Coupled chemo-mechanical deterioration of cementitious materials Part II: Numerical methods and simulations

Abstract

The paper is concerned with numerical solution procedures for coupled chemo-mechanical simulations of concrete structures subjected to calcium leaching and mechanical damage. The analyses are based upon the chemo-mechanical damage model for cementitious materials presented in the first part of the paper [Int. J. Solids Struct., in press]. These analyses are characterized by a non-linear transient two-field problem described by the displacement field, the pore fluid calcium concentration field and its rate as state variables. The related non-linear first order initial boundary value problem is solved numerically by a semi-discretization strategy. For the temporal discretization the second order accurate implicit generalized mid-point rule is used. The spatial discretization is based upon hierarchical finite elements. The non-linear algebraic system of equations is solved by consistent linearization and Newton–Raphson iteration. Representative simulations of calcium leaching and the coupled chemo-mechanical degradation of concrete structures are presented. In particular, the process of calcium leaching is studied in detail by means of a one-dimensional model problem. Chemo-mechanical interactions on the structural level are investigated in the numerical simulation of a concrete beam subjected simultaneously to mechanical loads and deionized water. It is demonstrated that chemical damage not only reduces the limit load and the stiffness of concrete structures but also their structural behavior.