional asphalt mixtures by 40 - 60°C or more, it is possible to produce asphalt mixtures even at low temperatures. Thus, it relates to a high - strength medium - low temperature asphalt modifier that reduces energy consumption by 60% or more and carbon dioxide emissions, an asphalt mixture produced using the same, and a construction method thereof.

Background Art

[0003] Asphalt paving is widely used in road paving because it produces less road noise and has faster construction and curing compared to concrete paving. Asphalt paving involves producing an asphalt mixture by mixing straight asphalt with aggregates, fillers, etc. in a plant, then transporting it to the site and constructing it using paving equipment and compaction equipment.

[0004] In a plant for producing asphalt mixtures, generally, the asphalt mixture is produced at a high temperature of 160 - 180°C, so there is a large amount of energy consumption, especially a large amount of carbon dioxide emissions. Considering that South Korea declared carbon neutrality in 2021 with the goal of reducing greenhouse gas emissions by 2050 to address the climate crisis and create a safe and sustainable society, and is participating in this across all industrial fields, it is necessary to reduce the carbon dioxide generated during the production of asphalt mixtures.

[0005] In recent years, research has been conducted on medium-temperature asphalt that can reduce energy and carbon dioxide emissions by approximately 20% or more by lowering the production temperature by 20 - 30°C during the production of asphalt mixtures. However, even if the production temperature of the asphalt mixture is only lowered by about 20 - 30°C, the aggregate will not be dried, and moisture will remain in the asphalt mixture. If the moisture in the aggregate is not dried, the asphalt binder (straight asphalt), which is the main material of the asphalt mixture, has weak resistance to moisture, and the bonding force and adhesiveness with the aggregate are significantly reduced, which are the main causes of the deterioration of the serviceability of the pavement, such as cracks, potholes, and plastic deformation after paving construction.

[0006] To solve this problem, Korean Patent No. 1594070 provides a medium-temperature asphalt additive containing a surfactant, distilled water, and vegetable coconut oil and a method for manufacturing an asphalt mixture. However, due to the use of oil, the penetration of the oil in the asphalt is increased, so it has vulnerability to cracks and deformation at high temperatures in summer. In the case of wax, the brittle characteristics increase at low temperatures, increasing the pavement damage caused by asphalt cracks at low temperatures. Considering the reality that more than 60% of carbon dioxide emissions and energy savings are required to achieve carbon neutrality, improvement is needed for this.

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present disclosure is to provide a medium-low temperature asphalt modifier that can lower the production temperature of an asphalt mixture in a plant for producing the asphalt mixture by 40 - 60°C or more, and provide an asphalt mixture with high-strength characteristics that can achieve carbon neutrality by reducing energy consumption and suppressing carbon dioxide emissions.

[0008] Preferably, the present disclosure enables the production temperature of the asphalt mixture in a plant for producing the asphalt mixture to be 120° C. or lower, and the produced asphalt mixture has excellent Marshall stability, excellent dynamic stability, can deodorize, reduce carbon dioxide emissions, can save energy, and also aims to provide a high-strength medium- and low-temperature asphalt modifier having high strength characteristics.

[0009] Furthermore, the present disclosure aims to provide a high-strength medium- and low-temperature asphalt modifier that can remove 99% or more of hydrogen sulfide, which is the main cause of odors during asphalt production, decompose and adsorb mercaptan-based and aldehyde-based harmful gases, and improve the working environment of workers at asphalt plants and construction sites and the surrounding environment.

[0010] Furthermore, the present disclosure aims to provide a high-strength medium- and low-temperature asphalt modifier and an asphalt mixture containing the same, which have the inherent function of lowering the production temperature of the asphalt mixture and can enhance the serviceability of pavements such as plastic deformation resistance at high temperatures in summer, fatigue cracking resistance at low temperatures in winter, moisture resistance, and asphalt oxidation resistance.

Means for Solving the Problems

[0011] One embodiment of the present disclosure provides a high-strength medium- and low-temperature asphalt modifier comprising i) a styrene-based thermoplastic elastomer powder, ii) a composite process oil, iii) a rosin resin tackifier modified with an aliphatic hydrocarbon, iv) a polymer-silica nanocomposite, and v) an asphalt odor remover.

[0012] In one embodiment of the present disclosure, preferably, a high-strength medium and low-temperature asphalt modifier is provided, which comprises: i) 30 to 60 parts by weight of styrenic thermoplastic elastomer powder; ii) 40 to 60 parts by weight of composite process oil; iii) 5 to 20 parts by weight of a rosin resin tackifier modified with aliphatic hydrocarbons; iv) 0.2 to 5 parts by weight of a polymer-silica nanocomposite; and v) 0.01 to 0.5 parts by weight of an asphalt odor remover.

[0013] In one embodiment of the present disclosure, the styrenic thermoplastic elastomer may be one or more selected from polystyrene-polybutadiene-polystyrene block copolymer (SBS), styrene-butadiene rubber (SBR), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-butylene-styrene block copolymer (SEBS), and styrenic thermoplastic elastomer (STE).

[0014] In one embodiment of the present disclosure, the styrenic thermoplastic elastomer powder may be polystyrene-polybutadiene-polystyrene block copolymer (SBS) powder.

[0015] In one embodiment of the present disclosure, the composite process oil may be produced by mixing 5 to 20 parts by weight of polybutene or polyisoprene liquid polymer with 100 parts by weight of a process oil such as paraffin oil. Examples of such products include, but are not limited to, products such as R10 manufactured by GTR, which is a mixture of 15 parts by weight of liquid polyisoprene with 100 parts by weight of paraffin oil.

[0016] In one embodiment of the present disclosure, the polymer-silica nanocomposite may be a composite produced by mixing nanosilica and a polymer resin. As an example of the polymer-nanosilica, it is preferable but not limited to those containing 10 to 20% by weight of nanoclay such as bentonite, 75 to 88% by weight of fumed nanosilica, and 2 to 5% by weight of a nano superabsorbent resin (for example, products crosslinked with polyacrylic acid such as LG Chem SAP). Since the object of the present invention can be better achieved in this case.

[0017] In one embodiment of the present disclosure, the asphalt odor remover may contain 10 to 30% by weight of an essential oil having the performance of decomposing and absorbing harmful gases, 20 to 40% by weight of an essential oil having ion exchange and reactivity, 20 to 40% by weight of a carrier oil, and 30 to 40% by weight of a composite process oil. Examples of the odor remover include products such as Asmell cut of Hansoo Road Ind.

[0018] One embodiment of the present disclosure provides an asphalt mixture containing 80 to 96.9% by weight of aggregates, 3 to 10% by weight of asphalt, and 0.1 to 10% by weight of the high-strength medium-low temperature asphalt modifier.

