JP6305764B2 - Goose asphalt composition - Google Patents

Description

  The present invention relates to a goose asphalt composition which is excellent in fluidity and suitable for exerting the strength required for heavy traffic pavement.

  Steel bridge slabs and elevated roads are more durable than ordinary asphalt pavement due to the increase in traffic volume in recent years, and also goose asphalt that is excellent in impact tracking due to traffic load and bending flexure. Is used. In addition, since goose asphalt has almost no voids, it has high water tightness and can also function as a waterproof layer. Furthermore, this goose asphalt has a higher fluidity during paving than general asphalt. For this reason, when using goose asphalt for pavement construction, this high fluidity is used to pour it onto the construction base made of steel floor and lay it flat on the asphalt finisher. In this process, it is possible to fill the goose asphalt to every corner such as bolts and stepped portions of the joints in the steel deck.

  Goose asphalt is formed by blending an aggregate and a filler into an asphalt composition obtained by mixing asphalt with a modifying material such as natural asphalt such as Trinidad lake asphalt or thermoplastic elastomer.

  Various techniques for spreading such goose asphalt with an asphalt finisher have been proposed in the past (see, for example, Patent Document 1).

JP 2013-147858 A

  By the way, with the recent significant increase in traffic, problems such as rutting are not negligible even on iron bridges and elevated roads paved with goose asphalt. For this reason, it is expected to develop a new goose asphalt that can be pavement by pouring using the high fluidity as well as the conventional goose asphalt while improving the resistance to rutting (DS value). In particular, the aging of bridges and expressways paved during the high growth period has become serious, and when repairing these, the need to replace with new goose asphalt with excellent resistance to rutting was also revealed. .

  Therefore, the present invention has been devised in view of the above-mentioned problems, and its object is to improve the resistance to rutting (DS value) while utilizing high fluidity as in the past. The object is to provide a goose asphalt composition which can be paved by pouring.

In order to solve the above-mentioned problems, the goose asphalt composition according to claim 1 is a solvent-developed asphalt: 50 to 70% by mass, a petroleum-based solvent extracted oil: 10 to 20% by mass, and a 25% toluene solution viscosity. Is a hydrogenated thermoplastic elastomer having a viscosity of 5000 mPa · s or less: 2.5% by mass or more, 5% by mass or more of a petroleum resin having a softening point of 95 ° C. or more and 9% by mass or more of a wax, or 15% by mass or more of the petroleum resin. It is characterized by containing.

  The goose asphalt composition according to claim 2 is characterized in that, in the invention according to claim 1, the solvent deasphalting asphalt is propane deasphalting asphalt, and the hydrogenated thermoplastic elastomer is SEBS.

  The goose asphalt composition according to claim 3 is characterized in that, in the invention according to claim 1 or 2, the softening point contains 10% by mass or more of the petroleum resin having a softening point of 130 ° C. or more and 10% by mass or more of the wax. .

  The goose asphalt composition according to claim 4 is the invention according to any one of claims 1 to 3, and further contains a carboxyl group-containing polycyclic diterpene having 20 carbon atoms: 0.2 to 1% by mass. It is characterized by that.

  According to the present invention having the above-described configuration, it is possible to provide goose asphalt with high fluidity, so that a layer made of goose asphalt can be formed on the steel floor based on the pouring method, particularly compaction. Therefore, it is possible to reduce construction labor and control construction costs.

  In addition, the goose asphalt to which the present invention is applied can be filled up to every corner of the tightening member or the like protruding from the surface of the steel floor based on its high fluidity, and minute voids remain inside the pavement. Can be prevented. In addition to this, goose asphalt is also excellent in deflection followability and can prevent the occurrence of minute cracks inside the pavement even when the repeated load and impact load applied to the road increase with the traffic volume .

It is a figure which shows the example which paves a goose asphalt composition on the construction base surface which consists of a steel floor. It is a figure for demonstrating the detail of the measuring method of DS value. It is a figure which shows the example of subsidence amount (mm) with respect to test time (minute) when the measurement test start time of DS value is made into the starting point.

  Hereinafter, embodiments of the goose asphalt composition to which the present invention is applied will be described in detail.

