Subcritical Crack Growth in Cementitious Materials Subject to Chemomechanical Deterioration: Numerical Analysis Based on Lattice Model

Abstract

The kinetics of subcritical crack growth (SCG) in hardened cement pastes attacked simultaneously by mechanical damage and calcium leaching was experimentally investigated by a novel test approach in a recent study. Anchored at the experimental benchmarks obtained in the macro- and microcharacterization, material modeling and numerical simulation for SCG under calcium leaching were performed. To utilize the unique physical or chemical laws involved in each individual deterioration process, a two-dimensional (2D) discrete model consisting of two orthotropic lattice systems was constructed to approximate mesostructures of the hardened cement pastes. The two lattice systems were interlinked by the physical variable—the porosity of hardened cement pastes—which evolves with the interaction of matrix cracking and cement dissolution. The proposed material model was implemented in Abaqus through user subroutine VUMAT. The artificial time scale, which allows coarse temporal discretization, was used in the numerical framework and served as the basis for a hybrid of implicit and explicit formulation. This discrete model can realistically describe SCG in hardened cement pastes subject to coupled chemomechanical deterioration.