JPS639552B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a recycled additive composition for pavement of recycled asphalt mixtures intended for high-grade pavement, simple pavement, bridge surface pavement, airport pavement, etc. In recent years, recycling of aged or unnecessary asphalt mixtures has been reconsidered due to the trend toward resource and energy conservation. Recycling for asphalt mixtures can be broadly divided into central plant methods and on-road methods. The central plant method is a method of recycling in a special or conventional type of plant, in which waste materials are collected in a stockyard, then loosened and classified by crushing or thermal crushing in a crushing facility, and then recycled into new aggregate, straight asphalt, etc. Add and mix supplementary materials such as or regeneration additives. In addition, in the on-site method, part or all of the existing asphalt mixture is cut at the site, and supplementary materials such as aggregate, straight asphalt, and recycled additives are added to the cutting waste and mixed. Then, it is leveled and compacted. The reason for adding straight asphalt and recycled additives in this way is that the maltene fraction (n-pentane soluble polar fraction, aromatic Asphaltene (referring to the fraction insoluble in n-pentane) is oxidized or polymerized and becomes asphaltene (referring to the n-pentane-insoluble fraction), which has a relatively chemical composition compared to the original straight asphalt. This is because the maltene fraction is insufficient, and therefore, as for the physical properties of this asphalt, increases in penetration, elongation, and softening point are observed compared to the original straight asphalt. However, in order to regenerate an aged asphalt mixture with such physical properties, if a low viscosity regeneration additive mainly composed of maltene fraction is added in the central plant method or on-the-road method, it will cause a decrease in the quality of the asphalt mixture compared to a new asphalt mixture. As a result, flow deformation phenomena are more likely to occur at high temperatures, and wear phenomena are more likely to occur at low temperatures. Furthermore, when straight asphalt is added to regenerate an aged asphalt mixture, it is necessary to add a large amount to restore the physical properties of the original straight asphalt, and as a result, asphalt in the recycled asphalt mixture becomes excessive. There is a drawback that flashing and flow phenomena are more likely to occur as the temperature increases. Therefore, when a recycled asphalt mixture containing straight asphalt or recycled additives is used as an asphalt mixture for paving,
Compared to general asphalt mixtures, when subjected to repeated traffic such as vehicles, flow deformation phenomena and wear phenomena are more likely to occur on the road surface, making it difficult to maintain a flat road surface condition for a long period of time. The present invention has been made to solve the above-mentioned drawbacks, and its purpose is to provide recycled asphalt mixtures with durability and flow resistance, while being usable in a wide range of applications regardless of the degree of aging of waste materials. An object of the present invention is to provide a pavement recycling additive composition that can be used as a pavement. In order to achieve the above object, the present invention utilizes an ethylene/vinyl acetate copolymer (hereinafter referred to as EVA).
The recycling additive is characterized in that the ratio of the rubber to 100 parts by weight is 20 to 100 parts by weight, and the total amount of both is 1 to 30 parts by weight to 100 parts by weight of the petroleum softener. The present invention will be explained below.
It consists of the following three components: petroleum softener, EVA, and rubber. 1 Petroleum-based softeners are distilled oils obtained by separating low-boiling fractions from crude oil using an atmospheric distillation column, and distilling the heavy crude oil remaining at the bottom of the atmospheric distillation column under reduced pressure. They can be separated into paraffinic softeners, naphthenic softeners, and aromatic softeners depending on the type, treatment process, and formulation, but all of these can be used in the present invention. Such petroleum softeners have a chemical composition close to that of the maltene fraction in asphalt. 2 EVA preferably contains 10 to 35% by weight of vinyl acetate and has a melt index of 1 to 40. In EVA, if the vinyl acetate content is less than 10%, the solubility in aged asphalt will be poor and the properties at low temperatures will be poor. 3. Various synthetic rubbers including natural rubber are used as the rubber, and one type or a mixture of two or more types may be used. Its properties are solid or latex type, and rubber with a Mooney viscosity of about 10 to 100 will give good results. As the synthetic rubber, chloroprene rubber, styrene/isoprene copolymer rubber, polyisoprene rubber, polybutadiene rubber, styrene/butadiene copolymer rubber, etc. are used. The composition of the present invention is usually obtained as follows. First, rubber is 20 to 100 parts by weight for 100 parts by weight of EVA.
EVA, rubber, and petroleum softener are each prepared in a ratio of parts by weight, and the total amount of both is 1 to 30 parts by weight per 100 parts by weight of petroleum softener. Then, a predetermined amount of rubber, such as rubber latex or solid rubber, is gradually added to a predetermined amount of petroleum-based softener heated and melted at a temperature of 90 to 160°C, and heated with continuous stirring to remove moisture and form a rubber-containing petroleum softener. Use as a softener. Furthermore, the above rubber-containing petroleum softener is heated to a temperature of 130~
The mixture is heated to 180°C, and a predetermined amount of EVA is added and dissolved to obtain the recycled pavement additive composition of the present invention. By using the present invention thus obtained in a central plant system, on-road system, etc., a recycled asphalt mixture can be produced. Incidentally, an anti-peeling agent or the like may be added if necessary. Examples of the present invention will be described in detail below. First, in the first example, an ethylene-vinyl acetate copolymer resin (containing 28% vinyl acetate in solid content) was added to 100 parts by weight of a petroleum softener heated and melted at a temperature of 140 to 160°C. ) was added, stirred until homogeneous and dissolved, then 17 parts by weight of chloroprene rubber latex (converted to solid content) was added, stirred to remove moisture, and stirred and dissolved until homogeneous. Thus, a pavement recycling additive composition according to the present invention is obtained. In this invention, when 10 parts by weight of the recycled pavement additive composition of the present invention is added and mixed with 100 parts by weight of aged asphalt extracted from a waste asphalt mixture, the properties shown in Table 1 below are obtained. It will be done. In the comparative example shown in Table 1, 15 parts by weight of mineral oil-based aromatic oil was added and mixed with 100 parts by weight of aged asphalt extracted from a waste asphalt mixture. In the second example, ethylene vinyl acetate copolymer resin (vinyl acetate in solid content
Contains 28%. ), stir until homogeneous and dissolve, then add styrene-isoprene copolymer rubber latex (45% solids, containing 70% isoprene in the solids). The recycled additive composition for pavement according to the present invention is obtained by adding 12 parts by weight of the mixture and stirring to remove moisture, and stirring and dissolving until uniform. In the present invention, when 11 parts by weight of the reclaimed pavement additive composition of the present invention is added to 100 parts by weight of aged asphalt extracted from a waste asphalt mixture and mixed, the properties shown in Table 1 below are obtained. In the third example, ethylene vinyl acetate copolymer resin (vinyl acetate in the solid content
Add 40 parts by weight of styrene-butadiene copolymer rubber latex (containing 28%), stir until homogeneous and dissolve, then add 10 parts by weight of styrene-butadiene copolymer rubber latex (converted to solid content), stir, remove moisture, and dissolve until homogeneous. By stirring and dissolving the mixture until the mixture is dissolved, the reclaimed pavement additive composition according to the present invention is obtained. In the present invention, when 13 parts by weight of the reclaimed pavement additive composition of the present invention is added to 100 parts by weight of aged asphalt extracted from a waste asphalt mixture and mixed, the properties shown in Table 1 below are obtained.

