About the research
BACKGROUND:Self-consolidating concrete (SCC) is a specially proportioned hydraulic cement concrete that enables the fresh concrete to flow easily into the forms and around the steel reinforcement without segregation. Use of this type of concrete in precast, prestressed bridge elements has increased in recent years because of the increased rate of production and safety, reduced labor needs, and lower noise levels at manufacturing plants. However, use of cast-in-place SCC has had limited application in bridge construction because of the lack of design and construction guidelines and concerns about certain design and construction issues that are perceived to influence the structural integrity of the bridge system. NCHRP Report 628: Self-Consolidating Concrete for Precast, Prestressed Concrete Bridge Elements, focused on the application of SCC in precast, prestressed bridge elements; some of the findings are applicable to cast-in-place concrete bridge components. Use of SCC in cast-in-place applications requires the consideration of conditions other than the controlled conditions existing in precast concrete plants. Research is needed to address the factors that significantly influence the design, constructability, and performance of cast-in-place concrete bridge components using SCC, and to develop guidelines for its use in these applications, including recommended changes to the AASHTO LRFD Bridge Design and Construction Specifications. These guidelines will provide highway agencies with the information necessary for considering cast-in-place SCC to expedite construction and yield economic and other benefits.
OBJECTIVES:The objectives of this research are to (1) develop guidelines for the use of self-consolidating concrete in cast-in-place concrete in highway bridge components and (2) recommend relevant changes to the AASHTO LRFD Bridge Design and Construction Specifications. The research shall deal with bridge substructure and superstructure components.
STATUS: Research is complete. The final report will be published as NCHRP Report 819.