The goose asphalt composition to which the present invention is applied has a solvent deasphalting asphalt: 50 to 70% by mass, a petroleum solvent extracted oil: 10 to 20% by mass, and a 25% toluene solution viscosity of 5000 mPa · s or less. Plastic elastomer: 2.5% by mass or more, 5% by mass or more of petroleum resin having a softening point of 95 ° C. or more and 9% by mass or more of wax, or 15% by mass or more of the petroleum resin. Hereinafter, the details of each component composition and the reason for limiting the content thereof will be described. The mass% in each component composition below is simply described as%.

Solvent removal asphalt: 50-70%
Asphalt used in the goose asphalt composition to which the present invention is applied is a solvent removal obtained by extracting a lubricating oil component with a solvent from a vacuum distillation residue obtained in a step of subjecting a crude oil atmospheric distillation residue to vacuum distillation. It is reclaimed asphalt. In the present invention, it is desirable to use propane deasphalted asphalt using propane or propane and butane as a solvent among the solvent deasphalted asphalt.

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 at 180 ° C. of 132 mPa · s , and a density at 15 ° C. of 1062 kg / m. You may make it use what is ³ . However, these physical properties in propane-deasphalted asphalt are merely examples, and it is needless to say that the present invention is not limited thereto.

  When the content of the solvent deasphalting asphalt is less than 50%, the ratio of petroleum-based solvent extracted oil increases, so that it is not possible to improve the digging property. On the other hand, when the asphalt content exceeds 70%, the ratio of petroleum solvent extracted oil decreases, and it becomes difficult to flow at the working temperature, so that workability is lowered. Further, the compatibility with the hydrogenated thermoplastic elastomer may be lowered. Therefore, the asphalt content is 50 to 70%.

Petroleum solvent extraction oil: 10-20%
Petroleum-based solvent extract oil is an oil extracted in the process of solvent extraction when producing lubricating oil from crude oil, and is an oily substance rich in aromatics and naphthenes ("until petroleum products are made", FIG. 6-1 “General Lubricating Oil Production Process”, published by the Petroleum Federation, November 1971, p. 99, and “New Petroleum Dictionary”, edited by the Japan Petroleum Institute, 1982, p. 304). This petroleum solvent extracted oil is a component that acts as a softener when added to an asphalt composition, has a boiling point of 350 ° C. or higher, a kinematic viscosity at 60 ° C. of 300 to 800 mm ² / s, and a flash point of 250. It is desirable that the aromatic content is 65% or more at a temperature of ° C or higher.

  Examples of such petroleum solvent extraction oil include bright stock solvent extractables extracted with a solvent such as phenol, N-methylpyrrolidone, liquid sulfur dioxide, and furfural in a crude oil refining process. When the content of this petroleum solvent extract oil is less than 10%, fluidity is lowered and good workability cannot be obtained. On the other hand, when the content of the petroleum-based solvent extraction oil exceeds 20%, the digging ability is reduced, so the content of the petroleum-based solvent extraction oil is set to 10 to 20%.

Hydrogenated thermoplastic elastomer: 2.5% or more As the hydrogenated thermoplastic elastomer, for example, styrene-ethylene-butylene-styrene block copolymer (SEBS) is used. SEBS eliminates double bonds by completely hydrogenating a butadiene block in a styrene-butadiene-styrene block copolymer (SBS), and greatly improves heat resistance and weather resistance over SBS. However, since the hydrogenation treatment changes the flexibility of molecular chains, the effect of addition on modified asphalt is also different from that of SBS. The hydrogenated thermoplastic elastomer includes any material such as SEPS other than SEBS as long as the double bond is eliminated by completely hydrogenating the butadiene block. The case where SEBS is employed as the hydrogenated thermoplastic elastomer will be described as an example.

  The reason for adopting SEBS is that goose asphalt is actually constructed at about 240 ° C, so it decomposes and gels in normal SBS, but SEBS can maintain its properties sufficiently even at high operating temperatures. It is. SEBS needs to have a styrene content in the range of 20 to 40% and a 25% toluene solution viscosity in the range of 5000 mPa · s or less. Preferably, the styrene content is 25 to 35% and the 25% toluene solution viscosity is 500 to 3000 mPa · s, more preferably the styrene content is 27 to 33% and the 25% toluene solution viscosity is 1000 to 1500 mPa · s. is there.

