Development of Recycled Asphalt Binder Using Eco-Friendly Bio-Additives

WPB: The rising demand for sustainable road construction has led to a focus on utilizing reclaimed asphalt pavement (RAP) as an alternative to virgin materials. However, the brittleness and stiffness of aged asphalt present challenges in achieving the desired performance. Traditional solutions, like synthetic polymer additives, improve asphalt properties but are costly and environmentally harmful. This research addresses these issues by introducing biodegradable, cost-effective bio-additives—starch (ST) and bone glue (BG)—to rejuvenate aged asphalt and enhance its durability.

RAP offers significant economic and environmental benefits but often exhibits reduced workability due to aging. Waste engine oil (WEO) has been used as a rejuvenator, softening the asphalt binder. However, its use compromises high-temperature rutting resistance, making additional modifications necessary. By combining ST and BG with WEO-treated asphalt, the researchers aimed to enhance high-temperature performance while retaining the environmental benefits of RAP.

Optimal proportions for the bio-additives were determined experimentally, with 0.75% ST and 0.5% BG (by weight of asphalt) providing the best results. These proportions improved rutting resistance, stability, and moisture resistance. Compared to virgin asphalt mixes, the bio-modified mix demonstrated significant performance enhancements, including a 62% reduction in rut depth and increased tensile strength.

The integration of ST and BG also improved cohesion within the asphalt, reducing air and water infiltration. These natural additives formed strong physical bonds with the binder, increasing viscosity and creating a denser, more uniform microstructure. Such properties make the bio-modified asphalt suitable for medium-traffic roads or binder layers in highways, where durability and cost-efficiency are critical.

Sustainability is a key advantage of this approach. The reuse of RAP, combined with biodegradable additives, reduces the demand for virgin materials, lowering energy consumption and greenhouse gas emissions. This not only conserves non-renewable resources but also minimizes construction waste, supporting global efforts for a greener environment.

Mechanical tests confirmed the durability of the modified asphalt, demonstrating superior resistance to rutting, cracking, and moisture-induced damage. The improved stability and reduced wear make the mix highly suitable for long-term road performance, even under challenging environmental conditions. While the mix performed exceptionally well in laboratory settings, further research is needed to evaluate its long-term performance in real-world applications.

The development of bio-modified asphalt represents a significant step forward in sustainable road construction. The natural additives ST and BG offer an eco-friendly alternative to synthetic polymers, combining economic benefits with improved mechanical properties. This approach aligns with global trends toward reducing the carbon footprint of industrial activities and promoting resource conservation.

Despite the promising results, certain limitations exist. Long-term performance assessments under traffic loads and diverse climatic conditions are essential for widespread adoption. Further studies using advanced testing methods, such as bending beam rheometers, could provide deeper insights into the mix’s durability and aging properties.

The introduction of bio-additives like starch and bone glue demonstrates that sustainable infrastructure can be achieved without compromising performance. By enhancing the rheological and mechanical properties of RAP, this innovative approach provides a viable pathway for eco-friendly road construction. With continued research and refinement, these advancements could revolutionize the paving industry, blending environmental responsibility with engineering excellence.

By Bitumenmag

Asphalt, Bitumen, Market, Petroleum