Torque plastic viscosity of the mixtures was measured at five different revolution speeds of 0.70, 0.55, 0.40, 0.25 and 0.10 rps. The selected speed values were determined by conducting trial tests and are similar to those applied by the other researchers  and . The measuring sequence started from the highest speed to the slowest speed (down-curve). Each speed was applied for a Q-VD(OMe)-OPh of 8 s. However, the torque values obtained only during the last 6 s of the test were used in calculating the average torque value corresponding to that speed. Since Pleistocene was possible to take 4 torque readings per second from the rheometer, 6 × 4 = 24 torque values were averaged for each speed. In this way, torque-rotation speed chart was generated for each concrete mixture. Bingham model was constructed by fitting the best line to the data. The intersection point of the trendline with the torque axis (apparent yield stress, g) and the slope of the trendline (torque plastic viscosity, h) were determined.