WO2021100343A1 - Asphalt mixture, paving method, and method for producing cured product of asphalt - Google Patents

Abstract

Provided are: an asphalt mixture having excellent transportability and workability at a low temperature (for example, at 100 °C or lower); and an application thereof. The asphalt mixture includes: an asphalt; an aggregate; at least one carboxylic acid compound selected from the group consisting of an aliphatic carboxylic acid and an aliphatic carboxylic acid ester; water; and an alkaline compound, wherein at least one selected from the group consisting of the carboxylic acid compound, the water, and the alkaline compound is encapsulated in a microcapsule.

Description

Asphalt mixture, pavement method, and asphalt hardened product manufacturing method

This disclosure relates to an asphalt mixture, a pavement method, and a method for producing a hardened asphalt product.

Asphalt mixture used at high temperature (hereinafter referred to as "heated asphalt mixture") is widely used for pavement of road surface, for example. On the other hand, since the heated asphalt mixture thickens or hardens as the temperature decreases, the pot life (that is, the usable time) of the heated asphalt mixture is limited. In addition, the heated asphalt mixture is used under conditions that cause a significant decrease in temperature (for example, when a small amount of the heated asphalt mixture is used in several times, when the heated asphalt mixture is transported for a long time, or when a thin layer overlay method is used, etc. It is hard to say that it is suitable for use in (when the heated asphalt mixture is spread thinly by the construction method). Therefore, when using the heated asphalt mixture, it is necessary to appropriately control the temperature of the heated asphalt mixture. For example, the initial rolling temperature of the heated asphalt mixture is adjusted to the range of 110 ° C to 140 ° C.

Therefore, an asphalt mixture that can be used under lower temperature conditions (for example, a temperature of 100 ° C. or lower) than the conventional heated asphalt mixture has been proposed.

For example, Patent Document 1 describes an aggregate and an asphalt emulsion as main components, and the aggregate and the asphalt emulsion are mixed with each other in a state where the volume of the asphalt emulsion is increased by foaming. A normal temperature asphalt mixture for pavement, which is characterized in that the granulation phenomenon is suppressed, is disclosed.

For example, in Patent Document 2, in addition to the materials normally used in producing a heated asphalt mixture, fats and oils or fatty acids and an alkaline additive are added and mixed, and a curing accelerator is added to the mixture during or immediately after the construction. Disclosed is a room temperature construction type heated asphalt mixture, which is characterized in that the added fat or fatty acid and an alkali content rapidly saponify with each other to develop strength.

Japanese Unexamined Patent Publication No. 11-12475 JP-A-2010-248472

However, the pavement method using the asphalt mixture described in Patent Document 1 has a problem that the strength of the obtained cured product is relatively small and the curing time is long.

In response to the above problems, in Patent Document 2, by supplying a curing accelerator (for example, water) to the asphalt mixture during or immediately after construction, fats and oils or fatty acids and alkalis rapidly saponify. By thickening the viscosity, it is possible to develop the strength that enables early traffic opening. On the other hand, in actual construction, it is necessary to spray the curing accelerator on the surface of the spread asphalt mixture to allow the curing accelerator to permeate into the asphalt mixture, and therefore improvement in workability is desired. Further, since the asphalt mixture using the saponification reaction is brought into contact with the curing accelerator, the saponification reaction proceeds. Therefore, adding the curing accelerator to the asphalt mixture before the construction hinders the transportability and workability of the asphalt mixture. there's a possibility that.

This disclosure has been made in view of the above circumstances.
One aspect of the present disclosure is to provide an asphalt mixture having excellent transportability and workability at a low temperature (for example, 100 ° C. or lower).
Another aspect of the present disclosure is to provide a pavement method using an asphalt mixture having excellent transportability and workability at a low temperature (for example, 100 ° C. or lower).
Another aspect of the present disclosure is to provide a method for producing a cured asphalt product using an asphalt mixture having excellent transportability and workability at a low temperature (for example, 100 ° C. or lower).

The present disclosure includes the following aspects.
<1> The above-mentioned carboxylic acid, which comprises at least one carboxylic acid compound selected from the group consisting of asphalt, aggregate, aliphatic carboxylic acid, and aliphatic carboxylic acid ester, water, and an alkaline compound. An asphalt mixture in which at least one selected from the group consisting of a compound, the above water, and the above alkaline compound is encapsulated in microcapsules.
<2> The asphalt mixture according to <1>, wherein the wall material of the microcapsules contains at least one polymer selected from the group consisting of polyurethane and polyurea.
<3> The asphalt mixture according to <1> or <2>, which further contains a cutback agent.
<4> The asphalt mixture according to any one of <1> to <3>, wherein at least the carboxylic acid compound is encapsulated in the microcapsules.
<5> The asphalt mixture according to any one of <1> to <4>, wherein the aliphatic carboxylic acid has 10 to 26 carbon atoms.
<6> The asphalt mixture according to any one of <1> to <5>, wherein the aliphatic carboxylic acid is a fatty acid.
<7> The asphalt mixture according to any one of <1> to <6>, wherein the aliphatic carboxylic acid ester has 10 to 26 carbon atoms.
<8> The asphalt mixture according to any one of <1> to <7>, wherein the aliphatic carboxylic acid ester is a fatty acid alkyl ester.
<9> Any of <1> to <8> in which the content of the carboxylic acid compound is 12% by mass to 20% by mass on a mass basis with respect to the total amount of the asphalt and the carboxylic acid compound. The asphalt mixture according to one.
<10> One of <1> to <9> in which the content ratio of the carboxylic acid compound, the water, and the alkaline compound is 50 to 150: 400 to 600: 1 on a mass basis. The asphalt mixture described.
<11> A pavement method including a step of laying the asphalt mixture according to any one of <1> to <10> on a paved body and a step of pressurizing the laid asphalt mixture.
<12> A method for producing a cured asphalt product, which comprises a step of pressurizing the asphalt mixture according to any one of <1> to <10>.

According to one aspect of the present disclosure, it is possible to provide an asphalt mixture having excellent transportability and workability at a low temperature (for example, 100 ° C. or lower).
According to another aspect of the present disclosure, it is possible to provide a pavement method using an asphalt mixture having excellent transportability and workability at a low temperature (for example, 100 ° C. or lower).
According to another aspect of the present disclosure, it is possible to provide a method for producing a cured asphalt product using an asphalt mixture having excellent transportability and workability at a low temperature (for example, 100 ° C. or lower).

Hereinafter, embodiments of the present disclosure will be described in detail. The present disclosure is not limited to the following embodiments, and can be carried out with appropriate modifications within the scope of the purpose of the present disclosure.

In the present disclosure, the numerical range represented by using "-" means a range including the numerical values before and after "-" as the lower limit value and the upper limit value. In the numerical range described stepwise in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. Further, in the numerical range described in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples.

In the present disclosure, the amount of each component in the composition means the total amount of the plurality of substances present in the composition when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified. ..

In the present disclosure, the term "process" is included in the term "process" as long as the intended purpose of the process is achieved, not only in an independent process but also in cases where it cannot be clearly distinguished from other processes. ..

In the present disclosure, "% by mass" and "% by weight" are synonymous, and "parts by mass" and "parts by weight" are synonymous.

In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.

<Asphalt mixture>
The asphalt mixture according to the present disclosure comprises at least one carboxylic acid compound selected from the group consisting of asphalt, aggregate, aliphatic carboxylic acid, and aliphatic carboxylic acid ester, water, and an alkaline compound. At least one selected from the group consisting of the carboxylic acid compound, the water, and the alkaline compound is encapsulated in microcapsules.

