The project reviewed literature pertaining to the use of supplementary cementitious materials in concrete bridge decks with emphasis on the use of fly ash, silica fume, slag, and natural pozzolans to enhance concrete durability. Consideration was given to concrete properties and construction practices that influence bridge deck performance, especially cracking resistance, permeability, and curing procedures. The project also presented a tentative plan for developing guidelines for the selection and use of supplementary cementitious materials in hydraulic cement concrete to enhance durability of bridge decks.

The use of supplementary cementitious materials, such as fly ash, silica fume, slag, and natural pozzolans, in concrete bridge decks has become a widely accepted practice by many state highway agencies, primarily due to the favorable effects on durability. Also, a great deal of research has been performed on the effects on concrete properties of partial replacement of the cement with a one or more supplementary cementitious materials. However, research has not provided clear conclusions concerning the optimum use of these materials and the curing procedures needed to ensure enhanced durability. Thus, there is a need to address the technical issues associated with the use of supplementary cementitious materials in concrete bridge decks and to develop guidelines on their use to help highway agency personnel to specify the materials, proportions, and procedures that will ensure long-term performance of concrete bridge decks. This project provided the first step in the process for achieving this objective. Further research will be performed under NCHRP Project 18-08A.

The research included a review of relevant domestic and foreign literature, analysis of current practices relative to the use of supplementary cementitious materials in concrete bridge decks, identification of test methods for evaluating the influence of using such supplementary materials on concrete durability, and identification of an approach for developing guidelines on their use in bridge decks.