JP6683855B2 - Asphalt composition - Google Patents

Description

  The present invention relates to a highly durable asphalt composition used in a drainage paving mixture.

  Conventionally, asphalt has been used in a wide range of fields such as road paving and waterproofing. One of the uses of the asphalt composition is a drainage pavement capable of effectively draining rainwater from the pavement surface. Drainage pavements are often constructed on highways and general roads, and contribute greatly to ensuring safety during running and noise countermeasures.

  In drainage pavement, it is necessary to provide a gap between the aggregates to allow rainwater to pass from the pavement surface to the base layer. Therefore, in the drainage pavement, an asphalt mixture containing a binder having a large grasping force of the aggregate is used in order to firmly bond the aggregate to each other in a situation where there are few contact points between the aggregates.

  In such a drainage pavement, the pavement is likely to be damaged due to the gap between the aggregates, and in particular, there is a concern that the frequency of occurrence of potholes where the pavement at the uppermost part of the pavement falls off over a large area is increased. There is a concern that the traveling vehicle will be damaged when the wheels of the traveling vehicle fall into the pothole, and it has been an urgent task to eliminate these concerns.

  Furthermore, since the asphalt composition used for drainage pavement is expensive as compared with that used for conventional pavement, it has been a cause of increasing the laying cost of drainage pavement.

  Therefore, for the purpose of reducing the impact when a pothole occurs and reducing the cost of laying drainage pavement, the surface layer of the road pavement, which was conventionally laid with a thickness of about 5 cm, was replaced with a small-grain aggregate. The drainage pavement is thinned to a thickness of about 3 cm.

  In such a thin layer drainage pavement, an aggregate having a particle size of 5 mm or less, which is significantly smaller than the aggregate used in the conventional drainage pavement, is used.

  By using aggregates with such a small particle diameter, the surface of the drainage pavement can be made thinner, and even if a pothole occurs, the depth can be reduced, which impedes the running of the vehicle. Can be reduced.

  Further, the pavement can be made thinner as compared with the conventional one using an aggregate having a particle size, the amount of materials used for laying can be reduced, and cost reduction can be realized.

  Further, by reducing the particle size of the aggregate used, it is possible to reduce the unevenness of the road surface as compared with the conventional one, and it is possible to reduce the running noise of the vehicle caused by the unevenness.

JP, 2005-48001, A

  However, when laying a drainage pavement using aggregates having a small particle size, it has been difficult for the conventional asphalt composition to secure the pavement strength by interlocking the aggregates.

  This is because it is difficult to secure the pavement strength due to the interlocking of aggregates in a drainage pavement composed of only aggregates of small particle size, as compared with the one containing aggregates of large particle size. This is because the aggregate is insufficient and the aggregate is displaced in the structure of the drainage pavement due to the load of the traveling vehicle.

  Therefore, the conventional asphalt composition has insufficient holding power and durability for preventing this displacement.

  And, in the conventional thin-layer drainage pavement, although the effect of the occurrence of potholes is small, it is difficult to reduce the frequency of occurrence, and there are concerns about the durability of the pavement, such as ruts. It was happening.

  Therefore, the present invention has been devised in view of the above-described problems, and ensures high strength and durability even in a thin-layer drainage pavement using an aggregate having a small particle size. It is an object of the present invention to provide an asphalt composition that can be used.

  In addition to this, the load on the road pavement has increased due to the increase in road traffic in recent years, and repair work due to damages such as ruts and perforations (potholes) on the pavement is increasing. Particularly in road pavement for expressways, a material having excellent strength and water resistance is used for the base layer mixture to be laid under the drainage pavement.

  On the other hand, road pavements such as highways that are laid on bridges must be constructed in an environment where the temperature tends to drop, such as in winter, so ensure good construction even at such low temperatures. There is a need for an asphalt composition capable of Particularly in concrete bridges, since the surface of cement concrete itself lacks flatness, it is necessary to increase the fluidity of the asphalt mixture in order to increase the flatness of the surface during paving.

  Conventional asphalt compositions for base layers have a high viscosity of asphalt in order to achieve high water resistance and strength, and therefore are heated to a certain temperature or higher in order to improve their fluidity during construction. There is a need. Especially when paving in cold regions or when the distance from the compounding plant to the construction site is long in the cold season, the temperature of the asphalt composition decreases, resulting in poor fluidity and poor workability. There was a problem that it would end up.

The present invention has been devised in view of the above problems, a first object is to provide a high strength and water resistance can be ensured asphalt composition.
A second object of the present invention is to provide an asphalt composition capable of improving workability by increasing the fluidity of asphalt.

  In order to solve the above-mentioned problems, the present inventor has invented an asphalt composition capable of ensuring high strength and durability even in a thin-layer drainage pavement using an aggregate having a small particle size. did.

The asphalt composition according to the first invention comprises a base asphalt, a styrene-butadiene-styrene block copolymer (SBS) of 8% by weight or more and 15% by weight or less , based on 100% by weight of the total weight of the composition. An asphalt composition containing more than 5% by weight and less than or equal to 5% by weight of ethylene ethyl acrylate (EEA), wherein the EEA has a melt mass flow rate (MFR) of 5 g / 10 minutes or less, the SBS and the EEA. mixture is less than 15% by weight greater than 13 wt% in a total amount of, characterized in that.

  The asphalt composition according to the second invention is the asphalt composition according to the first invention, wherein the SBS comprises a first SBS and a second SBS having a smaller molecular length than the first SBS and a high styrene content ratio. The mixture has a molecular length in the first SBS of 1.8 times or more of the molecular length in the second SBS, the styrene block length in the first SBS is LS1, and the molecular length in the second SBS is When the styrene block length is LS2, LS2 / LS1 is 0.7 to 1.4.

  The asphalt composition according to the third invention is characterized in that, in the second invention, the addition amount of the first SBS / the addition amount of the second SBS is 0.25 or more and 1.00 or less. .

An asphalt composition according to a fourth invention is characterized in that, in any one of the first to third inventions, it contains 6 to 10% by weight of a petroleum resin.

An asphalt composition according to a fifth aspect of the invention is characterized in that, in any one of the first to fourth aspects of the invention, the asphalt composition contains 0.2 to 2.0% by weight of a peeling preventing agent.