According to the asphalt mixture according to the present disclosure, it is possible to provide an asphalt mixture having excellent transportability and workability at a low temperature (for example, 100 ° C. or lower). The reason why the asphalt mixture according to the present disclosure exerts the above effect is presumed as follows. It is considered that the thickening or hardening of the asphalt mixture according to the present disclosure is promoted by the reaction (for example, neutralization or saponification) of the carboxylic acid compound and the alkaline compound in the presence of water. In the asphalt mixture according to the present disclosure, since at least one of the carboxylic acid compound, water, and the alkaline compound is encapsulated in the microcapsules, the progress of the reaction between the carboxylic acid compound and the alkaline compound can be suppressed. It is possible to suppress the progress of thickening or hardening of the asphalt mixture during the non-transportation period (for example, during transportation and during construction). On the other hand, breaking the microcapsules at the right time can cause thickening or hardening of the asphalt mixture. Therefore, according to the asphalt mixture according to the present disclosure, it is possible to provide an asphalt mixture having excellent transportability and workability at a low temperature. The term "low temperature" relating to transportability and workability is relatively low as compared with the temperature at which the conventional heated asphalt mixture is transported and the temperature at which the conventional heated asphalt mixture is used for construction. Means temperature.

[asphalt]
The asphalt mixture according to the present disclosure includes asphalt. The asphalt mixture according to the present disclosure may contain one or more asphalts.

The type of asphalt is not limited. As asphalt, known asphalt can be used. Examples of asphalt include natural asphalt and petroleum asphalt. The asphalt may be modified asphalt. Specific examples of asphalt include straight asphalt, blown asphalt, semi-blown asphalt, and polymer-modified asphalt. Polymer-modified asphalt is a polymer (eg, styrene-butadiene-styrene copolymer, styrene-butadiene rubber, styrene-isoprene-styrene copolymer, ethylene-vinyl acetate copolymer, and ethylene-ethyl acrylate copolymer). It is an asphalt containing. The asphalt preferably contains straight asphalt.

The asphalt content is not limited. The asphalt content may be determined, for example, according to the intended use and the desired properties.

The asphalt content is preferably 0.5% by mass or more, and preferably 1% by mass or more, based on the total mass of the asphalt mixture from the viewpoint of transportability and workability of the asphalt mixture before curing. It is more preferable, and it is particularly preferable that it is 2% by mass or more.

The content of asphalt is preferably 10% by mass or less with respect to the total mass of the asphalt mixture from the viewpoint of the strength of the cured product of the asphalt mixture (hereinafter, may be referred to as "hardened asphalt product"). It is more preferably 8% by mass or less, and particularly preferably 6% by mass or less.

The asphalt content is 2% by mass to 15% by mass with respect to the total amount of asphalt and aggregate from the viewpoint of transportability and workability of the asphalt mixture before curing and strength of the asphalt cured product. %, More preferably 3% by mass to 8% by mass.

[aggregate]
The asphalt mixture according to the present disclosure contains aggregate. The asphalt mixture according to the present disclosure may contain two or more aggregates.

The type of aggregate is not limited. As the aggregate, a known aggregate can be used. Examples of the aggregate include natural aggregate, artificial aggregate, and regenerated aggregate. Specific aggregates include, for example, sand, gravel, crushed stone (for example, No. 6 crushed stone), steel slag, limestone, stone powder, cement, slaked lime, fly ash, ceramics, sinopearl, aluminum grains, plastic grains, carbon black site , Emery, and carbon black. The aggregate preferably contains crushed stone.

The content of aggregate is not limited. The content of the aggregate may be determined, for example, according to the intended use and the desired characteristics.

From the viewpoint of the strength of the asphalt cured product, the content of the aggregate is preferably 75% by mass or more, more preferably 80% by mass or more, and 85% by mass or more with respect to the total mass of the asphalt mixture. Is particularly preferable.

The content of the aggregate is preferably 94% by mass or less, more preferably 92% by mass or less, based on the total mass of the asphalt mixture from the viewpoint of transportability and workability of the asphalt mixture before curing. It is preferably 90% by mass or less, and particularly preferably 90% by mass or less.

The content of aggregate is 85% by mass to 98% by mass with respect to the total amount of asphalt and aggregate from the viewpoint of the transportability and workability of the asphalt mixture before hardening and the strength of the hardened asphalt. It is preferably by mass%, more preferably 92% by mass to 97% by mass.

[Carboxylic acid compound]
The asphalt mixture according to the present disclosure contains at least one carboxylic acid compound selected from the group consisting of an aliphatic carboxylic acid and an aliphatic carboxylic acid ester. The carboxylic acid compound contributes to thickening or hardening of the asphalt mixture by reacting (for example, neutralizing or saponifying) with the alkaline compound in the presence of water.

The asphalt mixture according to the present disclosure may contain an aliphatic carboxylic acid or an aliphatic carboxylic acid ester as a carboxylic acid compound. In addition, the asphalt mixture according to the present disclosure may contain both an aliphatic carboxylic acid and an aliphatic carboxylic acid as the carboxylic acid compound. From the viewpoint of kneading property, the asphalt mixture according to the present disclosure preferably contains an aliphatic carboxylic acid ester as a carboxylic acid compound. The asphalt mixture according to the present disclosure preferably contains an aliphatic carboxylic acid as a carboxylic acid compound from the viewpoint of the strength of the asphalt cured product (for example, martial stability). The asphalt mixture according to the present disclosure contains both an aliphatic carboxylic acid and an aliphatic carboxylic acid ester as the carboxylic acid compound from the viewpoint of transportability, workability, and strength of the cured asphalt product (for example, martial stability). It is preferable to include it.

(Alphatic carboxylic acid)
Aliphatic carboxylic acids are aliphatic compounds having at least one carboxy group.

The type of aliphatic carboxylic acid is not limited. As the aliphatic carboxylic acid, a known aliphatic carboxylic acid can be used.

The carbon number of the aliphatic carboxylic acid is preferably 2 to 30, more preferably 10 to 26, and 16 to 22 from the viewpoint of the kneadability of the asphalt mixture before curing and the strength of the asphalt cured product. Is particularly preferable.

Examples of the aliphatic carboxylic acid include an aliphatic monocarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic tricarboxylic acid. The aliphatic carboxylic acid may be an aliphatic compound having four or more carboxy groups. Further, the aliphatic carboxylic acid may be a saturated aliphatic carboxylic acid or an unsaturated aliphatic carboxylic acid.

The aliphatic carboxylic acid is preferably a fatty acid, more preferably a fatty acid having 16 to 22 carbon atoms, from the viewpoint of transportability and workability of the asphalt mixture before curing. Fatty acids are aliphatic compounds having one carboxy group (ie, aliphatic monocarboxylic acids). Examples of fatty acids include saturated fatty acids and unsaturated fatty acids.

Saturated fatty acids include, for example, butanoic acid, pentanoic acid, hexanoic acid, heptanic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, icosanoic acid, docosan. Acids, tetracosanoic acid, hexacosanoic acid, octacosanoic acid, and triacanthanoic acid can be mentioned.

Examples of unsaturated fatty acids include oleic acid (also known as cis-9-octadecenoic acid), linoleic acid (also known as 9,12-octadecadienoic acid), and linolenic acid (also known as 9,12,15-octadeca). Trienoic acid).

The fatty acid is preferably an unsaturated fatty acid, more preferably an unsaturated fatty acid having 16 to 22 carbon atoms, and more preferably olein, from the viewpoint of the kneadability of the asphalt mixture before curing and the strength of the cured asphalt product. It is particularly preferably an acid.

