Southwest Research Institute® (SwRI®) News

Sulphlex Paving Material

San Antonio, Texas -- Sept. 20, 1979 -- Sulphlex, a new kind of asphalt-like material made of chemically modified sulphur that is intended to help conserve limited supplies of petroleum, has been chosen to receive an award as one of the 100 most significant advances in new technology of the year.

The new material, developed to serve as an alternative to asphalt and portland cement in paving, was selected as a winner in the 1979 I-R 100 Competition sponsored by Industrial Research/Development, officials of the publication announced Thursday in Chicago.

It was developed by Southwest Research Institute® (SwRI®), San Antonio, in a program sponsored by the Federal Highway Administration.

Looking ahead to prospective uses in highway paving, roofing and other applications, the developers of Sulphlex emphasize its significance both as a means of conserving valuable hydrocarbon resources, and as a means of providing engineers with a versatility in highway design not previously available.

Key figures in the development are Allen Ludwig, research engineer and principal investigator, and co-investigators John Dale, research manager, and Henry Frazier, technician. All are staff members of the process research and engineering group, Automotive Research Division, Southwest Research Institute.

Principal impetus for development of Sulphlex came from the increasing scarcity and cost of petroleum, and the threat to asphalt supplies posed by modern refiners' capabilities of cracking heavier crude oil fractions to produce gasoline and other products in high demand.

The asphalt industry currently produces about 30 million tons a year, with about 6 million tons being devoted to roofing, and the rest to construction and maintenance of approximately 1.6 million miles of U.S. highways that have some type of asphalt surface. The need for assuring a supply of an alternative paving material is urgent, the Sulphlex development group said.

In making Sulphlex, ordinarily crystalline sulphur, which is in plentiful supply, is modified by the use of low-cost chemical additives to produce plasticized formulations which resemble various grades of asphalt in both appearance and performance.

Used as a binder with appropriate aggregate materials, Sulphlex produces pavements which may be made either flexible, like asphalt, or rigid, like portland cement, or with properties falling in between.

Sulphlex thus represents a significant improvement in pavement binder materials, the developers said, by providing engineers with a new design versatility enabling them to bridge the gap in physical properties which separates the materials now in use.

It has been demonstrated that standard hot-mix construction procedures and equipment may be used in applying Sulphlex.

Southwest Research Institute, owner of the title rights in this invention, has filed applications for patents. The U.S. government, state and municipal governments have a nonexclusive, nontransferable, royalty-free license to make, use, sell the invention.

For more information about the Sulphlex Paving Material, contact Joe Fohn, Communications Department, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas, 78228-0510, Phone (210) 522-4630, Fax (210) 522-3547.

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