Biomass-Based Eco-Friendly Asphalt Recycling Additive Composition, Method for Manufacturing the Same, and Recycled Hot Mix Asphalt Mixture Comprising the Same

Abstract

The present invention relates to an eco-friendly asphalt regeneration additive composition comprising 75 to 80 parts by weight of TMPTO, a biomass-derived triester-based oil, 20 to 25 parts by weight of natural phospholipid-based soybean lecithin, and 0.1 to 1.5 parts by weight of a phenolic or amine-based antioxidant that is liquid at room temperature and has a molecular weight of 300 or more, forming a single-phase homogeneous structure under conditions of 50 to 60°C, a method for manufacturing the same, and a circulating heated asphalt mixture containing the same. Since it can be manufactured by low-temperature stirring at 50 to 60°C without a dissolution process of solid additives, it saves energy and fundamentally prevents the deterioration of natural raw materials, fully satisfies the GR F 4005 standard, and achieves Marshall stability of 8,450 to 8,620 N and TSR of 88 to 92%.

Description

Technology Field

[0001] The present invention relates to an asphalt regeneration additive composition and a circulating heated asphalt mixture using the same. More specifically, the invention relates to an eco-friendly asphalt regeneration additive composition that uses biomass-derived triester-based oil (TMPTO) and natural phospholipid-based soybean lecithin as main components, introduces a room-temperature liquid high molecular weight antioxidant to achieve a completely homogeneous phase through a low-temperature stirring process of 50 to 60°C, thereby fundamentally preventing the deterioration of natural raw materials and perfectly satisfying GR (Excellent Recycled Product) standards, a method for manufacturing the same, and a circulating heated asphalt mixture containing the same. Background Technology

[0002] Asphalt regeneration additives are widely used to recycle reclaimed asphalt pavement (RAP) from conventionally aged road pavements. These additives are key materials that reduce the viscosity of aged asphalt and restore its flexibility, enabling recycled mixtures to exhibit mechanical performance equivalent to that of new mixtures.

[0003] However, widely used petroleum-based regenerative additives (aromatic and naphthenic oils) contain harmful substances such as polycyclic aromatic hydrocarbons (PAHs), and their use is being restricted along with stricter environmental regulations. Accordingly, there are attempts to apply simple vegetable oils as substitutes, but vegetable oils have limitations in that they have low viscosity and are difficult to meet the kinematic viscosity standard (50–175 cSt) at 60°C of the GR standard.

[0004] To improve viscosity, methods are being attempted to add solid petroleum resins or powdered antioxidants, but a high-temperature stirring process of over 100°C is essential to completely dissolve these solid additives. The high-temperature process not only consumes a huge amount of energy but also causes thermal oxidation and cooking reactions of natural phospholipid-based additives, leading to fatal problems such as an increase in viscosity ratio and a decrease in the mechanical performance of the mixture after the RTFO test.

[0005] In addition, low molecular weight powdered antioxidants (e.g., BHT) are relatively soluble at low temperatures, but they volatilize significantly at the RTFO test temperature (163°C), exceeding the mass loss criteria and losing their antioxidant function.

[0006] Accordingly, there is a need to develop an eco-friendly asphalt regeneration additive composition and a method for manufacturing the same that uses 100% biomass-derived raw materials, satisfies the strict physical property standards of GR standards, and can be manufactured in a low-temperature process of 50 to 60°C without a dissolution process of solid additives, thereby preventing the deterioration of natural additives. The problem to be solved

[0007] The present invention was devised to solve the problems of the aforementioned prior art, and firstly, provides an eco-friendly asphalt regeneration additive composition that uses only 100% biomass-derived raw materials to completely exclude harmful substances such as PAHs, satisfies all the strict physical property standards of GR standards, and forms a single-phase homogeneous structure without phase separation.

[0008] Second, the invention provides an asphalt regeneration additive composition with significantly improved water resistance (TSR) by maximizing the bonding strength with the surface of acidic aggregates through the utilization of the amphoteric surfactant action of natural phospholipid-based soybean lecithin.

[0009] Third, the present invention provides a method for manufacturing an asphalt regeneration additive that introduces a high molecular weight antioxidant that is liquid at room temperature and has a molecular weight of 300 or more, thereby achieving a completely homogeneous phase with only a low-temperature stirring process of 50 to 60°C without a heating process of 100°C or more and a dissolution process of solid additives, and fundamentally blocking thermal oxidation of natural additives.

[0010] Fourth, the above-mentioned regenerative additive composition is applied to provide a circulated heated asphalt mixture that satisfies mechanical performance standards of Marshall stability of 7,500 N or higher and an indirect tensile strength ratio (TSR) of 80% or higher.

