JP7146808B2 - goose asphalt composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a goose asphalt composition that is excellent in fluidity and suitable for exhibiting the strength required for heavy traffic pavement.

Goose asphalt, which is more durable than general asphalt pavement, is used for steel bridges and elevated roads. In particular, steel floor slabs tend to flex downward due to impact from traffic loads and repeated bending loads.

Moreover, with the remarkable increase in traffic volume, problems such as the occurrence of rutting cannot be ignored even on iron bridges and elevated roads paved with goose asphalt. For this reason, development of a new goose asphalt that can be poured into pavement with improved rutting resistance (DS value) and high fluidity like conventional goose asphalt is expected.

In order to meet such demands, goose asphalt having the component composition shown in Patent Document 1 has been proposed.

JP 2016-113477 A

According to the goose asphalt composition described in Patent Document 1 mentioned above, it is necessary to heat it to a high temperature of about 240 ° C. when it is poured onto the construction base surface. There was a need to realize pouring even at 240°C or less by expressing a high fluidity. In addition, with the increase in traffic in recent years, it is necessary to improve the rutting resistance to the extent that the DS value always exceeds at least 500 (times/mm), and more preferably 600 (times/mm). It was necessary to improve to the extent that it always exceeded.

Therefore, the present disclosure has been devised in view of the above-mentioned problems, and the purpose thereof is to provide a goose asphalt composition capable of improving rutting resistance and exhibiting high fluidity. is to provide

According to one aspect of the present disclosure, solvent deasphalted asphalt: 40-60% by weight, petroleum solvent-extracted oil: 15-25% by weight, SEBS with a styrene content of 60-70%: 10-13% by weight and petroleum resin: 13 to 20% by mass.

According to the present invention, it is possible to provide a goose asphalt composition capable of improving rutting resistance and exhibiting high fluidity.

FIG. 2 is a diagram showing an example of a pavement structure using a goose asphalt composition suitable for use in embodiments of the present disclosure on a construction base composed of a steel floor; 1 is a schematic configuration diagram showing an apparatus for producing a goose asphalt composition in the present disclosure; FIG. FIG. 2 is a diagram showing the flow of the manufacturing process of the goose asphalt composition in the present disclosure; It is a figure for demonstrating the detail of the measuring method of DS value. FIG. 10 is a diagram showing an example of the amount of subsidence (mm) with respect to the test time (minutes) starting from the DS value measurement test start time;

As described above, the present inventors have diligently studied the component composition and content of the goose asphalt composition. As a result, we optimized the range of styrene-ethylene-butylene-styrene block copolymers (SEBS) to improve fluidity and added petroleum resins to improve rutting resistance. This led to the completion of the present invention.

Hereinafter, embodiments of the goose asphalt composition in the present disclosure will be described in detail.

The goose asphalt composition in this embodiment contains at least solvent deasphalted asphalt, petroleum solvent-extracted oil, SEBS with a styrene content of 60% to 70%, and petroleum resin. The content and properties of each component composition are as follows.

Solvent deasphalted asphalt: 40% by mass or more to 60% by mass or less Petroleum solvent-extracted oil: 15% by mass or more to 25% by mass or less SEBS with a styrene content of 60 to 70%: 10% by mass to 13% by mass or less Petroleum Resin: 13% by mass or more to 20% by mass or less Anti-stripping agent: 0.2% by mass or more to 1.5% by mass or less Penetration: 5 or more to 10 or less (1/10 mm)

The details of each component composition and the reason for limiting the content thereof will be described below.

(Solvent deasphalting asphalt)
In the present invention, among the solvent-deasphalted asphalts, it is desirable to use propane-deasphalted asphalts using propane, propane or butane, or both as solvents.

For example, propane deasphalted asphalt has a penetration of 12 (1/10 mm) at 25°C under JISK2207, a softening point of 63.5°C, a viscosity of 132 mPa s at 180°C, and a density of 1062 kg/m at 15°C. ³ may be used. However, these physical properties of the propane-deasphalted asphalt are merely examples, and the present invention is not limited thereto.

If the content of solvent-deasphalted asphalt is less than 40% by mass, the proportion of petroleum-based solvent-extracted oil increases, and rutting resistance cannot be improved. On the other hand, when the content of solvent-deasphalted asphalt exceeds 60% by mass, the proportion of petroleum-based solvent-extracted oil decreases, and the asphalt becomes difficult to flow at construction work temperatures, resulting in poor workability. In addition, there is a possibility that the compatibility with the hydrogenated thermoplastic elastomer may be lowered. Therefore, the content of solvent-deasphalted asphalt with respect to the entire goose asphalt composition should be 40% by mass or more and 60% by mass or less.

