Vegetable asphalt, asphalt mixtures, and methods for applying asphalt mixtures

Abstract

The goal is to further improve the heat resistance of plant-based asphalt. [Solution] A plant-based asphalt comprising a vegetable oil with an iodine value of less than 130 and a terpene resin which is a homopolymer of terpene monomers and has a molecular weight of 1000 or more.

Description

Technical Field

[0001] The present disclosure relates to vegetable asphalt composed of a predetermined vegetable oil and a terpene resin, an asphalt mixture using the vegetable asphalt, and a method for constructing an asphalt mixture using the vegetable asphalt.

Background Art

[0002] With the recent decrease in oil demand, the introduction of alternative materials for petroleum asphalt (see Patent Document 1) is desired. Also, from the perspective of building a recycling-based society, effective utilization of asphalt pavement generated materials, i.e., asphalt recycled aggregates, is desired. Therefore, in this field, attempts have been made to use vegetable asphalt composed of non-petroleum-based components, for example, various plant-derived components, as an alternative to petroleum asphalt or to utilize it for the reuse of asphalt recycled aggregates.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the field of general petroleum asphalt, heated asphalt and aggregates are mixed to produce an asphalt mixture, which is then applied under high-temperature conditions. For example, Patent Document 1 discloses that conventional asphalt mixtures are mixed and manufactured at 160°C to 170°C and applied at 130°C to 140°C (see paragraph

[0003] of the specification of Patent Document 1). When applying vegetable asphalt to an asphalt mixture, deterioration during the manufacturing and application of the mixture using this vegetable asphalt, i.e., deterioration during thin-film heating, should be suppressed as much as possible. For this reason, in this type of technology, efforts should be made to improve the heat resistance of vegetable asphalt, but development from this perspective has not progressed sufficiently. This disclosure was conceived in view of the above points, and the problem that this disclosure aims to solve is to further improve the heat resistance of vegetable asphalt. [Means for solving the problem]

[0005] According to one feature of this disclosure, vegetable asphalt is a homopolymer of vegetable oil with an iodine value of less than 130 and terpene monomers. There Molecular weight 1000 or more Furthermore, the softening point is less than 125°C. It consists of a terpene resin. The vegetable asphalt of this disclosure consists of a vegetable oil with a low degree of unsaturation and a high molecular weight that does not contain phenols (aromatic compounds). Furthermore, the softening point is less than 125°C. It consists of terpene resins, and its composition contributes to improved heat resistance by suppressing oxidative degradation of each component when heated.

[0006] Furthermore, one preferred embodiment of the plant-based asphalt does not contain petroleum-derived substances. Since the plant-based asphalt of this disclosure does not contain petroleum-derived substances, it can be suitably used as a substitute material for petroleum asphalt. Petroleum-derived substances are substances made from crude oil, and examples include various petroleum asphalts obtained by distilling crude oil, mineral oils (such as naphthenic oil and paraffin oil), and petroleum resins.

[0007] In one preferred embodiment of the vegetable asphalt, the vegetable oil is one or more vegetable oils selected from olive oil, rice bran oil, rapeseed oil, and waste cooking oil. In this disclosure, the use of specific types of vegetable oils can more reliably improve the heat resistance of the vegetable asphalt.

[0008] In one preferred embodiment of the vegetable asphalt, when the total amount of vegetable oil and terpene resin is 100 parts by weight, the vegetable oil is contained in 25 to 31 parts by weight. In this disclosure, the use of a specific content of vegetable oil can be used to further reliably improve the heat resistance of the vegetable asphalt.

[0009] This disclosure also provides an asphalt mixture using any one of the above-mentioned vegetable asphalts. This asphalt mixture includes vegetable asphalt containing 28 parts by weight or more of vegetable oil when the total amount of vegetable oil and terpene resin is 100 parts by weight, and recycled asphalt aggregate. This disclosure makes it possible to more reliably improve the physical properties of the asphalt mixture containing recycled asphalt aggregate through the action of the vegetable asphalt.

