Roller-compacted concrete is a stiff, dry concrete mix that has a low paste content and is placed and compacted using a roller, usually a 10-ton vibratory roller. In pavement construction, the process is similar to that for an asphalt pavement.
RCC mixes are used in a variety of heavy duty applications at logging yards, loading docks, intermodal port facilities, large parking areas and dams. Subcommittee C09.45 on Roller-Compacted Concrete, part of ASTM International Committee C09 on Concrete and Concrete Aggregates, is currently working on three proposed standards for roller-compacted concrete. All interested parties are invited to join in the ongoing development of the standards.
According to Stacy G. Williams, Ph.D., director, Center for Training Transportation Professionals at the University of Arkansas, and a C09.45 member, notes that the Superpave gyratory compactor was developed during the 1980s as a means to provide a laboratory simulation of the compactive effort imparted by rollers on an asphalt mat.
Roller-compacted concrete is compacted using the same type of roller, so preparing RCC specimens in a laboratory can be expected to provide similar results to those experienced in the field. WK33682 is being developed to establish a protocol for preparing laboratory specimens of RCC that more adequately represent field mixes.
"The most practical application is that you can use the gyratory-compacted specimens for determining density," says Williams. "Strength and density are key performance parameters for RCC, such that increases in these properties lead to increases in performance."
Once approved, WK41101 will be used to consolidate RCC into beam molds with established flexural strengths. This is important because RCC is gaining use as a pavement for roads, shoulders and streets and all pavements need flexural strength data for design purposes.
WK42461 covers the determination of density and air content of freshly mixed concrete. WK42461 will be used in the design of roller-compacted concrete mixtures and to aid in controlling the quality of those mixtures during RCC construction.
CONTACT Technical Information: Stacy G. Williams, Ph.D., P.E., Center for Training Transportation Professionals, University of Arkansas • Fayetteville, Ark. • Phone: 479-575-2220 | ASTM Staff: Scott Orthey • Phone: 610-832-9730 | Upcoming Meeting: Dec. 8-11 • December Committee Week • Jacksonville, Fla.