JP7238182B1 - Recycling method of asphalt for road paving - Google Patents

Abstract

[Problem] To provide a method for regenerating asphalt for road paving, which can increase the loss tangent of degraded asphalt by a viscoelasticity measurement test and close cracks in the degraded asphalt mixture under a temperature environment lower than the heating temperature of the road surface layer regeneration method. The method includes a step (SA) of infiltrating a liquid composition containing an emulsion from the surface of the deteriorated asphalt mixture into the interior of the deteriorated asphalt by at least one of spraying and coating, and the following conditions (1) and ( A reproduction method that satisfies 2). Condition (1): The penetration of the deteriorated asphalt mixture after penetration of the liquid composition is 150% or more in terms of ratio (percentage) to the penetration of the deteriorated asphalt mixture before penetration of the liquid composition. . Condition (2): The content of malten components in the deteriorated asphalt mixture after permeation of the liquid composition is a mass ratio (percentage) to the content of malten components in the deteriorated asphalt mixture before permeation of the liquid composition ) is 103.0% or more. [Selection drawing] Fig. 2

Description

The present invention relates to a method for recycling asphalt for road paving.

Roads on which vehicles travel are paved to enhance convenience and safety. In particular, the asphalt mixture used for asphalt pavement is easily available nationwide, and construction is highly convenient. In addition, asphalt pavement is widely used as a general pavement from the viewpoint of being recyclable, and has become an indispensable social infrastructure in modern society.

Asphalt pavement tends to become hard and brittle because the binder containing asphalt deteriorates when the surface is exposed to environmental loads such as ultraviolet rays, oxygen, and rainwater for a long period of time. In addition, the constant traffic load causes damage such as cracks and ruts on the pavement. Furthermore, rainwater permeates cracks in the surface of the asphalt pavement, causing damage to spread throughout the asphalt pavement.
Therefore, in the deteriorated asphalt mixture paved on the road, the deteriorated asphalt is brought closer to the properties of new asphalt, that is, the flexibility and viscosity of the deteriorated asphalt are improved, the cracks in the deteriorated asphalt mixture are closed, and the deteriorated asphalt mixture is removed. There is a demand for a technique for reproducing.

As a method for regenerating asphalt pavement, for example, after carrying the deteriorated asphalt mixture cut on the road to a recycling plant, the deteriorated asphalt mixture, recycled oil and new asphalt mixture are mixed while heating, and then again with the construction site. It is known to carry it in a heated state on the road.

In addition, as a method of regenerating the asphalt pavement on the road (at the current position), for example, after heating the deteriorated asphalt mixture layer at the current position with a heater, it is scraped off, and then a new asphalt mixture is mixed. After that, the surface layer is continuously leveled and compacted to regenerate as a new surface layer.

In addition, the "fog seal method" is known as a method for regenerating a deteriorated asphalt mixture paved on a road under a temperature environment lower than the heating temperature of the road surface layer regeneration method.
The fog seal method is a surface treatment method in which water-diluted asphalt emulsion is thinly sprayed on the surface of a deteriorated asphalt mixture. An asphalt emulsion is a liquid obtained by dispersing particles containing asphalt inside an emulsifier in water.
Deteriorated asphalt pavement tends to absorb water more easily than new asphalt pavement, and a water film is likely to form. Therefore, for example, in a rainy environment at night, there is a problem that the visibility of road markings, lane lines, etc. on the road surface is likely to be poor for people driving on deteriorated asphalt paved roads due to light reflection. On the other hand, when regeneration is performed using the fog seal method, a film of new asphalt with water repellency is formed on the surface of the deteriorated asphalt pavement, suppressing the generation of a water film and preventing light reflection. . In addition, the color of the surface of the asphalt pavement becomes closer to black, and the difference from the white color of the markings and lane lines becomes clearer, so there is an advantage that the visibility of drivers can be improved.
In order to prevent damage from spreading to the entire asphalt pavement, the Fog Seal method reconstructs the missing asphalt film to prevent rainwater from penetrating through the cracks on the pavement surface. Bonded so as not to scatter.

In addition, as a technology modified from the "road surface layer regeneration method", for example, after heating the surface of the asphalt pavement with a heater to soften the surface and base layers, the asphalt emulsion is spread on the pavement surface, and the surface layer and the base layer are spread from the pavement surface. A method is known in which the base layer is crushed to a predetermined depth, stirred and mixed, and then the crushed material is mixed with an asphalt emulsion, and the mixture is spread out and compacted (see, for example, Patent Document 1).

Pavement Restoration Handbook (2010 Edition), Japan Road Association

JP-A-59-228504

In the case of the method of carrying it to a recycling plant and heating it, it is necessary to carry the deteriorated asphalt mixture from the construction site to the recycling plant. In addition, it is necessary to transport the regenerated heated asphalt mixture to the construction site again. Therefore, when the construction site is very far from the recycling plant, there is a problem that the recycling method cannot be used.

In addition, in the road surface regeneration method described in Non-Patent Document 1 and the like, the surface of the asphalt pavement is generally heated to 110° C. or higher, but it is necessary to prepare large-scale mechanical equipment such as a heater. In addition, in the road surface layer regeneration method, it is necessary to continuously perform work such as scraping, stirring, mixing, leveling, and compaction of the existing asphalt mixture layer. However, since it is necessary for workers to remove manholes around road-occupied roads such as manholes and before and after bridge joints, continuous mechanical equipment is used to scrape and loosen the existing asphalt mixture layer. I have a problem that I can't. Furthermore, there is also the problem that it takes a very long time before the road can be opened to traffic after construction.

In the case of regeneration by the fog seal method, no heating is performed and it is performed in a temperature environment lower than the heating temperature of the road surface layer regeneration method, so there is no problem with the recycling plant or the road surface layer regeneration method.
However, in the fog seal method, although the asphalt emulsion penetrates into the voids of aggregate particles such as crushed stone at a depth of about 5 mm from the surface of the deteriorated asphalt, it does not penetrate into the interior of the deteriorated asphalt. In other words, new asphalt derived from asphalt emulsion is filled in the voids of aggregate particles, around deteriorated asphalt, and on the road surface, and a coating of asphalt is formed. It is not a technology that softens the binder contained. Therefore, the fog seal method does not change the chemical properties of the deteriorated asphalt itself.
Therefore, since the fog seal method is not essentially a technique for regenerating deteriorated asphalt, there is a problem that it may deteriorate again at an early stage over time. In addition, since the fog seal method involves coating the deteriorated asphalt surface, there is a problem that the new asphalt coating may peel off at the interface with the deteriorated asphalt.

Moreover, since the technique described in Patent Document 1 uses an asphalt emulsion, it is not a technique for regenerating deteriorated asphalt, like the fog seal method. In addition, after heating the deteriorated asphalt mixture layer with a heater, it is scraped and mixed, and then leveling and compaction are continuously performed, so the same problems as the general road surface regeneration method occur. be.

Therefore, it is desired to establish a recycling technology for road paving asphalt that chemically regenerates the deteriorated asphalt paved on the road under a temperature environment lower than the heating temperature of the road surface layer recycling method. As an index of chemical regeneration of deteriorated asphalt, an increase in loss tangent (tan δ) by a viscoelasticity measurement test is required.

The present invention has been made in view of the above problems, and in a temperature environment below the heating temperature of the road surface regeneration method, the loss tangent (tan δ) of the deteriorated asphalt by a viscoelasticity measurement test is increased, and further deteriorated. An object of the present invention is to provide a method for regenerating asphalt for road paving, which can close cracks in an asphalt mixture.

As a result of extensive studies, the present inventors found that the above problems can be solved by infiltrating the surface of the deteriorated asphalt mixture with a liquid composition containing an emulsion under specific conditions, and completed the present invention. rice field.

That is, the present invention provides the following [1].
[1] A method for regenerating asphalt for road paving, which regenerates a deteriorated asphalt mixture paved on a road in a temperature environment lower than the heating temperature of the road surface layer regeneration method,
A step (S _A ) of infiltrating a liquid composition containing an emulsion from the surface of the deteriorated asphalt mixture into the interior of the deteriorated asphalt by at least one of spraying and coating,
The step (S _A ) is a method for recycling asphalt for road paving, wherein the step (S A ) is performed so as to satisfy the following conditions (1) and (2).
Condition (1): The ratio (percentage) of the penetration of the deteriorated asphalt mixture after penetration of the liquid composition to the penetration of the deteriorated asphalt mixture before penetration of the liquid composition is 150% or more.
Condition (2): The content of the maltene component in the deteriorated asphalt mixture after the permeation of the liquid composition is, relative to the content of the maltene component in the degraded asphalt mixture before the permeation of the liquid composition, The mass ratio (percentage) is 103.0% or more.