[0019] In one embodiment of the present invention, when producing an asphalt mixture in the range of 110°C ± 15°C, the medium-low temperature asphalt modifier provides an asphalt mixture that reduces carbon dioxide emissions by 60% or more compared to the production of an asphalt mixture not containing the high-strength medium-low temperature asphalt modifier.

[0020] In one embodiment of the present disclosure, based on the sieve passing weight percentage of WC-1 particle size, the aggregates may be 90 - 100% for the 13 mm sieve, 76 - 90% for the 10 mm sieve, 44 - 74% for the 5 mm sieve, 28 - 58% for the 2.5 mm sieve, 11 - 32% for the 0.6 mm sieve, 5 - 21% for the 0.3 mm sieve, 3 - 15% for the 0.15 mm sieve, and 2 - 10% for the 0.08 mm sieve.

[0021] In one embodiment of the present disclosure, based on the sieve passing weight percentage of the WC-2 particle size, the aggregates may be 95-100% passing through a 13 mm sieve, 84-92% passing through a 10 mm sieve, 55-70% passing through a 5 mm sieve, 35-50% passing through a 2.5 mm sieve, 18-30% passing through a 0.6 mm sieve, 10-21% passing through a 0.3 mm sieve, 6-16% passing through a 0.15 mm sieve, and 4-8% passing through a 0.08 mm sieve.

[0022] In one embodiment of the present disclosure, based on the sieve passing weight percentage of the WC-3 particle size, the aggregates may be 90-100% passing through a 20 mm sieve, 72-90% passing through a 13 mm sieve, 56-80% passing through a 10 mm sieve, 35-65% passing through a 5 mm sieve, 23-49% passing through a 2.5 mm sieve, 10-28% passing through a 0.6 mm sieve, 5-19% passing through a 0.3 mm sieve, 3-13% passing through a 0.15 mm sieve, and 2-8% passing through a 0.08 mm sieve.

[0023] In one embodiment of the present disclosure, based on the sieve passing weight percentage of the WC-4 particle size, the aggregates may be 95-100% passing through a 20 mm sieve, 75-90% passing through a 13 mm sieve, 67-84% passing through a 10 mm sieve, 45-65% passing through a 5 mm sieve, 35-50% passing through a 2.5 mm sieve, 18-30% passing through a 0.6 mm sieve, 10-21% passing through a 0.3 mm sieve, 6-16% passing through a 0.15 mm sieve, and 4-8% passing through a 0.08 mm sieve.

[0024] In one embodiment of the present disclosure, based on the sieve passing weight percentage of the WC-5 particle size, the aggregates may be 90-100% passing through a 20 mm sieve, 69-84% passing through a 13 mm sieve, 56-74% passing through a 10 mm sieve, 35-55% passing through a 5 mm sieve, 23-38% passing through a 2.5 mm sieve, 10-23% passing through a 0.6 mm sieve, 5-16% passing through a 0.3 mm sieve, 3-12% passing through a 0.15 mm sieve, and 2-10% passing through a 0.08 mm sieve.

[0025] In one embodiment of the present disclosure, based on the sieve passing weight percentage of WC-6 particle size, the aggregates may be 90-100% on a 13 mm sieve, 73-90% on a 10 mm sieve, 40-60% on a 5 mm sieve, 25-40% on a 2.5 mm sieve, 11-22% on a 0.6 mm sieve, 7-16% on a 0.3 mm sieve, 4-12% on a 0.15 mm sieve, and 3-9% on a 0.08 mm sieve.

[0026] In one embodiment of the present disclosure, based on the sieve passing weight percentage of low-noise and water-permeable pavement, the aggregates may be 90-100% on a 20 mm sieve, 45-85% on a 13 mm sieve, 27-73% on a 10 mm sieve, 5-40% on a 5 mm sieve, 5-32% on a 2.5 mm sieve, 5-32% on a 0.6 mm sieve, 5-32% on a 0.3 mm sieve, 5-32% on a 0.15 mm sieve, and 1-15% on a 0.08 mm sieve.

[0027] In one embodiment of the present disclosure, based on the sieve passing weight percentage of low-noise and water-permeable pavement, the aggregates may be 85-100% on a 13 mm sieve, 57-92% on a 10 mm sieve, 5-43% on a 5 mm sieve, 5-32% on a 2.5 mm sieve, 5-32% on a 0.6 mm sieve, 5-32% on a 0.3 mm sieve, 5-32% on a 0.15 mm sieve, and 1-15% on a 0.08 mm sieve.

[0028] In one embodiment of the present disclosure, based on the sieve passing weight percentage of low-noise and water-permeable pavement, the aggregates may be 76-100% on an 8 mm sieve, 21-76% on a 5 mm sieve, 5-42% on a 2.5 mm sieve, 2-21% on a 0.6 mm sieve, 1-20% on a 0.3 mm sieve, 1-19% on a 0.15 mm sieve, and 1-16% on a 0.08 mm sieve.

[0029] In one embodiment of the present disclosure, based on the sieve passing weight percentage of low-noise and water-permeable pavement, the aggregates may be 70-100% on a 5 mm sieve, 10-63% on a 2.5 mm sieve, 6-31% on a 0.3 mm sieve, and 1-17% on a 0.08 mm sieve.

[0030] In one embodiment of the present disclosure, based on the sieve passing weight percentage of the low-noise dense granular pavement of 13 mm, the aggregates may be 80 - 100% of the 13 mm sieve, 40 - 95% of the 10 mm sieve, 20 - 70% of the 5 mm sieve, 10 - 60% of the 2.5 mm sieve, 5 - 35% of the 1.2 mm sieve, 3 - 32% of the 0.3 mm sieve, and 1 - 25% of the 0.08 mm sieve.

[0031] In one embodiment of the present disclosure, based on the sieve passing weight percentage of the low-noise dense granular pavement of 10 mm, the aggregates may be 85 - 100% of the 10 mm sieve, 25 - 70% of the 5 mm sieve, 10 - 50% of the 2.5 mm sieve, 5 - 25% of the 1.2 mm sieve, 2 - 20% of the 0.3 mm sieve, and 1 - 15% of the 0.08 mm sieve.

[0032] In one embodiment of the present disclosure, based on the sieve passing weight percentage of the low-noise dense granular pavement of 5 mm, the aggregates may be 85 - 100% of the 5 mm sieve, 65 - 85% of the 2.5 mm sieve, 5 - 25% of the 1.2 mm sieve, 15 - 35% of the 0.3 mm sieve, and 4 - 13% of the 0.08 mm sieve. In one embodiment of the present disclosure, the aggregates may contain 0.0001 - 100% of recycled aggregates.

[0033] One embodiment of the present disclosure provides a construction method for asphalt pavement, including: a) producing the asphalt mixture; b) transporting the asphalt mixture; c) paving the asphalt mixture; and d) compacting the asphalt pavement layer.

