A sustainable approach to dune sand concrete: combined contributions of gravel and wavy steel fibers

Purpose In arid regions, dune sand is abundant but generally unsuitable for conventional concrete due to its poor grading and high porosity. This study aims to address these limitations by incorporating limestone gravel and steel fibers to improve the density and mechanical performance of dune sand concrete. The combined effects of gravel addition and wavy steel fibers on the physico-mechanical behavior of dune sand concrete produced with locally available desert materials are investigated. The main objective is to optimize the balance between workability, mechanical strength and material efficiency. Design/methodology/approach Nine mix compositions were prepared by varying the gravel-to-dune sand ratio and the steel fiber content. A ternary binder composed of cement, silica fume and limestone filler was used. The investigated properties included density, workability, flexural strength and compressive strength. Findings The combined incorporation of limestone gravel and steel fibers significantly enhances the performance of loaded dune sand concrete (LDSC). The optimal mixture, LDSC-G/S1-MF25, achieved a compressive strength of 32.6 MPa (+13%) and a flexural strength of 4.9 MPa (+20%), along with an increased density. Optimizing the gravel-to-sand ratio and fiber content effectively improves both strength and ductility, providing a practical and efficient approach for the valorization of locally available dune sand in concrete production. Originality/value This study introduces a combination of gravel and steel fibers that has not been explored previously. A loaded concrete, in which the gravel-to-sand ratio is below 1, was used. This type of concrete represents a special case of sand concrete that has not been addressed in recent literature, making both the concrete type and the material combination novel aspects of the work. In addition, the study’s novelty lies in optimizing the gravel-to-sand ratio and the fiber content to achieve targeted mechanical performance.