National Concrete Pavement Technology Center

About the research

Underwater concrete placement in bridge substructures often raises concerns regarding concrete quality, primarily due to the potential for aggregate segregation, especially in deep drilled shafts. Recognizing these challenges, the goal of this research project was to critically evaluate and recommend enhancements to existing Wisconsin Department of Transportation (WisDOT) policies, standards, and specifications regarding underwater concrete placement for bridge substructures and the prevention of aggregate segregation in deep drilled shafts. Relevant research studies and the practices of other departments of transportation (DOTs) and the construction industry, especially agencies and companies operating in marine settings, were explored. Additionally, a nationwide survey was distributed to key personnel in 50 state DOTs to better understand current practices, trends, and common difficulties. This research synthesis report collates and presents a detailed assessment of concrete placement techniques, challenges in the construction of pile-encased piers, strategies to achieve non-segregating concrete in foundations, and the influence of materials- and construction-related variables. Based on the insights obtained, the report sets forth refinements to available guidelines, particularly those regarding the construction of concrete piers and abutments in aquatic environments.