(Aliphatic carboxylic acid ester)
The aliphatic carboxylic acid ester is a compound having a structure in which the hydrogen atom of at least one carboxy group (-COOH) of the aliphatic carboxylic acid is replaced with an organic group (for example, an alkyl group).

The type of aliphatic carboxylic acid ester is not limited. As the aliphatic carboxylic acid ester, a known aliphatic carboxylic acid ester can be used.

From the viewpoint of the kneadability of the asphalt mixture before curing and the strength of the asphalt cured product, the carbon number of the aliphatic carboxylic acid ester is preferably 2 to 30, more preferably 10 to 26, and 16 to 16. 22 is particularly preferable.

Examples of the aliphatic carboxylic acid constituting the partial structure of the aliphatic carboxylic acid ester include the aliphatic carboxylic acid described in the above section "Aliphatic carboxylic acid".

The aliphatic carboxylic acid ester may be an ester of an aliphatic carboxylic acid and a polyhydric alcohol. Examples of the ester of the aliphatic carboxylic acid and the polyhydric alcohol include an ester of a fatty acid and glycerin (that is, fat and oil).

The aliphatic carboxylic acid ester is preferably a fatty acid ester, more preferably a fatty acid alkyl ester, and a fatty acid alkyl having 16 to 22 carbon atoms, from the viewpoint of transportability and workability of the asphalt mixture before curing. It is particularly preferable that it is an ester. Further, the aliphatic carboxylic acid ester is preferably at least one fatty acid alkyl ester selected from the group consisting of fatty acid methyl ester and fatty acid ethyl ester, and more preferably fatty acid ethyl ester.

Examples of fatty acid ethyl esters include ethyl heptanoate, ethyl decanoate, ethyl icosanoate, ethyl oleate, and ethyl linoleate. The fatty acid ethyl ester is preferably ethyl oleate.

(Content rate)
The content of the carboxylic acid compound is preferably 0.1% by mass or more, preferably 0.3% by mass or more, based on the total mass of the asphalt mixture from the viewpoint of kneadability of the asphalt mixture before curing. Is more preferable, and 0.6% by mass or more is particularly preferable. In the present disclosure, "content of carboxylic acid compound" means the ratio of the total amount of the carboxylic acid compound not contained in the microcapsules and the carboxylic acid compound contained in the microcapsules unless otherwise specified. To do.

From the viewpoint of the strength of the asphalt cured product, the content of the carboxylic acid compound is preferably 5% by mass or less, more preferably 3% by mass or less, and more preferably 1.5% by mass, based on the total mass of the asphalt mixture. It is particularly preferable that it is mass% or less.

The content of the carboxylic acid compound is 10% by mass to 22% by mass with respect to the total amount of asphalt and the carboxylic acid compound from the viewpoint of the kneadability of the asphalt mixture before curing and the strength of the asphalt cured product. %, More preferably 12% by mass to 20% by mass, and particularly preferably 14% by mass to 18% by mass.

[water]
The asphalt mixture according to the present disclosure contains water. Water can accelerate the reaction between the carboxylic acid compound and the alkaline compound.

The type of water is not limited. Examples of water include tap water, groundwater, distilled water, ion-exchanged water, and industrial water.

From the viewpoint of the strength of the asphalt cured product, the water content is preferably 0.5% by mass or more, more preferably 1% by mass or more, and 2% by mass, based on the total mass of the asphalt mixture. The above is particularly preferable. In the present disclosure, "water content" means the ratio of the total amount of water not contained in microcapsules and water contained in microcapsules, unless otherwise specified.

From the viewpoint of kneadability of the asphalt mixture before curing, the water content is preferably 10% by mass or less, more preferably 8% by mass or less, and 6% by mass, based on the total mass of the asphalt mixture. It is particularly preferable that it is% or less.

[Alkaline compound]
The asphalt mixture according to the present disclosure contains an alkaline compound. The asphalt mixture according to the present disclosure may contain one or more alkaline compounds.

The type of alkaline compound is not limited as long as it is a compound capable of reacting (for example, neutralizing or saponifying) with a carboxylic acid compound. Further, the alkaline compound may be a compound that produces a chemical species capable of reacting (for example, neutralizing or saponifying) with a carboxylic acid compound by reacting with water. For example, calcium oxide (CaO) can produce calcium hydroxide (Ca (OH) ₂ ) capable of reacting with a carboxylic acid compound by reaction with water.

Examples of the alkaline compound include alkali metal hydroxides (eg, sodium hydroxide and potassium hydroxide), alkali metal oxides (eg, sodium oxide), and alkaline earth metal hydroxides (eg, water). Calcium oxide) and oxides of alkaline earth metals (eg, calcium oxide). Examples of the alkaline compound include sodium hydrogen carbonate and potassium hydrogen carbonate.

The alkaline compound is at least one alkaline compound selected from the group consisting of alkali metal hydroxides, alkali metal oxides, alkaline earth metal hydroxides, and alkaline earth metal oxides. Is preferable.

From the viewpoint of the strength of the asphalt cured product, the content of the alkaline compound ^{is preferably 5 × 10 -4} % by mass or more, preferably 20 × 10 ^-4 % by mass or more, based on the total mass of the asphalt mixture. Is more preferable, and 50 × 10 ^-4 % by mass or more is particularly preferable. In the present disclosure, "content of alkaline compound" means the ratio of the total amount of the alkaline compound not contained in the microcapsules and the alkaline compound contained in the microcapsules unless otherwise specified.

^{The content of the alkaline compound is preferably 1,000 × 10 -4} % by mass or less, preferably 500 × 10 with respect to the total mass of the asphalt mixture, from the viewpoint of transportability and workability of the asphalt mixture before curing. more preferably ^-4 or less by mass%, particularly preferably 100 × ^{10 -4%} by weight or less.

The content ratio of the carboxylic acid compound, water, and the alkaline compound (carboxylic acid compound: water: alkaline compound) is based on the mass from the viewpoint of the transportability and workability of the asphalt mixture before curing and the strength of the asphalt cured product. The ratio is preferably 20 to 250: 250 to 900: 1, more preferably 30 to 200: 300 to 750: 1, and particularly preferably 50 to 150: 400 to 600: 1.

[Microcapsules]
At least one selected from the group consisting of carboxylic acid compounds, water, and alkaline compounds contained in the asphalt mixture according to the present disclosure is encapsulated in microcapsules. By encapsulating at least one of the carboxylic acid compound, water, and the alkaline compound in the microcapsules, the progress of the reaction between the carboxylic acid compound and the alkaline compound in the asphalt mixture can be suppressed, and thus the unintended time (for example, transportation). It is possible to suppress the progress of thickening or hardening of the asphalt mixture during (during the process and during the construction).

It is preferable that at least one selected from the group consisting of a carboxylic acid compound, water, and an alkaline compound contained in the asphalt mixture according to the present disclosure is encapsulated in microcapsules for each type. By encapsulating at least one selected from the group consisting of carboxylic acid compounds, water, and alkaline compounds in microcapsules for each type, the controllability of the reaction between the carboxylic acid compound and the alkaline compound can be further improved. Therefore, the transportability and workability can be further improved.