  In the goose asphalt to which the present invention is applied, the DS value is based on the premise that the DS value is expressed mainly by petroleum resin and wax described later. However, in order to improve the DS value with petroleum resin + wax or petroleum resin alone, if only this concentration is increased, the resin may be excessively cured and brittle fracture may occur. For this reason, by adding elastic SEBS, both improvement of the DS value and prevention of brittle fracture due to hardening are achieved.

  Further, the content of SEBS as the hydrogenated thermoplastic elastomer is 2.5% or more. This is because when the SEBS content is less than 2.5%, the DS value decreases in relation to the petroleum resin and wax to be mixed.

Petroleum resin having a softening point of 95 ° C. or more and 5% or more of wax and 9% or more of wax is a polymer of unsaturated hydrocarbons present in the pyrolysis fraction in the petroleum refining process, and has a molecular weight of about 100 to 2,000, In general, it is a light yellow material having a softening point of about 60 to 150 ° C. in the range of 200 to 1500. Examples of the petroleum resin include aliphatic petroleum resins such as C5 petroleum resins (hereinafter referred to as C5 petroleum resins), aromatic petroleum resins such as C9 petroleum resins (hereinafter referred to as C9 petroleum resins), dicyclo Aliphatic petroleum resins such as pentadiene petroleum resins (hereinafter referred to as DCPD), petroleum resins such as C5 / C9 copolymerized petroleum resins (hereinafter referred to as C5 / C9 petroleum resins), and hydrogenation of these petroleum resins Hydrogenated petroleum resin obtained in this way can be used.

  When the softening point of this petroleum resin is less than 95 ° C., the softening point is close to 60 ° C., which is the DS value measurement temperature, and thus the DS value may be lowered.

  Wax improves rutting resistance in the same way as petroleum resin. However, wax is inferior in power to improve fluidity during construction as compared with petroleum resin.

  Therefore, when the petroleum resin mentioned above is less than 5% or the wax is less than 9%, the DS value is lowered in relation to the SEBS to be mixed. For this reason, there exists a problem that it becomes impossible to ensure a desired rutting resistance, or the fluidity | liquidity at the time of construction falls.

  For this reason, the goose asphalt composition to which the present invention is applied contains 5% or more of petroleum resin and 9% or more of wax from the viewpoint of preventing the DS value from decreasing and ensuring fluidity during construction.

  From the viewpoint of further improving the DS value, it is desirable to contain 10% by mass or more of petroleum resin having a softening point of 130 ° C. or more and 10% by mass or more of wax.

15% or more of petroleum resin In the goose asphalt composition to which the present invention is applied, 15% or more of petroleum resin may be added instead of adding 5% or more of petroleum resin and 9% or more of wax. In such a case, the wax content may be less than 9%, or the wax content may be 0%.

  When the content of the petroleum resin is less than 15%, the DS value is lowered in relation to the mixed wax or SEBS. For this reason, there exists a problem that it becomes impossible to ensure desired rutting resistance.

  For this reason, the goose asphalt composition to which the present invention is applied contains 15% or more of petroleum resin from the viewpoint of preventing a decrease in DS value.

C20 polycyclic diterpene having a carboxyl group: 0.2 to 1%

  In the present invention, it is preferable to add an anti-peeling agent in order to prevent exfoliation of the asphalt composition and aggregate.

  Resin acid can be preferably used as the anti-peeling agent, but the resin acid is a C20 polycyclic diterpene having a carboxyl group, and is abietic acid, dehydroabietic acid, neoabietic acid, pimaric acid, isopimaric acid, It is a rosin containing any one or more of parastrinic acid.

  As the resin acid, in addition to the above-mentioned rosin, disproportionated rosin, dimer acid or trimer acid originating from abietic acid, or a mixture of two or more of these can be used.