[0011] The problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0012] A biomass-based eco-friendly asphalt regeneration additive composition according to one embodiment of the present invention comprises: (a) 75 parts by weight or more and 80 parts by weight or less of TMPTO (Trimethylolpropane trioleate), a biomass-derived triester-based oil; (b) 20 parts by weight or more and 25 parts by weight or less of soy lecithin, a natural phospholipid-based thickener and aggregate adhesion-imparting agent; and (c) 0.1 parts by weight or more and 1.5 parts by weight or less of a phenolic or amine-based antioxidant that is liquid at room temperature and has a molecular weight of 300 or more, and can form a single-phase homogeneous structure in which phase separation does not occur under conditions of 50 to 60°C.

[0013] According to one embodiment of the present invention, the composition forms a single phase in which phase separation does not occur and can have storage stability for 7 days or more at 25°C.

[0014] According to one embodiment of the present invention, the composition can satisfy the following (Formula 1) when the weight part of TMPTO is A and the weight part of soybean lecithin is B.

[0015] (Formula 1) 0.25 ≤ B / A ≤ 0.33

[0016] (Equation 1) represents the optimal mixing ratio range of soybean lecithin relative to TMPTO, and is a condition for simultaneously achieving an indirect tensile strength ratio (TSR) of 80% or more while satisfying the GR specification range (50~175 cSt) for the kinematic viscosity of the composition at 60°C.

[0017] According to one embodiment of the present invention, the antioxidant may not substantially volatilize under RTFO (163°C) test conditions.

[0018] According to one embodiment of the present invention, the composition can simultaneously satisfy a kinematic viscosity of 50 cSt or more and 175 cSt or less at 60°C, a viscosity ratio after RTFO of 3.0 or less, and a mass change rate of 4.0% or less.

[0019] According to one embodiment of the present invention, the soybean lecithin combines with the surface of the aggregate to form a water-repellent coating layer, and can improve the indirect tensile strength ratio (TSR) according to KS F 2398 to 80% or more.

[0020] A method for preparing a biomass-based eco-friendly asphalt regeneration additive composition according to one embodiment of the present invention comprises: (a) a step of introducing TMPTO into a reactor and heating it to 50°C to 60°C; (b) a step of first introducing a liquid antioxidant into the heated TMPTO and performing primary homogenization stirring for 5 minutes to 30 minutes; and (c) a step of introducing soybean lecithin while maintaining a temperature of 50°C to 60°C and homogenizing it by secondary stirring for 20 minutes to 60 minutes, thereby preventing thermal oxidation of the soybean lecithin. Step (b) is performed prior to the introduction of soybean lecithin to suppress the oxidation environment, and the method does not include a heating process of 100°C or higher and a dissolution process of a solid additive.

[0021] A recycled heated asphalt mixture according to one embodiment of the present invention comprises the biomass-based eco-friendly asphalt regeneration additive composition; recycled aggregate (RAP); and a novel asphalt binder, wherein the recycled aggregate (RAP) may be included in an amount of 20% by weight or more and 50% by weight or less relative to the total mixture. The mixture simultaneously satisfies a Marshall stability of 7,500 N or more according to KS F 2337 and an indirect tensile strength ratio (TSR) of 80% or more according to KS F 2398, and preferably satisfies a Marshall stability of 8,000 N or more and a TSR of 85% or more.

[0022] The means to be solved by the present invention are not limited to the means mentioned above, and other unmentioned means will be clearly understood by those skilled in the art to which the present invention belongs from the description below. Effects of the invention

[0023] According to the present invention, the following effects can be achieved.

[0024] First, by using only 100% biomass-derived raw materials (TMPTO, soybean lecithin), it is possible to completely eliminate harmful substances such as PAHs and ensure eco-friendliness, while also satisfying all of the GR standard (GR F 4005) RA-1 criteria, including kinematic viscosity at 60°C (50~175 cSt), flash point (219°C or higher), mass change rate after RTFO (4.0% or lower), and viscosity ratio after RTFO (3.0 or lower).

[0025] Second, by introducing a room-temperature liquid high molecular weight antioxidant, the process temperature can be reduced by about 40–50% to 50–60°C compared to the existing high-temperature process (over 100°C), thereby reducing energy consumption and preventing thermal oxidation of soybean lecithin at the source, thus ensuring the stability of the physical properties of the composition.

[0026] Third, the amphiphilic surfactant structure of soybean lecithin forms a strong bond with the surface of acidic aggregate to form a water-repellent coating film, thereby achieving an indirect tensile strength ratio (TSR) of 88–92% and significantly improving moisture resistance.

[0027] Fourth, the recycled heated asphalt mixture with the above-mentioned regenerative additive can achieve a Marshall stability of 8,450 to 8,620 N, which is about 12 to 15% higher than the GR standard (7,500 N), thereby providing excellent resistance to plastic deformation.

