Análise Comparativa e de Reprodutibilidade do Teor de Ligante em Misturas Asfálticas: Métodos Rotarex, Soxhlet e Mufla (NCAT)

Abstract

Controlling the asphalt binder content is one of the main parameters for ensuring the structural performance and durability of flexible pavements, since deviations in dosage compromise the mechanical strength and service life of the mixtures. In this context, the present study aimed to compare the efficiency of binder extraction in dense asphalt mixtures using three methods used in Brazil: ignition (Muffle furnace), reflux extraction (Soxhlet), and centrifugation (Rotarex). Additionally, a comparative analysis of the results obtained by the ignition method was performed in two different laboratories to evaluate the reproducibility of the test. Test specimens molded with 30/45 Petroleum Asphalt Cement (PAC), classified in the C granulometric range, with a design content of 5.4%, adopted as a reference value, were analyzed. The tests followed the current technical standards (DNIT and ABNT), evaluating the contents obtained and their deviations from the reference. The granulometry of the aggregates after extraction was also evaluated to identify possible degradation or loss of fines, in addition to the operational time of each procedure. The results indicated variations between the methods, including between the muffles of the two laboratories. The ignition method stood out for its lower variability and greater proximity to the reference value. The Rotarex method presented binder content values higher than the actual ones, possibly associated with incomplete extraction of the binder and loss of fine material during the test, while the Soxhlet method required longer operating time and presented greater dispersion in the data. It is concluded that the choice of procedure should consider technical accuracy and operational, environmental, and safety aspects, with the muffle furnace being a robust alternative for technological control of pavements.