Performance comparison between different sourced bioasphalts and asphalt mixtures

Bioasphalt could replace petroleum-based asphalt due to its renewability and environmental friendliness. However, bioasphalt made from different raw materials or processing technologies has different properties and performance. This study investigates and compares the performance of two bioasphalts made from corn (DC) and castor (SH). Elemental analysis shows that both DC and SH have very high oxygen content. Fourier-transform infrared spectroscopy (FTIR) analysis indicates that a certain amount of alcohols and fatty acids exists in DC and SH, respectively. Thermogravimetry-differential scanning calorimetry (TG-DSC) analysis shows that SH exhibits excellent thermal stability whereas that of DC is poor. Moreover, it is found bioasphalt can reduce the viscosity of asphalt binder but has poor aging resistance, especially for DC. The viscosity temperature susceptibility (VTS) demonstrates that bioasphalt can increase the temperature susceptibility of base asphalt. Rheological tests using a dynamic shear rheometer (DSR) illustrate that DC can improve the high-temperature performance whereas SH can improve low-temperature performance. Mixture performance tests indicate that the addition of DC improves rutting resistance whereas SH causes the opposite trend. The addition of DC and SH reduce the low-temperature cracking resistance of mixtures to different extents. In addition, moisture damage resistance tests show that DC increases the moisture susceptibility whereas SH does not have adverse effects on moisture damage resistance. In summary, using differently sourced bioasphalt as an alternative binder to partially replace petroleum-based asphalt is feasible but caution is needed to evaluate the effect of bioasphalt on the dominant pavement failure mechanism.