Title:
Rational Methods for Evaluating Chloride Penetrability and Corrosion Performance of BCSA Cement Composites
Author(s):
Thomas
Publication:
Web Session
Volume:
ws_S23_Thomas.pdf
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
4/2/2023
Abstract:
Understanding chloride penetrability and corrosion performance is one of the key issues hindering the advancement and continued adoption of belitic calcium sulfoaluminate (BCSA) cements and composites. There has been little work to address the suitability of existing standardized test methods or the correct interpretation of test results for these materials. In this work, we use a wide variety of electrical (rapid chloride penetrability, surface resistivity, and bulk resistivity) and diffusion-based (ponding, bulk diffusion, non-steady-state migration) test methods to measure the chloride penetrability of a range of BCSA and portland cement concretes. Results suggest that there is a need to recalibrate chloride penetrability classifications based on electrical test methods to better align with ground truth results from diffusion-based tests. Furthermore, there is a need to recalibrate the chloride concentration threshold for color change with silver nitrate indicator, which is a critical factor in interpreting the results of the non-steady-state migration test. Finally, we applied the ASTM G109 corrosion test to the same concrete mixtures. Results indicate corrosion of rebars in BCSA concretes at early ages, but further analyses show this to be a function of the test conditions rather than a shortcoming of the material. The ASTM G109 testing age is not consistent with the time period required for steel passivation in BCSA systems.