[0028] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description below. Specific details for implementing the invention

[0029] Specific details of other embodiments are included in the detailed description and drawings.

[0030] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. Unless otherwise specified in the following description, all numbers, values, and / or expressions representing components, reaction conditions, and the content of components in the present invention should be understood as being modified by the term "approximately" in all cases, as these numbers are approximations reflecting the various uncertainties of measurement that occur in obtaining these values ​​among essentially different things. Furthermore, where a numerical range is disclosed in this description, such range is continuous and, unless otherwise indicated, includes all values ​​from the minimum value of such range to the maximum value including the maximum value. Furthermore, where such range refers to an integer, it includes all integers from the minimum value to the maximum value including the maximum value, unless otherwise indicated.

[0031] Additionally, when a range is described for a variable in the present invention, it will be understood that the variable includes all values ​​within the described range, including the described endpoints of the range. For example, the range "5 to 10" will be understood to include not only the values ​​5, 6, 7, 8, 9, and 10, but also any sub-ranges such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, etc., and any values ​​between integers valid for the category of the described range, such as 5.5, 6.5, 7.5, 5.5 to 8.5, and 6.5 to 9. For example, the range “10% to 30%” will be understood to include all integers including values ​​such as 10%, 11%, 12%, 13%, etc. and up to 30%, as well as any sub-range such as 10% to 15%, 12% to 18%, 20% to 30%, etc., and any value between valid integers within the stated range category such as 10.5%, 15.5%, 25.5%, etc.

[0032] A biomass-based eco-friendly asphalt regeneration additive composition according to one embodiment of the present invention comprises: (a) 75 parts by weight or more and 80 parts by weight or less of TMPTO (Trimethylolpropane trioleate), a biomass-derived tryster-based oil; (b) 20 parts by weight or more and 25 parts by weight or less of soy lecithin, a natural phospholipid-based thickener and aggregate adhesion-imparting agent; and (c) 0.1 parts by weight or more and 1.5 parts by weight or less of a phenolic or amine-based antioxidant that is liquid at room temperature and has a molecular weight of 300 or more, and is characterized by forming a single-phase homogeneous structure in which phase separation does not occur under conditions of 50 to 60°C.

[0033] According to one embodiment of the present invention, the composition forms a single phase in which phase separation does not occur and has storage stability for 7 days or more at 25°C. Here, a single phase refers to a storage stable state in which there is no layer separation or precipitation when observed visually, and the composition maintains a homogeneous appearance that is transparent or translucent, and there is no phase separation, precipitation, or change in viscosity even when stored at 25°C for 7 days or more.

[0034] Hereinafter, each component of the biomass-based eco-friendly asphalt regeneration additive composition of the present invention will be described in detail.

[0035] (1) Trimethylolpropane trioleate (TMPTO)

[0036] TMPTO is a biomass-derived oil with a triester structure (molecular formula C63H116O6) in which oleic acid is ester-bonded to three hydroxyl groups (-OH) of trimethylolpropane. Multiple highly polar ester bonds (-C(=O)O-) within the molecule interact strongly with the polar functional groups of aggregated asphaltenes in aged asphalt, redispersing the asphaltenes into fine particles and restoring the flexibility of the asphalt. It has a flash point of over 300°C, is 100% biodegradable, and emits no VOCs, making it highly eco-friendly.

[0037] The reason for limiting the content of TMPTO to 75 parts by weight or more and 80 parts by weight or less is as follows. If the TMPTO content is less than 75 parts by weight, there is a problem in that the absolute amount of ester bonds required for asphaltene redispersion is insufficient, resulting in a kinematic viscosity at 60°C exceeding 175 cSt or insufficient restoration of flexibility in aged asphalt. On the other hand, if the TMPTO content exceeds 80 parts by weight, the relative content of soybean lecithin decreases, which may lead to a reduction in bonding strength with the aggregate surface and a risk that the indirect tensile strength ratio (TSR) may fall below the target value. Therefore, by controlling the TMPTO content to 75 parts by weight or more and 80 parts by weight or less, it is possible to simultaneously achieve an appropriate viscosity and an excellent asphaltene redispersion effect.

