Evaluation of Alternative Materials to Control Drying-Shrinkage Cracking in Concrete Bridge Decks: Fid-Bau Portal

Evaluation of Alternative Materials to Control Drying-Shrinkage Cracking in Concrete Bridge Decks

K. Follisar / C. Smith / G. Sellers / M. Brown / J. E. Breen

In the United States, restrained shrinkage cracking of concrete bridge decks is a significant durability problem. The issues affecting restrained shrinkage cracking arise from design and construction practices, as well as material properties. The mechanisms of drying, autogenous, and carbonation shrinkage are presented and discussed along with related creep issues. Thermal stresses also play a role in bridge deck cracking. These stresses result from the heat of hydration, diurnal temperature changes, and solar radiation. Current and proposed test methods are introduced and evaluated as they relate to evaluating a materials resistance to restrained drying shrinkage cracking. Both conventional and innovative methods of controlling drying shrinkage are presented. Some innovative materials are discussed, including: fibers, shrinkage-compensating concrete, shrinkage-reducing admixtures, and extensible concrete. The use of innovative materials combined with improved design and construction practices can eliminate restrained shrinkage cracking. Large-scale bridge decks are constructed that permit evaluation of drying shrinkage cracking in a more realistic exposure setup. It is determined that several innovative mixtures including extensible concrete perform well at resisting drying shrinkage cracking. The need for an implementation study is discussed as well.