Types of Bitumen and asphalt derivatives

TYPES OF ASPHALT AND DERIVATIVES

The following types of bitumens and derivatives are available to meet the technical requirements of different applications.

Bitumens
There are three main types of bitumens:

- Penetration Grades
Are usually produced from crude petroleum oil atmospheric distillation residues by using further processing such as
vacuum distillation, thermal conversion, partial oxidation (air rectification/ semi-blowing) or solvent precipitation. A
combination of these processes can be used to make different grades which are normally classified by penetration
value specifications. They are principally used for road surfacing and in roofing.

- Hard Bitumens
Are manufactured using similar processes to penetration grades but have lower penetration values and higher
softening points, i.e. they are harder and more brittle. The main use is in the manufacture of bitumen paints and
enamels. They are normally classified by a softening point specification and designed by a prefix, H (hard) or HVB (high
vacuum bitumen).

- Oxidized Bitumens (Air Blown)
Are produced by passing air through a bitumen feedstock under controlled conditions. This produces a higher
softening point bitumen with reduced susceptibility to change with temperature and greater resistance to imposed
stresses. Applications include use in roofing materials, waterproof papers, electrical components and many other
building and industrial products. Classification is normally by both penetration value and softening point specifications.

Bitumen Derivatives

Many bitumen derivatives are proprietary formulations and can only be reviewed here in general terms. There are four basic types:

- Cutback Bitumens
- Fluxed Bitumens
- Bitumen Emulsions
- Modified Bitumens

MANUFACTURE

The various processes used in petroleum refineries to manufacture bitumens include distillation, air blowing, solvent precipitation (deasphalting) and thermal conversion processes. The products of these processes may be combined by blending operations to meet performance specifications. Ancillary processes are used to manufacture bitumen derivatives.

RELATIVE USAGE

Usage of bitumen and bitumen derivative types varies from country to country, but typically in Europe about 80% of the total is used in roads, about 10% in roofing and the remainder in a variety of other industrial applications.

In road applications, there are considerable variations in local practices but, on average, about 85% are penetration grades, 5% are cut-backs and 10% are emulsions. A few percent of the above types of bitumen and bitumen derivatives are used after modification with polymeric materials.

In roofing applications the average usage is about 50% oxidized bitumens and 50% polymer modified bitumen; the share of bitumen derivatives (liquid roofing) is marginal.

In industrial applications, the average usage is about 50% oxidized bitumen 50% penetration grades with only minor proportions of hard grades.

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