[0010] This disclosure also provides a method for constructing an asphalt mixture using one of the above-mentioned vegetable asphalts. In this method, the asphalt mixture, which is a mixture of vegetable asphalt and aggregates, is manufactured and constructed at 130°C to 150°C. This disclosure makes it possible to manufacture and construct an asphalt mixture under high-temperature conditions using vegetable asphalt and aggregates with desired heat resistance. [Effects of the Invention]

[0011] According to this disclosure, the heat resistance of plant-based asphalt can be further improved. Furthermore, according to this disclosure, the function of plant-based asphalt enables the reuse of recycled asphalt aggregate. And according to this disclosure, asphalt mixtures using plant-based asphalt can be manufactured and applied under high-temperature conditions. [Modes for carrying out the invention]

[0012] [Vegetable-based asphalt] The vegetable asphalt of this disclosure is a binder containing vegetable oil and terpene resin in predetermined proportions, and can be used, for example, as a substitute for petroleum asphalt. This vegetable asphalt consists of the two components described above (both non-petroleum components) and does not contain any petroleum-derived substances. Furthermore, since this type of vegetable asphalt is applied under heating conditions, as described later, it is desirable that it has the desired heat resistance. Therefore, in this disclosure, the heat resistance of the vegetable asphalt is further improved by using vegetable oil and terpene resin, as described later. The composition of this disclosure will be described below in the order of vegetable oil, terpene resin, and asphalt mixture.

[0013] [Vegetable oil] First, the vegetable oil in this disclosure is a vegetable oil containing unsaturated fatty acids and has a predetermined iodine value. Here, an unsaturated fatty acid is a fatty acid that has a methyl group and a carboxyl group at the ends of the hydrocarbon molecular chain, and has one or more unsaturated carbon bonds (double bonds) in the molecular chain, and ω3, ω6, or ω9 fatty acids can be exemplified. In the vegetable asphalt in this disclosure, the inclusion of a vegetable oil with an iodine value of less than 130, preferably 125 or less, and more preferably 115 or less, i.e., a vegetable oil with a low degree of unsaturation, makes it easier to ensure the desired heat resistance (see "Penetration Residue Rate After Thin Film Heating" etc. in [Table 1] below). Here, the iodine value is expressed as the number of grams of iodine I2 that can be added to 100g of oil. When a vegetable oil with an iodine value of 130 or more is used, it becomes difficult to ensure the heat resistance of the vegetable asphalt, and the acceptable ratio of vegetable oil content becomes extremely narrow, making it unsuitable for practical use.

[0014] The type of vegetable oil disclosed herein is not particularly limited, but one or more vegetable oils selected from the group consisting of olive oil, rice bran oil, rapeseed oil, and waste cooking oil (recycled oil) can be used. As the waste cooking oil, oils and fats refined from used cooking oil (such as tempura oil) can be used, and those adjusted to have an iodine value of less than 130, preferably 125 or less, and more preferably 115 or less can be suitably used. The lower limit of the iodine value of the vegetable oil is not particularly limited, but vegetable oils with an iodine value of 80 or higher (for example, the iodine value of olive oil is 82.3) have been experimentally proven to be practical.

[0015] [Terpene resin] Next, the terpene resin of this disclosure is a homopolymer of terpene monomers (polyterpene resin) and has a predetermined molecular weight. This type of terpene resin is a resin synthesized from naturally derived raw materials and can be obtained from pine trees or orange peels. Furthermore, since the terpene resin is a homopolymer of terpene monomers, it does not contain phenols (aromatic compounds) with a conjugated structure. For this reason, the terpene resin of this disclosure has a different chemical structure from terpenephenol resins, which are copolymers of terpene monomers and phenols, and is relatively less likely to bond with oxygen and has excellent heat resistance (see "Penetration Residue Rate After Thin Film Heating" etc. in [Table 2] below). Furthermore, the terpene resin of this disclosure has a molecular weight of 1000 or more, and more preferably 1300 or more. The molecular weight of this terpene resin can be measured by "gel permeation chromatography (GPC)". Furthermore, by using one or more types of high molecular weight terpene resins, the heat resistance of plant-based asphalt can be more reliably improved (see "Penetration Residue Rate After Thin Film Heating" etc. in [Tables 2] and [Table 3] below). Furthermore, in the case of terpene resins with a molecular weight of less than 1000, it may be difficult to adequately ensure the heat resistance of plant-based asphalt, and heat resistance cannot be ensured at molecular weights of 800 or less. Although there is no particular upper limit to the molecular weight of the terpene resin disclosed herein, considering the test results, it is estimated that the desired effect can be obtained in the range of molecular weight 1000 to 2000, preferably 1000 to 1700, more preferably 1000 to 1400, and even more preferably 1000 to 1350. Moreover, by setting the softening point of the terpene resin disclosed herein to less than 125°C, preferably 110°C to 120°C, it becomes easier to ensure the desired degree of penetration of plant-based asphalt and the like.

