Carbonated ground granulated blast furnace slag stabilising brown kaolin

Abstract

Proposals have been made by several researchers to conduct the sequestration of carbon dioxide (CO₂) through calcium and magnesium-rich materials. From these materials, ground granulated blast furnace slag (GGBS) containing 5% magnesium and 45% calcium is seen to be a good candidate and is available to sequester CO₂. This study intends to ascertain the ability to absorb CO₂, sequester it, and increase treated kaolin strength with different content of GGBS under various carbonation periods with varying CO₂ pressure. The impacts of carbonated GGBS on the mechanical attributes of soil were examined by conducting the unconfined compressive strength (UCS) test, and microstructure analysis was conducted to identify the changes in the structure and Crestline phase. Stationary carbonation in a triaxial test with pure CO₂ was conducted to accelerate the carbonation process. The outcome indicates that the strength rises as the carbonation period rises. Likewise, UCS rises as the CO₂ pressure rises from 100 to 200 kPa. It could be concluded that augmentation of the strength is because of carbonated calcium and magnesium products which stuff the soil voids. Changes occur on the microstructure level due to carbonation as well.

Keywords: Carbon dioxide; Ground granulated blast furnaces slag; Ground improvement; Kaolin clay; Unconfined compressive strength; X-ray diffraction.