ABSTRACT
ABSTRACT: Structural lightweight concrete has been used in long-span bridges, including the concrete box girder bridge with the current world record main span of 301 m and major suspension spans such as the San Francisco-Oakland Bay Bridge. Even with its use in such bridges, some owners, design engineers and contractors are reluctant to use this material for long-span structures. This paper introduces the process and types of raw materials used to manufacture structural lightweight aggregates in the USA. Material properties of lightweight concrete made with these aggregates that are of interest to long-span bridge designers are discussed. An historical perspective is provided by reviewing several documents about structural lightweight concrete for bridges and buildings that were written by prominent engineers of the last century. Examples of long-span bridges that have used lightweight concrete are discussed for a number of categories of long-span bridges.