[0034] The compacting step may include the following compaction. The compacting step may be a construction method for asphalt pavement, including performing primary compaction on the paving layer at 100 ± 10°C, secondary compaction at 90 ± 10°C, and tertiary compaction at 80 ± 10°C.

[0035] Preferably, one embodiment of the present disclosure provides a method for constructing an asphalt pavement, comprising: a) producing the asphalt mixture at 110 ± 10 °C; b) transporting the asphalt mixture at 110 ± 10 °C; c) paving the asphalt mixture at 110 ± 10 °C to form an asphalt pavement layer; d) performing primary compaction on the asphalt pavement layer at 100 ± 10 °C; e) performing secondary compaction on the asphalt pavement layer at 90 ± 10 °C; and f) performing tertiary compaction on the asphalt pavement layer at 80 ± 10 °C.

Advantages of the Invention

[0036] By using the medium- and low-temperature asphalt modifier of the present disclosure to lower the production temperature of the asphalt mixture by 40 to 60 °C or more and produce the asphalt mixture at 120 °C or lower, carbon neutrality can be achieved through energy conservation and suppression of carbon dioxide emissions. In this case, a fuel-saving effect of 60% or more and a carbon dioxide emission reduction effect are shown.

[0037] When using the medium- and low-temperature asphalt modifier of the present disclosure, by decomposing, absorbing, ion-exchanging, and chemically reacting with hydrogen sulfide, methyl mercaptan, acetaldehyde, etc., which are the causes of asphalt odor and harmful substances generated during the production process of the asphalt mixture, the effect of removing more than 99% of the asphalt odor is shown.

[0038] The high-strength medium- and low-temperature asphalt modifier of the present disclosure improves the serviceability grade of an asphalt binder of serviceability grade 64-22 to a serviceability grade of PG76-22 or higher, improves the moisture resistance of asphalt, which is a problem during low-temperature production, and can reduce the detachment and wear of aggregates on the asphalt surface. In addition, the high-strength medium- and low-temperature asphalt modifier improves the crack resistance at low temperatures and the deformation resistance at high temperatures, showing the effect of enhancing the serviceability of the asphalt pavement.

Embodiments for Carrying Out the Invention

[0039] In the present application, the term "asphalt mixture" means a state in which aggregates and asphalt are mixed before being paved on a road and compacted. In the present application, the terms "asphalt mixture" and "asphalt concrete mixture" are used interchangeably to mean the scope of the compositions and methods considered and described in the present application.

[0040] In the present application, the term "asphalt binder" means the asphalt component itself such as straight asphalt, and the term "modified asphalt binder" is a mixture of the said asphalt binder and the asphalt modifier of the present invention, and is used as a term distinguished from the asphalt mixture containing aggregates.

[0041] In the present application, the term "low- and medium-temperature asphalt modifier" or "high-strength low- and medium-temperature asphalt modifier" means an asphalt modifier that can be added to an asphalt mixture and enables the production of an asphalt mixture at low and medium temperatures of 140 °C or lower, preferably 120 °C or lower, more preferably 100 °C or lower, and can improve mechanical and mechanical properties such as the crack resistance of paved asphalt and the deformation resistance at high temperatures.

[0042] Hereinafter, the configuration of the present disclosure will be described in more detail with specific examples. However, it is obvious to those having ordinary knowledge in the technical field to which the present invention pertains that the scope of the present disclosure is not limited only to the description of the examples.

[0043] The low- and medium-temperature asphalt modifier of the present disclosure has a deodorizing function by decomposing and adsorbing substances that are the main causes of asphalt odors such as hydrogen sulfide, and can enable the production of high-strength asphalt mixtures at low and medium temperatures.

[0044] One embodiment of the present disclosure provides a high-strength medium- and low-temperature asphalt modifier comprising: i) styrenic thermoplastic elastomer powder, ii) composite process oil, iii) a tackifier resin modified with aliphatic hydrocarbons, iv) a polymer-silica nanocomposite, and v) an asphalt odor remover.

[0045] In one embodiment of the present disclosure, preferably, a high-strength medium- and low-temperature asphalt modifier is provided, comprising: i) 30 to 60 parts by weight of styrenic thermoplastic elastomer powder, ii) 40 to 60 parts by weight of composite process oil, iii) 5 to 20 parts by weight of a tackifier resin modified with aliphatic hydrocarbons, iv) 0.2 to 5 parts by weight of a polymer-silica nanocomposite, and v) 0.01 to 0.5 parts by weight of an asphalt odor remover.

[0046] More specifically, a high-strength medium- and low-temperature asphalt modifier is provided, comprising: i) 30 to 60 parts by weight of styrenic thermoplastic elastomer powder cryogenically pulverized to 0.1 to 1 mm at low temperature, ii) 40 to 60 parts by weight of composite process oil, iii) 5 to 20 parts by weight of a tackifier resin modified with aliphatic hydrocarbons, iv) 0.2 to 5 parts by weight of a polymer-silica nanocomposite, and v) 0.01 to 0.5 parts by weight of an asphalt odor remover.

[0047] In the present disclosure, the styrenic thermoplastic elastomer may be a mixture of one or more selected from polystyrene-polybutadiene-polystyrene block copolymer (SBS), styrene-butadiene rubber (SBR), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-butylene-styrene block copolymer (SEBS), and styrenic thermoplastic elastomer (STE).

[0048] In one embodiment of the present disclosure, the styrenic thermoplastic elastomer powder may be polystyrene-polybutadiene-polystyrene block copolymer (SBS) powder. Hereinafter, the components of the high-strength medium- and low-temperature asphalt modifier will be specifically described.

[0049] <Styrene-based thermoplastic elastomer powder> In the present disclosure, the styrene-based thermoplastic elastomer powder is for increasing the specific surface area and absorption rate and has a powdery form. The method for manufacturing the powder is not particularly limited. For example, it can be manufactured into a powder having a size of 0.1 to 1 mm by cryogenic grinding at a low temperature. Cryogenic grinding is a method of pulverizing a material using the low-temperature brittleness characteristic in which when a substance is cooled to a temperature below a certain level, it loses its elasticity and adhesiveness and becomes as hard as glass. As one embodiment, after cooling the styrene-based thermoplastic elastomer to -5°C to -20°C, it can be pulverized and crushed to form a powder with a uniform particle size.

[0050] The styrene-based thermoplastic elastomer may be selected from polystyrene-polybutadiene-polystyrene block copolymer (SBS), styrene-butadiene rubber (SBR), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-butylene-styrene block copolymer (SEBS), and styrene-based thermoplastic elastomer (STE). Preferably, it may be a polystyrene-polybutadiene-polystyrene block copolymer (SBS), or it may be a powder mixed with one or more of them. In the present disclosure, preferably, using a polystyrene-polybutadiene-polystyrene block copolymer (SBS) as the styrene-based thermoplastic elastomer is more preferable because it can improve the deformation resistance and low-temperature brittleness properties of the asphalt binder, but it is not limited thereto.

