What is Bitumen And Bitumens Types — CivilJungle

Krunal Rajput
2 min readOct 15, 2019
  • Bitumen is a viscous, solid, or nonvolatile liquid. Bitumen is a complex and complected colloid system, the chemical properties of that are determined by the properties of crude oil by which it’s produced.
  • Pure bitumen is a colloid dispersion of microscopic asphalt particles in oil (dispersion agent).
  • The chemical composition of bitumen is a mixture of various hydrocarbons with molecules of sulfur, oxygen, and nitrogen.
  • Hydrocarbons present in bitumen are mostly condensed aromatic rings and naphthene with a small number of side paraffin chains.
  • Mass fraction of hydrocarbons is 75–85%, oxygen 2–8%, hydrogen 9–10%, nitrogen 0.1–0.5%, and sulphur 5–7%.
  • Bitumen is completely or partially soluble in various organic solvents.
  • Dissolved fractions of bitumen in a solvent are called maltenes or petrolenes, and undissolved fractions are called asphaltenes.
  • The maltenes are a mixture of oil and resins, and they are a dispersing agent.
  • For the most part, the physical properties of bitumen depend on the dispersion degree of asphaltenes In maltenes.
  • It gradually softens as It is heated. Bitumen Is brown or black, waterproof, and it is good adhesive.
  • Bitumen can be obtained in several ways, which depends on the economy of certain processes under the actual conditions.
  • The majority of bitumen is produced by treatment of an appropriate atmospheric residue in the vacuum distillation unit.
  • Bitumen is a residue of vacuum distillation, and its hardness depends on the composition of the heavy oil distillates.
  • In addition to vacuum residue, the raw materials for bitumen production can be asphalt produced by a deasphalting process, slurry oil, and extract produced by the solvent extraction process.
  • If asphalt, slurry oil, and extract are mixed with vacuum residue, which is obtained from a particular raw material, and then they are oxidized by air, various bitumen types are obtained.
  • Oxidized bitumen is less temperature sensitive than bitumen obtained by mixing of particular fractions.
  • Oxidation of bitumen results in partial dehydrogenation of asphaltenes, which creates long chains of asphaltenes molecules by polymerization and condensation reactions.
  • Harder bitumen is produced by oxidation. The desired quality of hard bitumen cannot be produced from too soft raw material by oxidation.
  • Bitumen types depend on the volatility of oil substances in bitumen.
  • A small amount of volatile oil substances makes bitumen harder and more brittle.

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Krunal Rajput

Hey, I am Krunal Rajput. The Man Behind https://civiljungle.com I started this site to spread knowledge about Civil/Mechanical/Electrical Engineering.