Shear Characteristics and Design for High-Strength Self-Consolidating Concrete

Abstract

To achieve adequate flow and homogeneous concrete for precast, prestressed members, self-consolidating concrete (SCC) typically has higher paste and lower coarse aggregate volumes than conventional concrete (CC). The lower aggregate content of SCC can affect the shear capacity of concrete systems. This research performed 48 push-off tests to investigate the influence of SCC aggregate and paste volumes on the shear capacity and these results were compared with those obtained from similar CC samples. The variables included coarse aggregate type (river gravel and limestone), three coarse aggregate volumes for the SCC mixtures, and two target 16-h release strengths [34 and 48 MPa (5 and 7 ksi)]. The aggregate type, aggregate volume, and concrete strength were found to have significant effects on the aggregate interlock. Test results were used to propose new aggregate interlock models based on the modified compression field theory adopted in the AASHTO Load and Resistance Factor Design Specifications. More appropriate expressions have been developed to determine the limiting value of concrete shear strength for CC and SCC precast, prestressed concrete girders with similar mixture proportions, and a 28-day compressive strength greater than 70 MPa (10 ksi).