Durable marine concrete for the U.S. Navy

The median age of Navy piers is about 50 years and corrosion of the steel reinforcement is the most common mechanism of deterioration. Concrete repairs to a single Navy pier may range upwards to one million dollars and the cycle for major repairs varies from 7 to 10 years. The goal for constructing new Navy piers is to employ methods and materials that will provide for a longer design life with fewer repairs. Strategies to improve reinforced concrete durability have been investigated and demonstrated by the US Navy during the 1990s, including the use of fusion-bonded epoxy-coated reinforcing, stainless steel reinforcing, calcium nitrite admixture, silica fume, and high-range water-reducing admixtures. This paper presents an overview of design and material considerations for new waterfront construction. These considerations are applicable to new reinforced concrete structures in the marine environment and two specific Navy projects: the Mobile Offshore Base and a new class of Navy pier called the Modular Hybrid Pier. Laboratory test results are presented for a concrete mixture containing 30% class F fly ash and lightweight coarse aggregates