An asphalt composition according to a sixth aspect of the present invention comprises a base asphalt and a styrene-butadiene-styrene block copolymer (SBS) of 6.5% by weight or more and 11% by weight or less , based on 100% by weight of the total weight of the composition. 1% by weight to less than 3% by weight of ethylene ethyl acrylate (EEA), the SBS has a first SBS, a molecular length smaller than that of the first SBS, and a high styrene content ratio. 2 is a mixture with SBS, the molecular length in the first SBS is 1.8 times or more the molecular length in the second SBS, the styrene block length in the first SBS is LS1, When the styrene block length in the second SBS is LS2, LS2 / LS1 is 0.7 to 1.4, and the total content of the SBS and the EEA is 9 Wherein the 5% by weight to more than 12 wt% or less.

An asphalt composition according to a seventh invention is characterized in that, in the sixth invention, the addition amount of the first SBS / the addition amount of the second SBS is 0.25 or more and 1.00 or less. .

The asphalt composition according to the eighth invention is characterized in that, in the sixth or seventh invention, the asphalt composition further contains 0.2 to 2.0% by weight of a peeling preventing agent.

According to the asphalt composition according to the first to fifth inventions, it is possible to provide an asphalt composition capable of ensuring high strength and water resistance.
Moreover, according to the asphalt composition according to the sixth to eighth inventions, it is possible to provide an asphalt composition capable of improving the workability by increasing the fluidity of the asphalt.

It is a figure which shows the detail of the shape and size of a 1st SBS and a 2nd SBS. It is a figure which shows the concrete chemical structure of SBS. It is a figure for demonstrating the measurement procedure of the length of a styrene block.

  Hereinafter, the asphalt composition according to the embodiment of the present invention will be described in detail.

[First Embodiment]
The asphalt composition according to the first embodiment of the present invention comprises a base asphalt, a first styrene-butadiene-styrene block copolymer (SBS), and a second styrene-containing polymer having a smaller molecular weight and a higher styrene content. The SBS mixture (hereinafter referred to as "SBS mixture") is contained in a total amount of 13% by weight or more and 15% by weight or less with respect to the entire asphalt composition.

  In addition, petroleum resin and a peeling preventive agent (resin acid, fatty acid or aliphatic amide) are added if necessary. The petroleum resin is contained in an amount of 6 to 10% by weight based on the total asphalt composition. The antistripping agent is contained in an amount of 0.2 to 2% by weight based on the total asphalt composition.

Base asphalt As the base asphalt in the first embodiment, for example, straight asphalt (see JIS K 2207), blown asphalt (see JIS K 2207), solvent deasphalting asphalt ("New Petroleum Dictionary", edited by the Japan Petroleum Institute, 1982, p.308) or the like, or a mixture thereof, and such various asphalts to which aromatic heavy mineral oil or the like is added can be used.

  The base asphalt used in the present invention is preferably asphalt obtained by adding aromatic heavy mineral oil to solvent deasphalted asphalt.

  As the solvent deasphalting asphalt, propane or propane deasphalting asphalt using propane and butane is preferable.

  As the aromatic heavy mineral oil, petroleum solvent-extracted oil or aromatic hydrocarbon process oil containing at least 35% by mass of aromatic hydrocarbon defined in JISK6200, and vacuum distillation residual oil of crude oil are used. Solvent-extracted oil obtained by deasphalting with propane etc. is further solvent-extracted with polar solvent such as furfural to obtain bright stock (heavy lubricating oil), that is, extract There is.

  In the present invention, it is preferable to add an extract as the aromatic heavy mineral oil.

  The role of the extract in the present invention is to increase the solubility of the thermoplastic elastomer in asphalt and prevent it from being separated in storage stability. If the amount of the thermoplastic elastomer added is large, the amount of the extract required also increases. To increase. In addition, if the extract is added more than necessary with respect to the amount of the thermoplastic elastomer added, the strength will decrease.

  The content of the base asphalt in the entire asphalt composition is preferably 73.0 to 79.8% by weight.

  The content of the extract with respect to the entire asphalt composition is: penetration, softening point, storage stability, complex elastic modulus showing strength and dynamic stability (DS value) in a wheel tracking test, and low temperature showing low temperature properties. Although it is determined in consideration of the amount of cantablo loss, the content of the extract is preferably 10 to 20% by weight with respect to the entire asphalt composition within the range studied in the present invention.

Typical properties of the used propane deasphalted asphalt are those having a penetration of 13 (1/10 mm), a softening point of 61.5 ° C. and a density of 1066 kg / m ³ at 15 ° C. Also, extract used has a density kinematic viscosity kinematic viscosity at 61.2mm ² / s, 40 ℃ in a typical property is 100 ° C. is at 3970mm ² / s, 15 ℃ is at 976.4kg / m ³ belongs to.

SBS
As the SBS used, as shown in Table 1, the first SBS and the second SBS are used. The first SBS has a molecular weight of 150,000 and a styrene content ratio of 30%. The second SBS has a molecular weight of 80,000 and a styrene content ratio of 45%.

  The first SBS is a thermoplastic elastomer that is added as a reinforcement to the base asphalt.

  The molecular weight of the first SBS is set to 120,000 to 250,000. The first SBS has a larger molecular weight than a second SBS described later, and one polystyrene block (hereinafter, also referred to as styrene block) passes through a polybutadiene block (hereinafter, also referred to as butadiene block) to the other. The molecular length including the styrene block is longer than that of the second SBS.

  The styrene content of the first SBS is 25 to 35% by mass, preferably 27 to 33% by mass, based on the entire first SBS. The styrene content here is the mass% of styrene contained in the first SBS. The second SBS, like the first SBS, is a thermoplastic elastomer that is added as a reinforcement to the base asphalt.

  The molecular weight of the second SBS is said to be 60,000 to 100,000. That is, since the second SBS has a lower molecular weight than the first SBS, the molecular length including one styrene block, the butadiene block, and the other styrene block is shorter than that of the first SBS. ing.

  The second SBS has a styrene content of 40 to 50% by mass, preferably 42 to 48% by mass, based on the whole second SBS. The styrene content here is the mass% of styrene contained in the second SBS.

  FIG. 1 is a diagram showing details of the shapes and sizes of the first SBS and the second SBS. In the upper first SBS, the length of the styrene block indicated by “S” in the figure is LS1, the molecular length of the first SBS is L1, and the length of butadiene block LB1 indicated by “B” in the figure is , L1-2 × LS1.

  In the lower second SBS, the length of the styrene block indicated by "S" in the figure is LS2, the molecular length of the second SBS is L2, and the length LB2 of the butadiene block indicated by "B" in the figure is , L2-2 × LS2.

