Effect of Biochar from Oat Hulls on the Physical Properties of Asphalt Binder

Abstract

The purpose of this study was to verify the feasibility of using biochar from oat hulls (BO) as a potential bio-modifier to improve the physical properties of conventional asphalt binder. The BO and asphalt binder were characterized by confocal (fluorescence) laser microscopy, scanning electron microscopy and Fourier transform infrared spectroscopy. Then, an asphalt binder modification procedure was established and modifications with 2.5, 5.0 and 7.5% of BO on the weight of the asphalt binder were evaluated, using a particle size < 75 µm. The physical properties of the evaluated modified asphalt binder with BO were: rotational viscosity in original and aged state, aging index, Fraass breaking point, softening point, penetration, penetration rate and storage stability. The results indicated that the BO has a porous structure, able to interact with the asphalt binder by C=O and C=C bonds. In addition, modification of the asphalt binder with BO increases the rotational viscosity related to high-temperature rutting resistance. The results obtained from the Fraass breaking point and softening point indicated that the use of BO extends the viscoelastic range of the asphalt binder. In addition, the evaluated modifications present low susceptibility to aging and good storage stability.

High Temperature Rheological Properties and Storage Stability of Bitumen Modified with The Char Produced from Co-Pyrolysis of Different Wastes

“…In recent years, modification of bitumen with different bio chars has been investigated [6][7][8][9][10]. It was determined that the biochar had better effects than commercial graphite on high temperature performance of bitumen [6].…”

“…And all of these pyrolysis products can be potentially used for different purposes in various areas [12,13,19]. Biochar which is the solid pyrolysis product of biomass is a carbon rich material and has large surface area with high porosity [8,10,16,20]. Therefore, biochar can form a stiff structure with bitumen and can enhance the physical properties and high temperature performance of the bitumen due to its high porosity and high absorption properties [8,10].…”

“…In the literature, different biochars obtained from various biomasses have been used as additives in pure bitumen [6][7][8][9][10]. In a study [6], the pure bitumen was modified with biochar by adding into the neat bitumen at different ratios including 2%, 4% and 8%.…”

“…However, the biochars obtained from walnut shells and apricot shells increased the temperature susceptibility of pure bitumen for different ratios and had negative effect on bitumen for given ratios [9]. In another study [10], the oat hulls biochar was used as a modifier in bitumen at different contents with 2.5%, 5% and 7.5% by weight of bitumen. It was determined that oat hulls biochar increased the softening point and viscosity values while decreasing the penetration value of pure bitumen.…”

“…In the literature, different biochars from various biomasses have been used as additives in pure bitumen [6][7][8][9][10]. However, no study was found in which bitumen was modified with the char fabricated from co pyrolysis of three different wastes including paper cups, PET and PP wastes.…”