[0016] [Asphalt mixture] Furthermore, the asphalt mixture described herein can be obtained by mixing the above-mentioned vegetable asphalt with various aggregates (new aggregate, recycled asphalt aggregate). The aggregate content in the asphalt mixture is not particularly limited, but is preferably 90% to 98% by mass. The ratio of vegetable oil to terpene resin in the vegetable asphalt can be set according to the type of aggregate described later. Below, we will explain the details of the usable aggregates, namely new aggregate and recycled asphalt aggregate, and the ratio of vegetable oil to terpene resin corresponding to each aggregate.

[0017] [New aggregate] First, examples of new aggregates include crushed stone, crushed stone, gravel, sand, or mixtures thereof, and further, fillers may be included. Examples of this type of filler include stone powder, talc, calcium carbonate, or mixtures thereof. In addition to the new aggregates described above, the asphalt mixture of this disclosure may also contain various additives. Examples of this type of additive include peeling inhibitors such as slaked lime, amines, and amides; fibrous reinforcing materials such as methylcellulose and polyvinyl alcohol; elasticity improvers; viscosity reducers; viscosity improvers; fillers; pigments; softeners; antioxidants; ultraviolet absorbers; and light stabilizers.

[0018] [Ratio of vegetable oil and terpene resin content (1)] In asphalt mixtures containing new aggregates, various physical properties such as heat resistance can be more reliably ensured by adjusting the content ratio of vegetable oil and terpene resin in the vegetable asphalt. For example, if the total amount of terpene resin and vegetable oil is 100 parts by weight, the content of vegetable oil can be adjusted to obtain the target physical properties, for example, within the range of 23 to 32 parts by weight. When using terpene resin with a molecular weight of 1000 to 1350 and vegetable oil with an iodine value of less than 130 (preferably less than 120), the content of vegetable oil is set to a range of more than 24 parts by weight and less than 32 parts by weight, preferably in the range of 25 to 31 parts by weight (see [Table 5] below). This makes it possible to more reliably ensure the desired physical properties of the asphalt mixture while further reliably improving the heat resistance of the vegetable asphalt. The heat resistance of the vegetable asphalt can be evaluated by the value of the "penetration retention rate after thin film heating" described later. Furthermore, it is desirable that the plant-based asphalt not only satisfies the numerical value for "residual penetration after thin film heating," but also exhibits a good numerical value for "thin film heating mass change rate."

[0019] [Recycled asphalt aggregate] Next, recycled asphalt aggregate can be obtained by crushing and classifying used asphalt pavement. The physical properties of this type of recycled asphalt aggregate are not particularly limited, but for example, the crushing coefficient is 2.2 MPa / mm or less, preferably 2.0 MPa / mm or less, and more preferably 1.7 MPa / mm or less. It is also desirable that the amount of deteriorated asphalt (old asphalt) in the recycled asphalt aggregate is 3.8% or more. The penetration of the old asphalt is not particularly limited as it varies depending on the degree of deterioration, but it is preferably 10 (1 / 10 mm) or more, and more preferably 20 (1 / 10 mm) or more.

[0020] Then, after the asphalt recycled aggregate is adjusted to a predetermined particle size range by various classification methods such as sieving, it is used in an asphalt mixture (hereinafter referred to as recycled asphalt mixture). Here, in the recycled asphalt mixture, generally, the asphalt recycled aggregate and new aggregate can be combined and used. By adjusting the ratio of the asphalt recycled aggregate and the new aggregate, etc., the synthetic particle size can be set to conform to the target particle size range, for example, the particle size range of a dense particle size asphalt mixture (maximum particle size 13 mm) or the like. Although a recycled asphalt mixture consisting only of asphalt recycled aggregate (100% recycling rate) is not common at present, according to the present disclosure, it is possible to produce such a recycled asphalt mixture. In this case, it is desirable to obtain populations with different particle sizes by a classification method such as sieving. By adjusting the blending ratio of each population, the synthetic particle size can be made to conform to the target particle size range.