  In the present invention, when the styrene block length in the first SBS is LS1 and the styrene block length in the second SBS is LS2, LS2 / LS1 needs to be 0.7 to 1.4. . This prevents the styrene block length in the first SBS and the styrene block length in the second SBS from significantly different from each other. This LS2 / LS1 is preferably 0.8 to 1.25.

  The molecular length L1 in the first SBS is 1.8 times or more the molecular length L2 in the second SBS. As a result, the molecular length of the first SBS can be made considerably longer than the molecular length of the second SBS. The molecular length L1 in the first SBS is preferably twice the molecular length L2 in the second SBS or more.

  FIG. 2 shows a specific chemical structure of SBS. The above-mentioned molecular lengths L1 and L2 are the sum of the styrene block length LS × 2 and the butadiene block length LB.

Further, the length LS (LS1, LS2) of the styrene block is obtained based on the following procedure. First, the C—C bonds connecting styrenes in the styrene block are aligned in a straight line as shown in FIG. When the amount corresponding to the styrene monomer is “styrene unit”, the length of the styrene unit from C0 to C1 to C2 is theoretically 0.361 nm. The molecular weight of the styrene unit is 105 (C ₈ H ₉ ) from the carbon atoms C0, C1, C2, the benzene ring and the number of hydrogen atoms bonded to them.

  Since the styrene block exists at both ends of the SBS molecule with almost the same molecular weight, the length of the styrene block is calculated based on the following formula from the length of the styrene unit and the molecular weights of the styrene blocks at both ends.

  (Length of styrene block: LS) = (molecular weight of SBS) × (content ratio of styrene in SBS molecule) / 2 / (molecular weight of styrene unit) × (length of styrene unit)

  That is, in the above formula, the molecular weight of the styrene unit and the length of the styrene unit are uniquely determined as constants. Therefore, by substituting the molecular weight of SBS and the styrene content ratio in the SBS molecule into styrene, It is possible to calculate the block length (LS).

Further, the length of the butadiene block shall be determined based on the following procedure. First, the C—C bonds in the butadiene block are aligned linearly as shown in FIG. 3, and the C═C bonds are aligned linearly as a trans body. When the “butadiene unit” corresponding to the butadiene monomer is used, the length of the butadiene unit from C2 to C6 is theoretically 0.638 nm. The molecular weight contained in the butadiene unit is 54 (C ₄ H ₆ ) from the number of carbon atoms C3 to C6 and the number of hydrogen atoms bonded thereto.

  From the length of this butadiene unit and the molecular weight, the length of the butadiene block is calculated based on the following formula.

  (Length of butadiene block: LB) = (molecular weight of SBS) × (content ratio of butadiene in SBS molecule) / (molecular weight of butadiene unit) × (length of butadiene unit)

  That is, in the above formula, the molecular weight of the butadiene unit and the length of the butadiene unit are uniquely determined as constants. Therefore, by substituting the molecular weight of SBS and the butadiene content ratio in the SBS molecule, the butadiene unit It is possible to calculate the block length (LB).

The length S1 of the first SBS is calculated by the following formula.
L1 = LB1 + 2 × LS1

The length L2 of the second SBS is calculated by the following formula.
L2 = LB2 + 2 × LS2

It is preferable that the ratio of the addition amounts of the first SBS and the second SBS ((first SBS) / (second SBS)) is 0.25 or more and 1.00 or less. When it is less than 0.25, the complex elastic modulus G ^{* at} 70 ° C. becomes small and the strength of asphalt cannot be exhibited. Also 1.0
If it exceeds 0, the viscosity at 180 ° C. will increase, the workability will decrease, the desired mixture properties will not be obtained, and the durability will decrease.

  Further, by setting the total amount of the first SBS and the second SBS to 13% by weight or more with respect to the entire asphalt composition, it is possible to achieve the desired dynamic stability (DS value) of the asphalt pavement mixture. Often you can.

  Further, when the total of the first SBS and the second SBS exceeds 15% by weight with respect to the entire asphalt composition, the viscosity becomes high and the construction becomes difficult.

  Therefore, it is desirable that the total of the first SBS and the second SBS is 13% by weight or more and 15% by weight or less with respect to the entire asphalt composition.

  The styrene block length LS calculated from the molecular weight and the styrene content ratio is shown in Table 1.

  Further, LS2 / LS1 calculated from these styrene block lengths LS is 0.8.

  From the above, the first SBS and the second SBS are combinations in which the ratio of styrene block lengths and the ratio of SBS molecular lengths fall within the ranges specified in the present invention.

Petroleum resin Aliphatic resin such as C5 petroleum resin (hereinafter referred to as C5 petroleum resin), aromatic petroleum resin such as C9 petroleum resin (hereinafter referred to as C9 petroleum resin), dicyclopentanediene petroleum resin And other alicyclic petroleum resins (hereinafter referred to as DCPD), petroleum resins such as C5 / C9 copolymer petroleum resins (hereinafter referred to as C5 / C9 petroleum resins), and these petroleum resins obtained by hydrogenation Hydrogenated petroleum resins that can be used.

  By adding these petroleum resins, it is possible to secure the compatibility between SBS and other components while lowering the penetration, which will be described later, and improving the complex elastic modulus.

  The amount of petroleum resin added is 6 to 10% by weight. In the asphalt composition according to the present embodiment, if the amount of petroleum resin added is less than 6%, the viscoelastic properties of the asphalt cannot be improved, and if it exceeds 10% by weight, the effect is saturated. Resulting in.

  Petroleum resin has a softening point of 140 ° C., an acid value of 0.1 mgKOH specified by JIS K0070, a bromine value of 25 g specified by JIS K2543, and an average molecular weight of polyethylene equivalent measured by GPC method of about What was 1000 was used.

Peeling Prevention Agent In the present invention, it is preferable to add a peeling prevention agent in order to prevent peeling between the asphalt composition and the aggregate.

  A compound having a polar group can be used as a peeling preventive agent, and a resin acid can be preferably used. The resin acid is a polycyclic diterpene having a carboxyl group and having 20 carbon atoms, such as abietic acid, dehydroabietic acid, and neo. It is a rosin containing any one or more of abietic acid, pimaric acid, isopimaric acid, and parastophosphoric acid.

