Name: Negin Haghighat

Title of the project: Rheology of cement-based materials with low carbon binders, manufactured sand, upcycled powders for self-compacting concrete, spraying, pumping, and 3D-printing

Description of project

Industrialized concreting should reduce adverse environmental impacts while increasing construction speed in manufacturing complex structures. It should somehow also include a circular economy.

Self-compacting (SCC), spraying, pumping slip forming, and now also 3D printing are all techniques capable of meeting industrialization’s demands. Fresh concrete properties are paramount properties in this and exert significant influence on the construction process. In the quest for sustainable concrete based on a circular economy, the investigation of cement paste rheology influenced by manufactured and upcycled aggregates and low carbon binders is essential to increase the understanding of how to control properties in the above mentioned techniques. 

Studying deformation and flow of materials is called rheology. Measuring the rheological properties of fresh cement-based materials is more precise than testing their workability. The role of rheology in workability, prediction of the flow and placing behavior, stability etc., of cementitious composites is generally acknowledged.

Previous scholars suggested some models that incorporated microstructural parameters for the yield stress encompassing particle size distribution, maximum packing, interparticle forces, etc., were suggested by previous scholars. Despite previous research in the field, further investigation of the interparticle forces and particle properties on rheology is imperative, particularly considering aggregate characteristics and its function with additives.

The goal of the PhD project is to investigate and model the rheological behaviour of sustainable concrete for applications such as SCC, spraying, pumping, slip forming and 3DPrinting through experimental and numerical studies. The results will be used to predict the rheological behaviour of the aforementioned concretes. Relevant experiments are particle characterization of various sustainable binder and filler materials, rheometry on filler modified cement paste (static, viscoelastic, flow), characterization of superplasticizer adsorption and interstitial fluid properties. Relevant modelling tools are both “analog” (suspensions, interparticle forces) and numerical models (flow, AI) for suspension rheology parameters and flow.

Date of start of PhD: November 2021