  As the rosin, gum rosin, wood rosin, tall oil rosin and the like are used. These rosins can be classified as gum rosin, wood rosin, etc. as described above depending on the origin, raw materials, and collection method, but are obtained as a residual component at the time of steam distillation of pine resin. This rosin is a mixture containing, as components, abietic acid, parastrinic acid, neoabietic acid, dehydroabietic acid, pimaric acid, sandaracopimaric acid, isopimaric acid and the like. This rosin usually softens at about 80 ° C. and melts at 90-100 ° C. Note that rosin contains various resin acids such as abietic acid, dehydroabietic acid, dihydroabietic acid, tetrahydroabietic acid, parastrinic acid, neoabietic acid, and levopimaric acid. It may be used alone.

  In the present invention, gum rosin is used as a preferred rosin, but is not limited thereby.

  If the content of the resin acid is less than 0.2%, the effect of the resin acid is not sufficient, and it is impossible to prevent peeling and improve the compatibility as a final product. On the other hand, if the content of the resin acid exceeds 3% by weight, not only the effect of preventing the peeling and improving the compatibility is saturated, but also the amount of the expensive resin acid added is increased. This raises the problem that the cost of raw materials is significantly increased. Moreover, even if the resin acid content exceeds 3%, the prevention of peeling and the improvement of the compatibility are not significantly improved, but it is disadvantageous in terms of raw material costs. For this reason, it is desirable that the content of the resin acid is 0.2 to 3% (more preferably 0.2 to 1%).

  Some anti-peeling agents also have a performance as a lubricant, and in addition to the above-described anti-peeling effect, these act as a lubricant that improves compaction during construction and rolling.

  The fatty acid or fatty acid amide is added to function as a peeling inhibitor and a lubricant. Examples of fatty acids include, but are not limited to, saturated fatty acids such as stearic acid, palmitic acid, and myristic acid, and unsaturated fatty acids such as oleic acid, linoleic acid, and ricillenoic 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 the fatty acid or fatty acid amide is less than 0.2%, the effect is not sufficient, and the function cannot be improved as an anti-peeling agent as a final product and a lubricant. On the other hand, when the content of the fatty acid or fatty acid amide exceeds 3% by weight, not only the effect of improving the function as a peeling inhibitor and a lubricant is saturated, but also an expensive fatty acid, or There arises a problem that the raw material cost is remarkably increased due to an increase in the amount of fatty acid amide added. That is, even if the content of fatty acid or fatty acid amide exceeds 3%, the function improvement as a peeling preventive and a lubricant is not significantly improved, but it is disadvantageous in terms of raw material cost. .

  The goose asphalt composition having the above-described component composition is paved on a construction base surface made of a steel floor 3, for example, as shown in FIG. In such a case, the goose asphalt composition is manufactured in the asphalt plant so as to have the above-described component composition, further blended with coarse aggregate and filler, and further cooked at about 200 to 240 ° C. with a dedicated transport vehicle, at the construction site. It is conveyed to. Then, the heated goose asphalt 2 is poured onto the steel floor 3 using a dedicated asphalt finisher. In this process, the goose asphalt 2 to which the present invention composed of the above-mentioned components is applied has very high fluidity. For this reason, only by pouring the goose asphalt 2 into the steel floor 3, it becomes possible to fill the corners of the tightening member 4 such as a bolt protruding from the surface of the steel floor 3 and a stepped portion (not shown). Incidentally, a waterproof adhesive layer made of epoxy or the like may be provided between the steel floor 3 and the goose asphalt 2. Finally, a general asphalt concrete 1 is filled in the upper layer of the goose asphalt 2 to pave it.

  Thus, in the goose asphalt 2 to which the present invention is applied, since the pouring method is adopted, it is not necessary to perform a process such as compaction after the layer made of the goose asphalt 2 is formed on the steel floor 3. It is possible to reduce construction labor and control construction costs.

