Definition of Oxidized Bitumen 75/25
Oxidized Bitumen 75/25 is a semi-solid pure petroleum bitumen grade which comes under the category of polycyclic aromatic hydrocarbons. It is derived by blowing hot air through Bitumen 60/70, a process of oxidation that hardens, water-repellents the bitumen, and improves its adhesive property.
This grade of bitumen must be heated to approximately double its softening point temperature (200°C to 300°C) to give effective flow and viscosity when in use.
Understanding the 75/25 Specification
The term “75/25” defines two significant properties:
Softening Point (75°C): The temperature at which the bitumen begins to soften and lose its solid character.
Penetration Grade (25): Measures the depth (in tenths of a millimeter) a given needle penetrates the bitumen under specified conditions.
Applications of Blown Asphalt 75/25
Oxidized Bitumen 75/25 is used extensively in all sectors due to its unique characteristics:
Raw material for bitumen coats, roofing materials, and insulating materials, including isolation bitumen membrane sheets.
Chemical industry: used in the manufacture of fuel, paints, lacquers, varnishes, paper production, pulp, and textile treatment.
Road construction: paving, crack sealing, repair operations, and other civil applications.
Building industry: sealing and insulating buildings, adhesives, additives to building materials.
Other uses are dust binding, coating, manufacturing of rubber and plastic products, coating of pipes, corrosion protection for metals, and as a base for synthetic sports surfaces.
Health & Safety Guidelines for Oxidized Bitumen 75/25
To ensure safety while using Oxidized Bitumen 75/25, labour should take the following precautions:
Ventilation: Ensure good ventilation in the workplace to avoid inhaling poisonous fumes released when bitumen is hot.
Protective Equipment: Use heat-resistant gloves, protective shoes, long-sleeved tops, long trousers, and goggles.
Fire Safety: Keep bitumen away from open fire or sparks due to its high working temperature and have fire extinguishing tools handy.
Surface Preparation Before Application
For best performance, surfaces must be:
Dry and clean
Free from loose particles, curing compounds, or slurry-free
Application of oxidized bitumen 75/25 on non-prepared surfaces may result in poor adhesion and stripping.
Packaging and Loading Capacity
Oxidized Bitumen 75/25 is supplied in various packings:
Meltable Polyamide Bags (20 & 25 kg)
Carton Boxes (20, 25 & 40 kg)
Kraft Bags (20, 25 & 40 kg)
Blocks (20, 25 & 40 kg)
Drums (20 & 25 kg)
20ft container loading capacities:
25kg PP Pockets: 920 pouches (23 tons net)
25kg Carton Cases: 880 cases (22 tons net)
Specification of Oxidized Bitumen 75/25
| Bitumen 75/25 | Test method | Unit | Specification |
|---|---|---|---|
| Specific gravity @25/25 °C | ASTM D70 | (Kg/m3) | 1.05 approx. |
| Penetration @ 25 °C | ASTM D5 | mm/10 | 20/30 |
| Softening point °C | ASTM D36 | °C | 70/80 |
| Loss on heating (wt) % | ASTM D6 | Wt. % | 0.2 max |
| Flashpoint °C | ASTM D92 | °C | 250 min |
| Solubility is CS2 (wt) % | ASTM D4 | Wt. % | 99.5 max |
| Spot test | A.A.S.H.T.O 102 | — | Negative |