[0051] When adjusting the powder size of the present disclosure to 0.01 to 1 mm and manufacturing at 120°C or lower with the production temperature of the asphalt mixture lowered by 40 to 60°C, it has a high powder degree and specific surface area, and thus has a high absorption rate for the composite process oil. Therefore, more than 40% of the composite process oil contained in the high-strength medium and low-temperature asphalt modifier can be deposited in the styrene-based thermoplastic elastomer.

[0052] Generally, the melting temperature of a polystyrene - polybutadiene - polystyrene block copolymer (SBS) is as high as about 170 - 180 °C. However, in the present disclosure, when the polystyrene - polybutadiene - polystyrene block copolymer (SBS) deposits a high content of 40% or more of the composite process oil, it becomes possible to melt at a lower temperature in an asphalt plant, and it has also been found that it is possible to produce an asphalt mixture at an extremely low temperature 40 - 60 °C or lower.

[0053] In the present disclosure, the styrenic thermoplastic elastomer powder may be contained in an amount of 30 - 60% by weight based on 100% by weight of the high - strength medium - low temperature asphalt modifier. Preferably, the polystyrene - polybutadiene - polystyrene block copolymer (SBS) powder cryogenically ground to 0.1 - 1 mm at a low temperature may be contained in an amount of 30 - 60% by weight. When the polystyrene - polybutadiene - polystyrene block copolymer (SBS) powder is used in an amount of less than 30% by weight, it is difficult to ensure the grade of the high - strength medium - low temperature asphalt - modified binder to be PG 76 - 22 or higher. When used in an amount exceeding 60% by weight, it is impossible to produce an asphalt mixture at a temperature of 100 °C or lower. Therefore, the above range is preferred.

[0054] <Composite process oil> In the present disclosure, a composite process oil is used for dissolving the styrenic thermoplastic elastomer powder.

[0055] In conventional asphalt modifiers, wax or vegetable oil was added and used to lower the viscosity of the asphalt mixture. However, since the wax has a strong brittleness property at low temperatures, there is a problem that the cracking of asphalt increases in winter at low temperatures. In the case of vegetable oil, it has been found that there is a problem that the softening and oxidation of the asphalt binder increase, significantly increasing the deformation of the asphalt pavement in summer at high temperatures. Therefore, in the present disclosure, the use of wax and vegetable oil is excluded, and a composite process oil is adopted and used as a component of the asphalt modifier.

[0056] In the present disclosure, the composite process oil may be used at 40 to 60% by weight based on 100% by weight of the high-strength low-temperature asphalt modifier. When the content of the composite process oil is less than 40% by weight, the production temperature of the asphalt mixture cannot be lowered to 100°C or lower. When used in excess of 60% by weight, the content of the styrene-polybutadiene-styrene block copolymer (SBS) becomes excessively low, and the performance grade (PG) of the high-strength low-temperature asphalt cannot be made 76-22 or higher, which is not preferable.

[0057] In the present disclosure, when the composite process oil is used as a component of the asphalt modifier, the meltability of the styrenic thermoplastic elastomer powder at 100°C or lower is increased, and high softening and oxidation of the asphalt binder can be prevented, which is preferable.

[0058] As an example of the composite process oil, 5 to 20 parts by weight of polybutene or polyisoprene liquid polymer may be mixed with 100 parts by weight of process oil for production, but it is not limited as long as the object of the present invention is achieved. As the process oil, naphthenic, paraffinic, and aromatic oils may be used. Examples of the commercialized composite process oil include products such as R10 manufactured by GRT.

[0059] In one embodiment of the present disclosure, polybutene and polyisoprene can form a crosslink with an asphalt binder in an asphalt mixture together with a polystyrene-polybutadiene-polystyrene block copolymer (SBS) by a process oil. The crosslinked asphalt binder can not only prevent excessive softening and oxidation at high temperatures, but also suppress the brittleness of asphalt at low temperatures, improve the adhesion to aggregates, and improve the serviceability of asphalt pavement. The crosslink may be such that the double bonds of each component are crosslinked by heat during the heating in the production of the asphalt mixture.

[0060] <Resin tackifier modified with aliphatic hydrocarbons> The present disclosure uses a resin tackifier modified with aliphatic hydrocarbons to increase the adhesion between the asphalt binder and the aggregates and improve the adhesion of the asphalt binder.

[0061] When the production temperature of the asphalt mixture is lowered by 40 to 60 °C or more, the aggregates are not completely dried compared to general asphalt, and thus the adhesion between the asphalt binder and the aggregates can be significantly reduced due to the moisture present in the aggregates.

[0062] In addition, rosin, water-based rosin derivatives, disproportionated rosin derivatives, dimerized rosin derivatives, acid-added rosin derivatives, esterified rosin derivatives, terpene resins, terpene phenol resins, aromatic-modified terpene resins, hydrogenated terpene resins, aliphatic (C5), aromatic (C9), C5 / C9 copolymer systems, alicyclic systems, phenol, xylene, coumarone-indene resins, and ketone resins, etc., which are mainly used in the production of general asphalt modifiers, have been found to exhibit adhesiveness at high temperatures of 150 °C or higher. Therefore, it has been found that the tackifier is not suitable for use as a component of the adhesion-imparting agent in the low-temperature asphalt mixture of the present invention that produces asphalt at about 100 °C. There are many commercialized products as the tackifier, and examples include products such as Kolon P-120HS.

[0063] Therefore, in the present disclosure, when producing a high-strength medium- and low-temperature asphalt mixture, a rosin resin tackifier modified with an aliphatic hydrocarbon having a high adhesion to aggregates containing moisture and also having a high adhesion to an asphalt binder and aggregates even at a low temperature of about 100°C or lower is used, the adhesiveness between the asphalt binder and the aggregates can be increased, and excellent mechanical properties and strong resistance to brittleness can also be imparted even when producing an asphalt mixture at a low temperature.

[0064] In the present disclosure, the rosin resin modified with the aliphatic hydrocarbon can be produced by a synthesis step of a rosin polyol (or glycerin) ester by an esterification reaction of rosin and a polyol (or glycerin), a synthesis step of an aliphatic-modified rosin resin by a reaction of the rosin polyol ester and a monomer substance, and a step of removing unreacted monomers from the aliphatic-modified rosin resin by vacuum stripping.