  Further, the goose asphalt 2 to which the present invention is applied can be filled into every corner of the tightening member 4 and the like protruding from the surface of the steel floor 3 based on its high fluidity, and the inside of the pavement is minute. It is possible to prevent the voids from remaining. In addition to this, Goose Asphalt 2 is also superior in deflection followability and prevents the occurrence of minute cracks inside the pavement even when the repeated load or impact load applied to the road increases as the traffic volume increases. it can. For this reason, it is possible to improve the rutting resistance (DS value) by applying the goose asphalt 2 to which the present invention is applied. In particular, when the goose asphalt 2 is used for pavement of the bridge, the bridge girder itself is greatly shaken by the vehicle traveling on the bridge. Even in such a case, by applying the goose asphalt 2 to which the present invention is applied, It is possible to improve the rutting property (DS value). In particular, replacement of goose asphalt 2 used for such paving requires that the primary asphalt concrete be peeled off once, so once paved, it will continue to be used for 20-30 years. However, according to the present invention having the above-described configuration, it is possible to suitably exhibit the rutting resistance for 20 to 30 years or more. In particular, by exhibiting excellent rutting resistance in the goose asphalt 2 in the lower layer of the asphalt concrete 1, the durability of the entire pavement including the upper asphalt concrete 1 is improved.

  The present invention 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. In the following examples, when only% is described, it indicates mass%.

  In the present invention, as shown in Table 1, a performance test consisting of fluidity, DS value, penetration, viscosity, and softening point is performed on a sample obtained for experimental investigation. Hereinafter, a detailed test method will be described. The fluidity and DS value are a mixture test in which aggregates are mixed, and the penetration, viscosity, and softening point are all the test results of the asphalt composition alone. The numerical values in each component composition in Table 1 indicate the content (% by mass).

先ず流動性については、作成したグースアスファルト混合物に表３に示す条件で骨材を混合し、直径２００ｍｍ、高さ２５０ｍｍの円筒状の容器から２４０℃にてバットに流し入れ、自重にて平らになるかどうかを目視で確認した。その結果、自重で平らになったものについては、“○”とし、自重では平らにならず、塊状になってとどまるもの（塊状のまま冷え固まるもの）については“×”とした。

First, regarding fluidity, aggregate was mixed with the prepared goose asphalt mixture under the conditions shown in Table 3, and poured into a bat at 240 ° C. from a cylindrical container having a diameter of 200 mm and a height of 250 mm, and flattened by its own weight. It was confirmed visually. As a result, “○” was given to those flattened by the own weight, and “X” was given to those that did not become flat by the own weight but remained in a lump shape (those that cooled and solidified in the lump shape).

  The DS value (dynamic stability) is used exclusively as an index for measuring the strength of road pavements, but also when applying asphalt compositions to waterproofing materials and adhesives, etc. Since an improvement in strength may be required, it can be considered to evaluate this through the DS value as a result. Therefore, in this case, the DS value may be used as an evaluation index, and may be applied not only to road pavement but also to any use including a waterproof material and an adhesive material.

  Hereinafter, a method for measuring the DS value will be described. The DS value (dynamic stability) is an index for evaluating the flow resistance (hardness of rutting) of an asphalt composition at a high temperature, and is measured using a wheel tracking tester. The wheel tracking test is carried out at 60 ° C. assuming a summer road surface. A specimen prepared by mixing an asphalt composition with an aggregate (stone obtained by crushing rocks) adjusted to a predetermined particle size described in Table 1 described later is cured at 60 ° C. for 5 hours or more, and the wheels are allowed to travel for 1 hour. For example, as shown in FIG. 2, the specimen 5 consisting of 30 × 30 × 5 cm was cured. The time from the actual preparation of the specimen to the start of the measurement of the DS value is not particularly limited, but the property may change when stored at a high temperature for a long period of time. Therefore, in general, after preparing 1.8 kg of the asphalt composition of the present invention, it is put into an iron can having a diameter of 16 cm, a height of 17 cm, and a plate thickness of 1 mm, and is allowed to cool to room temperature, thereby completing the preparation of the asphalt composition. Within 48 hours, the asphalt composition is placed in an air circulation oven kept at 240 ° C. while being put in an iron can, and is kept for 3 hours and heated.

  Next, the test specimen 5 is reciprocated at a pace of 42 times / minute in the direction of the arrow in the drawing while applying a downward load of 686 N (70 kgf or 70 kg weight) by the wheel 11. By the way, the traveling position by the wheels 11 is the same traveling path without shifting.

