3D Investigation of ITZ Porosity and Pore Connectivity Relevant to Damage and Transport Properties.
Publication Name: Proceedings of the 10th International Conference on Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures, CONCREEP-10, C. Hellmich, B. Pichler, and J. Kollegger, Eds., 21-23, Vienna, Austria.
Publication URL: https://ascelibrary.org/doi/10.1061/9780784479346.049
In this work, we analyzed x-ray microtomographic images to quantify the porosity of small mortar specimens, with a particular focus on the porosity of the interfacial transition zone (ITZ). Specimens were nominally 5 mm diameter, 4 mm long cylinders with 0.5 mm diameter glass bead aggregates. Specimens were scanned via synchrotron-based x-ray microtomography while they were positioned in an in situ loading frame in a split cylinder configuration. Scans of undamaged specimens were evaluated for porosity both in the bulk paste and in the ITZ. Specifically, voids in the paste and porosity in the ITZ were superimposed onto a map of the tensile stress in the specimen in an attempt to identify critical flaws, and to measure their role in split cylinder strength. Preliminary results indicate that the ITZ porosity has a lower effect on split cylinder strength than the large flaws that occur either in the ITZ or the bulk cement past.