In the present disclosure, the term "type" relating to microcapsules means three classifications of carboxylic acid compounds, water, and alkaline compounds. In the present disclosure, the term "by type" relating to microcapsules means that carboxylic acid compounds, water, and alkaline compounds are treated separately. Therefore, in the embodiment that "at least one selected from the group consisting of a carboxylic acid compound, water, and an alkaline compound is encapsulated in a microcapsule for each type", the group consisting of a carboxylic acid compound, water, and an alkaline compound. The component that is allowed to be encapsulated in one of the microcapsules is, in principle, a carboxylic acid compound, water, or an alkaline compound. Then, in the embodiment that "at least one selected from the group consisting of a carboxylic acid compound, water, and an alkaline compound is encapsulated in a microcapsule for each type", from the group consisting of a carboxylic acid compound, water, and an alkaline compound. The two or three selected species are separately encapsulated in multiple microcapsules. For example, when the objects contained in the microcapsules are a carboxylic acid compound and water, the carboxylic acid compound and water are separately contained in a plurality of microcapsules. That is, the asphalt mixture according to the present disclosure may contain at least one selected from the group consisting of microcapsules containing a carboxylic acid compound, microcapsules containing water, and microcapsules containing an alkaline compound. .. However, there is no limitation on the mode in which a plurality of components belonging to the same type (for example, a plurality of compounds belonging to a carboxylic acid compound) are encapsulated in one microcapsule. In addition, two or more kinds selected from the group consisting of a carboxylic acid compound, water, and an alkaline compound for a part of the microcapsules contained in the asphalt mixture as long as the effects produced by the asphalt mixture according to the present disclosure are not significantly impaired. May be encapsulated in the same microcapsule.

Preferred embodiments of the microcapsules contained in the asphalt mixture according to the present disclosure include, for example, the following seven embodiments.
(1) Microcapsules containing carboxylic acid compounds (2) Microcapsules containing water (3) Microcapsules containing alkaline compounds (4) Microcapsules containing carboxylic acid compounds and microcapsules containing water ( 5) Microcapsules containing carboxylic acid compounds and microcapsules containing alkaline compounds (6) Microcapsules containing water and microcapsules containing alkaline compounds (7) Microcapsules containing carboxylic acid compounds, water Microcapsules containing, and microcapsules containing alkaline compounds

In the asphalt mixture according to the present disclosure, it is preferable that at least a carboxylic acid compound is encapsulated in microcapsules from the viewpoint of transportability and workability.

When the carboxylic acid compound is encapsulated in microcapsules, the content of the carboxylic acid compound contained in the microcapsules is preferably 85% by mass to 100% by mass with respect to the total mass of the carboxylic acid compound. , 90% by mass to 100% by mass, more preferably 95% by mass to 100% by mass.

When water is contained in microcapsules, the content of water contained in the microcapsules is preferably 85% by mass to 100% by mass, and 90% by mass to 100% by mass, based on the total mass of water. It is more preferably by mass%, and particularly preferably 95% by mass to 100% by mass.

When the alkaline compound is encapsulated in the microcapsules, the content of the alkaline compound contained in the microcapsules is preferably 85% by mass to 100% by mass, preferably 90% by mass, based on the total mass of the alkaline compound. It is more preferably% to 100% by mass, and particularly preferably 95% by mass to 100% by mass.

The components of the wall material (that is, the outer shell) of the microcapsules are not limited. The wall material of the microcapsules preferably contains a polymer.

Examples of the polymer include polyurethane, polyurea, polyester, polyether, polyolefin, polyamide, polyvinyl chloride, acrylic resin, styrene-ethylene / butylene-styrene block copolymer (SEBS), and styrene-butadiene-styrene block copolymer weight. Examples include coalescence (SBS), styrene-isoprene-styrene block copolymer (SIS), and styrene-ethylene / propylene-styrene block copolymer (SEPS).

The wall material of the microcapsules preferably contains at least one polymer selected from the group consisting of polyurethane and polyurea, and more preferably contains polyurethane. When the wall material of the microcapsules contains the above-mentioned polymer, it is possible to suppress the destruction of the microcapsules in the manufacturing process (for example, kneading) of the asphalt mixture, so that the transportability and workability can be improved.

The polyurethane structure is not limited as long as it has a urethane bond. Polyurethane preferably has a structural unit derived from a polyfunctional isocyanate compound. The polyfunctional isocyanate compound is an isocyanate compound having two or more isocyanate groups (that is, -NCO) or an isocyanate compound having three or more isocyanate groups from the viewpoint of kneadability of the asphalt mixture. It is preferable, and it is more preferable that it is an isocyanate compound having three or more isocyanate groups. Examples of the polyfunctional isocyanate compound include methylenediphenyl 4,4'-diisocyanate, methylenediphenyl 4,4'-diisocyanate, 1,4-phenylenediisocyanate, and 4,4'-diisocyanate-3,3'. Includes dimethylbiphenyl, tolylene diisocyanate (eg, tolylen-2,4-diisocyanate, and tolylen-2,6-diisocyanate), and trimethylolpropane adduct of tolylene isocyanate. Examples of commercially available products of the polyfunctional isocyanate compound include Barnock (registered trademark) D-750 (DIC Corporation) and Burnock DN-980 (DIC Corporation).

The structure of polyurea is not limited as long as it has a urea bond. Polyurea preferably has a structural unit derived from a polyfunctional isocyanate compound. Examples of the polyfunctional isocyanate compound include the polyfunctional isocyanate compound described in the description of polyurethane. A preferred embodiment of the polyfunctional isocyanate compound forming the constituent unit of polyurea is the same as that of the polyfunctional isocyanate compound described in the description of polyurethane.

The thickness of the wall material of the microcapsules is not limited. From the viewpoint of kneadability of the asphalt mixture, the average thickness of the wall material of the microcapsules is preferably 0.2 μm or more, more preferably 1 μm or more, further preferably 3 μm or more, and 4 μm or more. Is particularly preferable. From the viewpoint of the strength of the asphalt cured product, the average thickness of the wall material of the microcapsules is preferably 20 μm or less, more preferably 10 μm or less, and particularly preferably 5 μm or less. The average thickness of the wall material of the microcapsules is the arithmetic mean of the thickness of the wall material of 30 arbitrarily selected microcapsules. The thickness of the wall material of the microcapsules is measured using a scanning electron microscope (SEM).

The particle size of microcapsules is not limited. The average particle size of the microcapsules is preferably 1 μm or more, more preferably 5 μm or more, and particularly preferably 10 μm or more, from the viewpoint of the strength of the cured asphalt product. From the viewpoint of kneadability of the asphalt mixture, the average particle size of the microcapsules is preferably 500 μm or less, more preferably 300 μm or less, further preferably 100 μm or less, and particularly preferably 50 μm or less. preferable. The average particle size of the microcapsules is the arithmetic mean of the particle size of 30 arbitrarily selected microcapsules. The particle size of the microcapsules is measured using a scanning electron microscope (SEM).

The manufacturing method of microcapsules is not limited. As a method for producing microcapsules, for example, a known method can be used depending on the composition of the wall material of the microcapsules and the components contained in the microcapsules. Examples of the method for producing microcapsules include an interfacial polymerization method, an in-situ polymerization method, an in-liquid curing coating method, a phase separation method (core selvation method), an in-liquid drying method (interfacial precipitation method), and a spray-drying method. Can be mentioned.

Hereinafter, an example of a method for producing microcapsules containing a carboxylic acid compound will be described. For example, an oil droplet type emulsion (O / W type emulsion) in water can be obtained by dispersing an oil phase containing a carboxylic acid compound and a monomer (for example, a polyfunctional isocyanate compound) in the aqueous phase. it can. Next, by polymerizing the monomer contained in the oil-in-water emulsion, microcapsules containing a carboxylic acid compound can be formed. The conditions for polymerizing the monomer in the above method are not limited and may be determined according to the type of the monomer.