FIG. 3 shows an example of the amount of subsidence (mm) with respect to the test time (minutes) when the DS value measurement test start time is the starting point. As the test time increases starting from the test start time, the amount of settlement due to the reciprocating travel of the wheel 11 increases. This amount of subsidence is the subsidence depth (mm) from the surface of the specimen 5 to the depth direction.
When measuring the DS value, the amount of settlement from the start of the first test to 45 minutes before is not taken into account. The reason for this is to evaluate the flow resistance in its original meaning because the amount of settlement is determined from the initial test start time to 45 minutes before the elapsed time, based on factors such as meshing with the added aggregate. It is because it becomes impossible.

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

DS value (times / mm) = Number of tires run from 45 minutes to 60 minutes (times) / d (mm) (2)
Can be obtained from When the reciprocation frequency by the wheel 11 is 42 (times / minute), the following equation (2) ′ can be rewritten by modifying the equation (2).
DS value (times / mm) = 630 (times) / d (mm) (2) '

  The numerator of the formula (2) ′ means 42 (times / minute) × 15 (minutes) = 630 (times). In other words, the DS value can be obtained from the number of times the tire travels for 15 minutes with respect to d (mm). The higher the DS value, the smaller the amount of deformation of the asphalt composition itself, which means that the material is more resistant to digging and has a higher strength.

  In addition, DS value is not tested using only an asphalt composition, but the aggregates (crushed stone, limestone powder, etc.) shown in Table 2 and the predetermined conditions described later for the asphalt composition are the same as in actual road pavement. Measure using a specimen that was mixed and molded.

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

  A crushed stone made of hard sandstone is used as the aggregate, and stone powder obtained by pulverizing limestone is used to prepare a fine granule (constituent component having a small particle diameter) to prepare a specimen. Materials other than the above-mentioned crushed stone and stone powder such as sea sand and recovered dust are not used because they cause DS value fluctuations.

  The stone powder obtained by pulverizing limestone used for adjusting the particle size of the aggregate is JIS A 5008 “limestone powder for pavement”. The passing mass percentage is 100% at 600 μm sieve, 90-100% at 150 μm, 75 μm. 70 to 100%, and the water content is 1% or less.

  Aggregates other than stone powder use crushed stone made of hard sandstone, and satisfy the properties shown in (1) to (6) below.

(1) Water absorption is less than 1.5%, desirably less than 1.0%. (JIS A 1110)
Here, crushed stone having a water absorption rate of 0.64% is used. When the water absorption rate of the aggregate is high, the aggregate absorbs the coated asphalt, and as a result, the amount of asphalt in the mixture is small. In addition, aggregates with high water absorption greatly change the amount of asphalt absorbed depending on the humidity during use and the wet state of the surface, and as a result, the amount of asphalt in the mixture varies.

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

(2) apparent density 2.60 g / cm ³ or more, 2.70 g / cm ³ or less (JIS A 1110)
Here, crushed stone having an apparent density of 2.66 g / cm ³ was used.

(3) Stability 6% or less, desirably 3% or less (JIS A 1122)
Here, crushed stone having a stability of 2.4% was used. The term “stability” as used herein defines stability against freezing and thawing. The smaller the stability number, the less aggregate destruction during freezing and thawing. The pavement design and construction guidelines stipulate that it is 12% or less, but in order to suppress variations in the properties of aggregates, it is half of the guidelines.

(4) Abrasion weight loss 20% or less, desirably 15% or less (JIS A 1121)
Here, crushed stone with a weight loss of 12.6% was used. The abrasion loss test is a test for evaluating the hardness of the aggregate and the resistance to abrasion, that is, the durability of the aggregate. Since rutting increases when the abrasion loss exceeds 20% (see Non-Patent Document 1), the abrasion loss is 20% or less, preferably 15% or less.

