A new ASTM International standard on solubility of asphalt will provide an alternative for a solvent that has been banned as an ozone depleter by the Kyoto Protocol, an international environmental treaty with the goal of stabilizing greenhouse gas concentrations that may help minimize global warming.
The new standard, D7553, Test Method for Solubility of Asphalt Materials in n-Propyl Bromide, was developed by Subcommittee D04.47 on Miscellaneous Asphalt Tests, part of ASTM International Committee D04 on Road and Paving Materials.
According to Stephen Burhans, manager, asphalt quality assurance/quality control, Paramount Petroleum Corp., and a D04 member, the main impetus for developing D7553 was that almost all asphalt specifications have a requirement for a maximum amount of insoluble matter to ensure that undesirable materials are not blended into the products. However, the specified test to verify conformance (D2042, Test Method for Solubility of Asphalt Materials in Trichloroethylene) is now rarely used because trichloroethylene is a chlorofluorocarbon banned by the Kyoto treaty.
The solvent covered by D7553, n-propyl bromide, has been approved by the U.S. Environmental Protection Agency under its Significant New Alternatives Policy as an alternative to chlorofluorocarbons. Committee D04 had previously approved n-propyl bromide as a trichloroethylene replacement in D2172, Test Methods for Quantitative Extraction of Bitumen from Bituminous Paving Mixtures.
“Since D7553 does not have a complete multi-laboratory precision statement, it cannot yet be substituted in the various specifications for buying and selling purposes,” says Burhans. “We will be working with ASTM’s interlaboratory studies staff to seek participants in a round robin study to develop a complete precision statement later this year.”
Once the precision statement has been completed and D7553 has been revised accordingly, Burhans says the process of revising those standards that currently specify D2042 for solubility will begin. Standards from Committees D04 and D08 on Roofing and Waterproofing that reference D2042 will be revised at that time.
Technical Information: Stephen Burhans, Paramount Petroleum Corp., Paramount, Calif.
ASTM Staff: Daniel Smith