To enhance conventional paving asphalt to make it more suitable for containment applications, Wilder Construction Company of Everett, Washington, developed MatCon,TM a polymer modified asphalt system. The system is comprised of a proprietary binder, coupled with a selected aggregate type and gradation, and a specialized job mix formula. This system, when applied using installation specifications, results in a potentially superior substitution for conventional paving asphalt in cover containment applications. Under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program, the system was installed for evaluation at two locations, with another possible in 2003. MatCon (Trademark) is intended for use as a waste containment material, to comprise a single or multiple layer cover system. MatCon (Trademark) is noted for its superior engineering qualities and is designed for long-term performance, yet can be applied with conventional paving equipment. The hydraulic performance of the material was examined by both removing destructive samples for laboratory testing, as well as field evaluation. While the study focuses on hydraulic properties, accompanying engineering properties were evaluated in the laboratory. An important benefit of MatCon (Trademark) is the potential for multi-use as parking, storage of materials, and even recreational sites such as tennis courts, created by the more durable surface that does not need to be covered by soil or other protective materials. MatCon (Trademark) contributes to improved properties over conventional asphalt by rendering the binder less susceptible to deformation or rutting and less likely to crack in cold climates. The short-term results of this testing show that MatCon (Trademark) specimens were not adversely affected and conventional asphalt mixtures deteriorated over the 100-day test duration. This is a long-term research effort, but preliminary results from both laboratory and
field surface ponding tests show that the MatCon (Trademark) cover system yields hydraulic conductivity results that meet or exceed fundamental baseline targets for RCRA Subtitle C cover systems. Research will continue to assess performance over the long-term.