# Char from Pyrolysis of Waste Tires to Increase Bitumen Performances
## 2 Experimental Section
\begin{table}
\begin{tabular}{c c} \hline C (\% \(w\)/\(w\)) & 82.8 \\ H (\% \(w\)/\(w\)) & 7.1 \\ N (\% \(w\)/\(w\)) & 1.5 \\ S (\% \(w\)/\(w\)) & 1.6 \\ O (\% \(w\)/\(w\)) & 7 \\ \hline Humidity (\% \(w\)/\(w\)) & 0 \\ Volatiles (\% \(w\)/\(w\)) & 66 \\ Ashes (\% \(w\)/\(w\)) & 5 \\ Fixed carbon (\% \(w\)/\(w\)) & 29 \\ \hline \end{tabular}
\end{table} 
Table 1: WT composition. reported by other authors [23]: different conditions would deteriorate the final bitumen rheological properties, and also would render comparison with existing literature difficult. After mixing the bitumen with char at the aforementioned temperature of \(150\pm 10\)\({}^{\circ}\)C, the modified bitumen was poured into a sealed can, stored in a dark chamber and allowed to cool down to a temperature of 25 \({}^{\circ}\)C. Due to the sensitivity of the samples to the annealing time [24], i.e., the time required for cooling down to room temperature, care was taken to ensure that the temperature cooling rate (5 \({}^{\circ}\)C min\({}^{-1}\)) and annealing time (25 min) of all the investigated samples were the same. As a reference, a bitumen sample devoid of filler, hereafter labeled as \"ref\", was used. So, to evaluate the effect of the filler content during aging, all the above-mentioned samples (filler-modified bitumen samples and reference bitumen) were subjected to a 75 min aging cycle using the RTFOT (Rolling Thin-Film Oven Test according to ASTM D2872-04). However, in order to obtain bitumens with a rigidity, which simulate a prolonged aging process of about 10-12 years, typical of an asphalt pavement lifespan, the simulated aging was also prolonged to 225 min. Nitrogen (N\({}_{2}\)) adsorption isotherms were measured on ASAP 2460 (Micromerities) at \(-196\)\({}^{\circ}\)C so as to evaluate the porosity. Prior to the experiments, outgassing of all samples was carried out at 200 \({}^{\circ}\)C, with the exception of the sample \"as is\" char that was kept at room temperature, until a constant vacuum of \(10^{-7}\) mbar was reached. The BET method was used to calculate the specific surface area (S\({}_{\text{BET}}\)) while the volume of micropores (V\({}_{\text{mic}}\)), volume of mesopores (V\({}_{\text{mes}}\)), total pore volume (V\({}_{\text{T}}\)) and pore size distribution (PSD) were calculated using the Non-local Density Functional Theory (NLDFT) [25], with the assumption of the pore wall heterogeneity. A thermogravimetric analysis (TGA) was performed using a DSC-TGA STA409C analyzer (Netzsch-Geratebau GmbH, Selb, Germany) from 40 to 500 \({}^{\circ}\)C at a heating rate of 5 \({}^{\circ}\)C in static air. IR spectra were obtained using FTIR spectrometer Bruker Alpha Fourier transform spectrometer (Karlsruhe, Germany) in transmission. The measurements were recorded in the wavelength range 4000-400 cm\({}^{-1}\) with a resolution of 4 cm\({}^{-1}\). In each run, 100 sample scans were recorded, and the background was also taken before each sample. A KBr disc was placed in the sample holder, and the holder was placed in the FTIR spectrometer. Ten spectra were taken from each disc and the mean of them was used for a further analysis. The characterization of sample surface morphology was acquired using a Scanning Electron Microscope (SEM) (Field Emission SEM FEI Quanta 200 Kyoto, Japan) and Electron Probe Micro Analyzer (EPMA, JEOL JXA 8230t, Kyoto, Japan), equipped with a wavelength dispersive spectrometer (WDS) in order to determine both the elemental composition and spatial distribution. The surface of the samples was coated with a 5-nm-thick layer of carbon, using a Carbon Coater QUORUM Q150T-ES (Judges House, UK). The operating conditions for the SEM analysis were the following: HV of 15 KeV; Probe Current of 10-20 nA; working distance of 11 mm; image BSE signal; detector image of a solid state detector (SSD). The WDS analytical conditions (Spectrometers WDS XCE type and X type, Carl Zeiss AG, Oberkochen, Germany) were an accelerating voltage of 15 keV and a Faraday