Effect of dune sand on the physical and mechanical performances of gravel road

Purpose This study aims to examine the use of dune sand (DS) and granulated blast furnace slag (GBFS) to improve the physical and mechanical properties of gravel roads, with the goal of developing more sustainable and cost-effective pavement solutions. Design/methodology/approach Laboratory experiments were conducted on mixtures of crushed gravel and crushed sand containing 10% DS and varying GBFS contents (15%–25%), activated with lime. Performance was evaluated through particle size analysis, chemical and mineralogical testing (X-ray diffraction, scanning electron microscopy/energy dispersive spectrometry), modified proctor compaction and California bearing ratio (CBR) tests. Findings The incorporation of DS significantly improved the gradation, increased the maximum dry density and reduced the optimum moisture content. The addition of GBFS further enhanced the bearing capacity, with CBR values rising from 50% in untreated samples to over 220% in optimized mixtures. These improvements are attributed to improved particle packing and pozzolanic cementation. Research limitations/implications The results are based on laboratory-scale testing. Field trials and long-term assessments are required to validate durability and assess environmental performance. Practical implications The findings propose a sustainable and economical approach to improving road base layers, particularly in regions where high-quality aggregates are limited. Social implications The adoption of this technique promotes resource conservation and supports the development of resilient rural infrastructure, contributing to both environmental and economic sustainability. Originality/value To the best of the authors’ knowledge, this work is among the first to detail the combined effects of local DS and industrial slag by-products on gravel road stabilization in semi-arid regions.