According to the present invention, in a temperature environment below the heating temperature of the road surface layer regeneration method, the loss tangent (tan δ) of the deteriorated asphalt by the viscoelasticity measurement test can be increased, and cracks in the deteriorated asphalt mixture can also be closed. It becomes possible to provide a method for regenerating asphalt.

1 is a drawing-substituting photograph of the surface of a deteriorated asphalt mixture before application of the liquid composition of Example 1. FIG. 1 is a drawing-substituting photograph of the surface of a deteriorated asphalt mixture after application of the liquid composition of Example 1 and rolling compaction. 10 is a drawing-substituting photograph of the surface of a deteriorated asphalt mixture before applying the liquid composition of Comparative Example 6. FIG. 10 is a drawing-substituting photograph of the surface of the deteriorated asphalt mixture after applying the liquid composition of Comparative Example 6 and rolling compaction. 2 is a drawing-substituting photograph of the surface of a deteriorated asphalt mixture before rolling compaction in Reference Example 1. FIG. 2 is a drawing-substituting photograph of the surface of a deteriorated asphalt mixture after rolling compaction in Reference Example 1. FIG.

In this specification, for preferred numerical ranges (for example, content ranges), the lower and upper limits described stepwise can be independently combined. For example, the description of the lower limit "preferably 10 or more, more preferably 30 or more, more preferably 40 or more" and the upper limit "preferably 90 or less, more preferably 80 or less, more preferably 70 or less" From the description, as a suitable range, for example, "10 or more and 70 or less", "30 or more and 70 or less", "40 or more and 80 or less". can also Also, from the same description, for example, it is also possible to select a range in which either the lower limit value or the upper limit value is simply defined, such as "40 or more" or "70 or less".
In addition, in the description of numerical ranges in this specification, for example, the description "10 to 90" is synonymous with "10 or more and 90 or less". It should be noted that the numerical values of "greater than", "less than", "less than", and "greater than" regarding the description of numerical ranges can also be arbitrarily combined.

[Method for recycling asphalt for road paving]
The method for regenerating asphalt for road paving of the present embodiment is a method for regenerating asphalt for road paving, in which the deteriorated asphalt mixture paved on the road is regenerated under a temperature environment lower than the heating temperature of the road surface layer regeneration method, A step (S _A ) of permeating a liquid composition containing an emulsion from the surface of the deteriorated asphalt mixture into the interior of the deteriorated asphalt by at least one of spraying and coating, and the step (S _A ) is as follows: A method for regenerating road paving asphalt that satisfies conditions (1) and (2).
Condition (1): The ratio (percentage) of the penetration of the deteriorated asphalt mixture after penetration of the liquid composition to the penetration of the deteriorated asphalt mixture before penetration of the liquid composition is 150% or more.
Condition (2): The content of the maltene component in the deteriorated asphalt mixture after the permeation of the liquid composition is, relative to the content of the maltene component in the degraded asphalt mixture before the permeation of the liquid composition, The mass ratio (percentage) is 103.0% or more.

In order to solve the above problems, the inventors of the present invention have made intensive studies, and found that by infiltrating a liquid composition containing an emulsion under specific conditions on the surface of the deteriorated asphalt mixture, a temperature lower than the heating temperature of the road surface regeneration method We have found that it is possible to regenerate deteriorated asphalt under environmental conditions. Specifically, in a temperature environment below the heating temperature of the road surface regeneration method, the loss tangent (tan δ) of the deteriorated asphalt by the viscoelasticity measurement test is increased, and further cracks in the deteriorated asphalt mixture can be closed. I figured out how to play it.

<Step ( _SA )>
In the method for regenerating asphalt for road paving of the present embodiment, the step ( _SA ) satisfies the conditions (1) and (2) described later, and the liquid composition containing an emulsion from the surface of the deteriorated asphalt mixture to the inside of the deteriorated asphalt This is the process of permeating things.
In the method for regenerating asphalt for road pavement of the present embodiment, by infiltrating a liquid composition containing an emulsion from the surface of the deteriorated asphalt mixture to the inside of the deteriorated asphalt under specific conditions, the asphalt contained in the surface layer and base layer of the asphalt pavement Since the binder containing is softened, it is possible to increase the loss tangent (tan δ) of the degraded asphalt by viscoelasticity measurement test and also close cracks in the degraded asphalt mixture without heating.

In the method for regenerating asphalt for road paving according to the present embodiment, the deteriorated asphalt is regenerated by permeation of the liquid composition under a temperature environment lower than the heating temperature of the road surface layer regeneration method. Therefore, it can be operated at room temperature and does not require a recycling plant or large-scale machinery and equipment used in the road surface regeneration method.
In step (S _A ), the deteriorated asphalt mixture layer may be scraped off, but from the viewpoint of simplifying the work, it is preferable not to scrape off the deteriorated asphalt mixture layer. In the step (S _A ), even if the deteriorated asphalt mixture layer is not scraped off, it is sufficient to allow the liquid composition to permeate from the surface of the deteriorated asphalt mixture by at least one of spraying and coating. It can be used even on roads with existing facilities, and there is no need for workers to remove existing facilities. Furthermore, it can be opened to traffic in a short time after construction.

In the road surface layer regeneration method, it is generally necessary to heat the surface of the deteriorated asphalt pavement to 110° C. or higher. However, the present invention does not require such heating. In other words, in the method for regenerating asphalt for road pavement of the present embodiment, "under a temperature environment below the heating temperature of the road surface layer regeneration method" specifically means that the surface of the deteriorated asphalt pavement is under a temperature environment of less than 110 ° C. means.
If the surface temperature of the deteriorated asphalt pavement is less than 110 ° C., heating may be performed at a temperature higher than the surface temperature of the deteriorated asphalt pavement, but the regeneration method of the present invention is easier to implement. Therefore, the heating temperature is preferably low (preferably heating the surface of the deteriorated asphalt pavement to a temperature of less than 80 ° C., more preferably heating the surface of the deteriorated asphalt pavement to a temperature of 75 ° C. or less), more preferably heating is not to do
As will be described later, in the method for regenerating asphalt for road paving according to the present embodiment, when at least one of spreading and coating is performed, for example, a liquid composition is spread or applied by an asphalt distributor, which is a road paving machine. is done. However, heating by the operation of the asphalt distributor is not included in the above "heating".

In the method for regenerating asphalt for road paving according to the present embodiment, "deteriorated asphalt" means that unused straight asphalt is deteriorated due to long-term exposure to environmental loads such as ultraviolet rays, oxygen, and rainwater, and is unused. It means that the chemical properties have changed from
In addition, unused straight asphalt containing modifiers may deteriorate due to direct exposure to environmental loads such as ultraviolet rays, oxygen, and rainwater for a long period of time. Included in the "degraded asphalt" of the embodiment.

In the method for regenerating asphalt for road paving according to the present embodiment, "degraded asphalt mixture" means a mixture of the degraded asphalt and aggregate.
The "degraded asphalt mixture" may contain components other than the degraded asphalt and aggregate.

In the method for regenerating asphalt for road paving according to the present embodiment, the “surface of the deteriorated asphalt mixture” means the surface of the deteriorated asphalt mixture that has been directly exposed to environmental loads such as ultraviolet rays, oxygen, and rainwater for a long period of time. .

In the method for regenerating asphalt for road paving according to the present embodiment, "penetration" means permeation from the surface of the deteriorated asphalt mixture to "inside the deteriorated asphalt". Therefore, even if the liquid composition penetrates into the gaps between the aggregate particles in the asphalt mixture, if it does not penetrate into the deteriorated asphalt, this embodiment is not satisfied.

In the method for regenerating asphalt for road paving according to the present embodiment, "recycling" means "chemically regenerating" the deteriorated asphalt paved on the road without heating. Therefore, if the conditions (1) and (2), which will be described later, are not satisfied, it does not indicate chemical regeneration, and thus does not satisfy the present embodiment.

In the method for regenerating asphalt for road paving according to the present embodiment, there is no particular restriction on the place where the deteriorated asphalt mixture is regenerated, but from the viewpoint of simplifying the work, it is preferably on the road where the deteriorated asphalt mixture exists (current position).
In addition, after cutting the deteriorated asphalt mixture at the construction site, it is carried to the recycling plant, and the liquid composition is sprayed / applied to the deteriorated asphalt mixture at the recycling plant to regenerate it. It can be transported to the construction site.

