CO2 treatment of ground granulated blast furnace slag for enhancing geopolymer properties

Abstract

A novel and cost-effective method was developed for CO2 incorporation into ground granulated blast furnace slag as distorted carbonates, and subsequent value-added use of the captured carbon dioxide towards enhancement of the alkali-activated slag binding qualities. The distorted carbonate structures formed in slag induce carbonation reactions in the course of alkali-activation, yielding a hybrid system of carbonates and alkali aluminosilicates that act synergistically to produce improved binding effects. Integration of carbon dioxide into slag was accomplished by simple ball milling in the presence of CO2. Geopolymer binder was prepared via alkali activation of slag. Fundamental studies were conducted on the microstructure, chemical composition and bond environment, and crystalline structure of the slag particles, and also on the hybrid binders produced via concurrent alkali-activation and carbonation reactions. Concrete materials prepared with the hybrid binder were also characterized to confirm the value offered by the captured carbon dioxide towards enhancing the properties of concrete.

Keywords

• CO2 capture
• Slag
• Mechanochemistry
• Distorted carbonates
• Alkali activation
• Carbonation