Sustainable reuse of magnesite mine tailings in cement-treated expansive soil for enhanced subgrade performance: geotechnical and environmental analysis

Abstract

This study explores the use of Magnesite Mine Tailings (MMT) as an admixture in cement stabilization of Expansive Soil (ES) to improve subgrade performance and reduce environmental impact. Various combinations of Ordinary Portland Cement (OPC) and MMT were investigated using standard proctor compaction, Unconfined Compressive Strength (UCS), California Bearing Ratio (CBR), durability and Toxicity Characteristic Leaching Procedure (TCLP) tests. Results showed enhanced ES strength with MMT and OPC, with a maximum UCS of 1179 kPa and a soaked CBR of 25.1% after 28 days. However, higher cement content (>12%) is necessary for durability and meeting environmental regulations. X-Ray Diffraction and Field Emission Scanning Electron Microscopy confirmed hydration products, supporting MMT as a sustainable solution for stabilization and tailings disposal.