[0065] As the polyol for the esterification reaction of the polyol and rosin, one or more of triethylene glycol, diethylene glycol, pentaerythritol, glycerol, sorbitol, trimethanolpropane, 1,4-cyclohexanedimethanol, 1,4-butanediol, and ethylene glycol may be used, but are not limited thereto.

[0066] Also, as the monomer substance for the synthesis of the aliphatic-modified rosin resin by the reaction of the rosin polyol ester and the monomer substance, one or more of C6-C22 α-olefins, monomers having a vinyl end group, C6-C22 α-β unsaturated esters and acids, and C4-C22 aliphatic-chain or cyclic acrylic acid esters may be used, but are not limited thereto.

[0067] In the present disclosure, the tackifier rosin resin modified with aliphatic hydrocarbons may be used in an amount of 5 to 20% by weight based on 100% by weight of the medium- and low-temperature asphalt modifier, but is not limited thereto as long as the object of the present invention is achieved. In the present disclosure, when the tackifier rosin resin modified with aliphatic hydrocarbons is used in an amount of less than 5% by weight, the adhesion to the aggregate containing a moisture content of 2% or more decreases, and when used in an amount exceeding 20% by weight, the melting point of the high-strength medium- and low-temperature asphalt mixture increases, and a production temperature of 140°C or higher is required, which is not preferable.

[0068] <Polymer-silica nanocomposite> In the present disclosure, a polymer-silica nanocomposite is included to improve the water resistance and oxidation resistance of the high-strength low-temperature asphalt.

[0069] The polymer-silica nanocomposite may include 10 to 20% by weight of 1 to 100 μm-sized nanoclay having an ion exchange volume of 50 to 200 meq / g and an active specific surface area of 500 to 1,000 m 2 / g, 75 to 88% by weight of 1 to 100 μm-sized nano-silica fume having an ion exchange volume of 10 to 50 meq / g and an active specific surface area of 20 to 5,000 m 2 / g, and 2 to 5% by weight of the superabsorbent resin (SAP).

[0070] Since the nanoclay has a plate-like structure with a large aspect ratio, when forming a polymer and a nanocomposite, the contact area between the clay and the polymer becomes wide, and the filling effect is significantly increased compared to conventional composites. In addition, when manufacturing the high-strength low-temperature asphalt modifier, an intercalated structure polymer-silica nanocomposite is formed, and the polymer chains are inserted into the space between the clay layers to form a structure with an increased interlayer spacing.

[0071] In addition, the random arrangement of nanoclay between asphaltene and maltene in the asphalt binder increases the tensile strength and tensile modulus of the asphalt binder, and forms chemical bonding in the asphalt binder. Therefore, the nanoclay can improve the crack resistance at low temperatures with ductile behavior. In addition, the nanoclay independently forms a silicate layer, and has an excellent anti-oxidation effect on asphalt by preventing oxygen penetration and suppressing the evaporation of volatile components in the asphalt binder. Especially, due to its large active specific surface area, it is excellent in improving the moisture resistance of the asphalt binder by absorbing the moisture contained in the aggregate during the production of high-strength medium and low-temperature asphalt mixtures.

[0072] Different from nanoclay, the nano-silica fume has a spherical surface structure, excellent dispersibility, and a large active specific surface area. Therefore, it can increase the aggregate coating thickness due to the increase in the viscosity of the asphalt binder. In addition, the nano-silica fume is randomly distributed in the asphalt binder and has a significant effect on improving the toughness characteristics of the asphalt binder and preventing the oxidation of asphalt.

[0073] The superabsorbent resin (SAP) is a cross-linked polyelectrolyte produced by partially neutralizing polyacrylic acid with caustic soda, and can absorb about 500 times or more of the surrounding water in a dry state. The superabsorbent resin is effective in improving the adhesion between asphalt and aggregate by instantaneously absorbing the moisture contained in the non-dried aggregate of high-strength medium and low-temperature asphalt, which lowers the production temperature of the asphalt mixture by 40 - 60 °C. In particular, the polymer-silica nanocomposite containing nanoclay, nano-silica fume, and superabsorbent resin can improve the moisture resistance of asphalt by simultaneously absorbing the moisture of the non-dried aggregate and blocking the moisture contact of asphalt. In addition, the moisture absorbed by the superabsorbent resin binds to nanoclay and nano-silica fume through electrostatic interaction and Coulomb interaction to form a plastic solid, improving the toughness characteristics of asphalt.

[0074] The polymer-silica nanocomposite of the present invention is used at 0.2 to 5% by weight based on 100% by weight of the high-strength medium and low-temperature asphalt modifier. When the polymer-silica nanocomposite is used at less than 0.2% by weight, the oxidation of asphalt with 40% or more of the composite process oil deposited cannot be suppressed. When used at more than 5% by weight, the setting degree at low temperature may decrease due to excessive viscosity increase. Therefore, the above range is preferable.

[0075] <Asphalt odor remover> The present invention includes an asphalt odor remover and removes harmful substances such as hydrogen sulfide, methyl mercaptan, acetaldehyde, and butyraldehyde that may be generated during the production of asphalt mixtures and during on-site construction.

[0076] The asphalt odor remover of the present invention may contain 10 to 30% by weight of essential oil having decomposition and absorption performance of harmful gases, 20 to 40% by weight of essential oil having ion exchange and reactivity, 20 to 40% by weight of carrier oil, and 30 to 40% by weight of composite process oil.

[0077] The asphalt odor remover of the present disclosure may be used to remove harmful substances such as hydrogen sulfide, methyl mercaptan, acetaldehyde, and butyraldehyde, which are the main causes of odor generation during the production of asphalt mixtures.

[0078] As the essential oil having decomposition and absorption performance of the harmful gas, one or more of Korean pine essential oil, red pine essential oil, pine needle essential oil, cypress essential oil, cedar essential oil, and eucalyptus essential oil may be used, but are not limited thereto. The essential oil having decomposition and absorption performance of the harmful gas decomposes the odor-causing substances and absorbs the gas molecules by physical filling action using van der Waals force on the surface of the fine voids composed of the molecular layer to prevent them from flowing out into the air.

[0079] Since it is difficult to completely remove the inherent odor of asphalt using only essential oils with the ability to decompose and absorb the harmful gas, the present disclosure further includes an essential oil having ion exchange and reactivity.

[0080] As the essential oil having ion exchange and reactivity, one or more of jasmine essential oil, geranium essential oil, thyme essential oil, lime essential oil, lavender essential oil, tea tree essential oil, lemon essential oil, rose essential oil, and rosemary essential oil may be used, but it is not limited thereto.

[0081] The essential oil having ion exchange and reactivity removes or transforms odor-causing substances through reversible ion exchange between ions present in the oil and harmful substances, promotes chemical phase changes with odor-removing substances, and prevents the outflow of odor-causing substances.