  Here, gum rosin, wood rosin, tall oil rosin and the like are used as the rosin. These rosins can be classified as the above-mentioned gum rosin, wood rosin, etc., depending on the origin, raw materials, and collection method, but they are obtained at least as a residual component during steam distillation of pine resin.

  This rosin is a mixture containing abietic acid, parastophosphoric acid, neoabietic acid, dehydroabietic acid, pimaric acid, sandaracopimaric acid, isopimaric acid and the like as components. This rosin usually softens at about 80 ° C and melts at 90-100 ° C.

  The rosin contains various resin acids such as abietic acid, dehydroabietic acid, dihydroabietic acid, tetrahydroabietic acid, parastophosphoric acid, neoabietic acid, and levopimaric acid. It may be used alone.

The peeling preventing agent used is disproportionated gum rosin having an acid value of 156 (mgKOH / g: JIS K0070) and a softening point of 77.0 ° C. (JIS K2207).

  Although gum rosin is used as a preferred rosin in the present invention, it is not limited thereto.

  If the content of the resin acid is less than 0.2% by weight, the effect of the resin acid is not sufficient, and the prevention of peeling as the final product cannot be improved.

  On the other hand, when the content of the resin acid exceeds 2% by weight, not only the effect of improving the peeling prevention is saturated, but also the amount of the expensive resin acid added increases. There is a problem that the cost will increase significantly. That is, even if the resin acid content is added in excess of 2% by weight, the improvement in peeling prevention does not significantly improve, and is rather disadvantageous in terms of raw material cost.

  Therefore, the content of the resin acid is preferably 0.2 to 2.0% by weight.

  It is also possible to use fatty acids or fatty acid amides. Fatty acids are represented by, but not limited to, saturated fatty acids such as stearic acid, palmitic acid, myristic acid, and unsaturated fatty acids such as oleic acid, linoleic acid, and ricilenoic acid.

  Fatty acid amides are represented by, for example, stearic acid amide and ethylenebisstearic acid amide (EBS), but are not limited thereto.

  If the content of this fatty acid or fatty acid amide is less than 0.2% by weight, the effect is not sufficient and the prevention of peeling as a final product cannot be improved.

  On the other hand, when the content of the fatty acid or fatty acid amide exceeds 2% by weight, not only the effect of improving the peeling prevention is saturated, but also the amount of expensive fatty acid or fatty acid amide added is increased. However, there is a problem that the increase in raw material cost due to the increase in

  That is, even if the content of the fatty acid or the fatty acid amide exceeds 2% by weight, the improvement of the peeling prevention does not significantly improve, and it is rather disadvantageous in terms of the raw material cost.

  Therefore, the content of fatty acid or fatty acid amide is preferably 0.2 to 2.0% by weight.

[Second Embodiment]
The asphalt composition according to the second embodiment of the present invention has a base asphalt, a first styrene-butadiene-styrene block copolymer (SBS) and a second styrene content higher than that of the first SBS. SBS mixture (hereinafter referred to as "SBS mixture") in a total amount of 8 to 15% by weight, and ethylene ethyl acrylate (EEA) in an amount of more than 0% by weight and 5% by weight or less.

  In addition, petroleum resin and a peeling preventive agent (resin acid, fatty acid or aliphatic amide) are added if necessary. The petroleum resin is contained in an amount of 6 to 10% by weight based on the total asphalt composition. The antistripping agent is contained in an amount of 0.2 to 2% by weight based on the total asphalt composition.

  The base asphalt, the first SBS, the second SBS, the petroleum resin, and the anti-stripping agent have the same properties as those of the first embodiment described above.

  The contents of the first SBS and the second SBS in the entire asphalt composition are different from those in the first embodiment.

  In the second embodiment, the SBS mixture is contained in a total amount of 8 to 15% by weight.

  The total amount of EEA is more than 0% by weight and 5% by weight or less.

  Further, the total amount of the mixture of the SBS mixture and EEA is more than 13% by weight and less than 15% by weight.

EEA
EEA is a thermoplastic resin that is a copolymer of ethylene and acrylic acid ethyl ester, and is a resin that retains flexibility in a wide temperature range.

  When the content of EEA is 0% by weight, the composition has the same components as the asphalt composition according to the first embodiment described above, and thus the amounts of the respective components according to the first embodiment described above may be mixed. It will be.

  When the content of EEA exceeds 5% by weight, the asphalt composition is likely to be separated and the storage stability is deteriorated.

  Therefore, the content of EEA is preferably more than 0% by weight and 5% by weight or less.

EEA is MFR 0.5 g / 10 minutes in Examples 1 to 13 and Comparative Examples 1 to 10, EEA1 having an EA content of 23% by weight, and Comparative Example 11 MFR 20 g / 10 minutes and an EA content of 35% by weight.
EEA2 of Comparative Example 12 is MFR 20 g / 10 min, EEA3 having an EA content of 25% by weight.
Example 14 used EEA4 having an MFR of 1.6 g / 10 min and an EA blending ratio of 24% by weight, and Example 15 used MFR of 1.5 g / 10 min and an EEA5 having an EA blending ratio of 15% by weight.
[Third Embodiment]

  The asphalt composition according to the third embodiment of the present invention contains a base asphalt, 6.5 wt% or more and 11 wt% or less of SBS, and more than 1 wt% and less than 3 wt% EEA. At this time, the total content of SBS and EEA is 9.5 wt% or more and 12 wt% or less.

  The SBS is a mixture of the first SBS and the second SBS. The amount of the first SBS added / the amount of the second SBS added is 0.25 or more and 1.00 or less. About 1st SBS and 2nd SBS, although the content in the whole asphalt composition differs from 1st, 2nd embodiment, the effect obtained is the same.

  Further, in the third embodiment, 0.2 to 2.0% by weight of a peeling preventing agent may be further contained.

  The base asphalt, the first SBS, the second SBS, the EEA, and the anti-stripping agent have the same properties as those of the above-described first and second embodiments, respectively. The reasons for limiting the components of SBS, EEA, and the peeling preventing agent are the same as in the first and second embodiments.

  The point that the total content of SBS and EEA is 9.5 wt% or more and 12 wt% or less is different from the above-described first and second embodiments.

  If the total content of SBS and EEA is less than 9.5% by weight, the elastic modulus of the asphalt is insufficient and the asphalt existing between the aggregates is cohesively destroyed, resulting in impaired water resistance of the mixture. As a result, water easily enters the mixture, and the water resistance of the asphalt mixture deteriorates. In particular, when a load due to the running of an automobile is applied, the deterioration of water resistance becomes remarkable. Therefore, the lower limit of the total content of SBS and EEA is 9.5% by weight.

