Shrinkage of high-performance concrete overlays on Route 60 in Virginia

Thin concrete overlays are widely used to protect decks against corrosion caused by the infiltration of chloride ions. These overlays are designed to have low permeability and to be free of cracks that may adversely affect the performance of the deck by facilitating the penetration of chloride ions. Sixteen high-performance concrete overlays with 13 concrete mixtures placed on two bridges were evaluated, with an emphasis on shrinkage characteristics. One overlay was constructed with concrete containing a new shrinkage-reducing admixture. Specimens prepared with this admixture had the lowest shrinkage. Based on a visual survey, all overlays were performing satisfactorily at 1 year after placement.