Thermal behavior of asphalt binder with modifying agents from industrial residues

The thermal behavior of the petroleum asphalt binder (PA 50–70) modified with mixture of rubber tires and oily sludge, in the proportions of 15/85% m/m (M1) and 85/15% m/m (M2), was evaluated. For this purpose, M1 and M2 were added to PA 50–70, at concentrations of 10% and 20% m/m with and without 1% m/m of cashew nut shell liquid (CNSL). Results from thermogravimetric analysis (TG/DTG) of the PA 50–70 revealed initial degradation temperature at 290 °C, while with M1, without and with 1% CNSL the temperature was 270 °C and 240 °C at 10% addition, and 194 °C and 240 °C at 20% addition, respectively, and modified with M2, 270 °C and 247 °C, for 10% addition, and 230 °C and 247 °C, for 20% addition, respectively. All these temperatures of degradation were higher than the temperature (160 ± 5 °C) of processing asphalt mixtures. The differential scanning calorimetry (DSC) results showed the occurrence of melting of crystalline fractions only for those modified with the M1 mixture. Results of absorption spectroscopy in the Fourier transform infrared (FTIR) region revealed the existence of chemical interaction between the components of the mixture and PA 50–70 supported by the antioxidant action of CNSL. The evaluation of the thermal susceptibility by flow activation energy ( E f ), at a temperature of 160 ± 5 °C of the modified binders without and with 1% of CNSL, showed a reduction of 25% in relation to the PA 50–70, signaling a need for lower energy consumption when it is used in the process of obtaining asphalt mix for road pavement.