The step (S _A ) is performed so as to satisfy the following conditions (1) and (2).
Condition (1): The ratio (percentage) of the penetration of the deteriorated asphalt mixture after penetration of the liquid composition to the penetration of the deteriorated asphalt mixture before penetration of the liquid composition is 150% or more.
Condition (2): The content of the maltene component in the deteriorated asphalt mixture after the permeation of the liquid composition is, relative to the content of the maltene component in the degraded asphalt mixture before the permeation of the liquid composition, The mass ratio (percentage) is 103.0% or more.

The step (S _A ) includes at least one of spraying and coating.
The step (S _A ) is not particularly limited, and any known method can be used as long as it includes at least one of spraying and coating.
Note that "at least one of spraying and coating" means "spraying and/or coating", and is also referred to herein as "spraying/coating".

The method of spreading/coating includes, for example, spreading or coating with an asphalt distributor, which is a road paving machine.
The asphalt distributor is not particularly limited, and examples thereof include pneumatic, hydraulic, and mechanical types.

After subjecting the deteriorated asphalt mixture to at least one of spraying and application of the liquid composition, it is preferable to apply pressure (roll compaction) to the deteriorated asphalt mixture to which the liquid composition has been sprayed/applied.
Rolling allows the spread/applied liquid composition to quickly penetrate the degraded asphalt mixture.
As a method of rolling, for example, Macadam rollers for pavement, tire rollers, and the like can be used.
When using paving macadam rollers, the degraded asphalt mixture is contacted in a line. Therefore, when using paving macadam rollers, the pressure exerted on the degraded asphalt mixture is static linear pressure.
The static linear pressure is preferably 200 N/cm or more and 650 N/cm or less, more preferably 300 N/cm or more and 600 N/cm or less, and still more preferably 450 N/cm or more and 550 N/cm or less.
When a tire roller is used, since the material of the tire is rubber, it comes into contact with the deteriorated asphalt mixture on its surface. Therefore, when using a tire roller, the pressure exerted on the degraded asphalt mixture is the ground pressure.
The ground pressure is preferably 150 kPa or more and 460 kPa or less, more preferably 200 kPa or more and 420 kPa or less, and still more preferably 250 kPa or more and 380 kPa or less.

The amount of the liquid composition to be sprayed/coated on the surface of the deteriorated asphalt mixture is not particularly limited, but is preferably 0.10 L/m ² or more and 1.2 L/m ² or less, more preferably 0.15 L/m ² or more and 1.0 L/m ² or less, more preferably 0.20 L/m ² or more and 0.80 L/m ² or less.

<<Condition (1)>>
In the method for regenerating asphalt for road paving according to the present embodiment, the step (S _A ) is performed so as to satisfy the following condition (1).
Condition (1): The ratio (percentage) of the penetration of the deteriorated asphalt mixture after penetration of the liquid composition to the penetration of the deteriorated asphalt mixture before penetration of the liquid composition is 150% or more.
Penetration is a physical property value that indicates the hardness of asphalt. A higher penetration value indicates a softer asphalt.
Fresh straight asphalt is generally softer than degraded asphalt. When the penetration of the deteriorated asphalt mixture satisfies the condition (1), the penetration of the deteriorated asphalt mixture approaches the penetration of the unused asphalt mixture, so it can be said that the deteriorated asphalt is regenerated.

The ratio (percentage) of the penetration of the deteriorated asphalt mixture after penetration of the liquid composition to the penetration of the deterioration asphalt mixture before penetration of the liquid composition is the ratio (percentage) of the penetration of the deteriorated asphalt mixture after penetration of the liquid composition. can be calculated by dividing the penetration of the degraded asphalt mixture prior to penetration by the liquid composition.
The ratio (percentage) of the penetration of the deteriorated asphalt mixture after the penetration of the liquid composition to the penetration of the deterioration asphalt mixture before the penetration of the liquid composition is preferable from the viewpoint that the asphalt has sufficient flexibility. is 170% or more, more preferably 200% or more, still more preferably 300% or more, and even more preferably 400% or more. Also, from the viewpoint of suppressing rutting, it is preferably 600% or less, more preferably 500% or less.

The penetration of the deteriorated asphalt mixture at 25°C can be measured according to JIS K2207-2006.
The penetration of the deteriorated asphalt mixture after permeation of the liquid composition at 25° C. is preferably 20 or more and 100 or less, more preferably 25 or more, from the viewpoint of recovering the penetration properties of the virgin asphalt mixture. It is 90 or less, more preferably 35 or more and 80 or less.

<<Condition (2)>>
In the method for regenerating asphalt for road paving according to the present embodiment, the step (S _A ) is performed so as to satisfy the following condition (2).
Condition (2): The content of the maltene component in the deteriorated asphalt mixture after the permeation of the liquid composition is, relative to the content of the maltene component in the degraded asphalt mixture before the permeation of the liquid composition, The mass ratio (percentage) is 103.0% or more.
A maltene component is a component that dissolves in normal pentane in the chemical composition of straight asphalt. On the other hand, in the chemical composition of straight asphalt, the component that does not dissolve in normal pentane is the asphaltene component.
Unused straight asphalt generally has a maltene component of 70% to 90% by mass based on the total amount of straight asphalt, and is more flexible than deteriorated asphalt. That is, the more the maltene component and the less the asphaltene content in the deteriorated asphalt mixture, the more the flexibility and viscosity of the asphalt mixture improve, and the composition approaches that of a virgin asphalt mixture.
By satisfying the condition (2), the composition of the deteriorated asphalt mixture approaches the composition of the virgin asphalt mixture, so it can be said that the deteriorated asphalt has been regenerated.

The mass ratio (percentage) of the content of the malten component in the deteriorated asphalt mixture after permeation with the liquid composition to the content of the malten component in the deteriorated asphalt mixture before permeation with the liquid composition is It can be calculated by dividing the content of the maltene component of the post-degraded asphalt mixture by the content of the maltene component of the degraded asphalt mixture prior to penetration by the liquid composition.
The mass ratio (percentage) of the content of malten components in the deteriorated asphalt mixture after permeation with the liquid composition to the content of malten components in the degraded asphalt mixture before permeation with the liquid composition is compositional confirmation of the regeneration effect. From the viewpoint of, it is preferably 60 or more and 90 or less. Moreover, from the viewpoint of suppressing rutting, it is more preferably 70 or more and 80 or less.

The content of the maltene component in the asphalt mixture and the asphaltene component in the asphalt mixture is determined by thin layer chromatography in accordance with JPI-5S-77-2019 or JPI-5S-70-2010, which is the Petroleum Institute petroleum test standard. It can be determined by the photography/flame ionization detector (TLC/FID) method.
The content of the maltene component in the asphalt mixture is preferably 60 or more and 90 or less, more preferably 65 or less, from the viewpoint that the softness and tackiness (stickiness) of the deteriorated asphalt approaches the softness and tackiness of the virgin asphalt. 85 or less, more preferably 70 or more and 80 or less.
The asphaltene component is one of the indicators of hardness and brittleness. The content of the asphaltene component in the asphalt mixture is preferably 10 or more and 40 or less, more preferably 15 or more and 35 or less, still more preferably 20 or more and 30 or less, from the viewpoint that the binder for pavement has appropriate hardness.

<<Condition (3)>>
In the method for regenerating asphalt for road paving according to the present embodiment, the step (S _A ) is preferably carried out so as to further satisfy the following condition (3).
Condition (3): The liquid composition penetrates into the deteriorated asphalt mixture to a depth of 10 mm or more from the surface of the deteriorated asphalt mixture.
In the method for regenerating asphalt for road paving according to the present embodiment, the liquid composition penetrates into the deteriorated asphalt from the surface of the deteriorated asphalt mixture. By satisfying the condition (3), it can be confirmed that the liquid composition permeates from the surface of the deteriorated asphalt mixture into the deteriorated asphalt.
In addition, in the general fog seal method, the liquid composition of the present embodiment penetrates into the deteriorated asphalt mixture, compared to the depth to which the asphalt emulsion penetrates into the voids of the aggregate particles such as crushed stones of the deteriorated asphalt mixture. The depth penetrates deeper.
If there are voids or cracks on the surface of the deteriorated asphalt mixture, it is preferable to penetrate 10 mm or more from the deepest part of the void or crack.

Whether the liquid composition permeates the deteriorated asphalt mixture to a depth of 10 mm or more from the surface of the deteriorated asphalt mixture can be determined, for example, as follows.
First, in a normal temperature (25° C.) environment, a 10 mm thick piece is cut from the surface of the asphalt mixture. The liquid composition is then sprayed or applied to the surface of the asphalt mixture. Next, it can be determined by visually observing whether the sprayed or applied liquid composition penetrates from the surface of the asphalt mixture to the lower surface having a thickness of 10 mm.