Hereinafter, an example of a method for manufacturing microcapsules containing water will be described. For example, a water-in-oil emulsion (W / O emulsion) can be obtained by dispersing the aqueous phase in an oil phase containing raw materials (for example, a monomer and a polymerization initiator) for forming a wall material. it can. Next, by dispersing the water-in-oil emulsion in the aqueous phase, it is possible to obtain an emulsion (W / O / W-type emulsion) in which oil droplets containing water are dispersed in the aqueous phase. it can. By polymerizing the monomers contained in the W / O / W type emulsion, microcapsules containing water can be formed. The conditions for polymerizing the monomer in the above method are not limited and may be determined according to the type of the monomer.

[Other ingredients]
The asphalt mixture according to the present disclosure may contain components other than the above-mentioned components (hereinafter, referred to as "other components"). Other components include, for example, cutback agents, organic solvents, surfactants, and emulsifiers. In addition, as other components, various additives added to known asphalt mixtures can also be mentioned.

The asphalt mixture according to the present disclosure preferably further contains a cutback agent. Since the cutback agent can suppress an increase in the viscosity of the asphalt mixture, it is possible to improve the transportability and workability of the asphalt mixture. For the same reason, the cutback agent can also improve the kneadability of the asphalt mixture.

Examples of the cutback agent include mineral oil, tar, pitch, gasoline, kerosene, A heavy oil, B heavy oil, and C heavy oil. The cutback agent is preferably mineral oil.

The content of the cutback agent is not limited. When the asphalt mixture according to the present disclosure contains a cutback agent, the content of the cutback agent is 0.1 with respect to the total mass of the asphalt mixture from the viewpoint of kneadability, transportability, and workability of the asphalt mixture. It is preferably from mass% to 5% by mass, more preferably from 0.5% by mass to 5% by mass, and particularly preferably from 0.5% by mass to 3% by mass.

[Production method]
Examples of the method for producing the asphalt mixture according to the present disclosure include a method of mixing asphalt, an aggregate, a carboxylic acid compound, water, and an alkaline compound by a known method.

In the above method, it is preferable that at least one selected from the group consisting of a carboxylic acid compound, water, and an alkaline compound is encapsulated in microcapsules in advance.

In the method for producing an asphalt mixture according to the present disclosure, a composition containing a carboxylic acid compound may be used as a source of the carboxylic acid compound. Examples of the composition containing the carboxylic acid compound include tall oil.

In the method for producing an asphalt mixture according to the present disclosure, a composition containing an alkaline compound may be used as a source of the alkaline compound. Examples of the composition containing an alkaline compound include Portland cement.

Hereinafter, an example of a method for producing an asphalt mixture using microcapsules containing a carboxylic acid compound will be described. For example, microcapsules containing a carboxylic acid compound are prepared based on the method described in the above section "Microcapsules". Next, an asphalt mixture can be obtained by mixing asphalt, an aggregate, microcapsules containing a carboxylic acid compound, water, and Portland cement as a source of an alkaline compound by a known method.

[Use]
Since the asphalt mixture according to the present disclosure is excellent in transportability and workability, it can be used for construction of various asphalt pavements. By using the asphalt mixture according to the present disclosure, for example, the road surface can be paved. The asphalt mixture according to the present disclosure can also be used for repairing asphalt pavement.

<Pavement method>
The pavement method according to the present disclosure includes a step of laying the asphalt mixture according to the present disclosure on the paved body (hereinafter, may be referred to as a “laying step”) and a step of pressurizing the laid asphalt mixture (hereinafter, referred to as “laying step”). , May be referred to as "pressurization process"). According to the pavement method according to the present disclosure, it is possible to provide a pavement method using an asphalt mixture having excellent transportability and workability at a low temperature (for example, 100 ° C. or lower).

[Laying process]
The pavement method according to the present disclosure includes a step of laying the asphalt mixture according to the present disclosure on the paved body.

The asphalt mixture applied to the pavement method according to the present disclosure is as described in the above section "Asphalt mixture". Further, the asphalt mixture applied to the pavement method according to the present disclosure may be prepared before being laid on the paved body. For example, the asphalt mixture may be prepared, if desired, just prior to laying on the pavement.

The type of paved body is not limited. The paved body may be a tangible body on which an asphalt mixture can be laid. For example, as a paved body in road pavement, a layer called a roadbed or a roadbed can be mentioned. Materials contained in the pavement include, for example, sand, gravel, crushed stone, cement, and lime.

The method of laying the asphalt mixture is not limited. As a method of laying the asphalt mixture, a known method can be used. For example, an asphalt mixture can be laid using an asphalt finisher.

The temperature of the asphalt mixture when laying the asphalt mixture is preferably 0 ° C to 100 ° C, more preferably 15 ° C to 100 ° C.

[Pressure process]
The pavement method according to the present disclosure includes a step of pressurizing the laid asphalt mixture. By pressurizing the laid asphalt mixture, the inclusion components of the microcapsules are released by the destruction of the microcapsules, so that the asphalt mixture is thickened or hardened.

The method of pressurizing the asphalt mixture is not limited. As a method of pressurizing the asphalt mixture, a known method can be used. Examples of the method of pressurizing the asphalt mixture include a method using a compaction machine (for example, a road roller).

In the pressurizing step, the asphalt mixture may be pressurized multiple times.

The pressure when pressurizing the asphalt mixture is not limited as long as the pressure is such that the microcapsules contained in the asphalt mixture can be destroyed. The pressure at which the asphalt mixture is pressurized may be determined, for example, in the range of 0.1 MPa to 500 MPa.

The temperature of the asphalt mixture when pressurizing the asphalt mixture is preferably 0 ° C to 100 ° C, more preferably 15 ° C to 100 ° C.

[Other processes]
The pavement method according to the present disclosure may include steps other than the laying step and the pressurizing step as long as the gist of the present disclosure is not deviated.

The pavement method according to the present disclosure may include a step of leveling the surface of the laid asphalt mixture while arranging the asphalt mixture or between the laying step and the pressurizing step. By leveling the surface of the laid asphalt mixture, the asphalt mixture can be uniformly pressurized in the pressurizing step.

The pavement method according to the present disclosure preferably includes a step of curing the pressurized asphalt mixture (hereinafter, may be referred to as a "curing step") after the pressurizing step. In the present disclosure, "curing an asphalt mixture" includes protecting or allowing the asphalt mixture to stand. By including the curing step in the pavement method according to the present disclosure, the curability of the asphalt mixture can be improved.

In the curing process, it is preferable to appropriately adjust the environment (for example, temperature, humidity, and time) of the asphalt mixture.

The temperature at which the asphalt mixture is cured is preferably 10 ° C to 40 ° C, more preferably 15 ° C to 25 ° C.

The humidity (relative humidity) when curing the asphalt mixture is preferably 0% to 90%, more preferably 0% to 70%.

The time for curing the asphalt mixture is preferably 1 hour to 72 hours, more preferably 3 hours to 24 hours.

According to the pavement method according to the present disclosure, the surface of the paved body can be paved with a cured product (asphalt cured product) of the asphalt mixture after thickening or hardening of the asphalt mixture. For example, the asphalt cured product formed on the road surface can function as, for example, the surface layer of the road.

<Manufacturing method of hardened asphalt>
The method for producing a cured asphalt product according to the present disclosure includes a step of pressurizing the asphalt mixture according to the present disclosure (pressurization step). According to the method for producing a cured asphalt product according to the present disclosure, it is possible to provide a method for producing a cured asphalt product using an asphalt mixture having excellent transportability and workability at a low temperature (for example, 100 ° C. or lower).

The asphalt mixture applied to the method for producing a cured asphalt product according to the present disclosure is as described in the above section "Asphalt mixture".

