Shear Capacity of Prestressed Lightweight Self-Consolidating Concrete

In prestressed members, self-consolidating concrete (SCC) has in some cases exhibited lower shear capacity than conventional concrete, which has been attributed to decreased aggregate interlock. However, little data is currently available to assess whether use of lightweight aggregate in prestressed SCC beams has further impact on aggregate interlock and shear strength. This study measured the shear capacity of six prestressed beams made from three different concrete mixtures: lightweight self-consolidating concrete (LWSCC) with expanded shale aggregate, LWSCC with expanded clay aggregate, and control normal weight SCC with limestone aggregate. Predicted shear capacities were determined based on current ACI Building Code and compared with measured shear strengths. ACI predictions underestimated shear capacity for all tests and were more conservative for the control normal weight SCC beams than for the LWSCC beams