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Qizhenbi · Geregistreerd op: 20 Dec 2016 Berichten: 70

    Asphalt can be divided into coal tar asphalt, asphalt and natural asphalt three kinds:
    First, coal tar pitch: coal tar pitch is a byproduct of coking, there is no obvious boundaries, the general division method is to specify the softening point at 26.7 ℃ (cubic method) for the following tar, 26.7 ℃ above the asphalt. Coal tar pitch mainly contains volatile anthracene, phenanthrene, pyrene and so on. These substances are toxic, because the content of these components are different, so the nature is different. The change of temperature has great influence on coal tar pitch, which is easy to brittle in winter and easy to soften in summer. Heating with a special smell; heated to 260 ℃ in 5 hours later, it contains anthracene, phenanthrene, pyrene and other ingredients will be volatile.cheap asphalt pavement roller

    Second, the oil asphalt: oil asphalt is the residue after distillation of crude oil. According to the degree of extraction of different, at room temperature into a liquid, semi-solid or solid. Oil asphalt black, asphalt road and thus shiny, with a high temperature. Because it is in the production process has been distilled to 400 ℃ or more, and thus contains very little volatile components, these substances are more or less harmful to human health.concrete alligator cracks garage

    Third, natural asphalt: natural asphalt stored in the ground, and some of the formation of ore or in the crustal surface accumulation. Most of this asphalt through natural evaporation, oxidation, generally does not contain any toxins. Under normal circumstances, asphalt material is divided into asphalt and tar asphalt two categories. Asphalt is divided into natural asphalt and petroleum asphalt, natural asphalt is the oil exudation surface after long-term exposure and evaporation of the residue; after the appropriate process to deal with the product. Tar asphalt is coal, wood and other organic dry distillation processing of the tar after re-processing products. Most of the asphalt used in the project is petroleum asphalt, and petroleum asphalt is a mixture of complex hydrocarbons and their nonmetallic derivatives. Usually the asphalt flash point between 240 ℃ ~ 330 ℃, the ignition point than the flash point of about 3 ℃ ~ 6 ℃, so the construction temperature should be controlled below the flash point.best cheap asphalt maintenance machine