[0039] (2) Soy Lecithin

[0040] According to one embodiment of the present invention, the soybean lecithin combines with the surface of the aggregate to form a water-repellent coating layer and improves the indirect tensile strength ratio (TSR) according to KS F 2398 to 80% or more. Specifically, the soybean lecithin is a natural phospholipid mixture extracted from soybeans, and has phosphatidylcholine, phosphatidylethanolamine, etc. as main components. Among the amphiphilic structures of the soybean lecithin, the polar head portion (phosphate group -PO4-, amine group -N+) forms strong hydrogen bonds and electrostatic attraction with the silanol group (-SiOH) on the surface of the acidic aggregate, and the hydrophobic tail portion fuses with the asphalt matrix to form a water-repellent coating film, thereby maximizing water resistance (TSR). In addition, it has a higher viscosity than TMPTO and performs the role of thickening to adjust the kinematic viscosity of the composition at 60°C to within the GR specification range.

[0041] The reason for limiting the content of soybean lecithin to 20 parts by weight or more and 25 parts by weight or less is as follows. If the soybean lecithin content is less than 20 parts by weight, a phospholipid molecular layer sufficiently covering the aggregate surface is not formed, resulting in the indirect tensile strength ratio (TSR) falling short of the target value (80% or more) and the kinematic viscosity of the composition at 60°C failing to meet the lower limit of the GR specification (50 cSt). On the other hand, if the soybean lecithin content exceeds 25 parts by weight, the viscosity increases excessively, causing the kinematic viscosity at 60°C to exceed the upper limit of the specification (175 cSt), and a problem may arise where homogeneous mixing during the low-temperature stirring process becomes difficult. Therefore, by controlling the soybean lecithin content to 20 parts by weight or more and 25 parts by weight or less, excellent aggregate adhesion and moisture resistance can be achieved while maintaining the GR specification viscosity range.

[0043] (3) Liquid antioxidant

[0044] According to one embodiment of the present invention, the liquid antioxidant does not substantially volatilize under RTFO (163°C) test conditions. The antioxidant used in the present invention is a phenolic or amine-based antioxidant that is liquid at room temperature (25°C) and has a molecular weight of 300 or more. Representative examples include hindered phenolic Irganox L-135 (liquid, molecular weight about 775) and aromatic amine-based Irganox L-57 (liquid), but are not limited thereto; antioxidants such as sulfur-based (thio-based) or phosphorus-based (phosphite-based) that are liquid at room temperature and have a molecular weight of 300 or more may also be used. Such high molecular weight liquid antioxidants have excellent compatibility with TMPTO, so they are uniformly mixed even at low temperatures of 50 to 60°C, and under RTFO test conditions (163°C, 85 min), the vapor pressure is low and volatilization is suppressed, so the mass change rate criterion (4.0% or less) can be stably satisfied.

[0045] On the other hand, powdered high molecular weight antioxidants (e.g., Irganox 1010, molecular weight 1,178, melting point 110–125°C) require a high temperature of over 100°C for complete dissolution, which causes deterioration of soybean lecithin, and low molecular weight powdered antioxidants (e.g., BHT, molecular weight 220, boiling point 265°C) volatilize in large quantities at the RTFO test temperature (163°C), resulting in problems that exceed the standards for mass change rate and viscosity ratio. The present invention solves these two problems simultaneously by adopting a room temperature liquid high molecular weight antioxidant.

[0046] The reason for limiting the content of the liquid antioxidant to 0.1 parts by weight or more and 1.5 parts by weight or less is as follows. If the liquid antioxidant is less than 0.1 parts by weight, the oxidation chain reaction of lecithin and esters caused by free radicals under RTFO test conditions (163°C, 85 min) is not sufficiently suppressed, resulting in a problem where the viscosity ratio exceeds the standard value (3.0). On the other hand, if it exceeds 1.5 parts by weight, the cost increases without any additional performance improvement effect, and there is a risk of exceeding the kinematic viscosity range of the GR standard due to changes in viscosity. Therefore, by controlling the liquid antioxidant to 0.1 parts by weight or more and 1.5 parts by weight or less, the viscosity ratio standard after RTFO (3.0 or less) and the mass change rate standard (4.0% or less) can be stably met.

[0047] According to one embodiment of the present invention, the composition comprising the three-component combination satisfies a kinematic viscosity of 50 cSt or more and 175 cSt or less at 60°C, a viscosity ratio after RTFO of 3.0 or less, and a mass change rate of 4.0% or less. This satisfies all physical property items of the GR F 4005 RA-1 standard and is the result of the combined action of the content range of each component and the high molecular weight characteristics of the liquid antioxidant.

[0048] According to one embodiment of the present invention, the composition satisfies the following (Formula 1) when the weight part of TMPTO is A and the weight part of soybean lecithin is B.

