Shrinkage of Precast, Prestressed Self-Consolidating Concrete

The proper evaluation of shrinkage is critical for the design of prestressed structural members. An experimental program was undertaken to evaluate autogenous and drying shrinkage of precast, prestressed self-consolidating concrete (SCC). Sixteen SCCs with a slump flow of 680 +/- 20 mm (26.7 +/- 0.8 in.) were evaluated. These mixtures were made with 440 to 500 kg/m(3) (742 to 843 lb/yd(3)) of binder, Type MS cement or HE cement; and 20% Class F fly ash; 0.34 to 0.40 water-cementitious material ratio (w/cm); viscosity-modifying admixture content of 0 to 100 mL/100 kg (0 to 1.53 fl oz/cwt) of binder, and 0.46 to 0.54 sand-to-total aggregate volume ratio. Two high-performance concretes (HPCs) with 0.34 and 0.38 w/cm and slump of 150 mm (5.9 in.) were also investigated. The SCC developed 5 to 30% higher drying shrinkage at 300 days than the HPC but with similar autogenous shrinkage. The shrinkage was compared to prediction models proposed by AASHTO 2004 and 2007, CEB-FIP 90, GL 2000, and ACI 209R. The CEB-FIP 90 and a modified AASHTO 2004 model was found to provide an adequate prediction of shrinkage for precast, prestressed SCC.