[Liquid composition]
In the method for regenerating asphalt for road pavement of the present embodiment, the liquid composition contains an emulsion, and in the step ( _SA ), at least one of spraying and coating is performed to permeate from the surface of the deteriorated asphalt mixture. be done.

Liquid compositions include emulsions. By forming an emulsion of the liquid composition, it can be kept in a storage-stable state without separating until it is sprayed/applied.

The liquid composition may optionally contain at least one selected from asphalt rejuvenating agent (A), penetration enhancer (B), plasticizer (C), and emulsifier-containing water (D). .
In the following description, "asphalt regenerating agent (A)", "penetration enhancer (B)", "plasticizer (C)", and "emulsifier-containing water (D)" are respectively referred to as "component (A)", Also referred to as "component (B)", "component (C)", and "component (D)".

In the liquid composition of the method for regenerating asphalt for road pavement of the present embodiment, the total content of component (A), component (B), component (C), and component (D) is the total amount of the liquid composition ( 100% by mass), preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more. Also, it is usually 100% by mass or less, preferably less than 100% by mass, more preferably 99% by mass or less, and even more preferably 98% by mass or less.
In addition, the liquid composition of the method for regenerating asphalt for road paving according to the present embodiment contains components other than component (A), component (B), component (C), and component (D) within a range that does not impair the effects of the present invention. may contain other components.

<Asphalt regenerating agent (A)>
In the method for regenerating asphalt for road paving according to the present embodiment, the liquid composition preferably contains an asphalt regenerating agent (A).
The asphalt regenerating agent (A) is a component containing maltene components (resin content, aromatic content, saturated content).
The components of asphalt are divided into maltene components (resin content, aromatic content, saturated content) and asphaltene components according to solubility and the like. The virgin asphalt has softness mainly derived from the aromatic content among these.
However, when asphalt is exposed to ultraviolet light and oxygen for a long period of time, oxygen acts on the double bond of carbon contained in the aromatic component, and polymerization progresses due to oxidative degradation and radicalization of the bond. This reduces the aromatic content and increases the asphaltenic content. Degraded asphalt is therefore harder and more brittle than virgin asphalt.
Therefore, by replenishing the deteriorated asphalt with the asphalt regenerating agent (A) whose liquid composition contains maltene components (resin content, aromatic content, saturated content), the deteriorated asphalt sprayed/coated with the liquid composition is not Since the composition is closer to that of the asphalt used, the flexibility and viscosity can be improved.

In the liquid composition, the asphalt regenerating agent (A) preferably contains at least one selected from naphthenic mineral oil (A1), aromatic mineral oil (A2), and vegetable oil (A3).
The naphthenic mineral oil (A1) means a mineral oil containing saturated components and aromatic components and having a saturated component content of more than 35.0% and not more than 65.0%.
The aromatic mineral oil (A2) means a mineral oil containing saturated components and aromatic components and having a saturated component content of 35.0% or less.
Among these, the naphthenic mineral oil (A1) is preferable from the viewpoint of the balance between the saturated content and the aromatic content, the flexibility, and the suppression of re-deterioration.

The %C _P of the naphthenic mineral oil (A1) is preferably 30-60, more preferably 35-50.
The % _CN of the naphthenic mineral oil (A1) is preferably 40-60, more preferably 45-55.
The % _CA of the naphthenic mineral oil (A1) is preferably 8-16, more preferably 9-13.
The saturated content of the naphthenic mineral oil (A1) is preferably 35.1 to 65.0, more preferably 40.0 to 58.0.
% _CP of the aromatic mineral oil (A2) is preferably 5.0 to 30.0, more preferably 8.0 to 26.0.
% C _N of the aromatic mineral oil (A2) is preferably 20.0 to 50.0, more preferably 25.0 to 48.0.
The % _CA of the aromatic mineral oil (A2) is preferably 40.0 to 50.0, more preferably 42.0 to 48.0.
The saturated content of the aromatic mineral oil (A2) is preferably 20.1 to 35.0, more preferably 23.0 to 32.0.
The vegetable oil (A3) is not particularly limited, and examples thereof include soybean oil, rapeseed oil, corn oil, and refined palm oil.
These may be used individually by 1 type, and may use 2 or more types together.
The asphalt regenerating agent (A) may contain a mineral oil having a saturated component content of more than 65.0% (hereinafter referred to as "paraffinic mineral oil (A')"). However, when the asphalt regenerating agent (A) contains paraffinic mineral oil (A'), the deteriorated asphalt after regeneration may deteriorate again. It is preferable that the content is small.

The flash point of the asphalt regenerating agent (A) is preferably 250° C. or higher and 390° C. or lower, more preferably 260° C. or higher and 350° C. or lower, still more preferably 280° C. or higher and 320° C. or lower, from the viewpoint of safety.

The content of the asphalt regenerating agent (A) is preferably 10% by mass or more, more preferably 20% by mass or more, based on the total amount (100% by mass) of the liquid composition, from the viewpoint of penetration recovery and composition recovery. , More preferably 25% by mass or more, still more preferably 30% by mass or more, preferably 65% by mass or less, more preferably 50% by mass or less, still more preferably 45% by mass or less, still more preferably 40% by mass % by mass or less.

<Penetration enhancer (B)>
In the method for regenerating asphalt for road paving according to the present embodiment, the liquid composition preferably contains a penetration enhancer (B).
In the method for regenerating asphalt for road paving according to the present embodiment, the penetration enhancer (B) is a component that dissolves the deteriorated asphalt. It is also a component that allows the asphalt regenerating agent (A) and plasticizer (C) to permeate into the deteriorated asphalt. Furthermore, it is a component that quickly evaporates and dries after being mixed with deteriorated asphalt.
By containing the penetration enhancer (B) in the liquid composition, the asphalt regenerating agent (A) and plasticizer (C) in the liquid composition penetrate into the deteriorated asphalt under a normal temperature environment without heating. can be made In addition, since the penetration enhancer (B) evaporates and dries quickly thereafter, the tackiness (adhesiveness) of the asphalt pavement surface due to dissolution of the asphalt is weakened, and traffic can be opened in a short period of construction. In addition, rapid volatilization and drying after the penetration accelerator (B) can suppress the occurrence of rutting in the reclaimed asphalt pavement.

The boiling point of the penetration accelerator (B) is preferably 140° C. or higher from the viewpoint of quickly volatilizing and drying while being retained in the deteriorated asphalt until the asphalt regenerating agent (A) and plasticizer (C) are penetrated. , 160° C. or higher.

The penetration enhancer (B) is not particularly limited, and examples thereof include naphthenic hydrocarbons (B1), terpene hydrocarbons (B2), and alcohol-containing aliphatic hydrocarbons (B3).
These may be used individually by 1 type, and may use 2 or more types together.
Among these, from the viewpoint of drying property, asphalt solubility, persistence on the asphalt surface, and odor, preferably naphthenic hydrocarbon (B1), terpene hydrocarbon (B2), more preferably naphthenic hydrocarbon (B1 ).
The penetration enhancer (B) may contain kerosene (hereinafter referred to as "kerosene (B')"). However, when the penetration enhancer (B) contains kerosene (B'), volatilization and drying take a very long time, so the content of kerosene (B') in the penetration enhancer (B) is preferably small. .

Naphthenic hydrocarbons (B1) include, for example, aliphatic hydrocarbons having a cyclic structure represented by C _n H _2n (n represents an integer of 1 or more and 30 or less).
The naphthenic hydrocarbon (B1) as the penetration enhancer (B) has a smaller molecular weight and a lower boiling point than the naphthenic mineral oil (A1) as the asphalt regenerating agent (A). This is because the naphthenic mineral oil (A1) as the asphalt regenerating agent (A) is a component retained in the deteriorated asphalt, while the naphthenic hydrocarbon (B1) as the penetration accelerator (B) is the asphalt regenerating agent ( This is because A) and the plasticizer (C) must be quickly volatilized and dried after being retained in the deteriorated asphalt.
The boiling point of the naphthenic hydrocarbon (B1) is preferably 140° C. from the viewpoint of being retained in the deteriorated asphalt until the asphalt regenerating agent (A) and the plasticizer (C) are permeated, and then rapidly volatilizing and drying. 250° C. or higher, more preferably 180° C. or higher and 240° C. or lower, still more preferably 190° C. or higher and 220° C. or lower.

