Title:
Custom HPC Mixtures for Challenging Bridge Design
Author(s):
J. J. Holley, M. D. A. Thomas, D. S. Hopkins, K. M. Cail, and M.-c. Lanctot
Publication:
Concrete International
Volume:
21
Issue:
9
Appears on pages(s):
43-48
Keywords:
chlorides; durability; high-performance concrete; mixture proportioning; permeability
DOI:
Date:
9/1/1999
Abstract:
Spanning the Northumberland Strait between Prince Edward Island and mainland Canada, the Confederation Bridge was completed in July 1997. Since the start of construction in October 1994, more than 450,000 m3 (590,000 yd3) of concrete have been produced to meet demanding specifications, including a 100-year design life in an aggressive marine environment. Different concrete types were required to provide various combinations of the following properties: low permeability to chloride ions, high early strength (for post-tensioning), high resistance to ice abrasion, low heat rise in massive sections, underwater placement (tremie concrete), slipforming, high density for ballast, resistant to freezing and thawing, and seawater attack (all exposed concrete), pumping (most concrete), high flow in congested areas, and controlled set. High quality concrete was produced throughout this project despite very demanding production schedules; as many as six different concrete mixtures were required. This was made possible by applied concrete technology, rigorous material testing, high standards and quality control, and solid partnering between the producer and the general contractor working together to solve unexpected problems encountered during the placement of large volumes of high-performance concrete.