Marble processing waste as a sustainable structural fill material in reinforced soil structures

Abstract

Efforts to recycle marble processing waste (MPW), a by-product of dimensional marble production, are essential in mitigating environmental impacts but face challenges such as composition variability, low inclusion rates, and preprocessing requirements in current practices. This study evaluates the feasibility of utilising MPW as a sustainable structural fill material in Reinforced Soil Structures (RSS), an inevitable part of transportation infrastructure. Comprehensive characterisation of MPW—including particle gradation, plasticity, hydraulic conductivity, electrochemical properties, morphology, mineralogical composition, and shear strength—demonstrates its suitability as a structural fill material, comparable to Local Soil (LS). Although MPW exhibits slightly lower interaction characteristics with geogrids compared to LS, as evidenced by interaction coefficients (Ri) and interface apparent coefficients (µs/GSY) obtained from interface shear and pullout tests, the differences are minimal. For the MPW-geogrid interface, Ri and µs/GSY values ranged between 0.70–0.85 and 0.25–1.38, respectively. Being non-hazardous and environmentally safe, along with offering environmental benefits and approximately 51% cost savings in fill material, MPW establishes itself as a viable and sustainable alternative to natural soil. This addresses the dual challenges of MPW disposal while meeting the growing demand for structural fill, contributing to natural soil conservation efforts.