Carbonation Resistance of Mortar Mixed with Electrolysis Alkaline Aqueous Solution and Blast Furnace Slag

Abstract

Cement production is the primary source of global CO2 emissions in the construction industry. Blast furnace slag (BFS) has been examined as a potential substitute for cement to reduce CO2 emissions. In addition, this substitution increases the long-term strength and improves the chemical resistance of mortar. However, a glassy film is formed on the surface of BFS while it is generated as a byproduct, lowering the initial strength of mortar. Notably, this film is destroyed in an alkaline environment. Thus, several studies have used solutions with various alkali activators. However, alkali activators are unsafe, as they are strong alkaline materials, and have low economic efficiency. This study experimentally improved the initial hydration reactivity of a mortar containing BFS as a substitute for cement, thereby improving its initial strength. We observed an increase in carbonation resistance. In addition, this study focused on evaluating the compressive strength and carbonation resistance of mortar prepared using BFS and alkaline water obtained from the electrolysis of a K2CO3 electrolyte. Results show that alkali-activated mortar using an electrolyzed alkaline aqueous solution has higher strength and contains more hydration products than that using conventional mixing water.