Title: Use of Silica-Fume Concrete to Repair Abrasion-Erosion Damage in the Kinzua Dam Stilling Basin

Author(s): Terence C. Holland, Anton Krysa, Mark D. Luther, and Tony C. Liu

Publication: Symposium Paper

Volume: 91

Issue:

Appears on pages(s): 841-864

Keywords: abrasion resistance; admixtures; damage; dams; erosion; high-strength concretes; repairs; silica: stilling basins.

DOI: 10.14359/10100

Date: 2/1/1986

Abstract:
The stilling basin of Kinzua Dam on the Allegheny River in western Pennsylvania has experienced severe abrasion-erosion damage since the structure was put into operation in 1967. The basin was repaired in 1973-74 using a steel fiber-reinforced concrete overlay. Deterioration continued to the extent that repairs were again necessary in 1983. A laboratory program was undertaken to evaluate the abrasion-erosion resistance of several concrete mixtures proposed for the 1983 repairs. This program showed that high-strength concrete made with silica fume and limestone aggregates available near the project site would provide suitable abrasion-erosion resistance at a reasonable price. The Corps of Engineers, owner of the structure, required potential suppliers of silica fume to conduct full-sized placements to demonstrate that this concrete could be made and placed outside the laboratory. Based upon these demonstrations and the laboratory program, the repair concrete was specified with a compressive strength of 86 MPa (12,500 psi) at 28 days as a means of obtaining the required abrasion-erosion resistance. Approximately 1500 m* (2000 yd3) of 250-mm (9 3/4-in.) slump concrete were placed using silica fume delivered as a slurry that included water-reducing admixtures. The average 28-day compressive strength was over 90 MPa (13,000 psi). Diver inspection of the concrete after one year in service, including a period with a very large volume of debris in the stilling basin, has indicated that the silica-fume concrete is performing as intended.