Assessing the mechanical properties and workability of concretes with stone powder as a sustainable alternative material to natural sand

Abstract The extraction of sand from riverbeds through dredging is a common practice in construction and has given rise to significant environmental repercussions. Sand removal contributes to heightened turbidity and alterations in watercourses, reshaping the original channels due to equipment utilization, and disrupting their flow. In response to these challenges, crushed stone dust emerges as a sustainable alternative material for partially or entirely replacing natural sand in concrete production. This study aimed to evaluate the mechanical properties and workability of concrete with a characteristic compressive strength of 25 MPa, employing total replacement (100% crushed stone dust) and partial replacement (50% crushed stone dust and 50% sand). The materials utilized encompassed crushed stone, natural sand, Portland cement CP II F - 32, crushed stone dust, and a superplasticizer additive. The results indicated no significant difference in compressive strength (P < 0.05), with values of 36.85 MPa and 30.31 MPa for total and partial replacement, respectively, comparable to the reference concrete (33.47 MPa). In terms of tensile strength by split tensile testing, concrete with total and partial replacement achieved 3.09 MPa and 3.23 MPa, respectively, while the reference mix recorded 3.31 MPa. Total replacement posed challenges to the workability of fresh concrete, necessitating a higher dosage of superplasticizer. In conclusion, crushed stone dust demonstrates its capacity to substitute natural sand, either entirely or partially, while upholding mechanical properties comparable to traditional concrete. However, careful consideration of the impact on concrete workability is essential when opting for total replacement of the fine aggregate.