PD-FEM chemo-thermo-mechanical coupled model for simulation of early-age cracks in cement-based materials

Abstract

The hydration process during the hardening of early-age cement-based materials can lead to a considerable volume change, consequently causing considerable deformation, and even fracturing. In the present study, an efficient PD-FEM chemo-thermo-mechanical coupling approach is proposed with the aim of modeling fracturing in early-age concrete structures, taking into account coupled processes, such as thermal transfer, hydration heat, creep, evolution of strength, fracturing as well as hindering effect of cracks on the temperature and hydration fields. The coupled chemo-thermo-mechanical problem is solved in a staggered manner within the classical finite element (FE) and the non-ordinary state-based peridynamics (NOSBPD) framework. By doing so, fracturing in early-age concrete structures can be easily accommodated by NOSBPD featuring an elegant treatment of discontinuities. The accuracy of the proposed approach is evaluated by a benchmark problem with experimental and existing numerical solutions. The capability of the proposed approach for simulating the complex crack initiation and propagation in early-age ring and T-shaped concrete structures is demonstrated. The interaction and competition between different stress inducing mechanisms of hydration heat, autogenous shrinkage, and creep are analyzed.