[Table] As mentioned above, according to the reclaimed pavement additive composition of the present invention, 20 to 20 parts of rubber per 100 parts by weight of EVA
By setting the total amount of both to 1 to 30 parts by weight per 100 parts by weight of the petroleum-based softener at a ratio of 100 parts by weight, when the present invention is used as a recycling additive for waste wood, malten residue is added to the waste wood. The addition of EVA and rubber restores the aged asphalt to a state close to its original chemical composition, and the addition of EVA and rubber increases the durable viscosity and makes it highly adhesive, resulting in fluidity and It exhibits extremely high resistance to embrittlement and abrasion, and can form safe and smooth traffic roads. Furthermore, since a large amount of the present invention is not required for waste materials, a significant effect is achieved in that the recycling rate of waste materials is high.

Claims (1)

[Claims] 1 Prepare the rubber at a ratio of 20 to 100 parts by weight per 100 parts by weight of the ethylene/vinyl acetate copolymer, and use one or two of paraffinic softeners, naphthenic softeners, and aromatic softeners. The petroleum softener mixed with the above is heated from 90°C to 160°C to melt it, and the rubber is gradually added at the above ratio to 100 parts by weight of this petroleum softener and mixed by stirring while heating. Then, use this rubber-containing petroleum softener.
Heating from 130°C to 180°C, ethylene/vinyl acetate copolymer was dissolved in it at the above ratio, and as a whole, ethylene/vinyl acetate copolymer was added to 100 parts by weight of petroleum softener.
A method for producing a reclaimed pavement additive composition in which the total amount of vinyl acetate copolymer and rubber is 1 to 30 parts by weight.