Multiscale Modeling of Cohesive-Frictional Strength Properties in Cementitious Materials

Abstract

Computational modeling has been a valuable tool for studying the role of molecular structure and chemical composition in cementitious materials. A significant challenge is linking these molecular details to macroscale properties that define the durability of the material. This objective requires a holistic multiscale approach that translates the essential physics across atomistic (∼1 nm), mesoscale (∼100 nm), and microstructural (∼100 μm) length scales. Recent studies have identified the importance of cohesive-frictional interactions on the material strength development. Cohesive-frictional materials exhibit a higher strength under compression than tension loading and a shear strength that increases when an external confinement is applied. These concepts are well established for cementitious materials at the macroscale where they are routinely implemented in plasticity and strength models for structural design. However, macroscale phenomenological models are unable to identify the underlying structures and interactions that are the driving force behind this fundamental system response. In this chapter, observations from molecular dynamics (MD), discrete element method (DEM), and finite element method (FEM) modeling at multiple length scales are described to further understand the role of cohesivefrictional interactions in the strength development of cementitious materials.