Title:
Chloride Ingress and Chloride-Induced Corrosion in Concrete Produced with Calcium Sulfoaluminate Cements
Author(s):
Okechi
Publication:
Web Session
Volume:
ws_S23_Okechi.pdf
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
4/2/2023
Abstract:
Alternative cementitious materials (ACMs) such as calcium sulfoaluminate cement (CSA) have the potential to be successfully used in a variety of new structural applications. However, there is a significant concern about their ability to resist carbonation, which can result in accelerating the ingress of chloride and the corrosion of the steel reinforcement. In the same vein, the presence of cracks could drastically reduce the chloride threshold for the corrosion initiation of steel hence exacerbating the corrosion of steel reinforcement. In this study, the susceptibility to corrosion due to chloride ingress was accessed on several concrete mixtures produced with four different CSA based systems and one ordinary portland cement (OPC). Six samples were fabricated from each mix per ASTM G109 and subjected to three different pre-conditions prior to chloride exposuer: 1) two samples out of the six samples had cracks of a depth of 10 mm and width of 0.04 mm introduced in them during casting using a plastic shim inserted at the top of the mold; 2) another two out of the six were exposed to accelerated carbonation at 4% CO2 concentration and 57% RH for 28 days; and 3) the remaining two samples of the six were left without cracks or exposure to accelerated carbonation. The six samples for each mix were ponded with 3% NaCl (30g/liter of de-ionized water) for 2 weeks after which they were allowed to dry for another 2 weeks before the process is repeated. Microcell corrosion monitoring was conducted with Gamry testing equipment and software using the linear polarization resistance (LPR) technique. Whereas, microcell corrosion monitoring was done using a volunteer.