JPS6344886B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for recycling asphalt pavement waste. Asphalt pavement waste generated during subway construction, underground piping construction, and road pavement repair work has been disposed of as industrial waste, but issues such as land shortages, environmental destruction, and traffic pollution have already been raised. has been done. On the other hand, the asphalt in these waste materials has deteriorated considerably, so
Attempts have been made to regenerate this and reuse it as paving material, but sufficient results have not yet been achieved. An object of the present invention is to eliminate the industrial pollution and save resources by providing a method for recycling and reusing asphalt pavement waste. The purpose of the present invention is to crush asphalt pavement waste material and then heat soften it at 80 to 220°C, or prior to the heat softening process, to
This is achieved by a method for recycling asphalt pavement waste, which is characterized by mixing 1 to 30 parts by weight of an aromatic mineral oil having a flash point of 240°C or higher and a kinematic viscosity of 50 to 10,000 cSt (40°C) and applying the mixture. . The present invention will be explained in more detail below. The asphalt pavement waste referred to in the present invention is generated by excavating pavement during the various construction works mentioned above, and is usually a mixture of 2 to 20% by weight of asphalt and 80 to 98% by weight of aggregate. be. The crushing method is not particularly limited, and conventionally known methods can be used. The waste material is preferably crushed into particles with a particle size of 10 cm or less, particularly 5 cm or less. Crushed asphalt pavement waste is heated to 80 to 220℃,
Preferably, after heat softening treatment at 120 to 180°C, or prior to heat softening treatment in the above temperature range, aromatic mineral oil is mixed and applied. When the heating temperature is less than the above range, workability deteriorates, while when it exceeds the above range, the asphalt in the waste material deteriorates, which is also unfavorable from a safety and health standpoint. The aromatic mineral oil referred to in the present invention has a flash point of 240°C.
or higher, preferably 260℃ or higher, kinematic viscosity 50~
10000cSt (40℃), preferably 100-5000cSt (40℃)
Specifically, the total amount of aromatic content and resin content is 30% by weight or more, preferably 50% by weight or more. If the sum of aromatics and resin content is less than the above range, the low-temperature properties of the recycled asphalt may deteriorate and cracks may occur on the paved surface. The aromatic content and resin content herein are both defined in Asphalt Magazine, Vol. 16, No. 94, pp. 15-17. Particularly preferable aromatic mineral oils are 55 to 95% by weight extract obtained from the solvent extraction process of petroleum refining.
and 5 to 45% by weight of a lubricating oil fraction having a kinematic viscosity of 50 to 300 cSt (40°C). The amount of aromatic mineral oil mixed is 1 to 100 parts by weight of asphalt in asphalt pavement waste.
30 parts by weight, preferably 5 to 20 parts by weight. If the mixing amount is less than the above range, the regeneration effect will not be sufficient, and the workability, abrasion resistance, etc. during reuse will be insufficient. On the other hand, even if the mixing amount exceeds the above range, the addition effect commensurate with the increase in the mixing amount cannot be obtained, and on the contrary, the strength of the asphalt pavement decreases,
This is undesirable as it causes the pavement surface to become sticky. In the present invention, the waste material can be treated with steam or hot water before or after the heat softening treatment. These treatments loosen the waste materials and
Mixing with aromatic mineral oil proceeds smoothly. In addition, the aromatic mineral oil contains 0.5 to 10%
% by weight of anti-peeling agents, e.g. alkyl amines,
It may contain a surfactant such as an imidazoline compound, or a pour point depressant in an amount of 0.1 to 5.0% by weight, such as a chlorinated paraffin condensate, polyalkyl methacrylate, or the like. Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. The properties of each component in the aromatic mineral oil used are as shown in Table 1 below.

[Table] Examples 1 to 4 After steam-treating asphalt pavement waste material (asphalt content: 6% by weight, the rest being aggregate), the particle size was 4.
The mixture was crushed into pieces smaller than cm, mixed with aromatic mineral oil shown in Table 2, and heated and softened at 150° C. for 5 minutes. Based on the properties of the asphalt composite materials recycled in this way and these composite materials, ASTM D 1856
The properties of recycled asphalt extracted and recovered using the method No. 69 were examined, and the results are shown in Table 2. As is clear from Table 2, in all of Examples 1 to 4 using aromatic mineral oil of the present invention, recycled asphalt composite materials with excellent workability and wear resistance were obtained, and the recycled asphalt in the composite materials It also showed excellent properties.

[Table] Examples 5 to 8 Asphalt pavement waste material (asphalt content 7% by weight, remainder aggregate) was crushed to a particle size of 5 cm or less,
After heat softening treatment at 150℃ for 10 minutes, the third
Aromatic mineral oils shown in the table were mixed. The properties of the recycled asphalt mixture and the properties of the recycled asphalt extracted and recovered from these mixtures were examined in the same manner as in Example 1, and the results are also shown in Table 3. Table 3 shows that even in Examples 5 to 8 in which aromatic mineral oil was mixed after heat softening treatment, recycled asphalt composites with excellent workability and wear resistance were obtained as in Examples 1 to 4. The recycled asphalt inside also showed excellent properties.

【table】

[Table] Comparative Examples 1 to 4 The asphalt pavement waste used in Example 1 (asphalt content: 6% by weight, the rest is aggregate) was steam-treated, then crushed to a particle size of 4 cm or less, and no aromatic mineral oil was added. The as-is product (Comparative Example 1) and the product mixed with non-aromatic mineral oil shown in Table 4 (Comparative Examples 3-4) were heat-softened at 150° C. for 5 minutes. In addition, the asphalt pavement waste used in Example 5 (asphalt content: 7% by weight, the remainder being aggregate) was crushed to a particle size of 5 cm or less, and heat-softened at 150°C for 10 minutes without adding aromatic mineral oil. (Comparative Example 2). The properties of the asphalt thus recycled and the properties of the recycled asphalt extracted and recovered from these composite materials were examined in the same manner as in Example 1, and the results are also shown in Table 4. As shown in Table 4, Comparative Examples 1 and 2 in which aromatic mineral oil was not used had insufficient performance, including the wear resistance and workability of the recycled asphalt mixture. Furthermore, in Comparative Examples 3 and 4 in which non-aromatic mineral oil was used, although the workability of the recycled asphalt mixture was improved, the abrasion resistance was insufficient, and this was also evident from the low 15°C elongation. As such, the low-temperature properties were not sufficient, and cracks occurred on the pavement surface after construction.

【table】

Claims (1)

[Claims] 1. Asphalt pavement waste material is crushed, and then 80~
After heat softening treatment at 220 °C or prior to the heat softening treatment, an aromatic system having a flash point of 240 °C or higher and a kinematic viscosity of 50 to 10,000 cSt (40 °C) is applied to 100 parts by weight of asphalt in the waste material. A method for recycling asphalt pavement waste, characterized by mixing 1 to 30 parts by weight of mineral oil and applying the mixture. 2. The aromatic mineral oil contains 55 to 95% by weight of extract obtained from a solvent extraction process of petroleum refining;
Lubricating oil fraction 5 with kinematic viscosity 50-300cSt (40℃)
45% by weight of asphalt pavement waste material according to claim 1.