(5) Soft stone amount of 5.0% or less, desirably 3.0% or less (JIS A 1126)
Here, crushed stone with 2.5% soft stone was used. The amount of soft stone is a test for determining whether scratches are attached by a brass bar (Mohs hardness 3-4), and is a test for determining whether the aggregate is harder or softer than brass. The amount of soft stone is a test for evaluating the hardness of the aggregate and the resistance to abrasion, that is, the durability of the aggregate, in the same manner as in the abrasion loss test. The amount of soft stone generally needs to be 5% or less. (See pavement survey and test method manual A008.)

(6) The content of slender or flat stone pieces is 10.0% or less, preferably 5.0% or less (pavement design and construction guidelines (regulation values) and pavement survey / test method manual A008 (test method)).
Here, a crushed stone having an elongated or flat stone piece content of 2.8% was used. As the stone pieces here, those having a major axis / minor axis ratio of 3 or more are generally used as elongated or flat stone pieces. When elongated or flat stone pieces are mixed, there is a possibility that the specimen for paving or testing is likely to be deformed with respect to a load from a certain direction. That is, if a large number of slender or flat stone pieces are mixed, they are oriented in the same direction and are more easily deformed than a load perpendicular to a load parallel to that direction.

  Therefore, when measuring the rutting resistance (DS value), unless the amount of slender or flat stone pieces mixed in is limited, the obtained value will fluctuate greatly.

A crushed stone and stone powder satisfying these properties were used as aggregates, the aggregate composition shown in Table 2 was adjusted, and specimens were prepared under the conditions shown in Table 3.

  Actually, the preparation of the specimen consists of mixing the asphalt composition and the aggregate. In the mixing, 933 g of an asphalt composition heated to 240 ° C. and 10844 g of aggregate prepared by heating to 300 ° C. and synthesizing to the above-described particle size (hereinafter, the adjusted particle size is referred to as a synthetic particle size) are prepared.

  First, the aggregate was put into a mixer, and only the aggregate was mixed for 60 seconds to make it uniform. Mixing was temporarily stopped and 933 g of the asphalt mixture was charged into the mixer, and then the asphalt composition and the aggregate were mixed for 180 seconds. In addition, the temperature at the time of mixing will be about 260 degreeC.

  These asphalt compositions and aggregates that had been mixed were placed in a form for wheel tracking test (inner dimensions 30.0 cm in length, 30.0 cm in width, and 5.0 cm in depth).

なお、混合の使用した装置は、直径２００ｍｍ 高さ２５０ｍｍとされている。また、混合後転圧を行うことなく、そのままの状態で型枠に流し込み、試験を行っている。

In addition, the apparatus used for mixing is 200 mm in diameter and 250 mm in height. In addition, the test is performed by pouring into the mold as it is without performing rolling after mixing.

  The penetration (25 ° C.) was measured by JIS K 2207 “Petroleum Asphalt—Penetration Test Method”. This value is preferably about 7 to 20 (0.1 mm).

  Viscosity (180 ° C.) was measured under the conditions of JPI-5S-54-99 “Viscosity Test Method Using Asphalt Rotational Viscometer” at a measuring temperature of 180 ° C., a spindle SC4-21, a spindle rotation speed of 50 rpm. did.

  The softening point was measured by JIS K 2207 “Petroleum Asphalt—Softening Point Test Method”.

  Hereinafter, in the modified asphalt composition to which the present invention is applied, examples and comparative examples for verifying the effect will be described in detail.

In Table 1, the properties of the used propane deasphalting asphalt include typical penetration of 12 (1/10 mm), softening point of 63.5 ° C., and density at 15 ° C. of 1062 kg / m ³ . Is. The extract used has a typical property of kinematic viscosity at 60 ° C. of 542 mm ² / s and density at 15 ° C. of 976.6 kg / m ³ .

  The used SEBS1 has a styrene content in the range of 28 to 30% and a 25% toluene solution viscosity of 1200 mPa · s. SEBS2 has a styrene content in the range of 28-30% and a 25% toluene solution viscosity of 8800 mPa · s.

  The petroleum resin 1 used has a softening point of 140 ° C., and the petroleum resin 2 has a softening point of 100 ° C.

  The wax 1 used has a melting point of 112 ° C., and the wax 2 has a melting point of 131 ° C.