[0021] [Content ratio of vegetable oil and terpene resin (2)] Also in the recycled asphalt mixture, by adjusting the content ratio of the vegetable oil and terpene resin in the vegetable asphalt, various physical properties can be more reliably ensured. And the content ratio of the vegetable oil and terpene resin can be set mainly according to the physical properties of the old asphalt. At this time, by increasing the blending ratio of the vegetable oil, the permeability to the old asphalt is improved, and it becomes easier to recover the physical properties such as its penetration. Therefore, vegetable asphalt can also be expected to serve as a recycled additive used for the purpose of recovering the penetration. So, when the total of the terpene resin and vegetable oil is 100 parts by weight, the content of the vegetable oil can be adjusted so as to obtain the target physical properties, for example, it can be adjusted to exceed 27 parts by weight. That is, since the penetration of the old asphalt is decreased, it is desirable to use a relatively large amount of vegetable oil. And when using a terpene resin having a molecular weight of 1000 to 1350 and a vegetable oil having an iodine value of less than 130 (preferably less than 120), the content of the vegetable oil is set in the range of exceeding 27 parts by weight and less than 57 parts by weight, preferably 28 parts by weight or more (see [Table 6] below). Thereby, the physical properties of the recycled asphalt mixture can be more reliably improved by the action of the vegetable asphalt.

[0022] Here, the total amount of asphalt in the recycled asphalt mixture is not particularly limited and can be adjusted according to various target values (or known reference values). When combining recycled asphalt aggregates and new aggregates, or when using only recycled asphalt aggregates, the amount of vegetable asphalt can be used to supplement the difference between the designed asphalt amount and the amount of old asphalt, so that the total asphalt amount can be adjusted to various target values. And the content ratio of vegetable asphalt and old asphalt in the total asphalt amount is set according to the target value, etc., and can be set, for example, in the range of old asphalt: vegetable asphalt = 25:75 to 90:10.

[0023] [Method for manufacturing and constructing asphalt mixture] The method for manufacturing the asphalt mixture of the present disclosure is not particularly limited. For example, a method of mixing vegetable asphalt heated to about 150°C and aggregates can be exemplified. Subsequently, the manufactured asphalt mixture is constructed at a predetermined location to form an asphalt pavement. And the vegetable asphalt of the present disclosure has improved heat resistance by containing a specific vegetable oil and terpene resin in a predetermined ratio. For this reason, an asphalt mixture containing vegetable asphalt and aggregates can be manufactured and constructed at the same manufacturing temperature and construction temperature as petroleum asphalt, for example, 130°C to 150°C. In particular, the terpene resin of the present disclosure is set to have a softening point of 110°C to 120°C, so that it can be relatively easily mixed with vegetable oil at about 150°C. And the vegetable asphalt can be constructed in the range of 130°C to 150°C together with the aggregates while maintaining its mixed state appropriately. Thus, according to the present disclosure, since an asphalt pavement having desired physical properties can be formed, the vegetable asphalt can be suitably used as a substitute material for petroleum asphalt. Similarly, the recycled asphalt mixture can also be manufactured and constructed under the above-mentioned conditions, and as a result, an asphalt pavement having desired physical properties can be formed. Therefore, due to the function of the vegetable asphalt, the recycled asphalt aggregates can be reused.

[0024] As explained above, the plant-based asphalt of this disclosure consists of a low-unsaturation vegetable oil and a high-molecular-weight terpene resin that does not contain phenols (aromatic compounds). This composition suppresses oxidative degradation of each component during heating, thereby contributing to improved heat resistance. Therefore, according to this disclosure, the heat resistance of plant-based asphalt can be further improved. Furthermore, according to this disclosure, recycled asphalt aggregate can be reused thanks to the properties of the plant-based asphalt. And according to this disclosure, asphalt mixtures using plant-based asphalt can be manufactured and applied under high-temperature conditions.

[0025] [Example Test] The disclosure will be explained in detail below with reference to several test examples, but this disclosure is not limited to these test examples. Tables 1 to 3 below are tables showing the test results of various types of vegetable asphalt. Table 4 is a table showing the test results and reference values ​​of straight asphalt as a reference example. Table 5 shows the mass change rate and penetration rate when the blending ratio of vegetable oil and terpene resin is changed, and the test results of asphalt mixtures using these vegetable asphalts. Table 6 is a table showing the test results of recycled asphalt mixtures using vegetable asphalt.