(Petroleum-based solvent-extracted oil (extract))
The role of the extract, which is a petroleum-based solvent-extracted oil, is to increase the solubility of SEBS in the base asphalt and prevent separation during storage stability. also increases. Also, if the extract is added in excess of the amount of SEBS added, the strength will decrease.

The content of the extract relative to the total goose asphalt composition is determined by considering the dynamic stability (DS value) in the wheel tracking test, which indicates penetration, softening point, and strength (rutting resistance). In addition to this, the content of this extract is determined in consideration of the content ratio with the petroleum resin when considering the DS value. Within the range studied in the present invention, the content of the extract relative to the entire goose asphalt composition is preferably 15% by mass or more and 25% by mass or less.

(SEBS with a styrene content of 60% by mass or more and 70% by mass or less)
SEBS is a styrene-butadiene-styrene block copolymer (SBS) in which the butadiene blocks in the polymer are completely hydrogenated to eliminate double bonds, resulting in significantly improved heat resistance and weather resistance compared to SBS. . However, since this hydrogenation treatment changes the flexibility of the molecular chain, the addition effect on the modified asphalt is also different from that of SBS. This SEBS may be replaced by any material other than SEBS, such as SEPS, as long as the double bond is eliminated by completely hydrogenating the butadiene block in SBS. In the following description, the case of adopting SEBS will be described as an example.

The reason for adopting SEBS is that goose asphalt is applied at around 240°C, so normal SBS decomposes and gels, but SEBS can maintain its properties sufficiently even at high operating temperatures. . In order to obtain a goose asphalt composition having the desired properties, the SEBS to be adopted has a styrene content in the range of 60% by mass or more and 70% by mass or less, and a density of 940 kg / m ³ or more at 23 ° C. must be in If the styrene content is lower than 60% by mass, the ratio of butylene ethylene becomes high, resulting in a marked increase in viscosity. This marked increase in viscosity causes a significant decrease in fluidity of the resulting composition as a whole. On the other hand, if the styrene content exceeds 70% by mass, the decrease in the ratio of butylene ethylene causes a marked decrease in viscosity and an increase in fluidity. However, the strength of the composition as a whole cannot be developed in response to such a significant decrease in viscosity, resulting in a significant decrease in the DS value. For this reason, SEBS can suppress excessive viscosity increase, and from the viewpoint of suppressing excessive viscosity decrease and improving the strength of the entire composition, the styrene content is 60% by mass or more and 70% by mass or less, and , and a density at 23°C of 940 kg/m ³ or more and 980 kg/m ³ or less. By setting the 23° C. density to 940 kg/m ³ or more and 980 kg/m ³ or less, the styrene content can be suppressed to a range of 60 mass % or more and 70 mass % or less.

In addition, SEBS is more preferably manufactured so that the styrene content is 60% by mass or more and 70% by mass or less, so that excessive viscosity increase can be suppressed and excessive viscosity decrease can be prevented. It becomes possible to suppress and improve the strength of the composition as a whole.

In addition, in the goose asphalt composition of the present disclosure, by adding the elastic SEBS having the above-described structure, there is an aim to improve the DS value and prevent brittle fracture due to hardening.

In the goose asphalt composition of the present disclosure, the lower limit of the SEBS content is 10% by mass. This is because if the SEBS content is less than 10% by mass, the strength is lowered and the DS value is significantly lowered. Similarly, in the goose asphalt composition of the present disclosure, the upper limit of the content of SEBS is 13% by mass. If the content of SEBS exceeds 13% by mass, the resulting composition will have an excessively high viscosity, and the fluidity will deteriorate particularly in the working temperature range of 200 to 240°C, resulting in poor pouring method. The construction efficiency in doing Therefore, the content of SEBS in the goose asphalt composition of the present disclosure is 10% by mass or more and 13% by mass or less.

(petroleum resin)
Petroleum resin is a polymer of unsaturated hydrocarbons present in thermal cracking fractions in the petroleum refining process, has a molecular weight of 100 or more and 2000 or less, generally 200 or more and 1500 or less, and a softening point of 60 ° C. or more. It is a pale yellow material that is ~150°C or less. A hydrogenated resin is obtained by adding hydrogen to the double bond in the molecule of such a non-hydrogenated resin, and the softening point of this hydrogenated resin is usually 90° C. or higher and 150° C. or lower. be.

