Physico-chemical and mechanical properties of asphalt binders blended with waste bio-shell powder

Bio-shell is a renewable bio-waste resource being used to develop sustainable and environmentally friendly pavement materials. In this study, bio-shell was mixed with asphalt to prepare bio-shell-modified asphalt. The modified asphalt was divided into four groups with 0%, 5%, 10% and 15% of waste bio-shells. The morphology of the bio-shell was investigated by scanning electron microscopy tests. Penetration, softening point, and ductility tests were performed to analyse the basic physical properties of bio-shell asphalt. Dynamic shear rheometer and bending beam rheometer were used to high and low-temperature rheological properties of the bio-shell-modified asphalt. Fourier transform infrared spectroscopy and nuclear magnetic resonance hydrogen spectroscopy were used to analyse the atomic distribution and relative content of bio-shell-modified asphalt and reveal the modification mechanism. Atomic force microscopy was employed to observe the nano-microscopic morphology of the bio-shell-modified asphalt, and to analyse the changes of the bee structures in the asphalt. The results showed that the high-temperature rheology of 15% bio-shell asphalt was the best. The rutting factors of the asphalt increased by 38%, 43%, 45%, 50%, 55% and 63% at temperatures of 40 degrees C, 46 degrees C, 52 degrees C, 58 degrees C, 64 degrees C and 70 degrees C, respectively, compared to the matrix asphalt.