Collaborative Research: Coupling System Chemistry and Time-Dependent Deformation of Cementitious Materials through Evolving Thermodynamic States

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Recent research indicates that stress induced dissolution is a primary time-dependent deformation mechanism of various minerals. Based on recent modeling efforts, there is reason to believe that stress induced dissolution is also a significant deformation mechanism in cementitious materials. Thus, there is an expected coupling between the evolution of chemistry, microstructure development, and stress and strain states within cementitious materials. A primary objective of this project is to develop a fundamental thermodynamic model framework that links evolving system chemistry and mechanics of cementitious materials, and to implement the model through a computational method that predicts the fully coupled evolution of microstructure and viscoelastic/viscoplastic properties of the materials. In synergy with the fundamental modeling, novel experiments using time-stepping micro-computed tomography of stressed specimens will be performed to test the hypothesis that stress induces dissolution in cementitious materials. The results of this project will lead to important advances in understanding the evolution of constitutive properties and the underlying deformation mechanisms; this will ultimately help enable design of concrete with greater strength, toughness, durability, and sustainability. Concrete, the second most used commodity in the world, suffers from many structural and durability issues that result in substantial economic and environmental costs. The drawbacks of cementitious materials such as concrete may be attributed in part to design limitations associated with the lack of available modeling tools for effectively predicting the evolution of the material structure and properties. The results of this project will provide societal benefit by providing advanced modeling, experimental, and computational tools to help improve the economy, durability and sustainability of cementitious materials. Furthermore, other researchers will ultimately be able to freely implement the tools developed in this project to address a host of important issues with respect to concrete, such as degradation due to freeze-thaw cycling and chemical attack. A modeling approach that involves fundamental theory and coupling between chemistry and mechanical processes (such as deformation) has the capability to ultimately transform our understanding of the behavior of cementitious materials such as concrete.