A 3D Coupled Finite-Element Model for Simulating Mechanical Regain in Self-Healing Cementitious Materials

Abstract

Interest in self-healing techniques that can enhance the performance of cementitious materials has been ever increasing over the past two decades. Alongside the experimental developments, a great deal of progress has been made on the development of numerical models for simulating the self-healing behavior. In spite of this, many models do not consider the coupled physical processes that govern the healing response. In addition, few are developed in a 3D setting that is necessary for many self-healing systems. This study aims to address this through the development of a new 3D coupled model for simulating self-healing cementitious materials. Key features of the model are a new embedded strong discontinuity hexahedral element that employs a damage-healing cohesive zone model to describe the mechanical behavior, a new approach for describing the dependence of the mechanical regain on healing agent transport based on a local crack filling function, and a generalized healing front model that is applicable to different healing agents. The performance of the model is demonstrated with a healing front study and experimental tests on self-healing cementitious specimens. The examples consider a vascular self-healing cementitious specimen that uses a sodium silicate solution as the healing agent and the autogenous healing of a cementitious specimen with and without crystalline admixtures. The results of the validations show that the model is able to reproduce the experimentally observed behavior with good accuracy.