Transfer lengths of prestressed beams cast with self-consolidating concrete

Abstract

Self-consolidating concrete (SCC) is a recent advancement in the concrete industry. SCC is not much different from conventional concrete; the constituent materials are the same, but SCC typically contains more fine aggregate and cementitious materials, and less coarse aggregate. These different proportions may affect the transfer length and flexural bond performance for SCC specimens compared with conventional concrete specimens. These differences may contribute to larger transfer lengths than those predicted by the American Concrete Institute's (ACI's) Building Code Requirements for Structural Concrete (ACI 318-05) and Commentary (ACI 318R-05) and the American Association of Highway and Transportation Officials,' AASHTO LRFD Bridge Design Specifications. This research program compares the measured transfer lengths for prestressed SCC beams with those for prestressed, conventional, high-strength concrete beams. Furthermore, the measured transfer lengths for the SCC prestressed beams were compared with those calculated using the ACI 318-05 and AASHTO LRFD specifications equations. Results from the research program show that there was little difference in the transfer lengths of the SCC beams and the conventional concrete beams. Furthermore, the measured transfer lengths of the SCC beams were about 60% of those predicted by ACI 318-05 and AASHTO LRFD specifications equations.