What is Bitumen And Bitumens Types — CivilJungle

• 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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