Above all, since EEA has a large attraction force with the aggregate based on its polarity, the stress required for separating it is large. This means that the load required for peeling the asphalt composition from the aggregate increases, and it can be said that the peel resistance is high and the water resistance is improved accordingly. Therefore, by adding EEA, it becomes possible to secure high water resistance that cannot be achieved only by SBS.
Further, if the total content of SBS and EEA exceeds 12% by weight, the viscosity at 180 ° C. increases, and as a result, the workability at low temperatures deteriorates. Therefore, the upper limit of the total content of SBS and EEA is set to 12% by weight.

  It is desirable that EEA is further contained in an amount of more than 1% by weight and less than 3% by weight. The reason for this is that when EEA is 1% by weight or less, the content of polar EEA decreases, and as a result, the aggregate easily separates from the asphalt composition and water resistance decreases. On the other hand, when the EEA is 3% by weight or more, the asphalt composition is liable to be separated, and the storage stability is slightly deteriorated.

  In addition, in the third embodiment, the addition amount of the first SBS / the addition amount of the second SBS may deviate from 0.25 or more and 1.00 or less.

  The reason for the upper limit and the lower limit of the content of the anti-stripping agent is the same as in the first embodiment, but it acts to prevent the exfoliation by sucking the aggregate based on the polarity originally possessed by the anti-stripping agent. The point to do is similar to EEA. When the content of the anti-stripping agent is less than 0.2% by weight, the polarity of the anti-stripping agent is low and the attracting force of the aggregate cannot be exhibited more effectively. On the other hand, when the content of the anti-stripping agent is 0.2% by weight or more, the polarity in the composition can be improved together with the EEA, and the water resistance can be more effectively improved by more strongly attracting the aggregate. Can be realized in real time. On the other hand, when the amount of the peeling preventing agent exceeds 2% by weight, the elastic modulus is rather lowered. Therefore, the antistripping agent is contained in an amount of 0.2% by weight or more and 2% by weight or less.

  Hereinafter, the first embodiment and the second embodiment will be specifically described with reference to the test methods, examples, and comparative examples used in the present invention, but the present invention is not limited to these examples. . Further, in the following examples, when only “%” is described, it means “% by weight”.

  A method for producing the asphalt composition having Examples 1 to 15 and Comparative Examples 1 to 12 having the above-mentioned constitution will be described below.

  Propane deasphalted asphalt was melted at a temperature of about 150 ° C., mixed so that the extract had the above-mentioned mixing ratio, and a predetermined amount of the above-mentioned first SBS to second SBS was added in the same procedure. Further, the above-mentioned petroleum resin, gum rosin, and optionally (in the case of the second embodiment) EEA are added. The mixing was performed using a homomixer, and the number of rotations was set to 1500 to 5000 rotations / minute, and the mixture was stirred and mixed for about 3 to 5 hours. The temperature of asphalt at the end of mixing was adjusted to 200 to 215 ° C. The production amount was 1.8 kg in each case.

  In the present invention, a sample obtained for conducting an experimental study has a penetration degree (25 ° C.), a softening point, a viscosity (180 ° C.), a complex elastic modulus (70 ° C.), a DS value (70 ° C.) and a separation test. Performance test consisting of. The detailed test method will be described below.

  The penetration (25 ° C) was measured by JIS K 2207 "Petroleum asphalt-penetration test method". This value is preferably 30 or less.

  Viscosity (180 ° C) is measured under the conditions of JPI-5S-54-99 "Viscosity test method by asphalt-rotational viscometer" at a measurement temperature of 180 ° C, spindle SC4-27 used, spindle rotation speed 20 rpm. did.

  This viscosity (180 ° C.) is related to the hardness of the asphalt mixture at the time of construction, and if the viscosity becomes high, the workability deteriorates and it becomes impossible to make a predetermined pavement. Therefore, it is preferably 1400 mPa · s or less.

The complex elastic modulus (G ^* ) (70 ° C.) (Pa) was measured according to the dynamic shear rheometer (DSR) test method specified in the Pavement Survey and Test Method Handbook (edited by the Japan Road Association). The measurement principle of this test is that the asphalt composition, which is the measurement data, is sandwiched between two parallel disks (diameter is 25 mm), and one disk is subjected to sinusoidal wave distortion of a predetermined frequency, and the asphalt composition (thickness is The sinusoidal stress σ transmitted to the other disk via 1 mm) is measured, and the complex elastic modulus is calculated from the sinusoidal stress and the sinusoidal distortion.

  The measurement frequency was 10 rad / s and the strain was 10%.

The complex elastic modulus (G ^* ) is preferably 14000 Pa or more. When the complex elastic modulus (G ^* ) is less than 14000 Pa, the pavement has insufficient deformation resistance, and potholes and ruts are likely to occur.

The DS value (dynamic stability) was 30 cm in length, in which each asphalt composition and the aggregate having the composition shown in Table 1 were prepared with the amount of asphalt in the mixture being 5.3% by weight and the aggregate being 94.7% by weight, Using a sheet-shaped specimen having a width of 30 cm and a thickness of 5 cm, the measurement was performed according to the "B003 wheel tracking test method" described in the Pavement Evaluation and Test Method Handbook (edited by the Japan Road Association).

  The mixing temperature was 170 ° C., the compaction temperature was 155 ° C., and the porosity of the mixture was 17.3%.

  It has been experimentally confirmed that Japanese roads reach a temperature of about 60 ° C in the summer. In this state, when a car passes over the road, the pavement is fluidized and deformed, which causes ruts and the like.

  The wheel tracking test is a test designed to experimentally confirm the extent of occurrence of ruts, and is a test performed to evaluate dynamic stability that is an index of fluid resistance in pavement. is there.

  Specifically, generally, in a constant temperature bath maintained at 60 ° C, a tire under a predetermined load is reciprocated for 1 hour on a test piece (specimen) and the amount of change is measured. Is done.

  However, the present invention is an asphalt composition used for a thin-layer drainage pavement, and the thin-layer drainage pavement is required to have a DS value comparable to that of a conventional pavement even if it is a thin layer. Therefore, as a more severe condition, a DS value measurement test was performed in an environment of 70 ° C.