Terpene-based hydrocarbons (B2) include, for example, hydrocarbons having (C ₅ H ₈ ) _n (n represents an integer of 1 or more and 10 or less) as a basic skeleton.
The boiling point of the terpene-based hydrocarbon (B2) is preferably 140° C. from the viewpoint of quickly volatilizing and drying while being held in the deteriorated asphalt until the asphalt regenerating agent (A) and plasticizer (C) are permeated. 220° C. or higher, more preferably 150° C. or higher and 200° C. or lower, still more preferably 170° C. or higher and 190° C. or lower.
The terpene hydrocarbon (B2) is not particularly limited, and examples thereof include limonene, β-pinene, monoterpene and the like.
Limonene may include d- and l-isomers, which are optical isomers. In addition, d-isomer and l-isomer derivatives may also be included.
Derivatives of d-limonene include, for example, citral A and the like.

Alcohol-containing aliphatic hydrocarbons (B3) include, for example, alcohol-containing aliphatic hydrocarbons.
The boiling point of the alcohol-containing aliphatic hydrocarbon (B3) is preferably 140° C. or higher and 250° C. or lower, more preferably 160° C. or higher and 230° C. or lower, still more preferably 180° C. or higher and 210° C. or lower.
The alcohol-containing aliphatic hydrocarbon (B3) is not particularly limited, and examples thereof include aromatic alcohols.
Examples of aromatic alcohols include benzyl alcohol, 2,3-dimethoxybenzyl alcohol, 1-benzyl-2-methylpropanol, phenethyl alcohol, anis alcohol, salicyl alcohol, diphenylmethanol and the like.

The content of the penetration enhancer (B) is preferably 10% by mass or more based on the total amount (100% by mass) of the liquid composition, from the viewpoint of drying property, solubility in asphalt, persistence on asphalt surfaces, and odor. , more preferably 12% by mass or more, still more preferably 14% by mass or more, and preferably 65% by mass or less, more preferably 60% by mass or less, and still more preferably 50% by mass or less.

The blending ratio [(A)/(B)] of the asphalt regenerating agent (A) and the penetration accelerator (B) is preferably 0.3 or more and 2.7 or less in terms of mass ratio from the viewpoint of solubility. It is more preferably 0.4 or more and 2.5 or less, still more preferably 0.8 or more and 2.4 or less.

<Plasticizer (C)>
In the method for regenerating asphalt for road paving according to the present embodiment, the liquid composition preferably contains a plasticizer (C).
A plasticizer (C) is a component having a polar portion and a non-polar portion in its molecule.
When asphalt is exposed to ultraviolet light and oxygen for a long period of time, oxygen acts on the carbon double bonds contained in the aromatic components to oxidize them, increasing the number of polar portions. As a result, the contribution of the resin component and the asphaltene component increases. Polymerization progresses due to oxidative deterioration and radicalization of bonds, and the polymers (collections of polar resin and asphaltene components) in the deteriorated asphalt mixture exist in a state of being entangled by electrical attraction.
Therefore, by including the plasticizer (C) in the liquid composition, the plasticizer (C) acts between the molecules of the polar polymer in the deteriorated asphalt to cause entanglement (electrical attraction) of the molecules. Since it can be relaxed and the intermolecular distance can be widened, the flexibility of the deteriorated asphalt mixture can be improved.

The plasticizer (C) is not particularly limited, and examples thereof include esters and polyalkylamines. These may be used individually by 1 type, and may use 2 or more types together.
Examples of the acid constituting the ester include dibasic acids such as adipic acid, phthalic acid, isophthalic acid and terephthalic acid, tribasic acids such as trimellitic acid, and phosphoric acid.
Among these, dibasic acids are preferable, and adipic acid and phthalic acid are more preferable, from the viewpoint of being easily mixed with the asphalt regenerating agent (A) and the penetration accelerator (B), and from the viewpoint of ease of application to asphalt. , and adipic acid are more preferred.
The alcohol constituting the ester is not particularly limited as long as it is an alcohol having a linear or branched alkyl group, but an alcohol having a branched alkyl group is preferable. The number of carbon atoms in the alkyl group is preferably 1-20, more preferably 3-16, still more preferably 6-12.
Examples of the polyalkylamines include alkylamines and alkyldiamines. These may be used individually by 1 type, and may use 2 or more types together.
Examples of alkylamines include alkylamines having an alkyl chain having 10 or more and 30 or less carbon atoms. The number of carbon atoms in the alkyl chain is preferably 12 or more and 24 or less, more preferably 14 or more and 22 or less.
Examples of alkyldiamines include alkyldiamines having an alkyl chain having 10 or more and 30 or less carbon atoms. The number of carbon atoms in the alkyl chain is preferably 12 or more and 24 or less, more preferably 14 or more and 22 or less.
When alkylamine and alkyldiamine are a mixture, the number of carbon atoms in the alkyl chain of the main component alkylamine and alkyldiamine is preferably 14 or more and 22 or less, more preferably 16 or more and 22 or less.
The main component means a component having a content of 50% by mass or more based on the total amount of alkylamine and alkyldiamine.

The molecular weight of the plasticizer (C) is preferably 100 or more and 450 or less, more preferably 250 or more and 420 or less, still more preferably 280 or more and 400 or less, from the viewpoint of penetration recovery.
The boiling point of the plasticizer (C) is preferably 160.degree. C. or higher, more preferably 200.degree.
From the viewpoint of safety, the flash point of the plasticizer (C) is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 100°C or higher.

From the viewpoint of composition recovery, the content of the plasticizer (C) is preferably 5% by mass or more, more preferably 8% by mass or more, and still more preferably 9% by mass, based on the total amount (100% by mass) of the liquid composition. % or more, preferably 80% by mass or less, more preferably 40% by mass or less, and even more preferably 20% by mass or less.

<Emulsifier-containing water (D)>
In the method for regenerating asphalt for road paving according to the present embodiment, the liquid composition preferably contains emulsifier-containing water (D).
The asphalt rejuvenating agent (A), penetration enhancer (B), and plasticizer (C) are all oil-based components. However, the liquid composition should contain water from the viewpoint of flammability and odor.
By including emulsifier-containing water (D) in the liquid composition, an emulsion is formed in which the liquid composition surrounds the oil-based component in water. Thereby, each component of the liquid composition can be kept in a state that does not separate until it is sprayed/applied, that is, in a state that is excellent in storage stability.

The emulsifier-containing water (D) contains water from the viewpoint of flammability and odor.
Penetration enhancer (B) and plasticizer (C) can be flammable oil-based components, so safety can be maintained until the liquid composition is sprayed/applied to the deteriorated asphalt mixture. .

The emulsifier-containing water (D) contains an emulsifier.
The emulsifier is not particularly limited as long as it is a component that exhibits an emulsifying action, and examples thereof include cationic surfactants, anionic surfactants, amphoteric surfactants, and nonionic surfactants. be done.
Examples of the cationic surfactant include aliphatic amines such as alkylamines, alkyldiamines, and aliphatic quaternary amines.
Examples of alkylamines include beef tallow amine.
Examples of alkyldiamine include beef tallow diamine.
The number of carbon atoms in the alkyl chain of the alkylamine or alkyldiamine is preferably 10 or more and 30 or less, more preferably 14 or more and 28 or less, and even more preferably 18 or more and 24 or less.
When the alkylamine or alkyldiamine is beef tallow amine, beef tallow diamine, or the like, the number of carbon atoms in the alkyl chain of the main component alkylamine or alkyldiamine is preferably 18 or more and 22 or less, more preferably 22.
The main component means a component such as beef tallow amine, beef tallow diamine, etc. whose content is 50% by mass or more based on the total amount.
Examples of the anionic surfactants include carboxylates, sulfonates, sulfates, and phosphates.
Examples of the amphoteric surfactant include alkyl derivatives, aminocarboxylates, imidazoline derivatives and the like.
Examples of the alkyl derivatives include carboxybetaine, sulfobetaine, trimethylglycine and the like, with carboxybetaine and sulfobetaine being preferred.
Examples of the nonionic surfactant include ether-type surfactants, ester-type surfactants, ether-ester-type surfactants, and nitrogen-containing surfactants.
These may be used individually by 1 type, and may use 2 or more types together.

When the deteriorated asphalt pavement contains crushed stone such as basalt or andesite as the main component, the emulsifier contained in the emulsifier-containing water (D) is preferably a cationic surfactant that is charged with cations.

