Unfortunately, asphalt processing may cause the release of byproducts, such as hydrocarbons, hydrogen sulfide, nitrogen oxide and carbon monoxide, for example. These byproducts may be formed in a number of ways. For example, hydrogen sulfide (H2S) may be formed as a result of sulfur additions used during crude fraction processing or as a result of sulfur present in the crude fraction being processed, such as sour crude fractions, for example.
Further, the Strategic Highway Research Program (SHRP) was established in 1987 to improve the performance and durability of United States roads and to make those roads safer for both motorists and highway workers. One of the results of SHRP was the development of the Superior Performing Asphalt Pavements (SUPERPAVE™) specifications for asphalts. The SUPERPAVE™ system specifies materials characterization techniques and results thereof for the performance certification of asphalt.
By specifying acceptable limits for the characterization results, rather than any particular composition, the SUPERPAVE™ specifications are material independent. Thus, an end user can require that asphalt meets a particular SUPERPAVE™ specification and be reasonably confident that installed asphalt will perform satisfactorily, without regard to the specific crude oil source or other compositional parameters. Such specifications enable control of asphalt characteristics, such as rutting, low temperature cracking and fatigue cracking, for example.
As a result, it is desired to develop an asphalt composition and method of forming such that meets both EPA and SUPERPAVE™ specifications in a cost-effective manner.
USPTO Backgrounds
USPTO Backgrounds