Examples of resins employed in this disclosure include hydrogenated rosin resins, hydrogenated C5 petroleum resins, hydrogenated C9 petroleum resins, hydrogenated C5 petroleum resins and C9 petroleum resins. Copolymer resin, hydrogenated dicyclopentadiene resin, aromatic modified terpene, further unhydrogenated rosin resin, unhydrogenated C5 petroleum resin, unhydrogenated C9 petroleum resin, hydrogenated a copolymer resin of a C5 petroleum resin and a C9 petroleum resin which are not hydrogenated, a dicyclopentadiene resin which is not hydrogenated, or a terpene.

In the goose asphalt composition of the present disclosure, if the content of the petroleum resin is less than 13% by mass, the strength of the goose asphalt composition decreases, resulting in a significant decrease in the DS value. On the other hand, if the content of the petroleum resin in the goose asphalt composition of the present disclosure exceeds 20% by mass, the hardness of the petroleum resin reduces the penetration, and the viscosity of the resulting composition decreases. If the temperature rises too much, the fluidity deteriorates especially in the working temperature range of 200 to 240° C., and the efficiency of the pouring method decreases. Therefore, the petroleum resin content in the goose asphalt composition of the present disclosure is set to 13% by mass or more and 20% by mass or less.

In the present disclosure, as the petroleum resin, the optimum contents are found for each of petroleum resin 1 and petroleum resin 2 described below.

For the petroleum resin 1 in the present disclosure, for example, a C9 petroleum resin is used. Typical properties of the C9 petroleum resin used in the present disclosure are a softening point of 140 ° C., an acid value of 0.1 mg KOH / g specified by JIS K0070, and a bromine number of 25 g / 100 g specified by JIS K2543. and an average molecular weight of about 1,000 in terms of polyethylene measured by the GPC method. In addition, in the goose asphalt composition of the present disclosure, the content of petroleum resin 1 is set to 13% by mass or more and 17% by mass or less, and the content ratio of petroleum resin 1 to the petroleum solvent-extracted oil contained in the goose asphalt composition When (petroleum resin 1/petroleum solvent-extracted oil×100) is 60.0% or more, the DS value can be further improved. If the content ratio (petroleum resin 1/petroleum solvent-extracted oil×100) exceeds 90.0%, the penetration becomes low and the viscosity becomes high. Therefore, it is desirable to set the upper limit of the content ratio (petroleum resin 1/petroleum solvent-extracted oil×100) to 90.0%. If the content ratio of the petroleum resin 1 to the petroleum solvent-extracted oil is less than 60.0%, the DS value cannot be improved.

If the content of the petroleum resin 1 is less than 13% by mass, the penetration becomes high and the DS value becomes low. On the other hand, when the content of the petroleum resin 1 exceeds 17% by mass, the penetration becomes low, the viscosity increases, and the fluidity deteriorates.

As the petroleum resin 2 in the present disclosure, for example, a copolymer resin of hydrogenated C5 petroleum resin and C9 petroleum resin is used. Typical properties of the copolymer resin of C5 petroleum resin and C9 petroleum resin used in the present disclosure include a softening point of 140 ° C., a bromine number specified by JIS K2543 of 2 g / 100 g, polyethylene measured by the VPO method The converted average molecular weight is about 900. Further, in the goose asphalt composition of the present disclosure, the content of the petroleum resin 2 is set to 17% by mass or more and 20% by mass or less, and the content ratio to the petroleum solvent-extracted oil (petroleum resin 2 / petroleum solvent-extracted oil × 100) is preferably 89.0% or more. If the content ratio (petroleum resin 2/petroleum solvent-extracted oil×100) exceeds 100.0%, the penetration becomes low and the viscosity becomes high. Therefore, it is desirable to set the upper limit of the content ratio (petroleum resin 2/petroleum solvent-extracted oil×100) to 100.0%.

If the content ratio relative to the petroleum solvent-extracted oil is less than 89.0%, the penetration becomes high and the DS value cannot be improved.

When the content of the petroleum resin 2 is less than 17% by mass, the penetration becomes high and the DS value becomes low. On the other hand, when the content of the petroleum resin 2 exceeds 20% by mass, the penetration becomes low, the viscosity increases, and the fluidity deteriorates.

(Anti-peeling agent)
In the present disclosure, in order to prevent the delamination of the asphalt composition and the aggregate, the content of the delamination inhibitor with respect to the goose asphalt composition is added so as to be in the range of 0.2% by mass or more to 1.5% by mass or less. preferably.

In the present disclosure, for example, a resin acid can be suitably used as an anti-stripping agent. A resin acid is a polycyclic diterpene having 20 carbon atoms and having a carboxyl group, and is a rosin containing at least one of abietic acid, dehydroabietic acid, neoabietic acid, pimaric acid, isopimaric acid, and parastric acid. It's about.

As the resin acid, in addition to the rosin described above, disproportionated rosin, dimer acid or trimer acid derived from abietic acid, or a mixture of two or more thereof can be used.

