Substitution of Tailings Sand in Cement-Stabilized Gravel Base Material for Road Construction: Mechanical Properties, Durability, and Microstructure

Abstract

The aim of this research is to explore the feasibility of using tailings sand (TS) as a partial replacement for sand in the production of cement-stabilized base course materials. In this paper, the performance, economic and environmental benefits of cement-stabilized tailings sand–gravel base material (CSTSM) with various TS content were comprehensively studied. The results indicate that the mechanical properties, drying shrinkage strain and durability of CSTSM decreased with the increasing TS content (0%–30%) while adhering to the necessary engineering requirements (UCS>2.4 MPa). The TS inclusion reduces hydration product coverage, decreases compactness and increases porosity, resulting in reduced strength and durability of CSTSM. When the TS content is below 16%, the deterioration in mechanical properties and durability of CSTSM under dry-wet, freeze-thaw and sulfate corrosion conditions is relatively minor, sufficiently meeting with the heavy traffic demands on highway subgrades (UCS>4 MPa). Moreover, when compared to ordinary cement-stabilized base course materials, the use of TS reduces the cost and CO2 emissions. After a comprehensive comparison of performance, economic benefits and environmental factors, a 16% TS substitution ratio is recommended for achieving optimal outcomes. Utilizing CSTSM in subgrade engineering is promising and environment-friendly approach for large-scale solid waste treatment and achieving carbon neutrality goals.