Lattice Boltzmann method based framework for simulating physico-chemical processes in heterogeneous porous media and its application to cement paste

Concrete, during its service life is subjected to variety of physico-chemo-mechanical processes some of which have detrimental effects on its performance. Due to slow progression of these processes especially physico-chemical processes, only limited amount of information is available on the impact of such processes on the microstructure and the properties of concrete under natural conditions. By means of numerical simulations, it is possible to simulate changes in the microstructure as a result of physico-chemical mechanisms, and to determine the properties from the degraded microstructures. This thesis describes the development of a simulation suite, which has the ability to model microstructural changes in cement paste under chemical degradation, and to predict the transport properties (diffusivity) from these microstructures. The simulation environment is based on a lattice Boltzmann (LB) method. New developments have been made in the framework of LB method to simulate mass transport through multi-level porous media and multi-component reactive transport processes in pore scale and multi-level porous systems. Finally, the developed simulation environment is applied to compute diffusivity from virtual microstructures, and to simulate changes in microstructures due to calcium leaching from hardened cement paste.