[0082] Among the essential oils having ion exchange and reactivity, when using highly concentrated oil as a plant-based essential oil, even a small amount can be excellent in odor decomposition and absorption. However, conversely, the fragrance of the oil itself is strong and can become an odor-causing substance of other properties. Therefore, it is important to dilute and use it.

[0083] In the present disclosure, a carrier oil is included for dilution and dispersibility of the asphalt odor remover. As the carrier oil, one or more of jojoba, olive, argan, grape seed, rose hip, coconut, almond, avocado, calendula, and canola oil may be used, but it is not limited thereto.

[0084] In the present disclosure, the asphalt odor remover may be contained in an amount of 0.01 to 5% by weight based on 100% by weight of the total high-strength medium and low-temperature asphalt modifier. When the asphalt odor remover is used in an amount of less than 0.01% by weight, the asphalt odor cannot be removed 100% during the production of the asphalt mixture, and when used in an amount exceeding 5% by weight, secondary odors caused by the essential oil may be induced.

[0085] Another embodiment of the present disclosure provides an asphalt mixture containing 80 to 96.9% by weight of aggregates, 3 to 10% by weight of asphalt, and 0.1 to 10% by weight of the above-described medium and low-temperature asphalt modifier.

[0086] When the asphalt mixture is produced in the range of 110°C ± 15°C, the carbon dioxide emissions of general asphalt concrete mixing are reduced by 60% or more. When the asphalt content in the asphalt mixture is less than 3% by weight, sufficient strength cannot be exhibited due to the decrease in the aggregate coating thickness, and when it exceeds 10% by weight, the physical performance of the asphalt mixture may deteriorate due to the drain of the asphalt binder.

[0087] When the content of the aggregates is less than 80% by weight, potholes and deformations may occur due to the ductility of the pavement body at high temperatures in summer due to the excessive asphalt content. Also, when the content of the aggregates exceeds 96.9% by weight, cracks, aggregate detachment, etc. occur due to the decrease in the binding force of the binder due to the insufficient asphalt content.

[0088] When the content of the high-strength medium and low-temperature asphalt modifier according to the present disclosure is less than 0.1% by weight, the production temperature of the asphalt mixture cannot be lowered by 40 to 60°C, and when it exceeds 10% by weight, the viscosity of the asphalt binder becomes excessively low and the asphalt mixture cannot be produced.

[0089] Based on the sieve passing weight percentage of WC-1 particle size, the aggregates of the present disclosure may be 90-100% passing through a 13 mm sieve, 76-90% passing through a 10 mm sieve, 44-74% passing through a 5 mm sieve, 28-58% passing through a 2.5 mm sieve, 11-32% passing through a 0.6 mm sieve, 5-21% passing through a 0.3 mm sieve, 3-15% passing through a 0.15 mm sieve, and 2-10% passing through a 0.08 mm sieve.

[0090] Based on the sieve passing weight percentage of WC-2 particle size, the aggregates of the present disclosure may be 95-100% passing through a 13 mm sieve, 84-92% passing through a 10 mm sieve, 55-70% passing through a 5 mm sieve, 35-50% passing through a 2.5 mm sieve, 18-30% passing through a 0.6 mm sieve, 10-21% passing through a 0.3 mm sieve, 6-16% passing through a 0.15 mm sieve, and 4-8% passing through a 0.08 mm sieve.

[0091] Based on the sieve passing weight percentage of WC-3 particle size, the aggregates of the present disclosure may be 90-100% passing through a 20 mm sieve, 72-90% passing through a 13 mm sieve, 56-80% passing through a 10 mm sieve, 35-65% passing through a 5 mm sieve, 23-49% passing through a 2.5 mm sieve, 10-28% passing through a 0.6 mm sieve, 5-19% passing through a 0.3 mm sieve, 3-13% passing through a 0.15 mm sieve, and 2-8% passing through a 0.08 mm sieve.

[0092] Based on the sieve passing weight percentage of WC-4 particle size, the aggregates of the present disclosure may be 95-100% passing through a 20 mm sieve, 75-90% passing through a 13 mm sieve, 67-84% passing through a 10 mm sieve, 45-65% passing through a 5 mm sieve, 35-50% passing through a 2.5 mm sieve, 18-30% passing through a 0.6 mm sieve, 10-21% passing through a 0.3 mm sieve, 6-16% passing through a 0.15 mm sieve, and 4-8% passing through a 0.08 mm sieve.

[0093] Based on the sieve passing weight percentage of WC-5 particle size, the aggregates of the present disclosure may be 90-100% passing through a 20 mm sieve (the reference sieve), 69-84% passing through a 13 mm sieve, 56-74% passing through a 10 mm sieve, 35-55% passing through a 5 mm sieve, 23-38% passing through a 2.5 mm sieve, 10-23% passing through a 0.6 mm sieve, 5-16% passing through a 0.3 mm sieve, 3-12% passing through a 0.15 mm sieve, and 2-10% passing through a 0.08 mm sieve.

[0094] Based on the sieve passing weight percentage of WC-6 particle size, the aggregates of the present disclosure may be 90-100% passing through a 13 mm sieve, 73-90% passing through a 10 mm sieve, 40-60% passing through a 5 mm sieve, 25-40% passing through a 2.5 mm sieve, 11-22% passing through a 0.6 mm sieve, 7-16% passing through a 0.3 mm sieve, 4-12% passing through a 0.15 mm sieve, and 3-9% passing through a 0.08 mm sieve.

[0095] Based on the sieve passing weight percentage of low-noise drainage pavement, the aggregates of the present disclosure may be 90-100% passing through a 20 mm sieve, 45-85% passing through a 13 mm sieve, 27-73% passing through a 10 mm sieve, 5-40% passing through a 5 mm sieve, 5-32% passing through a 2.5 mm sieve, 5-32% passing through a 0.6 mm sieve, 5-32% passing through a 0.3 mm sieve, 5-32% passing through a 0.15 mm sieve, and 1-15% passing through a 0.08 mm sieve.

[0096] Based on the sieve passing weight percentage of low-noise drainage pavement, the aggregates of the present disclosure may be 85-100% passing through a 13 mm sieve, 57-92% passing through a 10 mm sieve, 5-43% passing through a 5 mm sieve, 5-32% passing through a 2.5 mm sieve, 5-32% passing through a 0.6 mm sieve, 5-32% passing through a 0.3 mm sieve, 5-32% passing through a 0.15 mm sieve, and 1-15% passing through a 0.08 mm sieve.

[0097] Based on the sieve passing weight percentage of low-noise drainage pavement, the aggregates of the present disclosure may be 76-100% passing through an 8 mm sieve, 21-76% passing through a 5 mm sieve, 5-42% passing through a 2.5 mm sieve, 2-21% passing through a 0.6 mm sieve, 1-20% passing through a 0.3 mm sieve, 1-19% passing through a 0.15 mm sieve, and 1-16% passing through a 0.08 mm sieve.

