Supplementary cementitious materials reactivity: chemistry-structure relationships for dissolution kinetics by upscaling atomistic modeling (SuperUptom)

• Applicant: Mohammadreza Izadifar, Ph.D.
• Subject Area: Construction Material Sciences, Chemistry, Building Physics
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 541788011

The primary objective of this project is to develop an atomistic modelling based on upscaling approach to provide essential insights and contributions to the understanding of pozzolans like silica fume (SF), fly ash (FA), and slag (S), as well as thermally activated clays like meta(dis)kaolinite in terms of their dissolution reactivity in alkaline media. This will establish a fundamental link between the atomistic dissolution mechanisms and the upscaling to meso-level by atomistic kinetic Monte Carlo dissolution reactivity for meta-clays and pozzolans, relevant for sustainable production of concrete and geopolymer based materials. The initial focus is on the dissolution mechanism for atomistic reaction rates computation, resulting the initial mesoscopic forward dissolution rate constants computation as a function of meta-clays and pozzolans structures with alkalinity. Parallel to the dissolution mechanism at the crystal surface, precipitation reaction mechanisms in the pore solution will thus not be considered. To measure and predict pozzolans and meta-clays reactivity from the atomistic (VASP) to meso-scale (KMC) level, the project is devided into three main subobjectives. First, a quantum chemistry simulation approach is employed to compute the energy for various possible atomistic dissolution scenarios of glassy phases and meta-clays, and tabulate their individual optimized energies of the initial structures, final structures, and at the transition state (TS). Second, computation of vibrational frequencies at the reactant and saddle point using the density-functional-perturbation theory (DFTP) method, which results in atomistic reaction rates computation. Finally, the atomistic model is scaled up to determine a fundamental meso-scale reactivity property known as forward dissolution rate constant, using an atomistic kinetic Monte Carlo computational approach. This will enable an investigation into the effects of the different crystal surfaces and meso-structural features of the meta-clays and pozzolans, taking into account the concentration effects of the alkaline solutions, followed by vaidation analysis with literatures values.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2436: Net-Zero Concrete