Sasobit is a product of Sasol Wax (formerly Schümann Sasol), South Africa. Sasobit is described as a modifier or "asphalt flow improver". It is available in 2, 5, 20 and 600 kg bags. On request it can be supplied in flakes or powdered form. Sasobit is a fine crystalline, long chain aliphatic hydrocarbon produced from coal gasification using the Fischer-Tropsch (FT) process and is otherwise know as an FT paraffin wax.

In the FT process, carbon monoxide is converted into a mixture of hydrocarbons having molecular chain lengths of 1 to 100 carbon atoms and greater. The starting point for the process is synthesis gas, a mixture of carbon monoxide and hydrogen (CO + H₂) produced by gasification of coal, a process involving the treating of white-hot hard coal or coke with a blast of steam. The gas is manufactured in vast quantities for commercial use. It is important in the preparation of hydrogen and as a fuel in the making of steel and in other industrial processes. The synthesis gas is reacted in the presence of an iron or cobalt catalyst; heat is created and products such as methane, synthetic gasoline, waxes, and alcohols are made. The liquid products are separated and the FT waxes are contained.

The makers of Sasobit emphasize the difference between naturally occurring bituminous waxes and FT waxes in terms of their structure and physical properties. The difference reportedly arises from their much longer chain lengths and the fine crystalline structure of the FT waxes. The predominant chain length of the hydrocarbons in Sasobit is in a range of 40 to 115 carbon atoms. The chain lengths of bituminous paraffin waxes naturally found in asphalt range from 22 to 45 carbon atoms, resulting in a lower melting point than FT waxes.

Sasol Wax states that the melting point of Sasobit is approximately 210° F and is completely soluble in asphalt binder at temperatures in excess of 240° F. It produces a reduction in the binder viscosity. This enables production temperatures to be reduced by 18° - 54° F. At temperatures below its melting point, Sasobit forms a lattice structure in the asphalt binder that is the basis for the reported stability of asphalts that contain Sasobit. At service temperatures, Sasobit modified asphalts are reported to display an increased resistance to rutting. In addition Sasol Wax reports improved "compactibility" with an increase in the degree of compaction for the same roller loading as unmodified asphalt.

Sasol Wax recommends adding Sasobit at 3 percent by weight of the mix to gain the desired reduction in viscosity and should not exceed 4 percent due to the possible impact on the binder''s low temperature properties. Sasobit can be blended into hot binder at the blending plant using a simple stirrer. A high shear mixer is not required. It is anticipated that in-line blending of melted Sasobit with the asphalt binder stream at the plant will be finalized in the near future. Direct blending of solid Sasobit at the plant is not recommended because it will not give a homogeneous distribution of Sasobit in the asphalt.