SKM 2023 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 57: Complex Fluids and Colloids, Micelles and Vesicles II (joint session CPP/DY)

CPP 57.4: Talk

Friday, March 31, 2023, 10:30–10:45, MER 02

Interparticle forces between real cement surfaces across aqueous and non-aqueous solvents — •Simon Becker and Regine von Klitzing — Soft Matter at Interfaces, TU Darmstadt, 64289 Darmstadt, Germany

Concrete and cement are highly abundant construction materials. Therefore, their flow behavior in early stages of processing is of great interest. By using chemical admixtures such as superplasticizers (e.g. polycarboxylate ethers - PCEs) their rheological performance can be enhanced. The rheology is governed by the forces between the particles and the forces between particles and the liquid phase.

The aim of this work is to map the force between cement surfaces across an electrolyte via colloidal probe atomic force microscopy (CP-AFM). Since cement hydrates in aqueous solutions the surface changes with time. The challenge is to disentangle different effects like hydration and roughness of the cement surfaces on the interaction. To prevent hydration of the cement the force measurements are conducted in ethanol solutions. For comparison the force measurements are carried out between two silica particles, between cement and silica as well as between cement and cement.

Furthermore, the time dependence of the cement surface due to hydration in water is mapped using tapping mode AFM. Moreover, the hydration time dependent interparticle force between cement surfaces is investigated in aqueous electrolyte solution with and without PCE to approach application related conditions.