NUMERICAL MODELING OF POROUS MEDIA FREEZING PROCESS BY MEANS OF A NON-EQUILIBRIUM APPROACH

Author(s): Dariusz Gawin (1), Francesco Pesavento (2)
Paper category: Proceedings
Book title: SynerCrete’18 International Conference on Interdisciplinary Approaches for Cement-based Materials and Structural Concrete
Editor(s): Miguel Azenha, Dirk Schlicke, Farid Benboudjema, Agnieszka Jędrzejewska
ISBN: 978-2-35158-202-2
e-ISBN: 978-2-35158-203-9
Publisher: RILEM Publications SARL
Publication year: 2018
Pages: 591-596
Total Pages: 6
Language : English

Abstract: Freezing-thawing cycles are one of the most significant causes of durability problems for concrete structures in cold climate countries. Water freezing in a porous material is a very complex physicochemical process, difficult to model numerically due to the interactions between different phases/components, the inner microstructure of the material and phase changes taking place in a confined environment, what leads to an alteration of the standard freezing and fusion points of water.
In this work, we present a coupled model for the numerical modelling of heat and mass transport and their mechanical effects in partially saturated porous media, exposed to freezing– thawing processes. Phase changes are modelled by means of a kinetic, non-equilibrium approach derived from the Thermodynamics of porous media. It is able to reproduce the cryo-
suction, supercooling and undercooling phenomena considering in such a way the hysteresis of ice content vs. temperature during the phase change, what results also in hysteresis of material strains. The latter ones are calculated here by means of appropriately formulated effective stress principle considering crystallization pressure in partially saturated materials. Some relevant numerical cases will be presented to show the effectiveness of the formulated model in the simulation of freezing-thawing process.

Online publication : 2018
Publication type : full_text
Public price (Euros) : 0.00