Análise técnica da incorporação do resíduo do beneficiamento da scheelita: reciclagem profunda de pavimento in situ com estabilização granulométrica

Abstract

Brazil has the road transport mode as its predominant one, accounting for about 60% of all active transport modes in the country. However, this large share does not reflect the quality of its highways. According to the latest survey by the National Confederation of Transport (CNT) (2025), most of the paved network shows defects, causing losses for those who use these roads. To correct pavement defects, several methods are employed, with Full Depht Reclamation (FDR) being one of the most commonly used due to its economic and sustainable advantages, as it allows the reuse of materials and eliminates the need for new inputs. Several studies have been conducted to analyze the feasibility of using waste and byproducts in civil engineering, and waste from scheelite beneficiation is one of them. The scheelite beneficiation process generates large volumes of waste that are disposed of in open areas, causing various environmental impacts. In this context, the present study aimed to analyze the feasibility of incorporating this mineral waste into the FDR process. Recycled mixtures were prepared by adding waste, Reclaimed Asphalt Pavement (RAP), and crushed stone to the base materials collected from km 51.16 and km 51.60 of the BR-427/RN highway, executing physical and mechanical tests like grain sizes, Atterberg Limits and Califórnia Bearing Ratio (CBR). The mixture composed of, Base + 50% RAP + 15% Crushed Stone 19 + 20% Waste, met all the physical and mechanical parameters required by the standard DNIT 141/2022 – ES. Resilient Modulus (MR) tests were also performed for mixture M2 at km 51.16 and km 51.60, yielding average values of 475 MPa and 354 MPa, respectively, exceeding the average value of 250 MPa for Crushed aggregate, a material commonly used in granular pavement layers. The regression models obtained for the materials showed a predominant influence of confining stress (σ₃) on MR values, consistent with their Unbound granular nature. A mechanistic analysis was additionally carried out considering pavement rehabilitation using a recycled base designed with mixture M2 at km 51.16. The performance of this solution was compared with that of an equivalent pavement structure in which the deteriorated base layer was replaced by Crushed aggregates. The results demonstrated that the pavement structure incorporating the recycled base with scheelite residue met all established failure criteria.