[0098] Based on the sieve passing weight percentage of low-noise drainage pavement, the aggregates may be 70-100% passing through a 5 mm sieve, 10-63% passing through a 2.5 mm sieve, 6-31% passing through a 0.3 mm sieve, and 1-17% passing through a 0.08 mm sieve.

[0099] Based on the sieve passing weight percentage of the 13 mm low-noise dense gradation paving, the aggregates of the present disclosure may be 80 - 100% passing through the 13 mm sieve, 40 - 95% passing through the 10 mm sieve, 20 - 70% passing through the 5 mm sieve, 10 - 60% passing through the 2.5 mm sieve, 5 - 35% passing through the 1.2 mm sieve, 3 - 32% passing through the 0.3 mm sieve, and 1 - 25% passing through the 0.08 mm sieve.

[0100] Based on the sieve passing weight percentage of the 10 mm low-noise dense gradation paving, the aggregates of the present disclosure may be 85 - 100% passing through the 10 mm sieve, 25 - 70% passing through the 5 mm sieve, 10 - 50% passing through the 2.5 mm sieve, 5 - 25% passing through the 1.2 mm sieve, 2 - 20% passing through the 0.3 mm sieve, and 1 - 15% passing through the 0.08 mm sieve.

[0101] Based on the sieve passing weight percentage of the 5 mm low-noise dense gradation paving, the aggregates of the present disclosure may be 85 - 100% passing through the 5 mm sieve, 65 - 85% passing through the 2.5 mm sieve, 5 - 25% passing through the 1.2 mm sieve, 15 - 35% passing through the 0.3 mm sieve, and 4 - 13% passing through the 0.08 mm sieve.

[0102] Also, in one embodiment of the present disclosure, the aggregates may contain 0.0001 - 100% by weight of recycled aggregates (Recycled concrete aggregate). Here, the recycled aggregate may be recycled aggregate obtained by crushing waste asphalt concrete generated at the cutting or repair site of aged asphalt concrete paving and classifying the size according to the application. In the present disclosure, the filler may mean a filler such as lime content, slaked lime, recovered dust, etc.

[0103] The present disclosure provides a method for constructing an asphalt pavement using the above-described asphalt mixture. The asphalt pavement is produced by mixing aggregates, fillers, etc. with straight asphalt in a plant to produce an asphalt concrete mixture, then transporting it to the site and constructing it using a paving device and a compaction device.

[0104] One embodiment of the present disclosure provides a method for constructing an asphalt pavement, including: a) producing the asphalt mixture; b) transporting the asphalt mixture; c) paving the asphalt mixture; and d) compacting the asphalt pavement layer.

[0105] The compacting step may include a method for constructing an asphalt pavement, which includes performing primary compaction on the pavement layer at 100 ± 10 °C, performing secondary compaction at 90 ± 10 °C, and performing tertiary compaction at 80 ± 10 °C.

[0106] Specifically, the method for constructing an asphalt pavement of the present disclosure includes: a) producing the asphalt mixture at 110 ± 10 °C; b) transporting the asphalt mixture at 110 ± 10 °C; c) paving the asphalt mixture at 110 ± 10 °C to form an asphalt pavement layer; d) performing primary compaction (macadam roller) on the asphalt pavement layer at 100 ± 10 °C; e) performing secondary compaction (tire roller) on the asphalt pavement layer at 90 ± 10 °C; and f) performing tertiary compaction (tandem roller) on the asphalt pavement layer at 80 ± 10 °C.

[0107] Production Example 1: Production of the asphalt modifier and modified asphalt binder according to the present invention Example 1 A low-temperature asphalt modifier was prepared by mixing 45 wt% polystyrene-polybutadiene-polystyrene block copolymer (SBS) powder pulverized to a size of 0.1 to 1 mm at low temperature, 45 wt% composite process oil (GTR R10) made by mixing 75 parts by weight of paraffin oil and 25 parts by weight of liquid polybutadiene, 5 wt% rosin resin tackifier (Kolon P-120HS) modified with aliphatic hydrocarbon, 4.97 wt% polymer-silica nanocomposite (15 wt% bentonite, 83 wt% nano silica fume (CHEMICON Sioxid Co., Ltd.), and 2 wt% SAP (LG chem)), and 0.03 wt% asphalt odor eliminator (Hansoo Road Ind., Asmell Cut) (Asmell Cut by Hansoo Natech Co., Ltd.). 14 parts by weight of the asphalt modifier produced above and 86 parts by weight of straight asphalt (PG 64-22) were mixed to produce a modified asphalt binder.

[0108] The asphalt binder modified using the modified asphalt binder was tested for penetration, elongation, softening point, and elastic recovery rate, and the results are shown in Table 1.

[0109] <Comparative Example 1> The properties were evaluated in the same manner as in Example 1, except that the modified asphalt binder was prepared by mixing 2 parts by weight of EOC-200WMA product and 98 parts by weight of straight asphalt (PG 64-22) as the asphalt modifier. The results are shown in Table 1.

[0110] <Comparative Example 2> The asphalt binder was tested for penetration, elongation, softening point, and elastic recovery rate using 100 parts by weight of straight asphalt (PG 64-22) without using any asphalt modifier. The results are shown in Table 1.

[0111] [Table 1]

[0112] In Example 1, it was revealed that the test results of penetration and softening point far exceeded the quality standards of modified asphalt of the Ministry of Land, Infrastructure, Transport and Tourism. In particular, Example 1 improved the low softening point of the asphalt binder, which was the most serious problem of conventional asphalt, to 80°C or higher, and the elongation rate characteristics at low temperature were 78 cm or more, demonstrating its effectiveness in improving low-temperature cracking resistance. There was no significant difference in terms of effectiveness between Comparative Example 1 and Comparative Example 2 which did not use additives.

[0113] The elastic recovery rate of the asphalt binder is the most important characteristic of road paving materials that are subject to repeated loads. In the case of both domestic and US scenarios, it is recommended that the numerical value be at least 60% or more. In the case of Example 1, it was confirmed to have an elastic recovery rate of 85% or more, while in the cases of Comparative Example 1 and Comparative Example 2, the elastic recovery rate was shown to be a low value of approximately 40%.

[0114] <Example 2> Production of asphalt mixture The medium and low temperature asphalt modifier of Example 1, straight asphalt (Exxon Mobile PG 64-22), aggregate (aggregate with the specifications in Table 2), and hydrated lime as a filler were mixed at the weight composition ratios described in Table 3 below and mixed at 160°C, 140°C, 120°C, and 100°C to produce an asphalt mixture. The mechanical properties were measured using the said mixture and shown in Table 4, the carbon dioxide reduction amount was shown in Table 5, and the deodorizing property was shown in Table 6.