  Examples 1 to 12 are all included in the range defined in the present invention. Among these examples, Examples 1 to 8, 11 and 12 contain 5% or more of petroleum resin and 9% or more of wax, and Examples 9 and 10 contain 15% or more of petroleum resin. It is what.

  These Examples 1 to 12 are all excellent because the fluidity is “◯”, and the DS value is over 400 times / mm, indicating that they have excellent rutting resistance. It had been.

  In particular, Examples 1 to 4 contain 10% by mass or more of petroleum resin and 10% by mass or more of wax, and 0.2% of rosin or dimer acid (polycarboxylic diterpene having 20 carbon atoms having a carboxyl group). It contains ~ 1.0%. Moreover, in all of Examples 1 to 4, the petroleum resin 1 is added, and the softening point of the petroleum resin 1 is 140 ° C.

  For this reason, Examples 1-4, and 12 are all excellent in fluidity, and DS value is also 700 (times / mm).

The reference example in Table 1 is a current product of goose asphalt, which contains 75% of goosephalt 20/40 and 25% of natural asphalt (lake asphalt: TLA) produced in Trinidad Island in the Central American Caribbean. . Goosephalt 20/40 has a penetration of 30, softening point 58.5 ° C., density 1046 kg / m ³ flash point 348 ° C., TLA has a penetration of 3, softening point 95 ° C., density 1392 kg / m ³ flash point 252 ° C. is there.

  In Comparative Examples 1, 3, and 9, the 25% toluene solution viscosity in SEBS is 1200 mPa · s, the content is 2.5% or more, the petroleum resin is 5% or more, but the wax is less than 9%. For this reason, the DS value was lowered, and the rutting resistance was deteriorated.

  In Comparative Examples 2 and 4, the 25% toluene solution viscosity in SEBS is 1200 mPa · s and the content is 2.5% or more, but the petroleum resin is less than 5% and the wax is less than 9%. As a result, the DS value decreased and the rutting resistance deteriorated.

  In Comparative Example 5, the petroleum resin is 5% or more and the wax is 9% or more, but the SEBS has a 25% toluene solution viscosity of 1200 mPa · s, but its content is less than 2.5%. For this reason, the DS value was lowered, and the rutting resistance was deteriorated.

  In Comparative Examples 6 to 8, in SEBS, the viscosity of a 25% toluene solution is 1200 mPa · s, the content is 2.5% or more, the wax is 9% or more, the petroleum resin is less than 5%, DS The value decreased, and the rutting resistance deteriorated.

  In Comparative Example 10, although the petroleum resin was 5% or more and the wax was 9% or more, the fluidity was lowered because the 25% toluene solution viscosity of SEBS was 8800 mPa · s.

  In Comparative Example 11, since the 25% toluene solution viscosity in SEBS was 1200 mPa · s, the content was 2.5% or more, and the petroleum resin was less than 5%, the fluidity was lowered.

  In Comparative Example 12, the DS value was good because the 25% toluene solution viscosity in SEBS was 1200 mPa · s, the content was 2.5% or more, and the wax was 20% or more. The fluidity has been reduced because of 0%.

1 Asphalt Concrete 2 Goose Asphalt 3 Steel Floor 4 Tightening Member 5 Specimen 11 Wheel

Claims (4)

Solvent deasphalting asphalt: 50-70% by mass,
Petroleum solvent extraction oil: 10 to 20% by mass,
Hydrogenated thermoplastic elastomer having a 25% toluene solution viscosity of 5000 mPa · s or less: 2.5% by mass or more,
A goose asphalt composition comprising 5% by mass or more of a petroleum resin having a softening point of 95 ° C. or more and 9% by mass or more of a wax, or 15% by mass or more of the petroleum resin. The solvent deasphalting asphalt is propane deasphalting asphalt,
The goose asphalt composition according to claim 1, wherein the hydrogenated thermoplastic elastomer is SEBS. The goose asphalt composition according to claim 1 or 2, comprising 10% by mass or more of the petroleum resin having a softening point of 130 ° C or more and 10% by mass or more of the wax. The goose asphalt composition according to any one of claims 1 to 3, further comprising 0.2 to 1% by mass of a polycyclic diterpene having 20 carbon atoms having a carboxyl group.

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