Comparative Study of Different Measurement Methods for Characterizing Rheological Properties of Lubrication Layer

Abstract

The lubrication layer plays a governing role in predicting the pumpability of fresh concrete. To determine the effect of measurement methods on the characterization of the rheological properties of the lubrication layer, different measurement systems, including Sliper, tribometer, and the utilization of a mortar rheometer, were employed. The rheological properties and workability of bulk concrete were measured in parallel to investigate the correlation between them and the rheological properties of the lubrication layer. The results show that the measured values of the rheological parameters of the lubrication layer differ due to the systematic deviation between different measurement methods. The results obtained by both tribometer and mortar rheometer were well-correlated, having a linear relationship with the rheological parameters of bulk concrete. The correlation coefficient between results gained with Sliper and rheological parameters of concrete or lubrication layer determined with other methods was not high enough. Addition friction led to the large accidental error and overestimated yield stress obtained with Sliper. The workability of concrete is only suitable for characterizing the rheological properties of bulk concrete.

Relevance of Specific Surface of Mixed Oxide Derived from Layered Double Hydroxides on the Rheological Properties and Porosity of Cement Pastes

“…This feature suggested that increase of the MO SSA favored the heterogeneous nucleation, accelerating the cement paste hydration and consolidation reactions. This acceleration of the storage modulus highlights the potential of these MO-modified pastes for different applications, such as 3D printing of cementitious materials, since they can comply with the main processing requirements, including (i) adequate initial fluidity for shaping by pumping or extrusion, and (ii) accelerated paste consolidation, avoiding flow/deformation under the influence of gravity. ,− …”