  The DS value (times / mm) is calculated by using the amount of deformation (mm) for 15 minutes from 45 minutes to 60 minutes after the start of the test and the number of tire running times (times) for 15 minutes from the start of the test to 15 minutes. It is calculated using the formula

    DS value (times / mm) = (number of tire runnings from 45 minutes to 60 minutes (times)) / (change amount from 45 minutes to 60 minutes (mm))

  The higher the DS value, the higher the strength of asphalt, which means that it is possible to provide a paving material that is resistant to rubbing. According to the above-mentioned pavement survey and test method handbook, when the DS value is 6000 times / mm or more, the DS value is to be reported as 6000 times / mm or more. In order to meet the requirements of 1), a product having a DS value at 70 ° C. of 6000 times / mm is a conforming product. In Tables 2 and 3 described later, those having a DS value of 6000 times / mm or more are represented by O, and those having a DS value less than that are represented by X.

  The separation test (180 ° C.) was carried out by injecting the asphalt composition of the present invention (about 250 g) to a position of 12 cm in depth in an aluminum cylindrical can having an inner diameter of 5.2 cm and a height of 13 cm and sealing it at 180 ° C. Heated for 72 hours.

  Then, the viscosity at 180 ° C. in the upper 4 cm and lower 4 cm of the asphalt composition injected into the aluminum cylindrical can was measured.

  The absolute value of the difference between the viscosity of the upper part and the viscosity of the lower part was taken, that is, the absolute value of the difference of the viscosity was divided by the value of the upper part to obtain the difference (%) in the viscosity at 180 ° C. In the example, 25% or less is a conforming product. If the difference in viscosity properties exceeds 25%, the storage stability becomes insufficient. In Tables 2 and 3, which will be described later, those having a viscosity property difference of 25% or less are represented by ◯, and those exceeding the difference are represented by x.

  In the present invention, the difference (%) in viscosity at 180 ° C. is preferably 15% or less, more preferably 10% or less.

  By using an asphalt composition satisfying all of the above criteria, it becomes possible to secure high strength and durability even for a thin layer type drainage pavement using an aggregate having a small particle size.

  Hereinafter, examples and comparative examples for verifying the effects of the asphalt composition to which the present invention is applied will be described.

In the present invention, in order to carry out an experimental study, for the obtained sample, the above-mentioned penetration degree (25 ° C.), viscosity (180 ° C.), complex elastic modulus (G ^* ) (70 ° C.), DS value (70 C.) and a separation test.

(Regarding Examples 1 to 12 and Comparative Examples 1 to 10)

  First, propane deasphalting asphalt as a base asphalt, aromatic heavy oil (extract), petroleum resin, first SBS, and second one shown in Examples 1 to 12 and Comparative Examples 1 to 10 of Table 3 An asphalt composition containing SBS, an anti-stripping agent and EEA in the compounding ratios shown in the table was prepared. It should be noted that in Table 2, only numerical values are shown by weight.

  Examples 1 to 8 are examples corresponding to the above-described second embodiment, and all are base asphalt, 8 wt% or more and 15 wt% or less SBS mixture, and more than 0 wt% and 5 wt%. An asphalt composition containing the following EEA and containing a mixture of SBS and EEA in a total amount of more than 13% by weight and less than 15% by weight.

The asphalt compositions according to Examples 1 to 8 all satisfied the criteria for the evaluation items described above. That is, all the asphalt compositions according to Examples 1 to 8 have a penetration of 30 or less, a viscosity (180 ° C.) of 1400 mPa · s or less, a complex elastic modulus (G ^* ) of 14000 Pa or more, and a DS value of 70 ° C. Was 6000 times / mm or more, and the difference in the property of viscosity was 25% or less.

  In addition, Examples 9 and 10 are also examples corresponding to the above-described second embodiment, and the first example is the sample of Example 2 in which the mixing ratio of the first SBS and the second SBS is 1: 2. The total amount of SBS and the second SBS mixed is not changed, and only the mixing ratio is set to 1: 1 and 1: 4, respectively.

The samples according to Examples 9 and 10 also have a penetration of 30 or less, a viscosity (180 ° C.) of 1400 mPa · s or less, a complex elastic modulus (G ^* ) of 14000 Pa or more, and a DS value of 600 at 70 ° C.
The sample satisfied all the criteria of 0 times / mm or more and the difference in viscosity property of 25% or less.

  In addition, Examples 11 and 12 are examples corresponding to the above-described first embodiment and do not contain EEA, and the content of the SBS mixture in the asphalt composition is 13% by weight or more and 15% by weight or more. It is below.

The asphalt compositions according to Examples 11 and 12 also have a penetration of 30 or less, a viscosity (180 ° C.) of 1400 mPa · s or less, a complex elastic modulus (G ^* ) of 14000 Pa or more, and a D of 70 ° C.
The sample satisfied all the criteria that the S value was 6000 times / mm or more and the difference in viscosity properties was 25% or less.

  On the other hand, in each of Comparative Examples 1 to 5, the total amount of the mixture of the SBS mixture and EEA is less than 13% by weight.

In Comparative Examples 1, 4 and 5, although the criteria that the penetration is 30 or less and the viscosity property difference is 25% or less are commonly satisfied, the complex elastic modulus (G ^* ) is less than 14000 Pa,
The DS value at 70 ° C. was less than 6000 cycles / mm, which did not satisfy the performance required by the present invention.

In Comparative Examples 2 and 3, the criteria that the penetration is 30 or less and the criteria that the viscosity property difference is 25% or less are satisfied in common, but the complex elastic modulus (G ^* ) is less than 14000 Pa and 70 ° C. Has a DS value of less than 6000 times / mm, which does not satisfy the performance required by the present invention.

  Further, in each of Comparative Examples 6 to 10, the total amount of the mixture of the SBS mixture and EEA exceeds 15% by weight.

Comparative Examples 6 to 10 all satisfy the conditions that the penetration is 30 or less, the complex elastic modulus (G ^* ) is 14000 Pa or more, and the DS value at 70 ° C. is 6000 times / mm or more, but the difference in viscosity is 25. It did not meet the standard of less than or equal to%.

(Regarding Examples 13 to 15 and Comparative Examples 11 and 12)

  Examples 13 to 15 and Comparative Examples 11 and 12 shown in Table 4 are the same as Example 2 shown in Table 1 except that ethyl acrylate (EA) is contained in the whole EEA while containing the same amount of EEA. ) Is a sample in which 5 kinds of materials having different contents and MFR are replaced. The MFR was measured according to JIS K 7210 at a test temperature of 190 ° C and a test load of 21.18N.

