Doctoral Defense by Simon Peters

On Friday, 12. September 2025 at 10 AM, Simon Peters presented his doctoral theses with the title "Computational Multiscale Modeling of Low-Carbon Concretes at Elevated Temperatures".

Dear Simon, congratulations on your successful PhD! We wish you all the best for your future and continued success!




Abstract:
Despite decades of research, the underlining mechanism of explosive concrete spalling at elevated temperatures remains unknown. This thesis proposes a fully coupled numerical chemo-thermo-hygro-mechanical model, advanced through a micromechanical framework, providing a deeper understanding of the multiphysical nature of explosive spalling.

Key contributions include the development and validation of the micromechanical framework to analyze the binder-specific dehydration behavior, chemically induced material evolution and microstructure. This framework enhances applicability and reduces experimental calibration requirements for the well-established multiphysical macroscale model, particularly for concretes based on CO₂-reduced cements.

By means of virtual parametric studies, the main findings of the thesis are: i) The binder-specific dehydration behavior of CO₂-reduced cement pastes is not the primary driving mechanism behind fire-induced concrete spalling. ii) Aggregates characterized by high thermal conductivity can lead to a significant increase (even more than 35%) in pore pressure when compared to aggregates with lower thermal conductivity. iii) The dense microstructure is the primary factor driving the susceptibility of concretes containing CO₂-reduced cements to fire-induced concrete spalling compared to ordinary concretes. iv) The moisture clog theory is not supported.


Promotionsaushang_Simon_Peters.pdf