[0115]

Table 2

[0116] <Comparative Example 3> An asphalt modifier was produced in the same manner as in Example 1, except that a medium temperature additive was mixed at the composition ratio as shown in Table 3 below. Its mechanical properties are shown in Table 4, the carbon dioxide reduction amount is shown in Table 5, and the deodorizing property is shown in Table 6.

[0117] <Comparative Example 4> The procedure was the same as in Example 1, except that no modifier was used. The results are shown in Table 4, the carbon dioxide reduction amount is shown in Table 5, and the deodorizing property is shown in Table 6.

[0118]

Table 3

[0119]

Table 4

[0120] The Marshall stability and dynamic stability of Example 2 showed 10,000 N and 4,000 times / mm or more, respectively, regardless of the production temperature of the asphalt mixture. This meets the quality standards of the modified asphalt of the Ministry of Land, Infrastructure, Transport and Tourism. In particular, in Example 2, even when the production temperature of the asphalt mixture was as low as 100 °C, it was possible to produce the mixture and ensure the quality standards.

[0121] In the case of Comparative Example 3, at the production temperature of 140 °C of the asphalt mixture, the quality standards of domestic asphalt pavement were met, but below 120 °C, the quality decreased significantly. In the case of Comparative Example 4, below the production temperature of 140 °C of the asphalt mixture, the quality decreased significantly and could not meet the domestic standards.

[0122] The above results showed a similar trend in the test results of the porosity and indirect tensile strength. Table 5 shows the test results of the energy consumption and carbon dioxide emissions according to the production temperature of the asphalt mixture.

[0123]

Table 5

[0124] It can be seen that in Example 2, Comparative Example 3, and Comparative Example 4, the energy consumption is significantly reduced along with the carbon dioxide emissions due to the lower production temperature of the asphalt mixture.

[0125] When the production temperature of the asphalt mixture is reduced by 40 to 60 °C, the carbon dioxide emissions and energy consumption are reduced by 40 to 60%. In particular, when the production temperature of the asphalt mixture is 120 °C or lower, harmful gases including carbon dioxide are significantly reduced, and an energy-saving effect is expected by setting the production temperature of the asphalt mixture to 120 °C or lower.

[0126] Table 6 shows the test results of the generation of harmful substances in the asphalt mixture according to the production temperature of the asphalt mixture in Example 2, Comparative Example 3, and Comparative Example 4. The content of harmful substances was measured by gas chromatography according to the malodor process test method immediately after the production of the asphalt mixture corresponding to each temperature.

[0127]

Table 6

[0128] As a result of the malodor process test in Example 2, it was confirmed that hydrogen sulfide was not detected regardless of the production temperature of the asphalt mixture, indicating that the high-strength medium- and low-temperature modifier has excellent asphalt odor removal effect. In contrast, in Comparative Example 3 and Comparative Example 4, hydrogen sulfide was detected at all temperatures regardless of the production temperature of the asphalt mixture.

[0129] Also, in the case of Example 2, no harmful gases such as acetaldehyde and butyraldehyde were detected when the production temperature of the asphalt mixture was 140 °C or lower. However, in Comparative Example 3 and Comparative Example 4, although the detected amount decreased as the production temperature of the asphalt mixture decreased, the reduction amplitude was not large.

[0130] The asphalt modifier according to the present invention can remove 99% or more of the odor-causing substances generated during the production of asphalt mixtures, thereby reducing the generation of complaints against asphalt odors by improving the environment of the surroundings of asphalt plants and asphalt paving sites and the workers.

Claims

1. i) a styrene-based thermoplastic elastomer powder, ii) a composite process oil, iii) a tackifier including a rosin resin or an aromatic petroleum resin modified with an aliphatic hydrocarbon, iv) a polymer-silica nanocomposite, and v) an asphalt odor eliminator; The composite process oil is produced by mixing 5 to 20 parts by weight of polybutene or polyisoprene liquid polymer with 100 parts by weight of process oil, The polymer-silica nanocomposite is a low- to medium-temperature asphalt modifier comprising 10-20 wt. % nanoclay, 75-88 wt. % nanosilica fume, and 2-5 wt. % superabsorbent polymer (SAP).

2. 2. The medium-low temperature asphalt modifier according to claim 1, wherein the styrene-based thermoplastic elastomer powder is one or more selected from polystyrene-polybutadiene-polystyrene block copolymer (SBS), styrene-butadiene rubber (SBR), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-butylene-styrene block copolymer (SEBS), and styrene-based thermoplastic elastomer (STE).

3. 2. The medium-low temperature asphalt modifier according to claim 1, comprising, relative to a total of 100% by weight of the medium-low temperature asphalt modifier, i) 30 to 45% by weight of a styrene-based thermoplastic elastomer powder, ii) 40 to 60% by weight of a composite process oil, iii) 5 to 20% by weight of a rosin resin modified with an aliphatic hydrocarbon as a tackifier, iv) 0.2 to 5% by weight of a polymer-silica nanocomposite, and v) 0.01 to 0.5% by weight of an asphalt odor eliminator.

4. The medium-low temperature asphalt modifier according to claim 1, wherein the asphalt odor eliminator comprises 10 to 30% by weight of an essential oil having the ability to decompose and absorb harmful gases, 20 to 40% by weight of an essential oil having ion exchange and reactivity, 20 to 40% by weight of a carrier oil, and 30 to 40% by weight of a mixture of process oil and liquid polymer.

5. i) Aggregates 80-96.9% by weight, ii) 3 to 10 wt. % asphalt, and iii) An asphalt mixture comprising 0.1 to 10 wt. % of the medium-low temperature asphalt modifier of claim 1.

6. The asphalt mixture according to claim 5, which, when produced at a temperature in the range of 110°C ± 15°C, reduces carbon dioxide emissions by 60% or more compared to a normal asphalt mixture that does not contain the medium-low temperature asphalt modifier according to claim 1 or 2.

7. The asphalt mixture according to claim 5, wherein the aggregates contain 0.0001-100% by weight of recycled aggregate.

8. a) producing an asphalt mixture according to claim 5; b) transporting the asphalt mixture; c) paving the asphalt mixture to form an asphalt pavement layer; d) compacting the asphalt pavement layer; A method for constructing asphalt pavement, including:

9. The asphalt pavement construction method according to claim 8, wherein the asphalt mixture is produced at 110±10°C.

10. The asphalt pavement construction method according to claim 8 , wherein the compaction steps are performed at different temperatures for each compaction step.

11. 11. The asphalt pavement construction method of claim 10, wherein the compaction step includes a step of performing a first compaction at 100±10°C, a step of performing a second compaction at 90±10°C, and a step of performing a third compaction at 80±10°C.