The growing demand for sustainable and environmentally friendly alternatives in road construction has led to the exploration of bio-based materials for bitumen modification. This study investigates the use of sugarcane molasses (SM) as a partial replacement of bitumen, evaluating its performance through an interlaboratory study conducted in India and Iraq. Bio-bitumen binders were prepared by partially replacing 30% of conventional bitumen with sugarcane molasses, and their chemical and thermal behaviour was studied. Additionally, laboratory tests were conducted on bio-bitumen mixtures, evaluating rutting resistance, cracking resistance, moisture susceptibility, and stiffness characteristics. A mechanistic-empirical pavement analysis using KENLAYER software was performed to evaluate pavement durability, determining critical tensile and compressive strains, allowable load repetitions, and design life estimates. The results indicated that sugarcane molasses inclusive bio-bitumen (SMBB) mixtures exhibited lower tensile and compressive strains compared to conventional asphalt mixtures, leading to enhanced fatigue and rutting resistance. The estimated design life increased by 29% and 11% when SMBB was used as a surface course in pavement structures in India and Iraq, respectively, demonstrating the potential of sugarcane molasses to improve pavement longevity. Field trial sections were constructed in both India and Iraq, confirming the feasibility of SMBB in real-world applications. Overall, the findings highlight the viability of sugarcane molasses as a sustainable and cost-effective alternative for bio-bitumen production, contributing to the development of eco-friendly road infrastructure.