[0026] [Oil and fat components] In this study, various oil components were selected and used in vegetable asphalt, etc. The vegetable oils used in each table included soybean oil (iodine value 130.8), olive oil (iodine value 82.3), rice bran oil (iodine value 105), linseed oil (iodine value 197.3), rapeseed oil (iodine value 95, manufactured by Miyoshi Oil & Fat Co., Ltd., product name Fine Oil N), and recycled cooking oil (iodine value 113, manufactured by Miyoshi Oil & Fat Co., Ltd., product name ISB-7R), which were selected as appropriate. In Table 5, naphthenic oil (manufactured by Sankyo Oil & Fat Industry Co., Ltd., product name Krisef Oil) was used as the petroleum-based oil component (mineral oil). Note that the recycled cooking oil is not limited to the examples above; for example, refined oil No. 2 (iodine value 110, manufactured by Tsukuno Oleochemicals Co., Ltd.) can also be used.

[0027] [Resin components] In this study, various resin components were appropriately selected and used in plant-based asphalt and other materials. For each table, the following terpene resin components were appropriately selected and used: Polyterpene resin A (softening point 115, molecular weight 1000, manufactured by Yasuhara Chemical Co., Ltd., product name YS Resin PX1150), Polyterpene resin B (softening point 115, molecular weight 1350, manufactured by Yasuhara Chemical Co., Ltd., product name YS Resin PX1150N), Polyterpene resin C (softening point 100, molecular weight 800, manufactured by Yasuhara Chemical Co., Ltd., product name PX1000), Polyterpene resin D (softening point 80, molecular weight 700, manufactured by Yasuhara Chemical Co., Ltd., product name PX800), Terpene phenol resin A (softening point 125, manufactured by Yasuhara Chemical Co., Ltd., product name YS Polystar G125), and Terpene phenol resin B (softening point 115, manufactured by Yasuhara Chemical Co., Ltd., product name YS Polystar T115). In addition, other resin components such as ester gum (softening point 85, manufactured by Arakawa Chemical Industries, Ltd., product name Ester Gum AA-L), rosin ester (softening point 105, manufactured by Arakawa Chemical Industries, Ltd., product name Pencel GA-100), and disproportionated rosin (softening point 93, manufactured by Harima Chemicals, Ltd., product name Hariester DS-90S) were selected and used as appropriate. Furthermore, in [Table 5], C9 petroleum resin (manufactured by ENEOS Material Corporation, product name Nisseki Neopolymer 120) was used as the petroleum-based resin component.

[0028] [Method for preparing plant-based asphalt samples] For the preparation of the plant-based asphalt samples shown in [Table 1] to [Table 3] below, the oil component heated to 150°C ± 5°C and the resin component heated to 150°C ± 5°C were mixed in a homomixer. If no clumps of resin component were visually observed during mixing, it was determined that the oil component and resin component were mixed (dispersed).

[0029] [Method for preparing asphalt mixture samples] Furthermore, in each sample (asphalt mixture) shown in [Table 5] below, 5.6 parts by weight of asphalt was mixed with 94.4 parts by weight of new aggregate. Each sample in [Table 5] was prepared by setting the mixing temperature of the asphalt and new aggregate to 150°C ± 5°C and the compaction temperature (corresponding to the construction temperature) to 130°C ± 5°C. Furthermore, in each sample (recycled asphalt mixture) shown in [Table 6] below below, recycled aggregate was used as the recycled asphalt aggregate with a crushing coefficient of 2.0 MPa / mm and 4.99% by weight of old asphalt (in this test, UV-degraded straight asphalt), and the penetration of the old asphalt was 13 (1 / 10 mm). The particle size range of the recycled asphalt aggregate was matched to the particle size range of the dense-graded asphalt mixture (maximum particle size 13 mm). For each sample in [Table 6], the total amount of old asphalt and vegetable asphalt was designed to be 5.3% by weight of the total weight of the mixture (content ratio: old asphalt:vegetable asphalt = 80:20). In the preparation of each sample in [Table 6], the mixing temperature was set to 150°C ± 5°C and the compaction temperature was set to 130°C ± 5°C.

[0030] Furthermore, in the asphalt mixtures containing StAs60 / 80 (Reference Example 1) and StAs80 / 100 (Reference Example 2) shown in [Table 4] below, 5.6 parts by weight of asphalt were mixed with 94.4 parts by weight of new aggregate in each case. In the preparation of each reference example, the mixing temperature was set to 160°C ± 5°C and the compaction temperature was set to 140°C ± 5°C.