Here, an example of the action of the liquid composition in the method for regenerating asphalt for road paving according to the present embodiment will be described.
In the liquid composition of the present embodiment containing emulsifier-containing water (D), water functions as a solvent. On the other hand, the asphalt regenerating agent (A), penetration enhancer (B), and plasticizer (C) contained in the liquid composition of the present embodiment are oil-based components. The emulsifier contained in the emulsifier-containing water (D) tends to be arranged at the interface between the water and the oil-based component. Therefore, the liquid composition of the present embodiment forms an emulsion in which the hydrophobic asphalt rejuvenating agent (A), the penetration enhancer (B), and the plasticizer (C) are enclosed in water as a solvent. do.
When the emulsifier is a cationic surfactant, the surfaces of the emulsion particles are cationically charged. In the liquid composition, since the emulsion particles whose surfaces are charged with cations repel each other, they do not separate and are stably dispersed until the liquid composition is sprayed/coated, and the liquid composition remains in a state of excellent storage stability. Each ingredient can be kept.

When the aggregate in the asphalt pavement is mainly composed of limestone containing a large amount of calcium carbonate CaCO ₃ , the surface of the asphalt pavement is electrified by cations when wet with rainwater.
On the other hand, as mentioned in JIS A 5001, when the crushed stone in the asphalt pavement is mainly composed of basalt, andesite, etc., these types of rocks contain about 50% silicon dioxide SiO ₂ . If the crushed stone in the asphalt pavement has a structure mainly composed of silicon-oxygen bonds, the surface of the asphalt pavement is electrified by anions when wet with rainwater.
Here, when the liquid composition of the present embodiment is sprayed/coated on a deteriorated asphalt pavement surface whose main component is basalt or andesite, the deteriorated asphalt pavement surface is charged with anions. When the emulsifier is a cationic surfactant, the cations on the surface of the emulsion attract the anions on the surface of the deteriorated asphalt pavement electrically, so that the emulsion form cannot be maintained, and the asphalt regenerating agent ( Separate into A), penetration enhancer (B), plasticizer (C), water and emulsifier.

Among the separated components, the asphalt regenerating agent (A) and the plasticizer (C) permeate the interior of the deteriorated asphalt mixture via the permeation enhancer (B). The asphalt regenerating agent (A) brings the deteriorated asphalt closer to the composition of the virgin asphalt mixture, thereby improving its flexibility and viscosity. In addition, since the plasticizer (C) widens the intermolecular distance of the polar polymer in the deteriorated asphalt, the flexibility of the deteriorated asphalt is improved.
Among the separated components, the penetration enhancer (B) is retained in the deteriorated asphalt until the asphalt rejuvenator (A) and the plasticizer (C) are permeated, dissolves the deteriorated asphalt, and contributes to softening. After that, it quickly evaporates and dries together with water.
Due to these actions, the deteriorated asphalt paved on the road can be chemically regenerated without heating.

The emulsifier-containing water (D) may contain other components as necessary. Examples of the other components include pH adjusters.

In the method for regenerating asphalt for road paving of the present embodiment, the content of the emulsifier-containing water (D) is based on the total amount (100% by mass) of the liquid composition from the viewpoint of safety and ease of contact with the deteriorated asphalt mixture. , preferably 0.5% by mass or more, more preferably 20% by mass or more, still more preferably 35% by mass or more, and preferably 60% by mass or less, more preferably 55% by mass or less, still more preferably 53% by mass. % by mass or less.

[Physical properties of liquid composition]
The Engler degree, which is an index for evaluating the viscosity of the liquid composition, is not particularly limited, but is preferably 1 or more and 15 or less, more preferably 2 or more, from the viewpoint of uniform mechanical spreadability and ease of spreading by application. 10 or less, more preferably 3 or more and 8 or less.
The Engler's degree of a liquid composition can be determined according to JIS K2208-2000 (petroleum asphalt emulsion) (6.3).

[Method for producing liquid composition]
In the method for regenerating asphalt for road paving according to the present embodiment, the liquid composition can be produced, for example, as follows.
First, at least one of the asphalt regenerating agent (A), the penetration enhancer (B), and the plasticizer (C) is mixed using a stirrer to prepare an oil phase mixture. Next, emulsifier-containing water (D) is prepared. Thereafter, the mixture is forcibly stirred using an emulsifier, and the oil phase mixture is emulsified with emulsifier-containing water (D), whereby a liquid composition containing an emulsion can be produced.
The oil phase mixture preferably contains two or more, more preferably three, of the asphalt regenerating agent (A), the penetration enhancer (B), and the plasticizer (C).

[Storage stability of liquid composition]
From the viewpoint of excellent storage stability, the liquid composition containing the emulsion that is permeated on the surface of the deteriorated asphalt mixture by the regeneration method of the present embodiment preferably does not separate for 3 hours or more, and more preferably does not separate for 5 hours or more. It is even more preferable not to separate for more than 24 hours.
The storage stability of the liquid composition of the present embodiment can be determined according to JIS K2208-2000 (petroleum asphalt emulsion) (6.15) by the method described in Examples.

[Loss tangent (tan δ) of deteriorated asphalt by viscoelasticity measurement test]
The loss tangent (tan δ) by a viscoelasticity measurement test (Dynamic Shear Rheometer test, DSR test) of the deteriorated asphalt to which the liquid composition is sprayed/applied, which is recycled by the recycling method of the present embodiment, is the tackiness (adhesiveness) From the viewpoint of recovery, it is preferably 1.43 or more, more preferably 1.5 or more, and still more preferably 1.8 or more and 3.0 or less.
Loss tangent (tan δ) indicates that the larger the numerical value, the higher the tackiness of the deteriorated asphalt and the closer to the tackiness of virgin asphalt.
The loss tangent (tan δ) of the deteriorated asphalt regenerated by the regeneration method of the present embodiment can be calculated by the method described in Examples using the following formula.
-formula-
σ ₀ represents stress, γ ₀ strain, and δ phase difference.
・Storage elastic modulus G′ = σ ₀ /γ ₀ × cos δ
・ Loss modulus G″ = σ ₀ / γ ₀ × sin δ
・Loss tangent tan δ=sin δ/cos δ=G″/G′
Here, the storage elastic modulus G' is a parameter that depends on the elasticity of the viscoelastic body. Also, the loss elastic modulus G″ is a parameter that depends on the viscosity of the viscoelastic body. Therefore, the larger the loss tangent tan δ, the larger the loss elastic modulus G″ relative to the storage elastic modulus G′. That is, since the contribution of viscosity to the viscoelastic body is large, the larger the loss tangent tan δ, the higher the viscosity and the higher the tackiness.

[Crack plugging property of deteriorated asphalt mixture]
In the deteriorated asphalt mixture regenerated by the regeneration method of the present embodiment, cracks are preferably clogged or partially clogged.
Plugging or partial plugging of cracks in the degraded asphalt mixture by penetration of the liquid composition indicates that the degraded asphalt mixture has been regenerated.
The crack plugging property of the deteriorated asphalt mixture regenerated by the regeneration method of the present embodiment can be determined by the method described in Examples.

