Beneficial use of dimensional stone industry wastes in geotechnical fills: Geotechnical, environmental and economic perspectives

Abstract

Efforts to recycle waste from the dimensional stone industry are vital due to its environmental impacts, hindered by limited inclusion rates and complex processing needs in current practices. Given the increasing demand for geotechnical fill materials and the depletion of natural soils, sustainable alternatives are necessary. The beneficial use (BU) of Dimensional Stone Processing Industry Wastes (DSPIWs) in geotechnical fills offers a novel solution, yet lacks a comprehensive evaluation. Following the USEPA approach, this study assesses the suitability of DSPIWs—specifically slurry generated in granite, sandstone, and marble processing—for geotechnical fills, examining their potential, relevant lifecycle stages, compatibility with geotechnical fill requirements, environmental concerns, and cost implications. Geotechnical investigations reveal that DSPIWs are non-plastic and non-swelling, with grain size distribution and hydraulic conductivity akin to silty sands. Maximum Dry Density ranges from 1.58 to 1.84 g/cm³ with minimal water-induced variation, and internal friction angles of 44.8° for granite, 40.2° for sandstone, and 36.5° for marble ensure high stability. Electrochemical analysis shows low leachability risks, with pH levels between 7.5 and 8.1 and electrical resistivity above 6200 Ω-cm. Heavy metal concentration in percolation-based leaching tests remains within allowable limits. A cost analysis of a typical embankment section using DSPIWs as fill material reveals a substantial cost reduction of nearly 52 percent compared to using natural soil. Considering the non-hazardous nature of DSPIWs, their compliance with geotechnical fill requirements, minimal environmental and health risks, and economic benefits, this study endorses their BU in geotechnical fills to cater waste disposal problem and advance resource conservation.