Experimental and analytical evaluation of stabilizing bauxite residue bearing layers using cement kiln dust

Abstract

The accumulation of bauxite residue (BR), an alkaline byproduct of the Bayer process, presents an environmental challenge. This study introduces an innovative approach to address the disposal dilemma by utilizing cement kiln dust (CKD), a byproduct of cement manufacturing, as a stabilizing agent for BR, aiming towards an integrated circular economy in geotechnical applications. To achieve this goal, an extensive experimental program was executed to compare the particle size (PS), Atterberg limits (AL), moisture–density (MD), volume change (VC), and unconfined compressive strength (UCS) characteristics of treated and untreated BR. The results indicate enhancements in the BR-CKD properties including improvements in particle coarseness, reduction in swell potential, and increase in unconfined compressive strength; however, the plasticity of the mixtures remained unchanged, and the MD relationships deteriorated. An analytical evaluation of the allowable bearing capacity of the BR-CKD bearing layers showed an improvement of almost 3.5 times that of the untreated layers at a CKD% of 7.5 %.