Determination of Rheological Parameters and Thixotropic Properties of Fresh SCC Mixtures with Varying Compositions

In this study, the rheological parameters and the thixotropic properties of the fresh SCC mixtures having varying compositions were determined. For this purpose nine series of SCC mixtures with three different w/b ratios (0.35, 0.42 and 0.50) and three different slump flow values (550 mm, 650 mm and720 mm) were prepared. The rheological parameters including apparent yield stress and torque-plastic viscosity as well as the magnitude of thixotropy were evaluated for all SCC mixtures by using concrete rheometer. In order to determine the effect of time, the rheological parameters and magnitude of thixotropy were measured at 0, 90 and 150 minutes after mixing. The magnitude of thixotropy was determined using by Breakdown Area, and Yield Value at Rest methods. According to the results, for a given w/b ratio, mixtures with high slump flow value showed low apparent yield stress, low torque-plastic viscosity and low thixotropy. For a given slump flow, as w/b ratio decreased, apparent yield stress decreased too, however, torque-plastic viscosity and thixotropy increased. Calculating the magnitude of thixotropy by using two different methods led to similar results

Keywords:

Self-Consolidating Concrete , Thixotropy , Rheology , Plastic Viscosity