[0049] (Formula 1) 0.25 ≤ B / A ≤ 0.33

[0050] (Equation 1) represents the optimal mixing ratio range of soybean lecithin relative to TMPTO. If B / A is less than 0.25, the absolute amount of soybean lecithin is insufficient, which may result in insufficient aggregate surface coating and a risk that the TSR may drop below the target value. On the other hand, if B / A exceeds 0.33, there is a risk that the kinematic viscosity of the composition at 60°C may exceed the upper limit of the GR specification (175 cSt) due to an excess of lecithin. Example 1 (A=79.5, B=20.0, B / A=0.252) and Example 2 (A=76.5, B=23.0, B / A=0.301) of the present invention are both within the range of (Equation 1), and it was confirmed that they satisfy all physical properties and Marshall stability criteria based on GR F 4005 RA-1.

[0051] A method for preparing a biomass-based eco-friendly asphalt regeneration additive composition according to one embodiment of the present invention comprises: (a) a step of introducing TMPTO into a reactor and heating it to 50°C to 60°C; (b) a step of introducing a liquid antioxidant into the heated TMPTO and performing first homogenization stirring for 5 minutes or more and 30 minutes or less; and (c) a step of introducing soybean lecithin while maintaining a temperature of 50°C to 60°C and homogenizing it by secondary stirring for 20 minutes or more and 60 minutes or less, thereby preventing thermal oxidation of the soybean lecithin.

[0052] Each step is explained in detail below.

[0054] (Step a) TMPTO heating step

[0055] TMPTO is introduced into a reactor and heated to 50°C to 60°C. The reason for limiting the heating temperature to between 50°C and 60°C is as follows. If the heating temperature is below 50°C, the viscosity of TMPTO is not sufficiently reduced, making it difficult to achieve homogeneous mixing with the liquid antioxidant and soybean lecithin in subsequent steps. On the other hand, if the temperature exceeds 60°C, it is undesirable as there is a risk that thermal oxidation of the soybean lecithin may begin during the stirring process. Compared to conventional technologies using powdered antioxidants or solid petroleum resins, which require high temperatures of 100°C or higher, the present invention completes the process at only a low temperature of 50 to 60°C, thereby reducing energy consumption by approximately 40 to 50%.

[0057] (Step b) First stirring step of the liquid antioxidant

[0058] According to one embodiment of the present invention, step (b) is performed prior to the addition of soybean lecithin to suppress the exposure of soybean lecithin to an oxidizing environment. A liquid antioxidant is added to heated TMPTO before soybean lecithin, and primary homogeneous stirring is performed for 5 minutes or more and 30 minutes or less. By completely dispersing the antioxidant in TMPTO before the addition of soybean lecithin, exposure of soybean lecithin to an oxidizing environment in subsequent steps is blocked. This pre-mixing sequence is a key technical feature of the present invention, and the oxidation inhibition effect of lecithin is significantly improved compared to cases where the antioxidant is added later or simultaneously with soybean lecithin. Limiting the primary stirring time to 5 minutes or more is intended to ensure uniform dispersion, and since exceeding 30 minutes only increases the process time without additional dispersion effects, the upper limit is set to 30 minutes.

[0060] (Step c) Secondary stirring step of soybean lecithin

[0061] Soy lecithin is added while maintaining a temperature of 50°C to 60°C, and homogenized by secondary stirring for 20 minutes or more and 60 minutes or less. At this stage, soy lecithin is uniformly dispersed within the TMPTO substrate to form a single-phase structure without phase separation. The reason for limiting the secondary stirring time to 20 minutes or more is that this is the minimum time required for soy lecithin to be uniformly dispersed and form a stable single-phase composition. Since exceeding 60 minutes only increases energy consumption without further improvement in homogeneity, the upper limit is set to 60 minutes.

[0062] According to one embodiment of the present invention, the manufacturing method does not include a heating process of 100°C or higher. Conventional techniques using solid additives (powdered Irganox 1010, C9 petroleum resin, etc.) inevitably require high temperatures of 100°C or higher for dissolution, which causes thermal oxidation and carbonization of soybean lecithin. The present invention fundamentally solves this problem by adopting a room-temperature liquid high molecular weight antioxidant.

[0063] According to one embodiment of the present invention, the manufacturing method does not include a dissolution process of a solid additive. This means that the entire process proceeds by mixing only liquid components at a low temperature of 50 to 60°C, providing the combined advantages of improved energy efficiency, protection of natural raw materials, and simplified process management.

[0064] A circulating heated asphalt mixture according to one embodiment of the present invention comprises a biomass-based eco-friendly asphalt regeneration additive composition according to any one of claims 1 to 6; recycled aggregate (RAP); and a novel asphalt binder. Each component is described below.

[0065] According to one embodiment of the present invention, the recycled aggregate (RAP) is included in an amount of 20% by weight or more and 50% by weight or less relative to the total mixture. RAP is a material recovered by cutting and crushing existing asphalt pavement, and includes aged asphalt binder and aggregate. If the RAP is less than 20% by weight, the recycling effect is negligible, and if it exceeds 50% by weight, the proportion of aged asphalt is excessive, making it difficult to restore sufficient performance using only the regeneration additive. Preferably, it is applied based on 30% by weight of RAP.

