ABSTRACT
Carbonation in concrete has been of wide interest lately due to its potential applications in self-healing, carbon capture/storage and carbon curing. Mineralization of CO2 in concrete is a chemo mechanical process, initiated by the dissolution of Ca2+ into the solution from portlandite (CH). It is further controlled by factors such as saturation index, mechanical stress and crystallization pressure. In a recent study by the authors (Alex et. al., 2023), the nanoscale modeling of concrete carbonation was carried out, focusing on nano-crystalline structure formation, dissolution/precipitation rates, and the development of mechanical properties, thereby establishing a benchmark for future research. In this work we make a further improvement to the simulator: coarse grain the nano-scale particles to microscale (1 particle=1 micron). The extended simulator is also designed to accommodate biologically mediated pathways such as microbially induced carbonate precipitation (MICP). Because MICP relies on the same coupled dissolution–precipitation chemistry as abiotic carbonation, the present coarse-grained formulation offers a natural bridge between these processes. In this paper we present the coarse graining part of the work. The coarse-grained system samples larger time and length scales and is validated against transition state theory (TST) rates of CH dissolution and precipitation.