The method and conditions of the pressurizing step in the method for producing a cured asphalt product according to the present disclosure can be applied to the method and conditions of the pressurizing step described in the above section "Pavement method".

The method for producing a cured asphalt product according to the present disclosure may include, if necessary, a step (laying step) of laying the asphalt mixture according to the present disclosure on the paved body before the pressurizing step. As the method and conditions of the laying process in the method for producing a cured asphalt product according to the present disclosure, the method and conditions of the laying process described in the above section "Pavement method" can be applied. When the method for producing a cured asphalt product according to the present disclosure includes a laying step, the pressurizing step is performed on the laid asphalt mixture. That is, the laid asphalt mixture is pressurized.

The method for producing a cured asphalt product according to the present disclosure may include other steps described in the above section "Pavement method", if necessary.

According to the method for producing a cured asphalt product according to the present disclosure, a cured product (hardened asphalt product) of the asphalt mixture according to the present disclosure can be obtained after thickening or curing the asphalt mixture. The method for producing a hardened asphalt product according to the present disclosure can be used, for example, for construction of asphalt pavement and repair of asphalt pavement.

Hereinafter, the present disclosure will be described in detail by way of examples. However, the present disclosure is not limited to the following examples. “Part” and “%” are based on mass unless otherwise specified.

<Ingredients>
Details of the components used in Examples or Comparative Examples are shown below.
"No. 6 crushed stone": Aggregate (Sakae Building Materials Co., Ltd.)
"Straight asphalt": Asphalt (straight asphalt 80-100, Showa Bitumen Kogyo Co., Ltd.)
"Mineral oil": Cutback agent (Pennzoil 20W-50, Red and Yellow Co., Ltd.)
"Portland cement": Composition containing alkaline compound (Na ₂ O _eq : 0.5% by mass, ordinary Portland cement, Taiheiyo Cement Co., Ltd.)
"Tall oil": Composition containing aliphatic carboxylic acid and aliphatic carboxylic acid ester (Hartall FA-1, Harima Chemicals Group, Inc.)
"Ethyl oleate": Aliphatic carboxylic acid ester (Kanto Chemical Co., Inc., carbon number: 20)
"Oleic acid": Aliphatic carboxylic acid (Kanto Chemical Co., Inc., carbon number: 18)

The term "Na ₂ O _eq " means the content (mass%) of total alkali in Portland cement calculated by the following formula described in "JIS R 5210: 2019". The content of alkaline compounds in the asphalt mixture containing Portland cement shall be calculated based on the value of _{"Na 2} O _eq".
Formula: Na ₂ O _eq = Na ₂ O + 0.658 × K ₂ O
Na ₂ O: Sodium oxide content (mass%) in Portland cement
K ₂ O: Potassium oxide content (mass%) in Portland cement

<Microcapsules (A) containing an aliphatic carboxylic acid and an aliphatic carboxylic acid ester>
Solution by mixing tall oil (15 parts by mass), ethyl acetate (3 parts by mass), and trimethylolpropane adduct of tolylene isocyanate (Bernock D-750, DIC Corporation, 1.2 parts by mass). A1) was obtained. The above solution (A1) was added to a solution (A2) obtained by dissolving polyvinyl alcohol (PVA-205, Kuraray Co., Ltd., 9 parts by mass) in water (140 parts by mass), and the solution was emulsified and dispersed. Water (340 parts by mass) was added to the emulsion after emulsification and dispersion, and the mixture was heated to 70 ° C. with stirring and stirred at 1,000 rpm (revolutions per minute) for 1 hour. The mixture was cooled at room temperature (25 ° C.) to obtain an aqueous dispersion of microcapsules (A) containing a fatty acid ester and a fatty acid. The obtained aqueous dispersion was heated and dried at 120 ° C. for 60 minutes to obtain microcapsules (A) containing an aliphatic carboxylic acid and an aliphatic carboxylic acid ester. Hereinafter, the microcapsules (A) containing the fatty acid ester and the fatty acid are simply referred to as "microcapsules (A)". The average thickness of the wall material of the microcapsules (A) is 2.1 μm. The average particle size of the microcapsules (A) is 45 μm. The content of the aliphatic carboxylic acid and the aliphatic carboxylic acid ester in the microcapsules (A) is 90% by mass.

<Microcapsules (B) containing an aliphatic carboxylic acid and an aliphatic carboxylic acid ester>
Solution (B1) by mixing tall oil (15 parts by mass), ethyl acetate (3 parts by mass), and styrene-ethylene / butylene-styrene block copolymer (Tuftec M1911, Asahi Kasei Co., Ltd., 2.0 parts by mass). ) Was obtained. The above solution (B1) was added to a solution (B2) obtained by dissolving polyvinyl alcohol (PVA-205, Kuraray Co., Ltd., 9 parts by mass) in water (140 parts by mass), and the solution was emulsified and dispersed. Water (340 parts by mass) was added to the emulsion after emulsification and dispersion, and the mixture was heated to 90 ° C. with stirring and stirred at 1,000 rpm for 1 hour. The mixture was cooled at room temperature (25 ° C.) to obtain an aqueous dispersion of microcapsules (B) containing a fatty acid ester and a fatty acid. The obtained aqueous dispersion was heated and dried at 120 ° C. for 60 minutes to obtain microcapsules (B) containing an aliphatic carboxylic acid and an aliphatic carboxylic acid ester. Hereinafter, the microcapsules (B) containing the fatty acid ester and the fatty acid are simply referred to as "microcapsules (B)". The average thickness of the wall material of the microcapsules (B) is 3.5 μm. The average particle size of the microcapsules (B) is 50 μm. The content of the aliphatic carboxylic acid and the aliphatic carboxylic acid ester in the microcapsules (B) is 88% by mass.

<Microcapsules (C) containing an aliphatic carboxylic acid and an aliphatic carboxylic acid ester>
Fatty acid ester and fatty acid ester and 3,000 rpm except that the amount of trimethylol propane adduct (Bernock D-750) added to Trilenid Isocyanate was changed to 3.6 parts by mass and the stirring condition of the emulsion was changed to 3,000 rpm. A fatty acid ester and a microcapsule (C) containing a fatty acid were obtained by the same procedure as that of the microcapsule (A) containing a fatty acid.
Hereinafter, the microcapsules (C) containing the aliphatic carboxylic acid and the aliphatic carboxylic acid ester are simply referred to as “microcapsules (C)”. The average thickness of the wall material of the microcapsules (C) is 4.9 μm. The average particle size of the microcapsules (C) is 45 μm. The content of the aliphatic carboxylic acid and the aliphatic carboxylic acid ester in the microcapsules (C) is 88% by mass.

<Microcapsules (D) containing an aliphatic carboxylic acid and an aliphatic carboxylic acid ester>
By the same procedure as the microcapsules (A) containing fatty acid ester and fatty acid, except that the trimethylol propane adduct (Bernock D-750) of Trilenis isocyanate was changed to Bernock DN-980 (DIC Co., Ltd.). , A fatty acid ester and a microcapsule (D) containing a fatty acid were obtained. Hereinafter, the microcapsules (D) containing the fatty acid ester and the fatty acid are simply referred to as "microcapsules (D)". The average thickness of the wall material of the microcapsules (D) is 2.1 μm. The average particle size of the microcapsules (D) is 45 μm. The content of the aliphatic carboxylic acid and the aliphatic carboxylic acid ester in the microcapsules (D) is 90% by mass.