[0031] [Test Method] In each table, "Thin Film Heating Mass Change Rate" and "Residual Penetration Rate after Thin Film Heating" were measured according to the method described in "A046 Thin Film Heating Test Method" of the Pavement Survey and Testing Methods Handbook. Furthermore, "(Initial) Penetration," "Marshall Stability (Standard)," "Flow Value," "Water Immersion Marshall Stability (60℃, 48h)," and "Residual Stability" were measured according to the method described in "B001 Marshall Stability Test Method" of the Pavement Survey and Testing Methods Handbook compiled by the Japan Road Association. In addition, "Dynamic Stability" and "Settlement after 60 minutes" were calculated by performing a wheel tracking test according to the method described in "B003 Wheel Tracking Test Method" of the Pavement Survey and Testing Methods Handbook compiled by the Japan Road Association. Finally, "Bending Strength at Fracture" was measured according to the method described in "B005 Bending Test Method" of the Pavement Survey and Testing Methods Handbook compiled by the Japan Road Association.

[0032] [Selection of oil and fat components] Table 1 below shows the test results for plant-based asphalt composed of various oil and fat components and polyterpene resin B as a resin component. In this test, the selection criteria for the oil and fat components were based on the ratio of penetration before and after thin film heating, i.e., the "penetration retention rate after thin film heating (hereinafter simply referred to as penetration retention rate)". In Table 1, from the perspective of relatively strictly evaluating the heat resistance of the oil and fat components, the standard value for the penetration retention rate was set to 55% or higher, and values ​​that do not meet the standard are underlined.

[0033] [Table 1]

[0034] The results in [Table 1] show that vegetable asphalt containing linseed oil (iodine value 197.3) (comparative example) had a remarkably low penetration retention rate and poor heat resistance (see samples No. 4A, 10A, and 16A in Table 1). Furthermore, vegetable asphalt containing soybean oil (iodine value 130.8) (comparative example) showed that the penetration retention rate decreased drastically as the soybean oil content increased, making it unsuitable for practical use (see samples No. 1A, 7A, and 13A in Table 1).

[0035] From the results in [Table 1], it was found that the vegetable asphalts (examples) containing olive oil (iodine value 82.3), rice oil (iodine value 105), rapeseed oil (iodine value 95), and recycled oil (iodine value 113) all had high penetration retention rates, indicating that oxidation of the vegetable oil during heating was suppressed (see samples No. 2A-6A, 8A-12A, 14A-18A in Table 1 (excluding 4A, 10A, and 16A)). From the above, it was found that, when focusing on heat resistance, vegetable oils with an iodine value of less than 130 can be suitably used in the vegetable asphalts of this disclosure, and in particular, one or more vegetable oils selected from olive oil, rice oil, rapeseed oil, and waste cooking oil (recycled oil) can be suitably used.

[0036] [Selection of resin components] Table 2 below shows the test results for various resin components and vegetable asphalt composed of rapeseed oil or waste cooking oil (recycled oil). In this test, the main selection criterion for the resin component was the penetration rate, with the "thin film heating mass change rate" being considered as a supplementary criterion. In Table 2, heat resistance was evaluated using a practically acceptable standard, with the standard value for the penetration rate set at 50% or higher, and unsatisfactory values ​​are underlined (the same criteria apply to Tables 3 and 5 below). In Table 2, test items that could not be measured are indicated with "-".

[0037] [Table 2]

[0038] The results in [Table 2] show that the plant-based asphalt containing terpene phenol resin A and terpene phenol resin B (comparative examples) all had remarkably low penetration retention rates (see samples No. 5B, 6B, 14B, and 15B in [Table 2]). In addition, the plant-based asphalt containing ester gum, rosin ester, or disproportionated rosin (comparative examples) had an initial penetration degree of 300 or higher and was excessively soft, and the penetration retention rate could not be measured (see samples No. 7B-9B and 16B-19B in [Table 2]).

