Sulfur Extended Asphalt - Saudi Arabian Experience
Jonathan J. Grosch and Mohammad H. Al-Mehthel, Saudi Aramco; Hamad I. Abdul Wahhab, King Fahd University of Petroleum and Minerals; and Michael R. Martin and Imants J. Deme, Shell Canada
Saudi Aramco, E-7070 EOB, Dhahran 31311, Saudi Arabia
Sulfur production has exceeded consumption since 1992, resulting in a significant inventory of surplus sulfur (1). Sulfur Extended Asphalt (SEA) offers a new market with the potential to use large quantities of this surplus sulfur while simultaneously reducing the demand for asphalt.
The role of sulfur in sulfur pavement technology is primarily as an extender for the asphalt binder and to impart strength, stability and durability to the asphalt mix. Typically, 20 to 40% by weight of the asphalt binder is replaced by sulfur in Sulfur Extended Asphalt mixes.
The most attractive market for Sulfur Extended Asphalt is in road, parking lot, airport runway and taxiway construction and maintenance.
Sulfur was used as an asphalt extender and modifier in the 1970s and 1980s. However, this technology was discontinued in the late 1980s and 1990s due to higher sulfur market price, limited availability of sulfur, and the side effects of elemental sulfur.
Sulfur prices have since dropped and asphalt prices have risen, making sulfur asphalt technology again economical. A new polymer modified asphalt additive, Sulfur Extended Asphalt Modifier (SEAM), has improved sulfur handling, safety and environmental concerns while providing more stable and durable sulfur-asphalt mixes.
Saudi Aramco has partnered with Shell Canada, King Fahd University of Petroleum and Minerals, the Saudi Arabian Ministry of Transport and local road contractors to successfully construct two SEAM roads in Saudi Arabia in 2006, including one on a heavily trafficked major highway.