Mineral waste valorization in road subgrade construction: Algerian case study based on technical and environmental features

Abstract

This study has focused on the dam sediments and marble waste reuse as subgrade materials for road construction, with the overarching goals of reducing greenhouse gas emissions and conserving natural resources. Different mixtures were prepared based on sediments and marble waste, and treated with hydraulic binders. The first mixture consisted solely of raw sediment, while the second mixture combined 50 % dredged sediments with 50 % marble waste. Additionally, this mixture was treated with 1 % aerial hydrated lime and hydraulic road binder to enhance its properties. The experimental study focused on assessing both the short-term and long-term mechanical properties of the prepared mixtures. Results highlighted that the mixtures containing dam sediments and marble waste were highly suitable for road subgrade construction. These mixtures satisfied the criteria for trafficability (UCS), wetting resistance (UCSI), freezing resistance (ITS), and overall mechanical strength. Furthermore, a comprehensive analysis of the mixtures' microstructure and their environmental impact was conducted. A significant relationship was observed between CaO/SiO2 ratio and the mechanical properties of the treated mix. The research contributes to the growing body of knowledge regarding sustainable construction practices by highlighting the viability of utilizing dredged sediments and marble waste as valuable resources in road subgrade construction. The study showed that recovering 20 % of sediment and marble waste to replace natural materials would reduce energy consumption and greenhouse gas emissions by at least 40 % and 28 % respectively.

Keywords

• Sediment
• Marble waste
• Granular corrector
• Road construction
• Circular economy
• Greenhouse emission