[0039] From the results in [Table 2], it was found that in the case of plant-based asphalt containing polyterpene resin, the heat resistance differs depending on the molecular weight of the resin. Specifically, plant-based asphalt containing polyterpene resin A (molecular weight 1000) or polyterpene resin B (molecular weight 1350) (Examples) both showed high penetration retention rates, indicating that oxidation of the resin components during heating was suppressed (see Samples No. 1B, 2B, 10B, and 11B in [Table 2]). In particular, plant-based asphalt containing polyterpene resin B showed a thin-film heating mass change rate of ±1.0 or less, indicating that it is particularly suitable for practical use. On the other hand, for plant-based asphalt containing polyterpene resin C (molecular weight 800) or polyterpene resin D (molecular weight 700) (Comparative Examples), the penetration retention rate could not be measured for the content ratio of each component in [Table 2] (see Samples No. 3B, 4B, 12B, and 13B in [Table 2]). From the above, it was found that, when considering heat resistance, terpene resins, which are homopolymers of terpene monomers and have a molecular weight of 1000 or more, can be suitably used in the plant-based asphalt of this disclosure.

[0040] [Physical properties of plant-based asphalt] Table 3 below shows the test results for each vegetable asphalt sample whose initial penetration was adjusted to 60±3 (note that sample No. 2C in Table 3 has the same components and the same content ratio as sample No. 11B in Table 2).

[0041] [Table 3]

[0042] The results in [Table 3] also show that the vegetable asphalt containing polyterpene resin A (molecular weight 1000) or polyterpene resin B (molecular weight 1350) (Examples) all had high penetration retention rates and improved heat resistance (see Samples No. 1C and 2C in [Table 3]). From the above, it was found that the vegetable asphalt of this disclosure possesses the desired heat resistance when the penetration rate is adjusted to approximately 60, that is, when it has binder properties similar to StAs60 / 80 in [Table 4] below. On the other hand, the vegetable asphalt containing polyterpene resin C (molecular weight 800) or polyterpene resin D (molecular weight 700) (Comparative Example) had a significantly low penetration retention rate and poor heat resistance (see Samples No. 3C and 4C in [Table 3]).

[0043] [Reference example] Table 4 below shows, as a reference example, the test results and standard values ​​for asphalt mixtures including straight asphalt (petroleum asphalt).

[0044] [Table 4]

[0045] [Test results of asphalt mixture (1)] Table 5 below describes the physical properties of each asphalt mixture (Examples) and each asphalt mixture containing petroleum-derived substances (Comparative Examples) of the present disclosure. Here, the asphalt mixtures of the present disclosure contain the vegetable asphalt (waste cooking oil (recovered oil), polyterpene resin A or B) and new aggregate. In the asphalt mixtures containing petroleum-derived substances, naphthenic oil (mineral oil) was used instead of the recovered oil mentioned above, and polyterpene resin A, B, or C9 petroleum resin was appropriately selected and used as the resin component. In Table 5, test items that were not measured are left blank. Furthermore, samples No. 17D to 19D had their naphthenic oil, polyterpene resin A or B, and C9 petroleum resin content ratios adjusted so that the initial penetration was approximately 60 (1 / 10 mm).

[0046] [Table 5]

[0047] The results in [Table 5] show that all asphalt mixtures containing petroleum-derived substances had remarkably low penetration retention rates (see samples No. 13D to 19D in [Table 5]). On the other hand, each asphalt mixture in this disclosure showed a significantly higher penetration retention rate compared to those containing petroleum-derived substances (see samples No. 1D to 12D in [Table 5]).

[0048] Furthermore, the results in [Table 5] show that the heat resistance of each asphalt mixture in this disclosure can be more reliably ensured by adjusting the content ratio of oil and resin components. Specifically, it was found that each asphalt mixture in this disclosure, when the total amount of vegetable oil and terpene resin is 100 parts by weight, can more reliably ensure the desired heat resistance by containing 25 to 31 parts by weight of vegetable oil (see the penetration retention rate of samples No. 3D to 12D in [Table 5]). In addition, various tests were conducted on some of the asphalt mixtures in this disclosure with reference to [Table 4] and [Table 5], and the values ​​of all test items satisfied the standard values ​​in [Table 4]. From the above, it was easily inferred that each asphalt mixture in this disclosure can have physical properties equivalent to those of the asphalt mixtures in each reference example by appropriately setting the initial penetration of the vegetable asphalt (for example, setting it to 60 (1 / 10 mm)). Furthermore, in each asphalt mixture disclosed herein, the mixing temperature is set to 150°C and the compaction temperature to 130°C. This revealed that the plant-based asphalt disclosed herein can be manufactured and constructed together with aggregates at a temperature of 130°C to 150°C.

