Crushed Granite Residue as a High-Performance and Sustainable Alternative to River Sand for Concrete

---

Résumé

The construction sector in Burkina Faso faces increasing challenges related to the scarcity and environmental impact of natural river sand extraction. In this context, quarry by-products, such as crushed granite sand (CGS), represent a potential alternative that remains under-exploited. This experimental study evaluated the feasibility of substituting natural river sand (NS) with CGS in the formulation of hydraulic concrete. Five concrete mixtures were prepared with substitution levels of 0%, 25%, 50%, 75%, and 100% CGS, while maintaining a constant water-to-cement ratio of 0.47. Workability was controlled by adjusting the dosage of the superplasticizer. The concrete samples were tested for density and porosity, compressive and tensile strength, ultrasonic pulse velocity, capillary absorption, and resistance to acid attack. The incorporation of CGS significantly improved the mechanical and durability properties of concrete. At 28 days, the compressive strength of CGS100 mix reached 39.33 MPa, compared to 30.64 MPa for the reference mix CGS0. The improved performance is attributed to the higher fines content and angular particle shape of CGS, which enhances packing density and intergranular bonding. This study demonstrates that CGS can effectively replace NS in hydraulic concrete without compromising performance. In contrast, it enhances both strength and durability while promoting the sustainable use of locally available CGS materials. Therefore, CGS represents a promising solution for addressing the dual challenges of environmental preservation and material supply in Burkina Faso and similar contexts.

Mots-clés

river sand replacement, concrete, compressive strength, tensile strength, concrete durability, acid attack resistance, capillary water absorption, ultrasonic pulse velocity, porosity, superplasticizer, sustainable construction materials, sand scarcity