Regensburg 2019 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 30: Complex Fluids and Colloids, Micelles and Vesicles (joint session CPP/DY)

CPP 30.5: Vortrag

Mittwoch, 3. April 2019, 10:45–11:00, H14

Interaction forces in model cement systems — •Simon Becker and Regine von Klitzing — Soft Matter at Interfaces, Institut für Festkörperphysik, TU Darmstadt

For the workability of concrete and cement as highly abundant construction materials the flow behaviour in the early stages of these materials is of special interest. This can be influenced using additives such as super plasticizers to decrease the viscosity of cement pastes, yielding an enhanced workability. A better understanding of the interactions on the nanoscopic level and the impact on the macroscopic rheology is of great importance in the development of higher performing additives.

The interaction between model particles is mapped via colloidal-probe atomic force microscopy (CP-AFM) in sphere-sphere geometry. Combining CP-AFM with optical microscopy allows to arrange colloidal particles coaxially and determine the interaction forces between these particles upon approach. Spherical silica beads with diameters in the micrometer range serve as model cement grains due to the restriction of the AFM technique to either spherical particles or particles with a defined roughness. The influence on the interaction forces of these model grains in presence of different pH and different salts such as KCl and CaCl₂ and their concentrations is investigated. Furthermore the change of the interaction between the model particles in presence of different concentrations of PCE is examined.