As the rosin in the present disclosure, for example, gum rosin, wood rosin, tall oil rosin, etc. are preferably used. Rosin can be classified into the aforementioned gum rosin, wood rosin, etc., depending on the place of origin, raw material, and extraction method, but at least it is obtained as a residual component during steam distillation of pine resin. Rosin is a mixture containing abietic acid, parastric acid, neoabietic acid, dehydroabietic acid, pimaric acid, sandaracopimaric acid, isopimaric acid, etc. as components. This rosin usually softens at about 80.degree. C. and mainly melts in the range of 90.degree. C. to 100.degree. Rosin contains various resin acids such as abietic acid, dehydroabietic acid, dihydroabietic acid, tetrahydroabietic acid, parastric acid, neoabietic acid, and levopimaric acid. It may be used alone.

Although gum rosin has been used as a preferred anti-stripping agent for addition in this disclosure, it is not so limited.

If the content of the resin acid is less than 0.2% by mass, the effect of the resin acid is insufficient, and the prevention of peeling and the improvement of the compatibility of the final product cannot be achieved. On the other hand, if the resin acid content exceeds 1.5% by mass, the effects of preventing peeling and improving compatibility become saturated, and the amount of the expensive resin acid to be added is increased. A problem arises in that the cost of raw materials increases remarkably due to the increase. Even if the content of the resin acid exceeds 1.5%, the prevention of peeling and the improvement of the compatibility are not significantly improved, and on the contrary, it is disadvantageous in terms of raw material cost. Therefore, it is desirable that the resin acid content be 0.2% by mass or more and 1.5% by mass or less (more preferably 0.2% by mass or more and 1% by mass or less).

In addition, some anti-stripping agents also have performance as a lubricant. Since it also works as a lubricant that improves the compaction property, it is possible to form a more suitable goose asphalt composition.

(penetration)
The penetration is an index representing the hardness of the goose asphalt composition. A higher penetration value indicates a softer composition, and a lower penetration value indicates a harder composition. The penetration (25° C.) is measured by the method specified by JIS K 2207 “Petroleum asphalt—Penetration test method”.

If the penetration is less than 5 (1/10 mm), the goose asphalt composition will be too hard, resulting in poor fluidity. On the other hand, if the penetration exceeds 10 (1/10 mm), the goose asphalt composition will be too soft, resulting in a rather low DS value. Therefore, the penetration must be 5 or more and 10 or less (1/10 mm).

The goose asphalt composition having the composition described above is prepared by blending (mixing) coarse aggregates and fillers to form goose asphalt 2, which is paved on a steel floor 3 as shown in FIG. be. Here, the manufacturing process of the goose asphalt composition composed of the component composition described above will be described with reference to FIGS. 2 and 3. FIG.

(Asphalt base material manufacturing process: S301)
As shown in FIG. 2, a goose asphalt composition is produced in a polymer-modified asphalt production plant 100 to have the component composition described above. The asphalt base material tank 101 serving as a base is supplied to the mixing tank 102 via the first supply pipe 104 (solvent deasphalted asphalt, petroleum-based solvent-extracted oil).

(Asphalt base material and additive blending step: S302)
Next, the above-described additives such as SEBS, petroleum resin, and anti-peeling agent are added from the additive supply device 106 to the asphalt base material, which is the base, in the mixing tank 102, and a stirring device (also referred to as a mixing device) is added. 105 stirs and mixes at a predetermined mixing temperature and mixing time. As a result, the asphalt base material and the additive are uniformly mixed to produce a goose asphalt composition (S302).

(Manufacturing and storage process: S303)
The goose asphalt composition stirred and mixed at a predetermined temperature and for a predetermined time is supplied to the product tank 103 through the second supply pipe 107 and stored (S303). The asphalt base tank 101, the mixing tank 102, and the product tank 103 may be provided with a heating device (heater) for heating or maintaining the asphalt base or goose asphalt composition at a predetermined temperature. . A goose asphalt composition is thus produced.

After that, the goose asphalt composition is blended (mixed) with coarse aggregate and filler at an asphalt mixture plant, and then transported to the construction site while being cooked to a temperature range of 200 ° C or higher and 260 ° C or lower by a dedicated truck. be done. Then, the goose asphalt 2 in a heated state is poured onto the steel floor 3 using a dedicated asphalt finisher. In this process, the goose asphalt 2 has a very high fluidity. Therefore, just by pouring the goose asphalt 2 into the steel floor 3, it is possible to fill every corner of the tightening members 4 such as bolts projecting from the surface of the steel floor 3 and stepped portions (not shown). As a result, the goose asphalt 2 can exhibit high waterproof performance and watertight performance. For this reason, compared with the rolling compaction method, filling can be achieved with less construction labor. Finally, the upper layer of this goose asphalt 2 is filled with general asphalt concrete 1 to pave it.

