Performance of Prestressed Girders Cast with Lightweight Self-Consolidating Concrete

University Transportation Centers Program2012PDFTech ReportFloyd, RoyceHale, W. MicahMack-Blackwell National Rural Transportation Study Center (U.S.)United States. Department of Transportation. University Transportation Centers (UTC) ProgramMack-Blackwell National Rural Transportation Study Center (U.S.)ArkansasPrestressed concreteSelf compacting concreteCoarse aggregatesBond strength (Materials)Bridge designGirdersLightweight concreteMBTC DOT 3021Bond of prestressing steel has been a much debated topic since the 1950s. Limited data are available on the transfer and development length of strands cast in self consolidating concrete (SCC) and even less for strands cast in light weight, self-consolidating concrete (LWSCC). The differences in material properties resulting from the lightweight coarse aggregate and mix proportioning used for LWSCC have potential to lead to longer transfer and development lengths than those for conventional concrete, which can be detrimental to shear and flexural performance. The transfer and development length equations provided in the ACI Building Code Requirements for Structural Concrete and AASHTO Bridge Design specifications are based on studies performed using conventional concrete. This research project examined the transfer and development length of LWSCC specimens using 0.6 in. (15.2 mm) Grade 270 prestressing strand. The bond performance of LWSCC with a release strength of 6000 psi (41 MPa) was very similar to normal weight SCC, the transfer lengths for both strength levels were accurately predicted by the code equations, and the measured development lengths were significantly less than those predicted.133