This paper presents an on-site control-by-sensors methodology, a nondestructive measuring means to obtain the main tribological parameters for concrete pumpability quality control (QC). Special emphasis is made on the accumulated knowledge of the different closed-loop circuit pumping experiments, which confirm that for actual concrete pumping conditions, some simplifying assumptions can be made to model the laws of the flow-pressure relationship. The simplifying solution refers to a mathematical expression similar to the Bingham plastic model, which considers the corresponding constants of yield stress and plastic viscosity. It also considers the multiplying factor of the tribological effect of the boundary layer. Assuming the simplifying conditions, the constants can be established for a given mixture, pump, and pumping environment. Experiments confirm that this is a promising procedure to obtain the constants and its suitability for QC, as they are very sensitive to the changes while a mixture is being pumped.

Peer reviewed