[0049] [Test results of asphalt mixture (2)] Table 6 below shows the test results for each recycled asphalt mixture (examples) of the present disclosure. Here, each recycled asphalt mixture of the present disclosure includes the vegetable asphalt (waste cooking oil (recovered oil), polyterpene resin B) and recycled asphalt aggregate.

[0050] [Table 6]

[0051] Referring to [Table 4] and [Table 6], the values ​​of various test items for each recycled asphalt mixture in this disclosure satisfied the standard values ​​in [Table 4] (see each test item for samples No. 1E to 8E in [Table 6]). It was found that each recycled asphalt mixture in this disclosure, when the total amount of vegetable oil and terpene resin is 100 parts by weight, can more reliably ensure the desired physical properties by containing 28 to 56 parts by weight of vegetable oil. From the above, it was found that the vegetable asphalt of this disclosure can be suitably used for the reuse of recycled asphalt aggregate. Furthermore, it was easily inferred that the desired physical properties can be ensured even when recycled asphalt aggregate and new aggregate are used in combination with each recycled asphalt mixture in this disclosure. In addition, since each recycled asphalt mixture in this disclosure is mixed at a temperature of 150°C and compacted at a temperature of 130°C, it was found that it can be manufactured and applied at temperatures between 130°C and 150°C.

[0052] Furthermore, the results in [Table 6] show that each recycled asphalt mixture in this disclosure exhibited good values ​​for "dynamic stability," "settlement after 60 minutes," and "flexural strength at fracture." The differences in the values ​​of the above test items among the recycled asphalt mixtures in this disclosure were due to differences in the content ratio of vegetable oil and terpene resin. From this, it was found that when adjusting the performance of recycled asphalt mixtures (such as flow resistance, support, and strength), the content ratio of vegetable oil and terpene resin should be adjusted as appropriate.

[0053] The vegetable asphalt, asphalt mixtures using vegetable asphalt, and methods for applying asphalt mixtures using vegetable asphalt described herein are not limited to the embodiments described above, and various other embodiments are possible. While examples of vegetable oil types are given in this disclosure, it is not intended to limit the types of vegetable oils. That is, any vegetable oil with an iodine value of less than 130 is acceptable, and a wide range of semi-drying oils with an iodine value of less than 130 and 100 or more, and non-drying oils with an iodine value of 100 or less can be used, within the range where practicality is deemed feasible through testing. Furthermore, if possible, the iodine value can be adjusted to 120 or less, or 115 or less, by mixing multiple vegetable oils in the semi-drying or non-drying oils. In addition, if practicality is deemed feasible through testing, terpene resins with a wide range of molecular weights (for example, terpene resins with a molecular weight significantly exceeding 1350) can be used in the vegetable asphalt. Furthermore, if practicality is proven through trial use, various cyclic terpene monomers (such as α-pinene resin and β-pinene resin) and chain-like terpene monomers can be used as appropriate. Vegetable asphalt only needs to consist substantially of vegetable oil and terpene resin, and may contain very small amounts of naturally derived additives. Various asphalt modifiers may also be added to the asphalt mixture. The application temperature of vegetable asphalt and aggregates is not necessarily limited to 130°C to 150°C, and the mixing temperature can be set as appropriate.

Claims

1. Vegetable oils with an iodine value of less than 130, A plant-based asphalt comprising a terpene resin, which is a homopolymer of terpene monomers with a molecular weight of 1000 or more and a softening point of less than 125°C.

2. A plant-based asphalt according to claim 1, wherein the plant-based asphalt does not contain petroleum-derived substances.

3. The vegetable asphalt according to claim 1, wherein the vegetable oil is one or more vegetable oils selected from olive oil, rice oil, rapeseed oil, and waste cooking oil.

4. A vegetable asphalt according to claim 1, wherein when the total amount of the vegetable oil and the terpene resin is 100 parts by weight, the vegetable asphalt contains 25 to 31 parts by weight of the vegetable oil.

5. An asphalt mixture comprising the vegetable asphalt according to any one of claims 1 to 3, wherein the total amount of the vegetable oil and the terpene resin is 100 parts by weight, and the vegetable oil is 28 parts by weight or more; and recycled asphalt aggregate.

6. A method for constructing a plant-based asphalt, comprising manufacturing and constructing an asphalt mixture obtained by mixing the plant-based asphalt described in any one of claims 1 to 4 with aggregates at 130°C to 150°C.

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