The concrete slump test—A rheometer by definition?
Callum White, Janet M. Lees
Abstract
While the slump test is often used to evaluate fresh state concrete performance, it is not considered a rheometer because it relies on slump height as a characterisation parameter. This study presents phenomenological slump observations obtained through 24 experimental tests. The relationships between the dimensionless groups are investigated, and three flow regimes are identified: slumping (dimensionless slump below 0.55), intermediate (dimensionless slump between 0.55 and 0.65) and spreading (dimensionless slump exceeding 0.65). A relationship between viscosity , yield stress and slump cessation time is presented, and a novel digital approach to obtain cessation time using an accelerometer is proposed. The slump measured viscosity is compared to the viscosity obtained via a torque vane rheometer , and an average error of 10% is observed. This work demonstrates that by incorporating digital tools such as 3D reconstruction and accelerometers, the slump test can provide accurate measurements of yield stress and viscosity in practical settings.