Bitumen properties and uses

Bitumen is a black, sticky, viscous hydrocarbon material obtained from crude petroleum distillation residue or natural deposits. It is a good binder and waterproofing agent.

Properties

• Black to dark brown, solid to semi-solid at normal temperature and softens on heating (thermoplastic).
• Highly adhesive: sticks well to stone aggregate.
• Waterproof, and resists acids, alkalis and salts.
• Soluble in carbon disulphide, carbon tetrachloride and petrol.
• Specific gravity about 1.01–1.06.
• Ductile and flexible, so it can resist small movements without cracking.
• Hardness is measured by the penetration test, consistency by viscosity, heat resistance by softening point (ring and ball), ductility test, flash and fire point.
• Ageing and oxidation slowly harden it.
• Electrical insulator and low cost.

Uses

• Binder for bituminous road surfaces (paving grades 30/40 to 80/100 and VG grades).
• Prime coat, tack coat, surface dressing and patching.
• Waterproofing of roofs, foundations, basements and bridge decks.
• Damp-proof courses and bituminous felt.
• Protective paints for steel, pipes and tanks.
• Joint sealant and filler in concrete pavements.