Van Reenen’s pass is a steep gradient on the N3 – the busiest road in South Africa, connecting Johannesburg and Durban. Traffic averages several thousands of vehicles a day. In 1996, South Africa’s Highways authority was experiencing quality problems with the local aggregate used for asphalt surfacing, in terms of premature deformation and fines stripping in asphalt.
A Consulting Engineer was appointed by the South African highways authority to investigate materials for resurfacing. Harsco developed a steel slag surfacing solution to meet the stringent safety and durability specification.
Lab tests and site trials were undertaken in partnership with a local asphalt manufacturer to prove material properties and demonstrate advantages of steel slag. The aggregate is processed by Harsco Metals, using slag sourced from the local ArcelorMittal Newcastle works.
As well as solving the technical requirements, it was a solution with considerable environmental benefits for both the steelmaker and the community. As a result of Harsco's investment and development work, we now continuously supply the asphalt aggregate demand for the entire N3 upgrading process.