This paper reviews silica-fume-concrete (SFC) use in bridges in the united states. Although the focus is on bridge-deck overlays, other bridge-related applications are discussed, including full-depth decks, approach slabs, and piles. The reasons for using SFC include providing a chloride barrier, developing high early strength, achieving high ultimate strength, obtaining abrasion resistance, and improving bond strength. The concretes, representing silica-fume dosages between 5 and 15.5 percent, were placed successfully, although some difficulties were encountered. These difficulties, along with their solutions, are discussed. One silica-fume-concrete feature that required particular attention was the need to take measures to prevent plastic shrinkage cracking. An attempt is made to characterise the performances of the concretes, which are generally acceptable and encouraging. Further experimental work with silica-fume concrete is being done, and the material is now being specified in bridges.
Samenvatting