ASTM subcommittee eyes RCC specimen testing standard

As concrete producers, promotion groups and contractors advance roller-compacted concrete as an alternative to asphalt pavements, a key specimen-testing standard is taking shape under ASTM Subcommittee C09.45 on Roller-Compacted Concrete, part of Committee C09 on Concrete and Concrete Aggregates.

The proposed standard, ASTM WK33682 Test Method for Preparation, Compaction and Density Determination of Roller-Compacted Concrete Specimens by Means of the Superpave Gyratory Compactor, is aimed at RCC mixture designers. C09 member Stacy Williams, Ph.D., P.E., of the Center for Training Transportation Professionals, notes that the superpave gyratory compactor, developed about 20 years ago, mimics the kneading compaction mechanism that takes place during field compaction.

“The compactor represented a major shift in the way asphalt mixtures were designed,” she says. “We are always looking for ways to get better correlations between field and laboratory material properties in order to close the gap between the design and production phases. Since RCC pavements are compacted just like asphalt pavements, it seems reasonable that a laboratory-scale compactor designed to imitate field roller compaction would also be appropriate for RCC.

“Because the gyratory compactor is primarily used in the asphalt industry, I would suspect it will be most applicable to contractors/designers who take part in both the asphalt and concrete industries.”

Development of ASTM WK33682 continues in advance of the next Committee C09 meeting, June 24-27 in San Diego. Technical contact: Stacy Williams, 479/575-2220; [email protected]