In this way, with the goose asphalt 2, after the layer of the goose asphalt 2 is formed on the steel floor 3, there is no need to perform a treatment such as rolling compaction (compaction) using heavy machinery, and high waterproof performance and Since it is possible to express watertight performance, it is possible to reduce the construction labor and suppress the construction cost.

In addition, because of its high fluidity, the goose asphalt 2 can fill every corner of the tightening member 4 protruding from the surface of the steel floor 3, leaving minute voids inside the pavement. can be prevented. Furthermore, by using goose asphalt 2, it becomes possible to improve the DS value to 500 (times/mm) or more. Especially when Goose Asphalt 2 is used for pavement of a bridge, the bridge girder itself shakes more due to vehicles running on the bridge, but even in such a case, applying Goose Asphalt 2 improves the DS value becomes possible. In particular, replacement of the goose asphalt 2 used for such pavement requires the asphalt concrete 1 to be peeled off once. However, by using the goose asphalt 2 with an improved DS value, it is possible to extend the life of the goose asphalt 2, and it is possible to improve the durability of the entire pavement, including the asphalt concrete 1 on the upper layer. Become.

The test method, examples and comparative examples described above will be specifically described below, but the present invention is not limited to these examples. Moreover, when only % is described in the following examples, it shall show the mass %.

In this example, as shown in Tables 1 and 2, the samples obtained for experimental studies were evaluated for penetration, softening point, viscosity at 180°C, DS value, and Ruell fluidity at 220°C (hereinafter referred to as , simply referred to as fluidity.) Perform a property and performance test. A detailed test method will be described below. The fluidity and DS value are test results of a mixture mixed with aggregate, and the penetration, viscosity, and softening point are all test results of the asphalt composition alone. Each numerical value for each component composition in Tables 1 and 2 indicates the content (% by mass).

First, regarding fluidity, aggregate was mixed with 12 kg of the prepared goose asphalt mixture under the conditions shown in Table 3, and the fluidity was measured.

The fluidity of the goose asphalt mixture was determined based on the results of the Reuel fluidity test. This Ruel fluidity test is performed based on C002 "Ruel fluidity test method of goose asphalt mixture" (hereinafter referred to as C002) of "Pavement Survey and Test Method Handbook" edited by the Japan Road Association.

In this Reuel fluidity test, first, the mixing of the goose asphalt mixture conforms to "C001 Penetration test method for goose asphalt mixture" in "Pavement Survey and Test Method Handbook". Samples should be prepared in accordance with C002 in the "Pavement Survey and Test Method Handbook", and representative samples with no variation in quality should be collected.

As for the test procedure, put the sample up to the edge of the container of the Luell fluidity tester described in C002. At this time, if the temperature of the sample is higher than the intended test temperature, it is allowed to cool to the test temperature while slowly stirring with a suitable tool. When the sample reaches the target test temperature, immediately wipe off the sample adhering to the surface, pass the shaft of the bell through the guide hole of the support, hold the top of the shaft and place it in the center of the sample surface. The bell shaft with a mass of 995 g is then released and allowed to penetrate under its own weight into the sample. A stopwatch is used to measure the time required for the upper end of the guide hole to pass from the lower line to the upper line (at intervals of 5 cm) marked on the shaft. This time is the Ruel liquidity. It also measures the temperature of the sample where the bell penetrates.

Such a fluidity test is performed 3-4 times while changing the test temperature within the range of 200-260°C to determine the relationship between temperature and fluidity, and to determine the Reuel fluidity at 220°C. In this example, if the obtained value of Luell fluidity at 220° C. is 3 seconds or more and 20 seconds or less, it is determined that the fluidity is excellent (○), and if it is outside the above range, the fluidity is inferior (×).

The DS value (dynamic stability) is used exclusively as an index for measuring the strength of road pavement. In this case, while the DS value is used as an evaluation index, it may be applied not only to road pavement but also to any applications including waterproof materials and adhesive materials.

