Using crushed stone dust as a substitute for fine aggregates in concrete

Abstract

Generation of waste from mining and high consumption of natural aggregates resulting from civil construction works have significant economic and environmental impacts. Aiming to use the stone dust residue from the rock crushing process, this study experimentally evaluates the use of crushed stone dust as a partial substitute for fine aggregates in concrete with a compressive strength of 30 MPa, thus providing an alternative in civil construction activities. Crushed stone dust was evaluated through physical, chemical, mineralogical, petrographic, and micromorphological characterization tests. The characterization results indicated that the material is classified as medium and fine sand, with 68.2% silicon dioxide and quartz peaks, i.e., similar to natural sand. Axial compression tests were performed on twenty cylindrical specimens with diameters of 100 mm and heights of 200 mm, broken at 28 days. Five of such specimens were made of reference concrete, without stone dust, while fifteen contained concretes with stone dust. In this approach, the percentage of stone dust in the concrete specimens ranged between 20%, 50%, and 100%, and compressive strength was kept constant at 30 MPa, with five cylinders with stone dust for each percentage of sand replacement. The results show the contribution of stone dust to the mechanical behavior of the concrete specimens, which corroborate the possibility of applying it as a substitute for fine aggregates, as compressive strength was higher in the concrete specimens with 20% and 50% stone dust compared to the reference concrete.