Microanalysis of fly ash–based composite landfill liners

Abstract

The production of low-cost and eco-friendly landfill liner materials is necessary in areas where engineered leachate collection systems are not available. This article investigates the potential of locally available fly ash (FA), white clay (WC) and cement kiln dust (CKD) for preparing a composite landfill liner system with satisfactory mechanical and containment properties. Laboratory tests revealed that the designed FA:WC:CKD mixture had a compressive strength of 1.64 MPa, fines content of 71%, and specific gravity 2.42, suggesting its applicability for liners. Samples were analyzed by SEM–EDS (Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy), where the dense microstructure found was observed to be well sintered, and calcium-, silicate- and aluminosilicate-rich phases dominated. The crystalline products of pozzolanic and cementitious reactions were verified by X-ray Diffraction (XRD). The integrated mechanical, microstructural, and mineralogical properties indicate that the FA–WC–CKD composite is a potential low-cost medium for long-term leachate confinement in landfills.

J. Bangladesh Acad. Sci. 50(3); 567–578: September 2026