Insights into thermo-hydro-mechanical (THM) behavior of cementitious materials by means of simultaneous neutron/X-ray tomography and 3D mesoscopic modeling.

Abstract

In the last few decades, the significant advances in full-field techniques have allowed unprecedented insight into local processes. Notably, for cement-based materials, x-ray and neutron tomography lend themselves as highly complementary tools for the study of their THM behavior. In this communication, the analysis of the in-situ neutron tomography data-set has allowed for the quantification of the 4D moisture profiles thanks to a multiphase partitioning method applied at the voxel level. In addition, the analysis of the acquired simultaneous neutron/x-ray tomography of the cement paste sample (once aligned in time and across modalities) has allowed for the extraction of the extensive fracture network and for the estimate of its interplay with local drying. Finally, a CT-FE mapping scheme was proposed which consisted of extracting the mesoscale morphology of concrete (aggregates and pores) from x-ray/neutron attenuation fields and presenting it explicitly on a FE mesh. This has permitted to perform 3D multiphase THM simulation of concrete at the mesoscale.