Concrete Bridges: Heading off the Impending Durability Burden

For bridges, concrete has long been the material of choice for components primarily loaded in compression and for short span structures where tensile stresses are small and weight of the structural elements is only a minor concern. In recent years, concrete use has exploded into applications that include longer span, curved, and complex structures that previously were reserved for structural steel. In addition, concrete materials engineering has provided everyday mixes that provide strengths up to 10,000 psi and new fiber-reinforced materials that promise strengths exceeding 20,000 psi coupled with improved tensile properties. Certainly, concrete will continue to be the primary structural material for highway infrastructure well into the future. As advances in structural concrete technology stretch the imagination and limits of bridge designers, the demands of increasing age, traffic loading, and road deicing substances are also stretching the demand envelope for in-service concrete. In this paper, the first in a series on durability of concrete bridge structures, the author provides an overview of current conditions and trends in the highway bridge inventory. Corrosion protection research carried out in the past 3 decades is reviewed. Data is primarily drawn from the Bridge Management Information System maintained by the FHWA.