Uncovering the Hidden Value of Waste Cow Bones Towards their Use as a Sustainable Biofiller for Hot-Mix Asphalt Paving Applications

This work is aimed at uncovering the hidden value of waste cow bones towards their use as a sustainable biofiller for hot-mix asphalt (HMA) paving applications. To do so, the effect of various contents of calcined cow bone powder (e.g., 5, 10, and 15 wt. % CBP) on the AP-5 bitumen performance was investigated. Numerous lab techniques were adopted to assess the physicochemical attributes of finished filler-asphalt mastics, namely: elemental analysis, Fourier transform-infrared spectroscopy (FT-IR), thin-layer chromatography-flame ionization detection (TLC-FID), needle penetration, ring and ball softening point, Brookfield viscometer, and ductility. Iatroscan analysis revealed that the CBP treatment did not alter the saturates but induced an increase in the fractions of aromatics/asphaltenes and a decrease in the resins. The FT-IR scan highlighted that the CBP–binder interactions were mainly governed by physical mechanisms rather than chemical ones. The empirical methods showed that the CBP incorporation enhanced the stiffness/hardness, the consistency, as well as the high-temperature performance of bituminous mixtures. Overall, the use of waste cow bones as a green biofiller is viable and profitable, and it has the potential to reduce the environmental pollution caused by the livestock industry while also improving the performance of hot-asphalt mixes and extending the pavement life at a low cost.