[0066] According to one embodiment of the present invention, the circulated heated asphalt mixture simultaneously satisfies a Marshall stability of 7,500 N or more according to KS F 2337 and an indirect tensile strength ratio (TSR) of 80% or more according to KS F 2398. This is a level that meets the standards for circulated heated asphalt mixtures for surface layers in GR F 4005.

[0067] According to one embodiment of the present invention, the circulated heated asphalt mixture satisfies a Marshall stability of 8,000 N or more according to KS F 2337 and an indirect tensile strength ratio (TSR) of 85% or more according to KS F 2398. This is a superior performance level exceeding the GR F 4005 standard and is supported by Example 1 (Marshall stability 8,450 N, TSR 88%) and Example 2 (Marshall stability 8,620 N, TSR 92%) of the present invention.

[0068] Hereinafter, the test specifications used for the performance evaluation of the present invention will be described.

[0069] GR F 4005 is a standard for recycled heated asphalt mixtures among the Good Recycled (GR) certification standards of the Korea Environmental Industry & Technology Institute, and specifies the physical property standards for recycling additives and the mechanical performance standards for asphalt mixtures. The recycling additives are subject to the RA-1 grade standards (kinematic viscosity at 60°C 50~175 cSt, flash point 219°C or higher, mass change rate after RTFO 4.0% or lower, viscosity ratio after RTFO 3.0 or lower).

[0070] The RTFO (Rolling Thin Film Oven) test is a thin-film heating test that simulates short-term aging by heating asphalt material in the form of a rotating thin film at 163°C for 85 minutes (in accordance with KS M 2259). Thermal and oxidation stability are evaluated by measuring the mass change rate (%) and viscosity ratio (viscosity after test / viscosity before test) after the test.

[0071] KS F 2337 is a test method for the resistance of bitumen mixtures to plastic flow using a Marshall tester. A load is applied to a specimen prepared under specified conditions (60°C water bath, 50 compactions on each side) to measure the maximum load (Marshall stability, N) and the corresponding deformation amount (flow value, 0.1 mm). According to GR F 4005 standards, the Marshall stability of a circulating heated asphalt mixture for surface layers must satisfy 7,500 N or more, and the flow value must satisfy 20 to 40 (0.1 mm).

[0072] KS F 2398 is a test method for the indirect tensile strength of bitumen mixtures, which measures the indirect tensile strength (ITS) by applying a load in the diametrical direction to a cylindrical specimen. The Tensile Strength Ratio (TSR) is the ratio (%) of the indirect tensile strength under water immersion conditions to the indirect tensile strength under dry conditions, and is an indicator for evaluating the moisture resistance (stripping resistance) of asphalt mixtures. According to GR F 4005 standards, the TSR must satisfy at least 80%.

[0074] (Example)

[0075] An embodiment of the present invention will be described.

[0076] To demonstrate the effects of the present invention, specimens of the regenerative additives of Examples 1 and 2 and Comparative Examples 1 to 4 were prepared with the following composition ratios (parts by weight) and process conditions, and their physical properties and mechanical performance were evaluated. Examples 1 and 2 are the optimal compositions according to the present invention, Comparative Example 1 is the case where no antioxidant is added, Comparative Example 2 is the case where a powdered high molecular weight antioxidant (Irganox 1010) is applied (high temperature process), Comparative Example 3 is the case where a low molecular weight powdered antioxidant (BHT) is applied, and Comparative Example 4 is the case where C9 petroleum resin is applied instead of soybean lecithin.

[0078] [Example 1 ― Composition and Manufacturing Conditions]

[0079] Table 1 below shows the composition (parts by weight) and manufacturing conditions of the regenerative additive specimen.

[0080] division TMPTO (parts by weight) Soy lecithin (parts by weight) Antioxidant (parts by weight) Stirring temperature (°C) note Example 1 79.5 20.0 Liquid phenolic (L-135) 0.5 55 Optimal of the present invention Example 2 76.5 23.0 Liquid Mixed Type (L-135+L-57) 0.5 60 The present invention (high viscosity) Comparative Example 1 80.0 20.0 None (0) 60 No added antioxidants Comparative Example 2 79.5 20.0 Powder form (Irganox 1010) 0.5 120 High-temperature process (powdered polymer) Comparative Example 3 79.0 20.0 Powder type (BHT) 1.0 70 Low molecular weight powder type application Comparative Example 4 79.5 C9 Petroleum Balance 20.0 Liquid phenolic (L-135) 0.5 130 Existing petroleum-based thickeners

[0081] As shown in Table 1, Examples 1 and 2 of the present invention were prepared by mixing 75 to 80 parts by weight of TMPTO, 20 to 25 parts by weight of soybean lecithin, and 0.5 parts by weight of a room-temperature liquid antioxidant in a low-temperature stirring process at 50 to 60°C. In contrast, Comparative Example 2 inevitably required a high-temperature process at 120°C to dissolve powdered Irganox 1010, and Comparative Example 4 required a high-temperature process at 130°C to dissolve C9 solid petroleum resin. This demonstrates that the process temperature of the present invention is reduced by approximately 40 to 50% compared to existing technology, thereby significantly improving energy efficiency.

