Advantages Of Bitumen

Bitumen is manufactured from crude oil. Bitumen is obtained as the last residue in fractional distillation of crude petroleum. Crude petroleum is a mixture of hydrocarbons of different molecular weights. In the petroleum refineries the individual components like LPG, naphtha, Kerosene, Diesel etc. are separated through the process of fractional distillation. The heaviest material obtained from the fractional distillation process is further treated and blended to make different grades of paving grade bitumen. The actual bitumen output can be controlled not only by selecting the appropriate crude but also by adopting varying processes in the refinery. The choice of process would depend on the availability of suitable crude, demand of the end

This is obtained by blowing air into hot bitumen at high temperatures (normally beyond 180 °C). Blowing hot air into bitumen at high temperatures results in structural changes in bitumen. Esters are formed in this process and these esters link up two different molecules and higher molecular weight material increases drastically. In the process the asphaltene content is increased which in turn results in higher softening points and very low penetration number. Industrial grade bitumen is used in industrial applications and in water proofing, tar felting etc.
2.3 Cutback
Cutback is a free flowing liquid at normal temperatures and is obtained by fluxing bitumen with suitable solvents. The viscosity of bitumen is reduced substantially by adding kerosene or any other solvent. Cutback has been used in tack coat applications.
2.4 Bitumen

• Adoption of viscosity-graded paving bitumen specifications will also reduce the number of total tests to 7 without compromising the quality of bitumen and also no new tests are required in implementing this specification.
Viscosity grades Bitumen are categorized according to Viscosity (degree of fluidity) grading. The higher the grade, the stiffer the Bitumen. In Viscosity Grade, Viscosity tests are conducted at 60 deg. C and 135 deg. C, which represents the temperature of road surface during summer and mixing temperature respectively. The penetration at 25 deg. C, which is annual average pavement temperature, has been also retained in