Feasibility Analysis of Cement-Stabilized Gravel Material Incorporating Aluminum Tailings Sand for Advanced Road Pavements

Aluminum tailings sand (ATS), rich in silica and alumina, offers a sustainable alternative to natural sand in road construction, reducing ecosystem damage from sand extraction. This study evaluates the feasibility and engineering performance of cement-stabilized gravel material (CSGM) incorporating ATS (ATS-CSGM) to mitigate tailings accumulation and resource depletion. Macroscopic and microscopic tests assessed mechanical properties, durability, and economic/environmental benefits at ATS substitution rates (0%–30%). Results show mechanical properties decline with increasing ATS content. However, mixes with 10% (ATS-10) and 16% (ATS-16) ATS achieved 7 days unconfined compressive strengths (UCS) of 5.56 MPa and 4.08 MPa, respectively, meeting the subgrade requirement (UCS > 4.0 MPa). ATS-CSGM exhibited enhanced durability and improved resistance to drying shrinkage. Microanalysis revealed that ATS addition reduced hydration product coverage, decreased compactness, and increased porosity. Despite this, ATS contributed to a denser surface structure of hydration products via filling and microaggregate effects, significantly delaying deterioration under environmental influences. A comprehensive assessment of performance, economic, and environmental benefits identified 16% as the optimal ATS substitution rate. The study concludes that ATS-modified CSGM presents a viable, environmentally friendly solution for waste management in road engineering, offering dual economic and environmental advantages and contributing to carbon neutrality goals.