Title:
Evaluation of Chloride-induced Corrosion in Reinforced Calcined Clays and Volcanic Ashes Based Alkali-activated Concretes
Author(s):
Mishra
Publication:
Web Session
Volume:
ws_F23_Mishra.pdf
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/29/2023
Abstract:
The recent decline in fly ash and blast furnace slag, the most commonly studied precursors, has led to the search for alternative aluminosilicate materials for alkali-activated concrete (AAC). Calcined clays (CCs) and volcanic ashes (VAs) are naturally occurring materials that can potentially replace the popular fly ash and slag to produce AAC. This study examines the chloride-initiated corrosion of reinforcement embedded in alkali-activated CCs and VAs. Three types of CCs and VAs with distinct oxide compositions were activated using sodium silicate and sodium hydroxide hybrid solutions. Lollipop concrete specimens enclosing test rebars were exposed to saline conditions after 28 days of curing. Potentiodynamic testing evaluated corrosion potential, resistance, and current. The results indicate low to moderate corrosion levels in reinforced AACs compared to OPC concrete, with no active local or general corrosion observed in the extracted rebars. New corrosion prediction limits are proposed for unconventional AACs.