NUMERICAL MODELING OF COUPLED HYGROMECHANICAL DEGRADATION OF CEMENTITIOUS MATERIALS

A coupled hygromechanical model for finite-element analyses of structures made of cementitious materials such as concrete or plaster is formulated within the framework of thermomechanics of partially saturated porous media. A multisurface elastoplastic-damage model, formulated in the space of plastic effective stresses, is employed to describe the nonlinear pre- and postfailure material behavior of concrete, taking the degradation of stiffness as well as the growth of inelastic strains as a consequence of the opening of microcracks into account. From relating stress and strain quantities defined on the mesolevel to respective homogenized quantities on the macrolevel, the hygromechanical coupling coefficients are identified. The effect of cracking on the isothermal liquid permeability is also accounted for. As a representative example, a two-dimensional simulation of a base restrained concrete wall subjected to both uniform drying and to rewetting at the foundation is described in the paper.

[1]  J. Shao.  Poroelastic behaviour of brittle rock materials with anisotropic damage , 1998 .

[2]  M. Biot.  General Theory of Three‐Dimensional Consolidation , 1941 .

[3]  Z. Bažant,et al.  Drying creep of concrete: constitutive model and new experiments separating its mechanisms , 1994 .

[4]  A. Cheng.  Material coefficients of anisotropic poroelasticity , 1997 .

[5]  B. K. Nyame,et al.  Relationships between permeability and pore structure of hardened cement paste , 1981 .

[6]  A. Alvaredo,et al.  Drying shrinkage and crack formation , 1994 .

[7]  Zdeněk P. Bažant,et al.  Drying of concrete as a nonlinear diffusion problem , 1971 .

[8]  G.P.A.G. van Zijl.  Computational Modelling of Masonry Creep and Shrinkage , 2000 .

[9]  P. Acker,et al.  Drying cracks: Kinematics and scale laws , 2000 .

[10]  Robert Eymard,et al.  Constitutive modeling of unsaturated drying deformable materials , 1998 .

[11]  Koen Van Den Abeele,et al.  Poromechanical modelling of shrinkage and damage processes in unsaturated porous media , 2000 .

[12]  Olivier Coussy,et al.  Mechanics of porous continua , 1995 .

[13]  G. E. Bessey,et al.  The relation between strength and free water content of aerated concretes , 1949 .

[14]  Bonnie Mae Savage,et al.  Soil physics principles validated for use in predicting unsaturated moisture movement in portland cement concrete , 1997 .

[15]  Zdeněk P. Baǎnt,et al.  Effect of cracking in drying and shrinkage specimens , 1982 .

[16]  S. E. Pihlajavaara,et al.  A review of some of the main results of a research on the ageing phenomena of concrete: Effect of moisture conditions on strength, shrinkage and creep of mature concrete , 1974 .

[17]  Van Genuchten,et al.  A closed-form equation for predicting the hydraulic conductivity of unsaturated soils , 1980 .

[18]  R. Helmig.  Multiphase Flow and Transport Processes in the Subsurface: A Contribution to the Modeling of Hydrosystems , 2011 .

[19]  M. Biot,et al.  THE ELASTIC COEFFICIENTS OF THE THEORY OF CONSOLIDATION , 1957 .

[20]  Eric Bourdarot,et al.  Poro-Damage Approach Applied to Hydro-Fracture Analysis of Concrete , 2000 .

[21]  Sanjay Govindjee,et al.  Anisotropic modelling and numerical simulation of brittle damage in concrete , 1995 .

[22]  Olivier Coussy,et al.  Characterization and identification of equilibrium and transfer moisture properties for ordinary and high-performance cementitious materials , 1999 .

[23]  Y. Mualem.  A New Model for Predicting the Hydraulic Conductivity , 1976 .

[24]  J. Bear,et al.  Introduction to Modeling of Transport Phenomena in Porous Media , 1990 .

[25]  N. Barton,et al.  Strength, deformation and conductivity coupling of rock joints , 1985 .

[26]  Roman Lackner,et al.  An anisotropic elastoplastic‐damage model for plain concrete , 1998 .

[27]  Olivier Coussy,et al.  Poroplastic analysis of concrete dams and their foundations , 1991 .

[28]  Luc Dormieux,et al.  Homogenization Approach of Advection and Diffusion in Cracked Porous Material , 2001 .

[29]  J. S. Y. Wang,et al.  Validity of cubic law for fluid flow in a deformable rock fracture. Technical information report No. 23 , 1979 .

[30]  D. T. Snow,et al.  Anisotropie Permeability of Fractured Media , 1969 .

[31]  B. Schrefler,et al.  The Finite Element Method in the Static and Dynamic Deformation and Consolidation of Porous Media , 1998 .

[32]  J. Blaauwendraad,et al.  Crack Models for Concrete, Discrete or Smeared? Fixed, Multi-Directional or Rotating? , 1989 .

[33]  Tada-aki Tanabe,et al.  WATER MIGRATION PHENOMENON MODEL IN CRACKED CONCRETE. II: CALIBRATION , 2000 .

[34]  J. Israelachvili.  Intermolecular and surface forces , 1985 .

[35]  Gerald Pickett,et al.  The Effect of Change in Moisture-Content on the Crepe of Concrete Under a Sustained Load , 1942 .

[36]  Masoud Ghandehari,et al.  Estimation of Water Flow through Cracked Concrete under Load , 2000 .

[37]  R. de Borst,et al.  A numerical model for the time‐dependent cracking of cementitious materials , 2001 .

[38]  J. Shao,et al.  Study of poroelasticity material coefficients as response of microstructure , 2000 .

[39]  Surendra P. Shah,et al.  Effect of Cracking on Water and Chloride Permeability of Concrete , 1999 .