Soil stabilization by using alkaline-activated ground bottom ash coupled with red mud

Abstract

This study evaluates the feasibility of incorporating bottom ash and red mud into a binder to stabilize soil. In this study, the bottom ash collected from Honam Thermal Power Plant in South Korea was ground to decrease particle size. It was then coupled with red mud to form a new binder based on the geopolymer synthesis theory. Sodium silicate solution (Na2SiO3) in terms of alkaline-activator was added into mixture to enhance the activity of binder. Weathered granite soil which is classified as SM in USCS is the target of stabilization. Unconfined compressive strength of stabilized soil and heavy metal content of leachate were examined. Experimental results showed that ground bottom ash coupled with red mud can be used to stabilize weathered granite soil at the ambient curing condition. The highest compressive strength of stabilized soil was 4.1 MPa. Red mud in certain limits has contributed to the increment of soil strength, however, the long-term strength decreased with the increase of red mud content. In addition, based on the results obtained with leaching test, it can be concluded that leachate from the stabilized soil is not harmful to the environment.