A method for measuring this DS value will be described below. The DS value is an index for evaluating the flow resistance (difficulty in rutting) of an asphalt composition at high temperatures, and is measured using a wheel tracking tester. The wheel tracking test is carried out at 60°C assuming a summer road surface. A test piece in which the asphalt composition is mixed with aggregate (crushed rock) adjusted to a predetermined particle size shown in Table 4 below is cured at 60° C. for 5 hours or more, and the wheel is run for 1 hour. For example, as shown in FIG. 4, a specimen 5 of 30×30×5 cm was cured. There is no particular limitation on the time from the actual preparation of the test piece to the start of the measurement of the DS value. For this reason, after preparing 1.8 kg of the asphalt composition formed using the above-described component composition, put it in an iron can with a diameter of 16 cm, a height of 17 cm, and a plate thickness of 1 mm, and allow it to cool to room temperature to prepare the asphalt composition. Within 48 hours after the completion of , put the asphalt composition in an air circulating oven maintained at 180°C while still in the iron can, hold for 3 hours and heat.

Next, while a downward load of 686 N (70 kgf or 70 kg weight) is applied to the specimen 5 by the wheels 11, the specimen 5 is reciprocated in the direction of the arrow in the figure at a pace of 42 times/minute. Incidentally, the traveling position by the wheels 11 is set to the same traveling path without being shifted.

FIG. 5 shows an example of the amount of subsidence (mm) with respect to the test time (minutes) starting from the DS value measurement test start time. With the test start time as the starting point, as the test time increases, the amount of subsidence due to reciprocating travel of the wheels 11 increases. This subsidence amount is the subsidence depth (mm) from the surface of the test piece 5 in the depth direction.

When determining the DS value, the amount of subsidence up to 45 minutes after the start of the first test is not taken into account. The reason for this is that from the start of the test until 45 minutes before the settling amount is determined based on factors such as meshing with the added aggregate, it is necessary to evaluate flow resistance in the original sense. because it will not be possible.

When measuring the DS value, the deformation amount d (mm) of the asphalt composition in 15 minutes from 45 minutes to 60 minutes after the start of the test is focused. This d can be calculated by determining the difference between the amount of settlement after 60 minutes from the start of the test and the amount of settlement after 45 minutes from the start of the test. The DS value can be obtained from the following formula (2).

DS value (times/mm) = Number of tire runs from 45 minutes to 60 minutes (times)/d (mm) (2)
can be obtained from When the reciprocating frequency of the wheels 11 is 42 (times/minute), the formula (2) can be transformed into the following formula (2)'.
DS value (times/mm) = 630 (times)/d (mm) (2)'

The numerator of this formula (2)′ means 42 (times/minute)×15 (minutes)=630 (times). That is, this DS value can be obtained by the number of tire runs for 15 minutes with respect to d (mm). The higher the DS value, the smaller the amount of deformation of the asphalt composition itself, the more resistant to rutting, and the higher the strength.

Incidentally, in this embodiment, the DS value is set to a desirable range of 500 (times/mm) or more.

In addition, the DS value is not tested using only the asphalt composition, but similar to actual road pavement, the aggregate (crushed stone, limestone powder, etc.) shown in Table 4 and the asphalt composition of the predetermined Measurement is performed using a test piece that is molded under the same conditions.

A specific method for measuring the DS value using the goose asphalt composition to which the present invention is applied is shown below.

Crushed stone composed of hard sandstone is used as the aggregate, and stone powder obtained by pulverizing limestone is used to mix and prepare fine grains (constituents with small particle diameters) to prepare specimens. Materials other than the crushed stone and stone powder, such as sea sand and collected dust, are not used because they cause fluctuations in the DS value.

The crushed limestone powder used to adjust the particle size of the aggregate has a passing mass percentage that conforms to JIS A 5008 "limestone powder for paving" of 100% with a sieve mesh size of 600 μm and 90% or more to 100% or less with a sieve size of 150 μm. , 75 μm, 70% or more to 100% or less, and a water content of 1% or less.

Crushed stone made of hard sandstone is used as aggregate other than stone powder, and those satisfying the following properties (1) to (6) are used.

(1) Water absorption less than 1.5%, preferably less than 1.0%. (JIS A1110)
In this embodiment, crushed stone with a water absorption of 0.64% is used. If the water absorption rate of the aggregate is high, the aggregate absorbs the coated asphalt, resulting in a low asphalt content in the mixture. Aggregates with a high water absorption rate greatly change the amount of asphalt they absorb depending on the humidity during use and the wetness of the surface, resulting in fluctuations in the amount of asphalt in the mixture.

Therefore, in order to keep the amount of asphalt in the mixture constant, the water absorption should be less than 1.5%, preferably less than 1.0%.

(2) Apparent density of 2.60 g/cm ³ or more and 2.70 g/cm ³ or less (JIS A 1110)
Crushed stone with an apparent density of 2.66 g/cm ³ was used in this example.

(3) Stability 6% or less, preferably 3% or less (JIS A 1122)
Crushed stone with a stability of 2.4% was used in this example. The term "stability" as used herein defines the stability against freezing and thawing. The lower this stability number, the less aggregate destruction during freeze-thaw. Although the pavement design and construction guideline specifies 12% or less, it is set to half of the guideline specification in order to suppress variations in aggregate properties.

