Wednesday  |  Conference Center A  |  11:30 AM–11:50 AM

#13601, Examining the Micromechanics of Cementitious Composites and Rocks Using In-Situ X-ray Tomography and 3D X-ray Diffraction

Micromechanics theories such as Mori-Tanaka’s approximation have been used extensively to predict elastic and inelastic behavior in cementitious composites. While the macroscopic stiffness predicted by these theories has been validated with macroscale lab experiments, the assumptions regarding stresses and strains within individual phases has not been assessed using in-situ measurements. Here, we use in-situ X-ray tomography (XRT), 3D X-ray diffraction (3DXRD), and digital volume correlation (DVC) to evaluate inclusion- or particle-resolved stresses and strains in cementitious composites and sandstones under unconfined compression. For cementitious composites, we use XRT, 3DXRD, and DVC to examine strengths and weaknesses of Mori-Tanaka’ approximation, highlighting that inaccurate macroscopic stiffness predictions of the approximation may stem from inaccurate mean field strain predictions despite accurate inclusion stress predictions. For sandstone, we use XRT, 3DXRD, and DVC to reveal grain-resolved stress heterogeneity and to assess grain-resolved cohesive strength. The utility of our methods for examining other aspects of the micromechanics of composites and rocks will be discussed.

Ryan Hurley   Johns Hopkins University
Darren Pagan   Pennsylvania State University
Eric Herbold   Lawrence Livermore National Laboratory
Chongpu Zhai   Johns Hopkins University
Ghassan Shahin   Johns Hopkins University
Brett Kuwik   Johns Hopkins University