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    Classification of asphalt

    2016-03-08 17:04:15   
    Asphalt can be divided into coal tar, asphalt and natural asphalt three:
    Coal tar pitch
    Coal tar is a byproduct of coking, namely tar distillation residue after distillation kettle in black substance. It is the physical properties of refined tar, respectively, there is no clear boundaries, the general classification method is to soften the point in the 26.7 C (cubic block method) the following for the tar, above 26.7. Tar contains difficult volatile anthracene, phenanthrene and pyrene etc.. These substances are toxic, because the content of these different components, properties of coal tar pitch is different. Great influence of temperature on coal tar, winter easy embrittlement, easy to soften in summer. Heating has a special smell; heating to 260 degrees Celsius in 5 hours later, the content of its ingredients such as the content of the content of the.
    Petroleum asphalt
    Petroleum asphalt is the residue after the distillation of crude oil. According to the degree of refinement, in the room temperature into a liquid, semi solid or solid. Oil dark blue and shiny, with a high sense of temperature. Because it in the production process once distillation to 400 DEG C, which contains volatile components little, but may still be polymer of hydrocarbons without volatile, these substances more or less on human health is harmful.
    Natural bitumen
    In the underground storage of natural asphalt, some form of ore or piled up on the surface of the crust. Most of this asphalt through natural evaporation, oxidation, generally do not contain any toxins.
    Bituminous materials are divided into two major categories: asphalt and tar. Asphalt and natural asphalt and petroleum asphalt, natural asphalt oil seeping from the surface by long-term exposure and evaporation residue; petroleum asphalt is the refining oil residual residue, the appropriate processing products. Tar asphalt is coal tar, wood and other organic matter processed by distillation after processing products. Most of the asphalt used in the project is petroleum asphalt, and the petroleum asphalt is a complex mixture of hydrocarbons and non metal derivatives. Usually asphalt flash point between 240 DEG C ~330 DEG C, ignition point than the flash point was approximately 3 degrees to 6 degrees Celsius, so construction temperature should be controlled below the flash point.

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