(4) Wear loss of 20% or less, preferably 15% or less (JIS A 1121)
Crushed stone with an abrasion loss of 12.6% was used in this example. The abrasion weight loss test is a test that evaluates the hardness and resistance to abrasion of the aggregate, ie, the durability of the aggregate. If the weight loss due to wear exceeds 20%, rutting becomes large. Therefore, in this embodiment, the weight loss due to wear is set to 20% or less, preferably 15% or less.

(5) Soft stone content of 5.0% or less, preferably 3.0% or less (JIS A 1126)
In this example, crushed stone with a soft stone content of 2.5% was used. The amount of soft stone is a test to determine whether a brass rod (Mohs hardness 3 to 4) leaves a scratch mark, and is a test to determine whether the aggregate is harder or softer than brass. Similar to the wear loss test, the soft stone content is a test to evaluate the hardness of the aggregate and resistance to wear, that is, the durability of the aggregate. The amount of soft stone should generally be 5% or less. (See pavement survey/test method handbook A008.)

(6) Content of slender or flat stone chips 10.0% or less, preferably 5.0% or less (Pavement Design and Construction Guideline (regulatory value) and pavement survey and test method handbook A008 (test method))
In this example, crushed stone containing 2.8% of elongated or flat stone pieces was used. The stone chips referred to here generally have a major axis/minor axis ratio of 3 or more, and are used as slender or flat stone chips. When slender or flat pieces of stone are mixed in, pavement or test specimens may be easily deformed by loads from a certain direction. That is, if many slender or flat pieces of stone are mixed in, they are oriented in the same direction and are more likely to deform under parallel loads than perpendicular loads.

Therefore, when measuring the rutting resistance, unless the amount of slender or flat stones mixed in is limited, the values obtained will fluctuate greatly.

Crushed stone and stone powder satisfying these properties were used as aggregates, and the aggregate composition shown in Table 4 was adjusted, and specimens were produced under the conditions shown in Table 3.

The actual preparation of the specimen consists of mixing the asphalt composition and the aggregate. For mixing, prepare 1080 g of asphalt composition heated to 180° C. and 10920 g of aggregate heated to 180° C. and synthesized to the particle size described above (hereinafter, the adjusted particle size is referred to as synthesized particle size).

First, 1080 g of the asphalt composition was placed in a mixer (mixing device) equipped with a heater (heating device), 10920 g of aggregate was added to the mixer, and the asphalt composition and the aggregate were mixed for 1 hour. In addition, the temperature at the time of mixing is about 220°C.

The mixed asphalt composition and aggregate are placed in a formwork for wheel tracking test (inner dimensions: length 30.0 cm, width 30.0 cm, depth 5.0 cm) and allowed to cool to prepare a specimen. did.

The device used for mixing had a diameter of 210 mm and a height of 250 mm. In addition, the test was conducted by pouring the mixture into the formwork as it was without performing rolling compaction after mixing.

Penetration (25° C.) was measured according to JIS K 2207 “Petroleum asphalt—Penetration test method”. This value is preferably 5 to 10 (1/10 mm).

Viscosity (180°C) was measured under the conditions of JPI-5S-54-99 "Asphalt-Viscosity test method using a rotational viscometer" at a measurement temperature of 180°C, a spindle SC4-21, and a spindle speed of 20 to 50 revolutions/minute. measured in This viscosity (180° C.) is preferably 400 mPa·s or less.

The softening point was measured according to JIS K 2207 "Petroleum asphalt-softening point test method".

Hereinafter, examples and comparative examples for verifying the effects of the goose asphalt composition described in the above embodiment will be described in detail.

In Tables 1 and 2, the properties of the solvent-deasphalted asphalt used are, as typical properties, a penetration of 12 (1/10 mm), a softening point of 63.5 ° C., and a density of 1062 kg / m ³ at 15 ° C. There is something. The petroleum-based solvent-extracted oil (extract) used has typical properties of a kinematic viscosity of 445 mm ² /s at 60°C and a density of (976.6) kg/m ³ at 15°C.

The SEBS used has a styrene content of 67%, which is within the range described in the above embodiments, and has a density of 976.6 kg/m ³ or more at 23°C.

The petroleum resin 1 used is a C9 petroleum resin, and has a softening point of 140° C., an acid value of 0.1 mgKOH/g as specified in JIS K0070, and a bromine number as specified in JIS K2543. 25 g/100 g, and an average molecular weight of about 1,000 in terms of polyethylene measured by the GPC method.