<Microcapsules (E) containing an aliphatic carboxylic acid ester>
Microcapsules (E) containing a fatty acid ester were obtained by the same procedure as for microcapsules (A) except that the tall oil was changed to ethyl oleate. Hereinafter, the microcapsules (E) containing the fatty acid ester are simply referred to as "microcapsules (E)". The average thickness of the wall material of the microcapsules (E) is 2.1 μm. The average particle size of the microcapsules (E) is 45 μm. The content of the aliphatic carboxylic acid ester in the microcapsules (E) is 90% by mass.

<Microcapsules (F) containing aliphatic carboxylic acid>
Microcapsules (F) containing fatty acids were obtained by the same procedure as for microcapsules (A) except that the tall oil was changed to oleic acid. Hereinafter, the microcapsules (F) containing fatty acids are simply referred to as "microcapsules (F)". The average thickness of the wall material of the microcapsules (F) is 2.1 μm. The average particle size of the microcapsules (F) is 45 μm. The content of the aliphatic carboxylic acid in the microcapsules (F) is 90% by mass.

<Microcapsules (G) containing water>
Trimethylol propanetriacrylate (60 parts by mass), polyethylene glycol dimethacrylate as a polymerizable monomer (number of polyoxyethylene units: 1, Blemmer PDE-50R, Nichiyu Co., Ltd., 40 parts by mass), azobisisobuty as a polymerization initiator A monomer solution was obtained by mixing butyronitrile (AIBN, 0.25 parts by mass) and glycerin monostearate (2 parts by mass) as a lipophilic emulsifier. Sodium chloride and sodium nitrite as a water-soluble polymerization inhibitor were added to ion-exchanged water to prepare a sodium chloride-sodium nitrite aqueous solution. The concentration of sodium chloride in the sodium chloride-sodium nitrite aqueous solution was adjusted to 1% by mass. The concentration of sodium nitrite in the sodium chloride-sodium nitrite aqueous solution was adjusted to 0.02% by mass. A primary emulsion of a water droplet (W / O) type emulsion in oil was prepared by adding a sodium chloride-sodium nitrite aqueous solution (100 parts by mass) to the monomer solution and then stirring the mixture using a stirring / dispersing device. The obtained primary emulsion contains 1% by mass of polyvinyl alcohol (PVA, Poval PVA-205, Kuraray Co., Ltd.) as a dispersant and 0.02% by mass of sodium nitrite as a water-soluble polymerization inhibitor. After adding to (600 parts by mass), the mixture was stirred at 1,000 rpm using a stirring and dispersing device to form a (W / O / W) type composite emulsion in which oil droplets containing water were dispersed in an aqueous medium. A secondary emulsion was obtained. After deoxidizing the inside of the polymerizer (internal volume: 20 L) equipped with a stirrer, jacket, reflux condenser, and thermometer to deoxidize the inside of the polymerizer, nitrogen substitution is performed to create a nitrogen atmosphere inside the polymerizer. did. The secondary emulsion was put into the polymerizer all at once, and the temperature of the polymerizer was raised to 60 ° C. to start the polymerization. After polymerizing for 4 hours, the temperature was raised to 80 ° C., and an aging period of 1 hour was provided. The polymerizer was cooled to room temperature (25 ° C.) to obtain a slurry containing microcapsules (G) containing water. By substituting the dispersion medium in the slurry with isopropanol (IPA) by solvent substitution using a centrifuge, a microcapsule (G) isopropanol (IPA) dispersion liquid containing water was obtained. Solvent replacement using a centrifuge was performed by sedimenting the microcapsules (G) in the slurry, removing the supernatant, and then redispersing the microcapsules (G) in isopropanol. The dispersion was heated and dried at 120 ° C. for 60 minutes to obtain microcapsules (G) containing water. Hereinafter, the microcapsules (G) containing water are simply referred to as "microcapsules (G)". The average thickness of the wall material of the microcapsules (G) is 4.0 μm. The average particle size of the microcapsules (G) is 60 μm. The water content in the microcapsules (G) is 87% by mass.

<Example 1>
An asphalt mixture was obtained by kneading each of the following components using a three-one motor (Shinto Kagaku Co., Ltd.). The kneading conditions are as follows.

(component)
(1) No. 6 crushed stone: 100 parts by mass (2) Straight asphalt: 5 parts by mass (3) Mineral oil: 2 parts by mass (4) Portland cement: 2 parts by mass (5) Water: 5 parts by mass (6) Microcapsules (A): 1 part by mass

(Kneading conditions)
(1) Temperature: 110 ° C
(2) Time: 60 minutes (3) Three-one motor rotation speed: 1,000 rpm

<Example 2>
An asphalt mixture was obtained by kneading each of the following components using a three-one motor (Shinto Kagaku Co., Ltd.). The kneading conditions are as follows.

(component)
(1) No. 6 crushed stone: 100 parts by mass (2) Straight asphalt: 5 parts by mass (3) Mineral oil: 2 parts by mass (4) Portland cement: 2 parts by mass (5) Water: 5 parts by mass (6) Microcapsules (B): 1 part by mass

(Kneading conditions)
(1) Temperature: 110 ° C
(2) Time: 60 minutes (3) Three-one motor rotation speed: 1,000 rpm

<Example 3>
An asphalt mixture was obtained by kneading each of the following components using a three-one motor (Shinto Kagaku Co., Ltd.). The kneading conditions are as follows.

(component)
(1) No. 6 crushed stone: 100 parts by mass (2) Straight asphalt: 5 parts by mass (3) Mineral oil: 2 parts by mass (4) Portoland cement: 2 parts by mass (5) Tall oil: 1 part by mass (6) Micro Capsule (G): 5 parts by mass

(Kneading conditions)
(1) Temperature: 110 ° C
(2) Time: 60 minutes (3) Three-one motor rotation speed: 1,000 rpm

<Example 4>
An asphalt mixture was obtained by kneading each of the following components using a three-one motor (Shinto Kagaku Co., Ltd.). The kneading conditions are as follows.

(component)
(1) No. 6 crushed stone: 100 parts by mass (2) Straight asphalt: 5 parts by mass (3) Mineral oil: 2 parts by mass (4) Portland cement: 2 parts by mass (5) Water: 5 parts by mass (6) Microcapsules (C): 1 part by mass

(Kneading conditions)
(1) Temperature: 110 ° C
(2) Time: 60 minutes (3) Three-one motor rotation speed: 1,000 rpm

<Example 5>
An asphalt mixture was obtained by kneading each of the following components using a three-one motor (Shinto Kagaku Co., Ltd.). The kneading conditions are as follows.

(component)
(1) No. 6 crushed stone: 100 parts by mass (2) Straight asphalt: 5 parts by mass (3) Mineral oil: 2 parts by mass (4) Portland cement: 2 parts by mass (5) Water: 5 parts by mass (6) Microcapsules (D): 1 part by mass

(Kneading conditions)
(1) Temperature: 110 ° C
(2) Time: 60 minutes (3) Three-one motor rotation speed: 1,000 rpm

<Example 6>
An asphalt mixture was obtained by kneading each of the following components using a three-one motor (Shinto Kagaku Co., Ltd.). The kneading conditions are as follows.

(component)
(1) No. 6 crushed stone: 100 parts by mass (2) Straight asphalt: 5 parts by mass (3) Mineral oil: 2 parts by mass (4) Portland cement: 2 parts by mass (5) Water: 5 parts by mass (6) Microcapsules (E): 1 part by mass

(Kneading conditions)
(1) Temperature: 110 ° C
(2) Time: 60 minutes (3) Three-one motor rotation speed: 1,000 rpm

<Example 7>
An asphalt mixture was obtained by kneading each of the following components using a three-one motor (Shinto Kagaku Co., Ltd.). The kneading conditions are as follows.

