Role of Calcium Lignosulphonate in Developing Bio-Binders for Asphalt Pavements

Abstract: The use of bio-binders is steadily increasing to reduce reliance on natural resources such as traditional asphalt binders. This study investigates the feasibility of using Calcium Lignosulphonate (CLS) to produce bio-binders, with CLS content varying from 0 to 10% by weight of binder, in 2% increments. The performance of the prepared bio-binders was compared to that of a neat asphalt binder (PG64-16), both at the binder level, assessing physical properties and binder grading, and at the mixture level, focusing on rutting, fatigue, and moisture sensitivity. Additionally, SARA analysis was conducted to identify changes in the chemical composition of the neat asphalt binder upon CLS incorporation. The study's findings revealed that bio-binders exhibited higher viscosity and softening points, along with lower penetration values, as the CLS content increased, indicating an improvement in binder grade and stiffness. Changes in SARA composition, particularly the increase in asphaltenes and aromatics, were also observed with the addition of CLS. Due to the increased stiffness, the bio-binders demonstrated enhanced resistance to rutting and reduced susceptibility to moisture damage compared to the control asphalt mixture, regardless of CLS dosage. However, cracking resistance decreased beyond a CLS content of 6%, suggesting that 6% is the optimal CLS dosage for durable asphalt pavements. Statistical analysis further highlighted that CLS dosage has a significant effect on the performance of both asphalt binders and mixtures, emphasizing the importance of precise dosage selection.