Análise das propriedades de um ligante asfáltico modificado com terpolímero reativo e partículas micro e nanométricas de carbonato de cálcio e de rejeito da mineração do quartzito.

Abstract

The search for sustainable and high-performance solutions in pavement engineering has driven the investigation of alternative materials capable of enhancing the properties of asphalt binders. In this context, quartzite mining waste was selected as an asphalt binder modifier due to its wide availability in ornamental stone processing regions and its physicochemical characteristics, especially its high silica content, which gives it potential as a functional additive in asphalt binders. Calcium carbonate, in both micro and nanometric forms, was chosen for its well-known antioxidant potential, in addition to being a commercially available nanoparticle that is accessible and relatively low-cost compared to other nanomaterials. Based on these premises, this study evaluated the incorporation of micro and nanoparticles of calcium carbonate (CaCO₃) and quartzite mining waste as modifiers of CAP 50/70 asphalt binder, applied either individually or in combination with a commercial reactive elastomeric terpolymer (Polimul S74) at a concentration of 1.8% by weight. Three contents of particulate modifiers were investigated (3%, 7%, and 10%), and the modified binders were compared with both the reference CAP 50/70 binder and a high-performance binder (AMP 60/85-E). The study was conducted in three main stages: (i) chemical characterization using Fourier-transform infrared spectroscopy (FTIR), (ii) empirical characterization through penetration, softening point, thermal susceptibility index (TSI), elastic recovery, short-term aging (RTFO), and storage stability tests, and (iii) rheological characterization, including performance grade (PG), multiple stress creep recovery (MSCR), Linear Amplitude Sweep (LAS), and master curve analysis. The results showed that the isolated incorporation of micro and nanoparticles did not promote qualitative chemical changes in the binders, suggesting predominantly physical interactions. However, the association of these particles with the terpolymer revealed changes in FTIR transmittance bands, indicating chemical interactions that improved the mechanical performance of the binder. The empirical characterization showed that the modifiers increased binder consistency (decreased penetration and increased softening point), improved thermal stability (reduced TSI), and reduced mass loss during RTFO aging, indicating greater resistance to volatilization. Rheological results confirmed these trends, showing reduced Jnr values in the MSCR test—indicating lower susceptibility to permanent deformation—and improved traffic level classification based on the Fatigue Factor of the Binder (FFL). Binders modified with microparticles showed increasing performance with higher dosages, while those modified with nanoparticles achieved better results at 7%, suggesting a possible saturation limit beyond this point. Master curve data also revealed increased stiffness and improved viscoelastic response in the modified binders. Overall, the study concludes that the addition of micro and nanoparticles of CaCO₃ and quartzite mining waste improved the physicochemical and rheological properties of the asphalt binder, with performance superior to that of conventional CAP 50/70 and, in some cases, comparable to AMP 60/85-E. The best-performing contents were 10% for microparticles and 7% for nanoparticles. The results demonstrate the technical potential of using quartzite mining waste in asphalt binder modification, contributing to the valorization of industrial residues and the development of more durable and sustainable pavements.