Rheological approach in proportioning and evaluating prestressed self-consolidating concrete

The successful development of self-consolidating concrete (SCC) requires a careful control of rheological properties of matrix. In this investigation, a parametric study was undertaken to evaluate the influence of binder type, w/cm (water-to-cementitious materials ratio), and coarse aggregate type and nominal size on rheology of prestressed SCC. The rheological measurement of the 33 SCC mixtures investigated in parametric study was performed using a modified Tattersall two-point workability rheometer. The yield stress and plastic viscosity values derived from the SCC mixtures were correlated to the various workability test results to identify combinations of rheological parameters necessary to secure adequate filling ability, filling capacity, and stability of SCC for successful casting of prestressed elements. Based on the results, it is recommended that SCC should have a plastic viscosity of 30-70 Pa s and 30-130 Pa s for concrete made with crushed aggregate and gravel, respectively, to ensure proper workability. Higher viscosity levels could lead to limitation in passing ability should be avoided. Better understanding of the rheological parameters that control the workability of SCC is important in developing mix design approaches and interpreting quality control test methods.