Synthesis and characterization of bentonite-based lightweight ceramic aggregates using coal combustion residue and kerosene bloating agent

Abstract

Coal combustion residue (CCR) is an industrial by-product that has been widely adopted in civil engineering applications. However, a significant portion of CCR is still left unused around the world. This study investigates the feasibility of incorporating CCR into ceramic aggregates to enhance their engineering properties. Through a combination of kerosene as a bloating agent and CCR addition, the study demonstrates significant improvements in ceramic aggregate properties. Particle strength ranged from 0.33 to 8.53 MPa, with density variations between 0.39 and 0.95 g/cm³. Additionally, the additives also promoted the crystallization process, as shown by the increase in crystallinity from 40.67% to 61.87%. This was confirmed by the X-ray diffraction analysis, which revealed the changes in the mineral composition and crystallinity due to the additives. Furthermore, the micro and macro pores of bentonite profoundly influence the bloating process of aggregate, contributing to the formation of a well-distributed porous structure in ceramic pellets. The resulting ceramic aggregate exhibited favorable strength-to-density ratios suitable for both structural and non-structural concrete applications. This research highlights the potential of CCR utilization in ceramic aggregates, offering sustainable solutions for the construction industry while mitigating waste disposal concerns.