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Georiga Institute of Technology: Lightweight Concrete for High Strength and Performance Precast Prestressed Bridge Girders
Lawrence F. Kahn, Kimberly E. Kurtis, James S. Lai, Karl F. Meyer,
Mauricio Lopez, and Brandon Buchberg
The purpose of the research was to determine if lightweight aggregate, high strength/high performance concrete is applicable for construction of precast prestressed bridge girders. The research found not only that expanded slate lightweight aggregate is applicable for bridge girder construction but also that the material demonstrated advantages. The latter include (1) reduced weight of less than 120 lb/ft3 leading to the ability to construct girders with over a 150 ft. span which would have a girder plus transit vehicle weight less than 150,000 pounds, (2) design compressive strengths up to 10,000 psi, and (3) creep deformations and prestress losses less than found with normal weight, normal strength concrete. Tests of AASHTO Type II composite girders made with the high performance lightweight concrete (HPLC) showed that the flexural and shear strengths, the transfer and development lengths, and prestress losses can be conservatively predicted using the current AASHTO Standard Specifications for Highway Bridges (1996).
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