Micro- and macro-scale thermomechanical modelling of bulk deformation in early-age cement-based materials

摘要

Final user properties of concrete and other silicate composite structures are conditioned by their early-age history. Bulk deformation in early-age cement-based material system, not subjected to external forces, but generating significant stresses and temperature and humidity redistributions, is associated with the internal volume reduction of cement/water mixture during the hydration process. The proposed experimentally supported computational model starts at the micro-scale balance of mass, momentum and energy to and comes to the macroscopic mixture analysis with (at most) 20 primary variable fields, taking into account full coupling between mechanic strains and stresses, thermal and moisture transfer and chemical phenomena, including phase changes. The evolution of all variables is driven by kinetics of cement hydration, characterized by hydration degree as a function of chemical affinity.