Bitumen

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There are several main factors used to classify petroleum Bitumen, such as:

• Viscosity: The higher that the bitumen viscosity is, the higher solid properties it will show. At lower temperatures, the viscosity is smaller - this property of bitumen is measured using the Saybolt Furol machine or by the kinematic method.
• Flash point: Flash point is the temperature in which, if the bitumen reaches that temperature, the resulting gases ignite when a flame approaches, and therefore a flame occurs at its surface. The maximum temperature at which the bitumen can be heated in the workshop is limited to the flash point.
• Weight loss on heating: The weight loss of bitumen at high temperature is due to the evaporation of part of its oil and its petroleum components. This characteristic is also one of the significant properties of bitumen. The weight loss of bitumen is measured at the temperature of 163° C and within 5 hours (approximate conditions for cooking asphalt).
• Solubility in CS2: We know that the solvent of bitumen is carbon tetra-chloride and carbon-sulfur. If we dissolve a sample of bitumen in each of these materials, its impurities remain and therefore we can determine the purity of bitumen. The degree of purity is: (sample bitumen weight) ÷ [(impurity weight) – (bitumen weight)]