What are the best practices and lessons learned from asphalt binder rejuvenation and modification projects?

2 Modification methods

There are various ways to modify asphalt binder, depending on the desired properties of the pavement, the cost of the materials, and the compatibility and stability of the mixture. For instance, synthetic or natural polymers, such as styrene-butadiene-styrene (SBS) or ethylene vinyl acetate (EVA) can be added to improve elasticity and strength. Alternatively, fibers like cellulose, polyester, or glass can be incorporated to enhance viscosity and stability. Crumb rubber from recycled tires can be added to increase elasticity and durability, while bio-based materials like vegetable oils, animal fats, or lignin can be used to reduce environmental impact and improve rheological properties.

3 Benefits and challenges

Rejuvenation and modification of asphalt binder can offer several benefits for pavement engineering, such as extending the service life and reducing maintenance needs, improving performance and functionality under different traffic and climatic conditions, reducing consumption of non-renewable resources and emissions of greenhouse gases, and enhancing the sustainability and cost-effectiveness of asphalt pavements. However, there are also challenges associated with rejuvenation and modification of asphalt binder, such as selecting the appropriate method and material for each pavement situation, evaluating the short-term and long-term effects on pavement behavior and performance, developing standardized specifications and test methods for rejuvenated and modified asphalt binders, and balancing the initial and life-cycle costs and benefits.

4 Best practices and lessons learned

Pavement engineers and practitioners have identified several best practices and lessons learned from asphalt binder rejuvenation and modification projects. It is important to conduct a thorough pavement assessment and diagnosis before selecting a rejuvenation or modification method and material. Additionally, environmental, economic, and social impacts should be taken into consideration alongside the technical aspects. Furthermore, recommended guidelines and procedures for design, construction, and quality control of rejuvenated and modified asphalt pavements should be followed. To ensure the success of the projects, it is essential to monitor and evaluate the performance and durability of rejuvenated and modified asphalt pavements over time in comparison to conventional pavements. Lastly, knowledge and feedback from rejuvenation and modification projects should be shared with other stakeholders and professionals.

5 Resources and references

If you want to learn more about asphalt binder rejuvenation and modification, some valuable resources and references to consult include the Asphalt Institute's Asphalt in Pavement Preservation and Maintenance (2016), the Federal Highway Administration's Asphalt Binder Basics (2017), the Transportation Research Board's Practices for Performance Testing of Asphalt Binders (2019), RILEM Publications' State-of-the-Art Report on Use of Bio-Based Materials for Asphalt Pavement Engineering (2018), and the Transportation Research Board's Advances in Asphalt Binder Aging Research (2020).