(component)
(1) No. 6 crushed stone: 100 parts by mass (2) Straight asphalt: 5 parts by mass (3) Mineral oil: 2 parts by mass (4) Portland cement: 2 parts by mass (5) Water: 5 parts by mass (6) Microcapsules (F): 1 part by mass

(Kneading conditions)
(1) Temperature: 110 ° C
(2) Time: 60 minutes (3) Three-one motor rotation speed: 1,000 rpm

<Example 8>
An asphalt mixture was obtained by kneading each of the following components using a three-one motor (Shinto Kagaku Co., Ltd.). The kneading conditions are as follows.

(component)
(1) No. 6 crushed stone: 100 parts by mass (2) Straight asphalt: 5 parts by mass (3) Portland cement: 2 parts by mass (4) Water: 5 parts by mass (5) Microcapsules (A): 1 part by mass

(Kneading conditions)
(1) Temperature: 110 ° C
(2) Time: 60 minutes (3) Three-one motor rotation speed: 1,000 rpm

<Comparative example 1>
An asphalt mixture was obtained by kneading each of the following components using a three-one motor (Shinto Kagaku Co., Ltd.). The kneading conditions are as follows.

(component)
(1) No. 6 crushed stone: 100 parts by mass (2) Straight asphalt: 5 parts by mass (3) Mineral oil: 2 parts by mass (4) Portland cement: 2 parts by mass (5) Water: 5 parts by mass (6) Tall oil 1 part by mass

(Kneading conditions)
(1) Temperature: 110 ° C
(2) Time: 60 minutes (3) Three-one motor rotation speed: 1,000 rpm

<Comparative example 2>
An asphalt mixture was obtained by kneading each of the following components using a three-one motor (Shinto Kagaku Co., Ltd.). The kneading conditions are as follows.

(component)
(1) No. 6 crushed stone: 100 parts by mass (2) Straight asphalt: 5 parts by mass (3) Mineral oil: 2 parts by mass (4) Water: 5 parts by mass (5) Microcapsules (A): 1 part by mass

(Kneading conditions)
(1) Temperature: 110 ° C
(2) Time: 60 minutes (3) Three-one motor rotation speed: 1,000 rpm

<Preparation of hardened asphalt>
Each asphalt mixture (1,150 g) is put into a cylindrical mold (form, inner size: diameter 101.6 mm × thickness 63.5 mm) heated to 100 ° C., and then compacted (50 times on both sides). went. Next, a cured asphalt product for testing was obtained by curing for 1 day under the conditions of 20 ° C. (temperature) and 60% (humidity). However, a cured asphalt product could not be obtained with the asphalt mixture of Comparative Example 1 and Comparative Example 2.

<Evaluation>
[Kneading property]
Each asphalt mixture (1,500 g) was kneaded at 80 ° C. for 60 minutes, and the kneadability was evaluated according to the following criteria. The kneading of each asphalt mixture was carried out using a three-one motor (Shinto Kagaku Co., Ltd.). The rotation speed of the three-one motor was set to 800 rpm. Of the following criteria, A, B, or C will be accepted. The evaluation results are shown in Table 1.
A: The asphalt mixture could be kneaded for 60 minutes, and the rate of increase in viscosity after kneading with respect to the viscosity before kneading was within 5%.
B: The asphalt mixture could be kneaded for 60 minutes, and the rate of increase in viscosity after kneading with respect to the viscosity before kneading was more than 5% and 25% or less.
C: The asphalt mixture could be kneaded for 60 minutes, and the rate of increase in viscosity after kneading with respect to the viscosity before kneading was more than 25% and 50% or less.
D: The asphalt mixture could not be kneaded for 60 minutes because the asphalt mixture aggregated during the kneading.

<Transportability and workability>
Each asphalt mixture (1,500 g) was kneaded for 20 minutes and then allowed to stand in an environment of 40 ° C. for 1 hour. The kneading of each asphalt mixture was carried out using a three-one motor (Shinto Kagaku Co., Ltd.). The rotation speed of the three-one motor was set to 1,000 rpm. Then, each asphalt mixture was spread on a cylindrical metal frame (diameter 101.6 mm) and then rolled until the height of each asphalt mixture reached 63.5 mm. Transportability and workability were evaluated according to the following criteria. Of the following criteria, A or B is accepted. The evaluation results are shown in Table 1.
A: When the asphalt mixture was allowed to stand and spread, the asphalt mixture was not cured, and the asphalt mixture was cured by rolling compaction.
B: Since the asphalt mixture started to harden when the asphalt mixture was spread and leveled, the workability was slightly lowered.
C: Construction was not possible because the asphalt mixture hardened when the asphalt mixture was allowed to stand.
D: The asphalt mixture did not cure even when compacted.

<Marshall stability test>
The martial stability of each asphalt cured product was measured based on the "B001 Marshall Stability Test Method" described in the "Pavement Survey / Test Method Handbook" (Japan Road Association, 2018 edition). The value of martial stability was taken as the average value of the values obtained by measuring 5 times under the condition of 30 ° C. The measurement results are shown in Table 1. However, "-" shown in Table 1 means that measurement is not possible. The higher the value of martial stability, the sooner a stable and high-strength specimen can be obtained.

The component described as "microcapsule" in the column of "asphalt mixture" in Table 1 means the component contained in the microcapsule.

The component described as "-" in the "Asphalt mixture" column of Table 1 means a component not contained in the asphalt mixture.

From Table 1, it was found that the transportability and workability of Examples 1 to 8 were superior to those of Comparative Examples 1 and 2.

From Table 1, it was found that the kneadability of Examples 1 to 8 was superior to that of Comparative Example 1.

From Table 1, it was found that the Marshall stability of Examples 1 to 8 was superior to that of Comparative Examples 1 and 2.

Claims (12)

Asphalt and
Aggregate and
At least one carboxylic acid compound selected from the group consisting of an aliphatic carboxylic acid and an aliphatic carboxylic acid ester, and
water and,
Contains alkaline compounds,
An asphalt mixture in which at least one selected from the group consisting of the carboxylic acid compound, the water, and the alkaline compound is encapsulated in microcapsules. The asphalt mixture according to claim 1, wherein the wall material of the microcapsules contains at least one polymer selected from the group consisting of polyurethane and polyurea. The asphalt mixture according to claim 1 or 2, further comprising a cutback agent. The asphalt mixture according to any one of claims 1 to 3, wherein at least the carboxylic acid compound is encapsulated in the microcapsules. The asphalt mixture according to any one of claims 1 to 4, wherein the aliphatic carboxylic acid has 10 to 26 carbon atoms. The asphalt mixture according to any one of claims 1 to 5, wherein the aliphatic carboxylic acid is a fatty acid. The asphalt mixture according to any one of claims 1 to 6, wherein the aliphatic carboxylic acid ester has 10 to 26 carbon atoms. The asphalt mixture according to any one of claims 1 to 7, wherein the aliphatic carboxylic acid ester is a fatty acid alkyl ester. The item according to any one of claims 1 to 8, wherein the content of the carboxylic acid compound is 12% by mass to 20% by mass on a mass basis with respect to the total amount of the asphalt and the carboxylic acid compound. The asphalt mixture described. The asphalt according to any one of claims 1 to 9, wherein the content ratio of the carboxylic acid compound, the water, and the alkaline compound is 50 to 150: 400 to 600: 1 on a mass basis. mixture. The step of laying the asphalt mixture according to any one of claims 1 to 10 on the paved body, and
The step of pressurizing the laid asphalt mixture and
Pavement method including. A method for producing a cured asphalt product, which comprises a step of pressurizing the asphalt mixture according to any one of claims 1 to 10.