  Since EA is a polar group, the higher the EA content of EEA, the more easily SBS is mixed in the asphalt composition, and the storage stability can be improved. Therefore, the EA content in EEA is preferably 20% by weight or more.

  Further, the smaller the MFR of EEA, the higher the complex elastic modulus of the asphalt composition, and the higher the mechanical strength of the pavement.

In each of Examples 13 to 15, EEA having an MFR of 5 g / 10 minutes or less was used. When the MFR is 5 g / 10 minutes or less, the penetration value is 30 or less, the complex elastic modulus (G ^* ) is 14000 Pa or more, and the DS value at 70 ° C. is 6000 times / mm, as in Example 2 described above. As described above, the sample is a sample that satisfies all the criteria that the difference in viscosity properties is 25% or less.

  On the other hand, in Comparative Examples 11 and 12, EEA of 20 having an MFR of more than 5 is used. In the asphalt compositions according to Comparative Examples 11 and 12, the DS value at 70 ° C. was less than 6000 times / mm, and the performance required by the present invention was not satisfied.

As described above, according to the present invention, by using the asphalt composition having the composition described in Embodiment 1 or 2 above, the penetration is 30 or less, the viscosity (180 ° C.) is 1400 mPa · s or less, and the complex Elastic modulus (G ^* ) is 14000Pa or more, DS value at 70 ° C is 6000 cycles / mm
As mentioned above, it is possible to satisfy all the criteria that the difference in the properties of viscosity is 25% or less, and to secure high strength and durability even when laying a thin-layer drainage pavement using aggregate with a small particle size. You can

The present invention is not limited to the content of each component in the above-mentioned examples, the content of the SBS mixture and EEA satisfies the content described in the above-mentioned first or second embodiment, and the penetration is 30 or less, viscosity (180 ° C) is 1400 mPa · s or less, complex elastic modulus (G ^* ) is 14000 Pa or more, DS value at 70 ° C is 6000 times / mm or more, and viscosity difference is 25% or less. As long as it is a substance, other contents can be used for other components.

  The third embodiment will be specifically described below with reference to test methods, examples and comparative examples used in the present invention, but the present invention is not limited to these examples. Further, in the following examples, when only “%” is described, it means “% by weight”.

  The method for producing the asphalt composition including Examples 16 to 23 and Comparative Examples 13 to 20 having the configuration of the above-described third embodiment will be described below.

  Propane deasphalted asphalt was melted at a temperature of about 150 ° C., and mixed so as to have the weight mixing ratio shown in Table 5 below, and the above-mentioned first SBS to second SBS were mixed in the same procedure. It is added in a fixed amount, and further the above-mentioned peeling preventing agent (resin acid) and EEA are added. The mixing was performed using a homomixer, and the number of rotations was set to 1500 to 5000 rotations / minute, and the mixture was stirred and mixed for about 3 to 5 hours. The temperature of asphalt at the end of mixing was adjusted to 200 to 215 ° C. The production amount was 1.8 kg in each case.

  In the present invention, with respect to the sample obtained for conducting the experimental examination, the penetration (25 ° C.), softening point, viscosity (180 ° C.), complex elastic modulus (60 ° C.), separation test, water immersion WT wheel tracking test The peeled area ratio is measured by. The penetration (25 ° C.), the softening point, and the viscosity (180 ° C.) are the same as in Example 1 described above, and therefore the description thereof is omitted below.

The separation test (180 ° C.) was carried out by injecting the asphalt composition of the present invention (about 250 g) to a position of 12 cm in depth in an aluminum cylindrical can having an inner diameter of 5.2 cm and a height of 13 cm and sealing it at 180 ° C. Heated for 72 hours. Then, the viscosity at 180 ° C. in the upper 4 cm and lower 4 cm of the asphalt composition injected into the aluminum cylindrical can was measured. The absolute value of the difference between the viscosity of the upper part and the viscosity of the lower part was taken, that is, the absolute value of the difference of the viscosity was divided by the value of the upper part to obtain the difference (%) in the viscosity at 180 ° C. In the examples, 5% or less is a conforming product. If the difference in viscosity is more than 5%, the storage stability will be insufficient. In Table 5, which will be described later, those having a viscosity property difference of 5% or less are represented by ◯, and those exceeding that are represented by x. The complex elastic modulus (G ^* ) (60 ° C.) was measured according to the dynamic shear rheometer (DSR) test method specified in the Pavement Survey and Test Method Handbook (edited by the Japan Road Association). The measurement principle of this test is that an asphalt composition, which is a measurement sample, is sandwiched between two parallel disks (diameter is 25 mm), and one disk is subjected to sinusoidal distortion of a predetermined frequency to obtain an asphalt composition (thickness: The sinusoidal stress σ transmitted to the other disk via 1 mm) is measured, and the complex elastic modulus is calculated from the sinusoidal stress and the sinusoidal distortion. The measurement frequency was 1 rad / s and the strain was 10%. The complex elastic modulus (G ^* ) was measured at 60 ° C.

  The water immersion wheel tracking test is intended to measure the state of peeling of the asphalt mixture under the action of water caused by running the wheel in water. In this water immersion wheel tracking test, the peeling condition of the asphalt mixture is identified by measuring the peeling area ratio described below.

  The details of the water immersion wheel tracking test are carried out in accordance with the B004 water immersion wheel tracking test method in the "Pavement Survey and Test Method Handbook [Part 3]" edited by the Japan Road Association. In the water immersion wheel tracking test, each asphalt composition and the aggregate (weight percentage) shown in Table 6 were prepared with the amount of asphalt in the mixture being 5.4% by weight and the aggregate 94.6% by weight. , A sheet-shaped specimen having a width of 30 cm and a thickness of 5 cm is used. The test conditions for the immersion wheel tracking test are based on Table 7 below.

  In the water immersion wheel tracking test, water at a temperature of 60 ° C. ± 0.5 ° C. is immersed in the upper surface of the test piece, and then subjected to water immersion curing for 12 hours. Next, the test piece is subjected to a running test based on the B004 water immersion wheel tracking test method in the above-mentioned "Pavement Survey and Test Method Handbook [Part 3]" to measure the peeled area. This peeling area was measured by dividing the specimen after the test into four parts, observing the cross section, and peeling the cross-sectional area that had not been peeled and peeled according to "5. Organizing the results" in Handbook B004 of the same test method. Calculated from the ratio of the cross-sectional area. If the peeled area ratio is 12% or less, it can be said that the asphalt has high strength and excellent water resistance.

