Characterization data of reference industrial polycarboxylate superplasticizers used within Priority Program DFG SPP 2005 "Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials"

The Slump Flow of Cementitious Pastes: Simulation vs. Experiments

Understanding the transient properties of cementitious pastes is crucial for construction materials engineering. Computational modeling, particularly through Computational Fluid Dynamics (CFD), offers a promising avenue to enhance our understanding of these properties. However, there are several numerical uncertainties that affect the accuracy of the simulations using CFD. This study focuses on evaluating the accuracy of CFD simulations in replicating slump flow tests for cementitious pastes by determining the impact of the numerical setup on the simulation accuracy and evaluates the transient, viscosity-dependent flows for different viscous pastes. Rheological input parameters were sourced from rheometric tests and Herschel-Bulkley regression of flow curves. We assessed spatial and temporal convergence and compared two regularization methods for the rheological model. Our findings reveal that temporal and spatial refinements significantly affected the final test results. Adjustments in simulation setups effectively reduced computational errors to less than four percent compared to experimental outcomes. The Papanastasiou regularization was found to be more accurate than the bi-viscosity model. Employing a slice geometry, rather than a full three-dimensional cone mesh, led to accurate results with decreased computational costs. The analysis of transient flow properties revealed the effect of the paste viscosity on the time- and shear-dependent flow progress. The study provides an enhanced understanding of transient flow patterns in cementitious pastes and presents a refined CFD model for simulating slump flow tests. These advancements contribute to improving the accuracy and efficiency of computational analyses in the field of cement and concrete flow, offering a benchmark for prospective analysis of transient flow cases.

Characterization data of reference industrial polycarboxylate superplasticizer VP 2020/15.2 used for Priority Program DFG SPP 2005 "Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials"

An industrial polycarboxylate superplasticizer sample has been chosen in the Priority Program 2005 of the German Research Foundation (DFG SPP 2005). The molecular properties of this superplasticizer sample, such as molecular weight (Mw, Mn ), the polydispersity index (PDI) and the macromononmer conversion rate were determined using Size Exclusion Chromatography (SEC), and the sample's specific anionic charge amount was obtained via charge titration. Furthermore, the dispersing effectiveness of this superplasticizer sample was assessed through 'mini-slump' tests in pure OPC (CEM I 42.5 R) and in a limestone-calcined clay (LCC) cement. Moreover, the adsorption of the superplasticizer on both cements, and the dosage-dependent development of the zeta potential of both cement suspensions were captured. The data shall be used for the ongoing research within the Priority Program.