This paper examines the valorization of local materials from the Algerian arid region, particularly dune sand and limestone rock, which are abundantly available. The experimental program investigated the effect of adding limestone fines (LF) on the physical properties and mechanical behavior of dune sand. After the geotechnical characterization of both materials, five dune sand-limestone fines (DS-LF) mixtures were prepared, and their physicomechanical characteristics were determined. A series of unconfined compressive strength (UCS) tests was then carried out on samples compacted at the Modified Proctor Optimum (MPO). Laboratory results showed that the incorporation of limestone fines increases the optimum water content (wₘₚₒ), maximum dry density (γdmax), California Bearing Ratio (CBR) index, and UCS of dune sand. The optimal formulation, consisting of 60% dune sand and 30% limestone fines, was selected to balance economic and environmental constraints. This experimental investigation demonstrates that the incorporation of dune sand produces a material that meets standard requirements and can be used in Sahara Road construction. The study confirms that dune sand, an abundant material, can be valorized at minimal cost by adding limestone fines, thereby reconciling economic feasibility with environmental considerations.