Characterization of High Early-Strength, Self-Consolidating Concrete for Design of Pretensioned Bridge Elements

Abstract

Self-consolidating concrete (SCC) is an innovative construction material that can be placed into forms without mechanical vibration. Precast, prestressed concrete plants require that the concrete used to fabricate their structural members attain high early strength. High early-strength SCC could provide significant value for precast plants. However, the high early-strength SCC mixture constituents, proportions, and construction may affect the hardened properties, and SCC may not provide the same performance as conventional concrete. SCC and conventional concrete mixture proportions designed for precast, prestressed bridge elements were evaluated to characterize the associated mechanical properties, shear characteristics, bond characteristics, and creep. To assess the applicability of SCC in prestressed girder systems, four full-scale girder–deck systems containing conventional concrete and SCC precast girders were fabricated and tested. Results from this research indicate that the AASHTO Load and Resistance Factor Design Specifications can be used to estimate the mechanical properties of high early-strength SCC. With respect to shear characteristics, a more appropriate expression is proposed to estimate the concrete shear strength for SCC girders with a compressive strength greater than 10 ksi (69 MPa). Bridge girder–deck systems containing relatively small (Texas Type A) girders containing high early-strength SCC exhibited similar flexural performance as bridge girder–deck systems with girders containing conventional concrete. Results indicate that the AASHTO equations for computing the nominal moment capacity, strand transfer length, and strand development length may be used for SCC girder–deck systems similar to those tested in this study.