Asphalt Oxidation – Bitumen can be further processed by blowing air through it at elevated temperatures (280°C on average) to alter its physical properties for commercial applications.
Oxidized bitumen covers two distinct types depending on the degree of oxidation: air rectified and oxidized. Oxidized bitumen has a distinctive consistency at room temperature and a rubbery nature which affects how it responds to stress, or imprint. The process of oxidation increases the stiffness and softening point of the bitumen and considerably alters key physical properties. Varying the length of the oxidation or air blowing process varies the extent of the reaction and produces distinctive end products. Oxidized bitumen is used in roofing applications, while air rectified bitumen is used in paving applications and some roofing applications.
Asphalt Oxidation | Delayed Coking Process Overview
The final bitumen product can be produced to technical specification either directly in the refining process or by blending bitumens with different physical properties. Blending of higher and lower viscosity residues in the required proportions may take place at the refinery, at terminals or at a third party facility, where blend components and finished products can be easily transported and distributed for use.