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
Introduction
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.