Petroleum resin 2 is a copolymer resin of hydrogenated C5 petroleum resin and C9 petroleum resin, and its properties are a softening point of 140 ° C., a bromine number specified in JIS K2543 of 2 g / 100 g, VPO The average molecular weight in terms of polyethylene measured by the method is about 900.

The resin acid used was a disproportionated rosin having an acid value of 156 (mgKOH/g: JIS K 0070) and a softening point of 77.0°C (JIS K 2207).

In Examples 10 to 17 and 24 to 31, each content of solvent deasphalted asphalt, petroleum solvent-extracted oil, SEBS having a styrene content of 60% or more to 70% or less, petroleum resin, and resin acid is the same as described above. within the ranges described in the embodiments.

All of Examples 10 to 17 and 24 to 31 have excellent fluidity, and the DS value exceeds 500 times/mm, demonstrating excellent rutting resistance. was

In Examples 10 to 17 and 24 to 31, the penetration was 5 to 10 (1/10 mm), which was an appropriate hardness, and the 180° C. viscosity was 400 mPa·s or less.

Among Examples 10 to 17 and 24 to 31, Examples 10 to 15 and 17 further use petroleum resin 1, and the content ratio of petroleum resin 1 to petroleum solvent-extracted oil is 60% or more. rice field. As a result, the DS value was 600 times/mm or more. In addition, fluidity was also excellent.

Among Examples 10 to 17 and 24 to 31, Examples 24 to 28 and 30 to 31 further use petroleum resin 2, and the content ratio of petroleum resin 2 to petroleum solvent-extracted oil is 89.0. % or more. As a result, the DS value was 750 times/mm or more. In addition, fluidity was also excellent. In particular, this fluidity is judged based on the Ruel fluidity at 220°C. Since the standard temperature for judging the general Reuel fluidity is 240°C, the present invention, which was judged to be good through the judgment of the Reuel fluidity at 220°C, is superior in terms of fluidity compared to the prior art. It can be said that

In contrast to these examples, in Comparative Examples 1 to 3, the SEBS content exceeds 13%, so the DS value is 500 times/mm or more, but the viscosity (180 ° C.) is 400 mPa.・It became more than s, and the fluidity deteriorated.

In Comparative Examples 4 to 9, since the content of petroleum resin 1 was less than 13%, the penetration was soft, exceeding 10, and the DS value was less than 500 times/mm.

In Comparative Example 18, the DS value was less than 500 times/mm because the content of SEBS was less than 10%.

In Comparative Example 19, the content of SEBS was more than 13%, so the DS value was good at 500 times/mm or more, but the viscosity (180°C) was 400 mPa·s or more, and the fluidity deteriorated. Was.

In Comparative Examples 20 to 23, since the content of petroleum resin 2 was less than 13%, the penetration was soft, exceeding 10, and the DS value was less than 500 times/mm.

In Comparative Example 32, since the petroleum solvent-extracted oil is less than 15%, the viscosity (180 ° C.) is 400 mPa s or more, the penetration is as hard as less than 5, and the DS value is 500 times / mm or more. was good, but the fluidity was deteriorating.

In Comparative Example 33, since the content of petroleum resin 2 was more than 20%, the penetration was less than 5, which was hard, and the DS value was as good as 500 times/mm or more, but the fluidity was deteriorated. .

As described above, it is possible to form a goose asphalt composition with high fluidity while improving rutting resistance by using the component composition described in the above-described embodiment.

1 Asphalt concrete 2 Goose asphalt 3 Steel floor 4 Clamping member 5 Specimen 11 Wheel 100 Polymer-modified asphalt manufacturing plant 101 Asphalt base tank 102 Mixing tank 103 Product tank 104 First supply pipe 105 Stirrer 106 Additive supply device 107 Second supply pipe

Claims (3)

Solvent deasphalted asphalt: 40% by mass or more to 60% by mass or less,
Petroleum-based solvent-extracted oil: 15% by mass or more to 25% by mass or less,
SEBS with a styrene content of 60% by mass or more and 70% by mass or less: 10% by mass or more and 13% by mass or less;
Petroleum resin: A goose asphalt composition characterized by containing 13% by mass or more and 20% by mass or less. When the petroleum resin is a C9 petroleum resin, the content ratio of the petroleum solvent-extracted oil is 60.0% or more,
When the petroleum resin is a copolymer resin of hydrogenated C5 petroleum resin and C9 petroleum resin, it contains 17% by mass or more to 20% by mass or less, and the content ratio with respect to the petroleum solvent-extracted oil is , 89.0% or more. The goose asphalt composition according to claim 1 or 2, having a penetration (25°C) of 5 to 10 (1/10 mm).

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