Self-consolidating concrete (SCC) is a new, innovative construction material thatcan be placed into forms without the need for mechanical vibration. The mixtureproportions are critical for producing quality SCC and require an optimized combinationof coarse and fine aggregates, cement, water, and chemical and mineral admixtures. Therequired mixture constituents and proportions may affect the mechanical properties,bond characteristics, and long-term behavior, and SCC may not provide the same inserviceperformance as conventional concrete (CC). Different SCC mixture constituentsand proportions were evaluated for mechanical properties, shear characteristics, bondcharacteristics, creep, and durability. Variables evaluated included mixture type (CC orSCC), coarse aggregate type (river gravel or limestone), and coarse aggregate volume.To correlate these results with full-scale samples and investigate structural behaviorrelated to strand bond properties, four girder-deck systems, 40 ft (12 m) long, with CCand SCC pretensioned girders were fabricated and tested.Results from the research indicate that the American Association of StateHighway Transportation Officials Load and Resistance Factor Design (AASHTOLRFD) Specifications can be used to estimate the mechanical properties of SCC for aconcrete compressive strength range of 5 to 10 ksi (34 to 70 MPa). In addition, theresearch team developed prediction equations for concrete compressive strength rangesfrom 5 to 16 ksi (34 to 110 MPa). With respect to shear characteristics, a more appropriate expression is proposed to estimate the concrete shear strength for CC andSCC girders with a compressive strength greater than 10 ksi (70 MPa). The author foundthat girder-deck systems with Type A SCC girders exhibit similar flexural performanceas deck-systems with CC girders. The AASHTO LRFD (2006) equations for computingthe cracking moment, nominal moment, transfer length, development length, andprestress losses may be used for SCC girder-deck systems similar to those tested in thisstudy. For environments exhibiting freeze-thaw cycles, a minimum 16-hour releasestrength of 7 ksi (48 MPa) is recommended for SCC mixtures.
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