[0083] [Example 2 ― Evaluation of Physical Properties]

[0084] The physical properties of Examples 1 and 2 and Comparative Examples 1 to 4 were evaluated according to the GR F 4005 regenerating additive RA-1 standard.

[0085] Table 2 shows the results of the physical property test of the regenerating additive (based on GR F 4005 RA-1).

[0086] division 60°C kinematic viscosity (cSt) Flash point (°C) Mass change rate (%) after RTFO Viscosity ratio after RTFO Mixture TSR (%) Overall judgment Standard value 50~175 219 or higher 4.0 or lower 3.0 or lower 80 or more - Example 1 82 312 0.8 1.5 88 Passed Example 2 128 315 0.6 1.3 92 Passed Comparative Example 1 79 308 2.5 3.9 (Exceeds) 86 Failure Comparative Example 2 188 (exceeds) 305 1.2 1.9 78 Failure Comparative Example 3 81 302 4.6 (Exceeds) 3.4 (Exceeds) 85 Failure Comparative Example 4 75 290 1.0 1.6 72 (Underperformed) Failure

[0087] As confirmed in Table 2, Example 1 of the present invention (kinematic viscosity at 60°C 82 cSt, flash point 312°C, mass change rate after RTFO 0.8%, viscosity ratio 1.5, TSR 88%) and Example 2 (kinematic viscosity 128 cSt, flash point 315°C, mass change rate after RTFO 0.6%, viscosity ratio 1.3, TSR 92%) satisfied all items of the GR F 4005 RA-1 standard.

[0089] Comparative Example 1 exceeded the standard (3.0) with a viscosity ratio of 3.9 during the RTFO test due to the absence of an antioxidant. Comparative Example 2 exceeded the upper specification limit (175 cSt) with an initial kinematic viscosity of 188 cSt due to the degradation and polymerization of soybean lecithin caused by the high-temperature process (120°C). Comparative Example 3 exceeded the standard with both a mass change rate of 4.6% and a viscosity ratio of 3.4 due to volatilization during the RTFO test of BHT (molecular weight 220). Comparative Example 4 fell short of the standard (80%) with a TSR of 72% due to the lack of natural surfactant function caused by the use of C9 petroleum resin.

[0091] [Example 3 ― Evaluation of Mechanical Performance]

[0092] Recycled heated asphalt mixture specimens were prepared by mixing the regeneration additives of the examples and comparative examples with 30 wt% aged recycled aggregate (RAP) and new asphalt binder / aggregate, and Marshall stability and flow value according to KS F 2337 and the indirect tensile strength ratio (TSR) according to KS F 2398 were measured.

[0093] Table 3 shows the results of the mechanical performance test of the circulating heated asphalt mixture (for surface layer).

[0094] division Marshall stability (N) Flow value (0.1 mm) Indirect Tensile Strength Ratio (TSR, %) Overall judgment GR F 4005 standard 7,500 or more 20~40 80 or more - Example 1 8,450 28 88 Excellent (Passed) Example 2 8,620 26 92 Top (Passed) Comparative Example 1 (No antioxidant added) 8,900 15 (Underperformed) 86 Fail (Insufficient flow value / Brittleness) Comparative Example 2 (High-temperature process / Lecithin degradation) 6,800 (Underperformed) 35 78 Failed (insufficient stability) Comparative Example 3 (Volatile Antioxidant) 8,750 18 (Underperformed) 85 Fail (Flow value insufficient) Comparative Example 4 (Petroleum-based thickener) 7,100 (Underperformed) 30 72 (Underperformed) Failed (Stability / TSR insufficient)

[0095] As can be seen in Table 3, Example 1 of the present invention (Marshall stability 8,450 N, flow value 28, TSR 88%) and Example 2 (Marshall stability 8,620 N, flow value 26, TSR 92%) both exceeded the GR F 4005 standard (Marshall stability 7,500 N or higher, flow value 20–40, TSR 80% or higher), and also satisfied the upper standard of Marshall stability 8,000 N or higher and TSR 85% or higher. The Marshall stability is about 12–15% higher than the standard value, and the flow value is located near the median value (26–28) of the specification range (20–40), ensuring appropriate flexibility.