  Propane deasphalting asphalt as a base asphalt, aromatic heavy oil (extract), 1st SBS, 2nd SBS, and anti-stripping agent shown in Examples 16-23 and Comparative Examples 13-20 of Table 5. And EEA were prepared with the blending ratios shown in the table.

  Examples 16 to 23 are examples corresponding to the above-described third embodiment, and all of them are base asphalt, an SBS mixture of 6.5% by weight or more and 11% by weight or less, and more than 1% by weight. It contains less than wt% EEA, and the total content of SBS and EEA is 9.5 wt% or more and 12 wt% or less. Further, the addition amount of the first SBS / the addition amount of the second SBS is 0.25 or more and 1.00 or less.

All the asphalt compositions according to Examples 16 to 23 satisfy the criteria for the above-described evaluation items. That is, the asphalt compositions according to Examples 16 to 23 all had a penetration of 40 or more, a softening point of 70 or more, a viscosity (180 ° C.) of 600 mPa · s or less, and a complex elastic modulus G ^* (measurement frequency: 1 rad. / S) was 1900 or more, and the results of the separation test were all good, and all the criteria of the peeled area ratio in the water immersion wheel tracking test of 12% or less were satisfied. Therefore, according to the asphalt compositions according to Examples 16 to 23, it is possible to secure high strength and water resistance and improve the workability by increasing the fluidity of the asphalt.

  The asphalt compositions according to Examples 16 to 23 contained EEA in the range of more than 1% by weight and less than 3% by weight, so that good results were obtained particularly in the peeling area ratio in the water immersion wheel tracking test. It was

On the other hand, in Comparative Example 13, since the total content of SBS and EEA exceeds 12% by weight, the viscosity at 180 ° C. is increased to 820 mPa · s, which indicates that the workability is deteriorated. It was
Further, in Comparative Example 14, the content of EEA was 3% by weight or more, so the storage stability was slightly lowered, and the result of the separation test was deteriorated. Further, the water immersion wheel tracking test could not be measured.

Further, in Comparative Example 15, the content of EEA is 3% by weight or more, the storage stability is slightly lowered, the result of the separation test is deteriorated, and the blending ratio of SBS and EEA is less than 9.5%. Therefore, the complex elastic modulus G ^* was also low and the strength was lowered. The immersion wheel tracking test
The measurement was impossible.

  In Comparative Example 16, since the total content of SBS and EEA was less than 9.5% by weight, the elastic modulus of the asphalt composition was low, and the asphalt between the aggregates failed cohesively and the water resistance of the mixture decreased. The peeled area ratio was 20.5%.

  In Comparative Example 17, since the total content of SBS and EEA was less than 9.5% by weight, the elastic modulus of the asphalt composition was low, and the asphalt between the aggregates caused cohesive failure to reduce the water resistance of the mixture. The peeled area ratio was 22%.

In Comparative Example 18, since the content of EEA is 1% or less, the amount of polar components contained in the asphalt composition is small, so the suction force to the aggregate is low, and the peeled area ratio is 14.0%. And the complex elastic modulus G ^* was also low.

  In Comparative Example 19 as well, since the content of EEA is 1% or less, the amount of polar components contained in the asphalt composition is small, so the suction force to the aggregate is low, and the peeled area ratio is 17.3%. It was getting worse.

In Comparative Example 20, since the EEA was 0%, the polarity of the asphalt composition was drastically decreased, the adhesiveness with the aggregate was significantly decreased, and the peeled area ratio was rapidly deteriorated to 29.8%. However, the complex elastic modulus G ^* was also low.

The present invention is not limited to the content of each component in the above-mentioned examples, the content of the SBS mixture and EEA satisfies the content described in the third embodiment described above, and the penetration of each is 40 or more. If the softening point is 70 or more, the viscosity (180 ° C.) is 600 mPa · s or less, the complex elastic modulus G ^* is 1900 Pa or more, the separation test is good, and the peeling area ratio is 12% or less, all of the criteria are satisfied. The other components may have other contents.

Claims (8)

With the total mass of the composition being 100% by weight,
Base asphalt,
8% by weight or more and 15% by weight or less of styrene-butadiene-styrene block copolymer (SBS),
Ethylene ethyl acrylate (EEA) of more than 0% by weight and 5% by weight or less,
An asphalt composition containing:
The melt mass flow rate (MFR) of the EEA is 5 g / 10 minutes or less,
The total amount of the mixture of SBS and EEA is more than 13% by weight and less than 15% by weight,
An asphalt composition characterized by the above. The SBS is a mixture of a first SBS and a second SBS having a smaller molecular length and a higher styrene content ratio than the first SBS,
The molecular length in the first SBS is 1.8 times or more the molecular length in the second SBS,
When the styrene block length in the first SBS is LS1 and the styrene block length in the second SBS is LS2, LS2 / LS1 is 0.7 to 1.4.
The asphalt composition according to claim 1, wherein:   The asphalt composition according to claim 2, wherein the amount of the first SBS added / the amount of the second SBS added is 0.25 or more and 1.00 or less. The asphalt composition according to any one of claims 1 to 3 , which contains 6 to 10% by weight of a petroleum resin. The asphalt composition according to any one of claims 1 to 4 , which contains 0.2 to 2.0% by weight of a peeling preventing agent. With the total mass of the composition being 100% by weight,
Base asphalt,
6.5 wt% or more and 11 wt% or less of styrene-butadiene-styrene block copolymer (SBS),
Containing more than 1% by weight and less than 3% by weight of ethylene ethyl acrylate (EEA),
The SBS is a mixture of a first SBS and a second SBS having a smaller molecular length than the first SBS and a high styrene content ratio, and the molecular length in the first SBS is the second SBS. When the styrene block length in the first SBS is LS1 and the styrene block length in the second SBS is LS2, LS2 / LS1 is 0.7 to 0.7. 1.4,
The asphalt composition, wherein the total content of the SBS and the EEA is 9.5 wt% or more and 12 wt% or less. The asphalt composition according to claim 6, wherein the amount of the first SBS added / the amount of the second SBS added is 0.25 or more and 1.00 or less. The asphalt composition according to claim 6 or 7, further comprising 0.2 to 2.0% by weight of a peeling preventive agent.

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