Title: Production of HPC for Offshore Concrete Platforms
Author(s): George C. Hoff
Publication: Symposium Paper
Appears on pages(s): 309-322
Keywords: blended cements; compressive strength; concrete construction; high-strength concretes; mixing plants; mix proportioning; precast concrete; offshore structures; quality control; General
The use of high-performance concrete (HPC) for offshore concrete structures is necessitated by the need to have very high strengths to accommodate both operating and environmental loads and also to provide a concrete which can resist the severe marine environment. This is typically obtained through the use of high cement contents implemented by supplementary cementing materials, low water-binder ratios, competent aggregates, and chemical admixtures. The proportions of these HPC mixtures are also influenced by the manner of delivery of the concrete to the form work during construction. In most instances, high workability is necessary because the reinforcing bar densities are typically much greater than for onshore structures. The methods of mixing are also critical in obtaining a uniformly consistent concrete. This paper describes the concrete materials, mixture proportions, unhardened concrete properties, and quality control results for a HPC used in the construction of the Hibernia offshore concrete platform constructed in Newfoundland, Canada. Concrete cylinder strengths for portions of the structure averaged 82 MPa at 28-days age.