[0096] Comparative Example 1 (no antioxidant added) had a high Marshall stability (8,900 N), but the flow value was 15, which fell short of the lower limit of the specification (20), showing a brittle phenomenon in the mixture. Comparative Example 2 (high-temperature process) had a Marshall stability of 6,800 N, which fell short of the standard value due to the loss of bonding strength at the aggregate-binder interface caused by lecithin degradation. Comparative Example 3 (BHT applied) had a flow value of 18, which fell short of the standard due to prolonged oxidation after the antioxidant volatilized. Comparative Example 4 (petroleum-based thickener) had a Marshall stability of 7,100 N and a TSR of 72%, which fell short of the standard for both items.

[0097] From the above results, it was confirmed that only the three-component combination of the present invention (75-80 parts by weight of TMPTO + 20-25 parts by weight of soybean lecithin + 0.1-1.5 parts by weight of room temperature liquid high molecular weight antioxidant) and the low-temperature stirring manufacturing process are the optimal technical means to simultaneously satisfy all criteria of GR F 4005.

[0098] A person skilled in the art to which the present invention pertains will understand that the present invention may be implemented in other specific forms without altering its technical concept or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included within the scope of the present invention.

Claims

Claim 1 A biomass-based eco-friendly asphalt regeneration additive composition comprising: (a) 75 parts by weight or more and 80 parts by weight or less of TMPTO (Trimethylolpropane trioleate), a biomass-derived triester-based oil; (b) 20 parts by weight or more and 25 parts by weight or less of soy lecithin, a natural phospholipid-based thickener and aggregate adhesion-imparting agent; and (c) 0.1 parts by weight or more and 1.5 parts by weight or less of a phenolic or amine-based antioxidant that is liquid at room temperature and has a molecular weight of 300 or more; wherein the composition forms a single-phase homogeneous structure in which phase separation does not occur under conditions of 50 to 60°C, and has storage stability in which phase separation, precipitation, or viscosity change does not occur when stored at 25°C for 7 days or more. Claim 2 A biomass-based eco-friendly asphalt regeneration additive composition according to claim 1, characterized in that the composition simultaneously satisfies a kinematic viscosity of 50 cSt or more and 175 cSt or less at 60°C, a viscosity ratio after RTFO of 3.0 or less, and a mass change rate after RTFO of 4.0% or less. Claim 3 A biomass-based eco-friendly asphalt regeneration additive composition according to claim 1, characterized in that the composition satisfies the following (Formula 1), where the weight part of TMPTO is A and the weight part of soybean lecithin is B. (Formula 1) 0.25 ≤ B / A ≤ 0.33 Claim 4 A biomass-based eco-friendly asphalt regeneration additive composition according to claim 1, characterized in that the liquid antioxidant does not substantially volatilize under RTFO (163°C) test conditions. Claim 5 A method for manufacturing a biomass-based eco-friendly asphalt regeneration additive composition according to claim 1, comprising: (a) a step of introducing TMPTO into a reactor and heating it to 50°C to 60°C; (b) a step of first introducing the liquid antioxidant into the heated TMPTO and performing primary homogenization stirring for 5 minutes to 30 minutes; and (c) a step of introducing the soybean lecithin while maintaining the temperature of 50°C to 60°C and homogenizing it by secondary stirring for 20 minutes to 60 minutes; wherein the method is characterized by preventing thermal oxidation of the soybean lecithin. Claim 6 A method for manufacturing a biomass-based eco-friendly asphalt regeneration additive composition, characterized in that, in claim 5, step (b) is performed prior to the addition of soybean lecithin to suppress an oxidizing environment, and the manufacturing method does not include a heating process of 100°C or higher and a dissolution process of a solid additive. Claim 7 A recycled heated asphalt mixture characterized by comprising: a biomass-based eco-friendly asphalt recycling additive composition according to any one of claims 1 to 4; recycled aggregate (RAP); and a novel asphalt binder. Claim 8 A recycled heated asphalt mixture according to claim 7, characterized in that the recycled aggregate (RAP) is included in an amount of 20% by weight or more and 50% by weight or less relative to the total mixture. Claim 9 In claim 7, the circulated heated asphalt mixture is characterized by having a Marshall stability of 7,500 N or more according to KS F 2337 and an indirect tensile strength ratio (TSR) of 80% or more according to KS F 2398. Claim 10 In claim 7, the circulated heated asphalt mixture is characterized by having a Marshall stability of 8,000 N or more according to KS F 2337 and an indirect tensile strength ratio (TSR) of 85% or more according to KS F 2398.