why is bitumen used in road surfaces?

what is the reason behind why bitmeun is used in modern road surfaces?

3 Answers

  • It is waterproof – impermeable. This prevents water from reaching soil beneath it, thus preventing weak soil and collapse.

    It is flexible, more elastic then most materials and since roads are exposed to both tension and compression forces by cyclic motion of the tires, ithe surface has to be flexible/ductile so as not to crack easily and break.

    Also note that concrete is weak in tension. Bitumen is also a more resistant toward temperature variation. Concrete requires expansion joints at regular intervals, bitumen does not require it as it can expand freely without cracking as much as concrete would.

    It is a very good adhesive. It sticks well to sublayers.

    it has high durability – long life before wearing out and deteriorating.

    It absorbs sound better then concrete and thus less noisy when vehicles drive on it.

    The design can be altered to either increase or decrease roughness such that on road bends cars do not slip, and on race tracks or freeways lower roughness can decrease friction and improve vehicle performance.

  • I like your first answer but bitumen’s sticky property allows it to stick to the hardcore and gravel to make a solid and water-proof road suface which if well made will prevent frost-heave.

  • Bitumen is a black, oily, viscous material that is a naturally-occurring organic byproduct of decomposed organic materials. Also known as asphalt or tar, bitumen was mixed with other materials throughout prehistory and throughout the world for use as a sealant, adhesive, building mortar, incense, and decorative application on pots, buildings, or human skin. The material was also useful in waterproofing canoes and other water transport, and in the mummification process toward the end of the New Kingdom of ancient Egypt. It is also flammable. And, thanks to recent scholarship, this gooey stuff is also identifiable to source.

    also glass would cause accidents!

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