GROUT ENRICHED RCC: THE PAST AND FUTURE IN THE USA

摘要

Grout Enriched RCC (GERCC) refers to the process of adding grout to the surface of uncompacted RCC and using internal vibration to create a homogeneous facing material similar to traditional conventional concrete. The process is traditionally used at the upstream and downstream faces of RCC dams, but has also been used for consolidation near rock abutments and around imbedded waterstops and dam penetrations. The benefits of GERCC include its simplicity, efficiency, low cost, and relatively low permeability. Since its inception at the Yantan Dam cofferdam in China in 1987, GERCC has become the mostly widely used facing system in China and has been used extensively on a number of RCC dams internationally. In the United States, the use of GERCC has been somewhat limited. This paper will explore the reasons why GERCC has not been more successful in the limited domestic applications to date and why it is not used more frequently in the U.S. In particular, the paper will compare the RCC mix designs used domestically with limited success with those used internationally with marked success. The current state of the practice for RCC and grout proportions, equipment, placement arrangements, and vibration techniques will be compared and evaluated. Furthermore, the paper will present a cost comparison between GERCC and traditionally used RCC facing systems and consider domestic technical concerns with RCC including freeze thaw susceptibility, general constructability, and quality control issues.