Líquido da castanha de caju (LCC) e seus derivados como agentes modificadores de ligante asfáltico

Abstract

This work studies the effects of the modification of the 50/70 asphaltic binder by adding different types of liquid derivatives of the cashew nuts (LCC) that were synthesized. The additives considered in the binder modification were: LCC, hydrogenated LCC, cardanol, hydrogenated cardanol, nitrated hydrogenated cardanol, ethoxylated hydrogenated cardanol and sulfonated hydrogenated cardanol. The objective was to incorporate several groups in the structure of the LCC, in order to alter the surfactant characteristics of the same and to analyze the effect of these additives on the physical-chemical, empirical and rheological properties of the binder. The evaluation of the synthesized additives was performed using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis and nuclear magnetic resonance (NMR) techniques. The FTIR analysis of the LCC and its derivatives showed the characteristic bands of the products and it was possible to confirm the synthesis of the additives. Through the thermal analysis it was verified that all the derivatives synthesized from the LCC present thermal stability up to 227 ºC. All binders (pure and modified) presented typical behavior of Newtonian fluids. The binder modified by the nitrated hydrogenated cardanol had the highest values of viscosities, indicative of increased consistency of the binder. The rheological parameters: complex modulus G * and phase angle δ obtained in dynamic shear rheometer (DSR) related to stiffness and elasticity, respectively, show that the best performance in relation to resistance to permanent deformations due to heavy traffic on the highways was the modified binder with nitrated hydrogenated cardanol (capcardhidNit). The degree of performance (PG) evaluated by the SUPERPAVE specification classified the samples as the maximum service temperature without permanent deformation. A more recent specification proposed to evaluate the permanent deformation by the creep test and multiple strain recovery (MSCR) was used and it was found that the sample capcardhidNit had lower values of non-recoverable compliant (Jnr) and, therefore, suggests that this has a better performance in relation to avoiding permanent deformations. In addition, the MSCR test classified this sample for its possibility of use in heavy traffic routes (70-H-XX). The Linear Amplitude Scan (LAS) test showed that the LCC modified binder presented the best profile with regard to fatigue crack resistance.