According to one aspect of the present invention, the following [1] to [11] are provided.
[1] A method for regenerating asphalt for road paving, which regenerates a deteriorated asphalt mixture paved on a road in a temperature environment lower than the heating temperature of the road surface layer regeneration method,
A step (S _A ) of infiltrating a liquid composition containing an emulsion from the surface of the deteriorated asphalt mixture into the interior of the deteriorated asphalt by at least one of spraying and coating,
The step (S _A ) is a method for recycling asphalt for road paving, wherein the step (S A ) is performed so as to satisfy the following conditions (1) and (2).
Condition (1): The ratio (percentage) of the penetration of the deteriorated asphalt mixture after penetration of the liquid composition to the penetration of the deteriorated asphalt mixture before penetration of the liquid composition is 150% or more.
Condition (2): The content of the maltene component in the deteriorated asphalt mixture after the permeation of the liquid composition is, relative to the content of the maltene component in the degraded asphalt mixture before the permeation of the liquid composition, The mass ratio (percentage) is 103.0% or more.
[2] The method for recycling asphalt for road paving according to [1] above, wherein the step (S _A ) is further performed so as to satisfy the following condition (3).
Condition (3): The liquid composition penetrates into the deteriorated asphalt mixture to a depth of 10 mm or more from the surface of the deteriorated asphalt mixture.
[3] The method for regenerating asphalt for road paving according to [1] or [2], wherein the liquid composition contains a penetration enhancer (B).
[4] The method for regenerating asphalt for road paving according to [3] above, wherein the liquid composition further contains at least one selected from an asphalt regenerating agent (A) and a plasticizer (C).
[5] The method for regenerating asphalt for road paving according to [3] or [4], wherein the liquid composition further contains emulsifier-containing water (D).
[6] The method for recycling asphalt for road paving according to any one of [3] to [5], wherein the penetration accelerator (B) has a boiling point of 140° C. or higher.
[7] The above [4] to [6], wherein the asphalt regenerating agent (A) contains at least one selected from naphthenic mineral oil (A1), aromatic mineral oil (A2), and vegetable oil (A3). 3. The method for regenerating asphalt for road paving according to any one of .
[8] The method for regenerating asphalt for road paving according to any one of [4] to [7], wherein the asphalt regenerating agent (A) has a flash point of 250°C or higher and 390°C or lower.
[9] The mixing ratio [(A)/(B)] of the asphalt regenerating agent (A) and the penetration accelerator (B) is 0.4 or more and 2.5 or less in terms of mass ratio [4] ] The method for regenerating asphalt for road paving according to any one of [8].
[10] The plasticizer (C) contains at least one selected from esters composed of acids and alcohols selected from dibasic acids, tribasic acids, and phosphoric acids, alkylamines, and alkyldiamines. The method for recycling asphalt for road paving according to any one of [4] to [9] above.
[11] containing a penetration enhancer (B),
containing at least one selected from an asphalt regenerating agent (A) and a plasticizer (C),
The asphalt regenerating agent (A) contains at least one selected from naphthenic mineral oil (A1), aromatic mineral oil (A2), and vegetable oil (A3),
The penetration enhancer (B) is a liquid having a boiling point of 140° C. or higher,
The plasticizer (C) contains an ester composed of an acid and an alcohol selected from dibasic acid, tribasic acid, and phosphoric acid, and at least one or more selected from alkylamines and alkyldiamines. A liquid composition for regenerating asphalt for paving.

The present invention will be specifically described by the following examples, but the present invention is not limited to the following examples.

The component ratio of the asphalt mixture coated with each liquid composition described below was measured by the following method.

[Content of maltene component, etc., mass ratio (percentage) of content of maltene component after permeation to content of maltene component before permeation: Condition (2)]
The content of the maltene component in the asphalt mixture and the content of the asphaltene component in the asphalt mixture were obtained in accordance with JPI-5S-77-2019, which is the Petroleum Institute petroleum test standard.
Further, by dividing the content of malten components in the deteriorated asphalt mixture after applying and rolling the liquid composition by the content of malten components in the deteriorated asphalt mixture before applying the liquid composition, the liquid composition The mass ratio (percentage) of the content of the malten component in the deteriorated asphalt mixture after applying and rolling the liquid composition to the content of the malten component in the deteriorated asphalt mixture before applying was calculated.
As the maltene content increases, the softness of the asphalt mixture improves, so that the composition approaches that of a virgin asphalt mixture.

The physical properties of the asphalt mixture coated with each liquid composition described later were measured by the following methods.

[Penetration, ratio of penetration after penetration to penetration before penetration (percentage): condition (1)]
Penetration at 25° C. was measured according to JIS K2207-2006.
In addition, by dividing the penetration of the deteriorated asphalt mixture after applying and rolling the liquid composition by the penetration of the deteriorated asphalt mixture before applying the liquid composition, The ratio (percentage) of the penetration of the deteriorated asphalt mixture after applying and rolling the liquid composition to the penetration of the deteriorated asphalt mixture was calculated.

[Penetration into deteriorated asphalt, depth of penetration of liquid composition: condition (3)]
Under normal temperature (25 ° C.) environment, after cutting a thickness of 10 mm from the surface of the asphalt mixture, apply the liquid composition to the surface of the asphalt mixture, and visually check whether the liquid composition penetrates inside the deteriorated asphalt. Observed. Also, it was visually observed whether or not the applied liquid composition permeated from the surface of the asphalt mixture to the lower surface having a thickness of 10 mm.

[material]
Asphalt regenerating agent (A), penetration enhancer (B), plasticizer (C), and emulsifier used as raw materials for preparing liquid compositions in Examples 1 to 6 and Comparative Examples 1 to 8, which will be described later. Contained water (D) was as follows.

<Asphalt regenerating agent (A)>
Asphalt regenerating agent (A-1): naphthenic mineral oil (%C _P : 30-60, %C _N : 40-60, %C _A : 8-16, saturated content: 35.1%-65. 0%)

<Penetration enhancer (B)>
・Penetration enhancer (B-1): naphthenic hydrocarbon (boiling point: 199.5°C, drying rate at 25°C: 0.04 mg/h x mm ² )
- Penetration enhancer (B-2): terpene hydrocarbon (boiling point: 175.5°C, drying rate at 25°C: 1.81 mg/h x mm ² )
- Penetration enhancer (B-3): alcohol-containing aliphatic hydrocarbon (boiling point: 205°C, drying rate at 25°C: 0.0003 mg/h x mm ² )

<Plasticizer (C)>
- Plasticizer (C-1): bis(2-ethylhexyl) adipate (boiling point: 335°C, molecular weight: 371)
- Plasticizer (C-2): mixture of alkylamines (boiling point: 180°C, flash point: 61°C, distribution of carbon number in alkyl chain: C14 to C22, number of carbon atoms in main component alkyl chain: C16 to C22)

<Emulsifier-containing water (D)>
The following mixtures were used.
・Water: ion-exchanged water ・Alkylamine: beef tallow amine (boiling point: 180°C, flash point: 61°C, carbon number distribution of alkyl chain: C18 to C24, carbon number of main component alkyl chain: C22)
・Alkyldiamine: beef tallow diamine (flash point: 165°C)
Alkyldiamine: beef tallow diamine (boiling point: 250°C or higher, flash point: 190°C, molecular weight: 129)
・pH adjuster and other ingredients

[Preparation of liquid composition]
First, liquid compositions of Examples 1 to 6 and Comparative Examples 1 to 8 below were prepared.

<Example 1>
First, 0.7 kg of asphalt regenerating agent (A-1), 0.3 kg of penetration enhancer (B-1), and 0.2 kg of plasticizer (C-1) were stirred at 100 rpm to 1,000 rpm using a stirrer. Mixed at high speed to make oil phase mixture 1.
Next, 0.79 kg of ion-exchanged water warmed to 45° C. to 60° C., 0.004 kg of a mixture of alkylamine and alkyldiamine, a pH adjuster and 0.0072 kg of other ingredients were stirred with a stirrer at 100 rpm to 1,000 rpm. They were mixed at a speed of 000 rpm to prepare emulsifier-containing water (D).
Next, the liquid composition of Example 1 was obtained by emulsifying the produced oil phase mixture 1 and emulsifier-containing water (D) at a ratio of 6:4 using an emulsifier.

<Examples 2 to 6, Comparative Examples 1 to 8>
Liquid compositions of Examples 2 to 6 and Comparative Examples 1 to 8 were prepared in the same manner as in Example 1, except that the types and contents of each component were changed as shown in Tables 1 to 3. was prepared.

<Reference example 1>
Reference Example 1 was a deteriorated asphalt mixture (aggregate: 94.7% by mass, deteriorated asphalt: 5.3% by mass) without applying the liquid composition.

<Reference example 2>
94.7% by mass of aggregate of dense particle size mixture (13) shown in the type and particle size range of asphalt mixture in Pavement Construction Handbook (2006 edition) and 5.3% by mass of unused straight asphalt 60/80 The mixture was referred to as Reference Example 2.

Each obtained liquid composition was evaluated as follows. The results are shown in Tables 1-3.

[Evaluation of Storage Stability of Liquid Composition]
The obtained liquid compositions of Examples 1 to 6 and Comparative Examples 1 to 8 were placed in 250 mL test tubes and allowed to stand at 25° C. for 24 hours. After 3 hours and 24 hours, the appearance of each liquid composition was visually observed, and the storage stability of the liquid composition was evaluated according to JIS K2208-2000 (6.15). The results are shown in Tables 1-3.
If no separation occurred after 3 hours and after 24 hours, it was indicated as "no separation". In addition, when separated, the number of separated phases was also confirmed.

