Measurements of yield stress and plastic viscosity of cement-based materials via concrete rheometer

摘要

A rheometer can be used to measure yield stress and viscosity of a cement-based material with excellent results. It mainly includes a drum and at least one adaptive vane assembly. The adaptive vane assembly is replaceably connected to a shaft. The shaft rotates relative to the drum. The ratio of radius (r₁) of the adaptive vane assembly to radius (r₀) of the drum is between 0.1˜0.6. The shaft is rotated with a minimum rotational speed more than 0.001 rad/s, and then can measure its torque at constant speed. Accordingly, the rheometer can greatly reduce the disturbance of vanes of the adaptive vane assembly upon the cement-based materials and reduce the slippage among particles and the vanes. Moreover, the minimum shear stress is defined as a yield stress.