[Evaluation of loss tangent (tan δ) of deteriorated asphalt by viscoelasticity measurement test]
Each of the obtained liquid compositions of Examples 1 to 6 and Comparative Examples 1 to 5 was applied to the surface of a deteriorated asphalt mixture (aggregate: 94.7% by mass, deteriorated asphalt: 5.3% by mass). 4 L/m ² was applied. After that, it was allowed to stand in an environment of 25° C. for 24 hours, and a test piece that was dry to the touch was used.
Next, using the asphalt obtained from the asphalt extraction test and asphalt recovery test shown in the Pavement Investigation Test Method Handbook (2019 edition 4th volume, G028 and G029), Examples 1 to 6 and Comparative Examples 1 to 5 , and each asphalt mixture of Reference Examples 1 and 2, a Dynamic Shear Rheometer test (DSR test) was performed, and the loss tangent (tan δ) of the deteriorated asphalt by the viscoelasticity measurement test was calculated using the following test conditions and the following formula. and evaluated. The results are shown in Tables 1-3.
Loss tangent (tan δ) indicates that the larger the numerical value, the higher the tackiness (adhesiveness) of the deteriorated asphalt. Note that a loss tangent (tan δ) of "1.43" or more is a practicable level.
-Test condition-
・ Device name: MCR 102 (manufactured by Anton-Paar)
・Loading speed: 1.0 rad/s
・Strain: 0.1%
・Test temperature: 25°C
・Test jig: inner diameter 8 mm
・Sample thickness: 1 mm
-formula-
σ ₀ represents stress, γ ₀ strain, and σ phase difference.
・Storage elastic modulus G′ = σ ₀ /γ ₀ × cos δ
・ Loss modulus G″ = σ ₀ / γ ₀ × sin δ
・Loss tangent tan δ=sin δ/cos δ
=G"/G'
In Comparative Examples 6 to 8, this evaluation could not be performed because the liquid composition did not permeate the deteriorated asphalt mixture.

[Evaluation of crack blockage of deteriorated asphalt mixture]
First, a test in which a solid-state deteriorated asphalt mixture (aggregate: 94.7% by mass, deteriorated asphalt: 5.3% by mass) was molded inside a test formwork (size: 300 mm × 300 mm × 50 mm). made the body. The surface of the deteriorated asphalt mixture used had cracks (length: 30 cm, depth: 5 cm).
Next, on the surface of the deteriorated asphalt mixture, the liquid compositions of Examples 1 to 6 and Comparative Examples 1 to 8 were applied, respectively, on the surface residual active ingredient amount: 21.6 g (0.4 L / m ² ) (degraded asphalt It was applied so that the active ingredient permeated inside from the surface of the mixture: 60%). The deteriorated asphalt mixture itself was used as Reference Example 1. Reference Example 2 was a new asphalt mixture (aggregate of dense-grained mixture (13): 94.7% by mass, virgin straight asphalt 60/80: 5.3% by mass).
Next, the surface of each asphalt mixture of Examples 1 to 6, Comparative Examples 1 to 8, and Reference Examples 1 and 2 was subjected to rolling compaction using a wheel tracking tester so that a ground pressure of 0.63 MPa was applied. , and traveled by the traverse mechanism shown in the pavement investigation test method handbook "B004 water immersion wheel tracking test method". In the running test, a dry specimen was used without being immersed in water. After that, it was visually observed whether or not the cracks on the surface of each test piece were closed, and the crack closing property of the deteriorated asphalt mixture was evaluated. The results are shown in Tables 1-3. 1 to 6 show photographs of the surfaces of the deteriorated asphalt mixtures of Example 1, Comparative Example 6, and Reference Example 1 as substitutes for drawings. (Figures 1 and 3 are photographs before coating and rolling, Figures 5 are before rolling, Figures 2 and 4 are after coating and rolling, and Figure 6 is photographs after rolling.)

As can be seen from Table 1, all of the deteriorated asphalt mixtures coated and permeated with the liquid compositions of Examples 1 to 6 that satisfy the conditions (1) and (2) have a loss tangent (tan δ) of 1.43 or more. Met. That is, in Examples 1 to 6, the tackiness of the deteriorated asphalt is higher than that of Reference Example 1, which is the deteriorated asphalt mixture itself without applying the liquid composition, and approaches the tackiness of Reference Example 2 containing virgin asphalt. rice field. Further, as can be seen from Table 3 and FIGS. 5 to 6, the cracks are not closed in Reference Example 1, but as can be seen from Table 1 and FIGS. 1 to 2, the liquid compositions of Examples 1 to 6 are permeated The degraded asphalt mixture that was tested had cracks plugged or partially plugged. That is, from the results shown in Table 1, it was confirmed that the deteriorated asphalt mixture was regenerated by infiltrating the liquid composition satisfying the conditions (1) and (2).
On the other hand, Comparative Examples 1, 2, and 4, which did not satisfy the condition (1), all had a loss tangent (tan δ) of less than 1.43. In Comparative Examples 3 to 5, which did not satisfy the condition (2), the loss tangent (tan δ) was less than 1.43, and cracks were not closed as shown in FIGS. 3 and 4.
In Comparative Examples 6 to 8, in which the liquid composition did not "penetrate into the deteriorated asphalt", the liquid composition only remained on the surface of the deteriorated asphalt mixture, and the loss tangent (tan δ) of the deteriorated asphalt was evaluated. could not do Moreover, in Comparative Examples 6 to 8, cracks in the deteriorated asphalt mixture were not blocked.

Claims (11)

A method for regenerating asphalt for road paving, which regenerates a deteriorated asphalt mixture paved on a road in a temperature environment lower than the heating temperature of the road surface layer regeneration method,
A step (S _A ) of infiltrating a liquid composition containing an emulsion from the surface of the deteriorated asphalt mixture into the interior of the deteriorated asphalt by at least one of spraying and coating,
The liquid composition comprises an asphalt regenerating agent (A), a penetration enhancer (B), and emulsifier-containing water (D),
The asphalt regenerating agent (A) contains at least one selected from naphthenic mineral oil (A1), aromatic mineral oil (A2), and vegetable oil (A3),
The penetration enhancer (B) contains at least one selected from naphthenic hydrocarbons (B1), terpene hydrocarbons (B2), and alcohol-containing aliphatic hydrocarbons (B3),
The step (S _A ) is a method for recycling asphalt for road paving, wherein the step (S A ) is performed so as to satisfy the following conditions (1) and (2).
Condition (1): The ratio (percentage) of the penetration of the deteriorated asphalt mixture after penetration of the liquid composition to the penetration of the deteriorated asphalt mixture before penetration of the liquid composition is 150% or more.
Condition (2): The content of the maltene component in the deteriorated asphalt mixture after the permeation of the liquid composition is, relative to the content of the maltene component in the degraded asphalt mixture before the permeation of the liquid composition, The mass ratio (percentage) is 103.0% or more. The method for recycling asphalt for road paving according to claim 1, wherein the step (S _A ) is further performed so as to satisfy the following condition (3).
Condition (3): The liquid composition penetrates into the deteriorated asphalt mixture to a depth of 10 mm or more from the surface of the deteriorated asphalt mixture. The method for recycling asphalt for road paving according to claim 1 or 2 , wherein the liquid composition further contains a plasticizer (C) . The method for regenerating asphalt for road paving according to any one of claims 1 to 3 , wherein the penetration accelerator (B) has a boiling point of 140°C or higher. The method for regenerating road pavement asphalt according to any one of claims 1 to 4 , wherein the asphalt regenerating agent (A) has a flash point of 250°C or higher and 390°C or lower. 6. The composition of claims 1 to 5 , wherein the blending ratio [(A)/(B)] of the asphalt regenerating agent (A) and the penetration accelerator (B) is 0.4 or more and 2.5 or less by mass. The method for recycling asphalt for road paving according to any one of the above items. The plasticizer (C) contains an ester composed of an acid and an alcohol selected from dibasic acid, tribasic acid, and phosphoric acid, and at least one or more selected from alkylamine and alkyldiamine. The method for recycling asphalt for road paving according to any one of claims 3 to 6 . Containing an asphalt regenerating agent (A), a penetration enhancer (B), and emulsifier-containing water (D) ,
The asphalt regenerating agent (A) contains at least one selected from naphthenic mineral oil (A1), aromatic mineral oil (A2), and vegetable oil (A3),
Regeneration of asphalt for road paving, wherein the penetration enhancer (B) contains at least one selected from naphthenic hydrocarbons (B1), terpene hydrocarbons (B2), and alcohol-containing aliphatic hydrocarbons (B3) liquid composition for 9. The liquid composition for regenerating asphalt for road paving according to claim 8, wherein the penetration accelerator (B) has a boiling point of 140[deg.] C. or higher. 10. The liquid composition for recycling asphalt for road paving according to claim 8 or 9, further comprising a plasticizer (C). The plasticizer (C) contains an ester composed of an acid and an alcohol selected from dibasic acid, tribasic acid, and phosphoric acid, and at least one or more selected from alkylamine and alkyldiamine. The liquid composition for recycling asphalt for road paving according to claim 10.

Images