Recycled Materials in Asphalt Pavement: Bridging the Lab-Field Performance Gap for Sustainable Roadways

The adoption of recycled materials—particularly reclaimed asphalt pavement (RAP) and recycled plastics—has become increasingly prominent in the asphalt pavement industry. Their utilization promises conservation of natural resources, reduced environmental impact, and lower construction costs. While laboratory studies consistently highlight the improved performance characteristics of asphalt mixtures incorporating these recycled components, a critical challenge remains: many state transportation agencies restrict RAP and similar materials due to concerns about long-term field performance. This highlights a persistent gap between the benefits observed under controlled laboratory settings and the variability observed in actual roadway conditions.

Key Challenges Include:
o Mix Design Optimization: Determining optimal recycled material content without compromising durability and longevity.
o Material Aging: Understanding how recycled materials behave and degrade over time in real-world environments.
o Evaluation Methods: Developing robust, performance-based or mechanistic tests that reliably predict field behavior.
o Performance Predictability: Bridging the disconnect between lab-tested results and field performance outcomes.
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Despite regulatory caution, advances such as Balanced Mix Design (BMD), sophisticated aging simulation, and the application of machine learning and advanced modeling tools offer fresh opportunities to address these issues. Collaborative, interdisciplinary research is essential to transform promising laboratory results into sustainable, high-performance infrastructure solutions.

Aims & Scope

This Research Topic seeks original research articles, reviews, and case studies that address (but are not limited to) the following areas:

1. Innovative Mix Design Approaches:
o Strategies for maximizing recycled material content while maintaining or enhancing pavement performance.
2. Advanced Performance Testing:
o Development and application of performance-based, mechanistic, and aging simulation tests for asphalt mixtures with recycled content.
3. Predictive Modeling:
o Use of advanced modeling techniques (e.g., finite element analysis, artificial intelligence, and machine learning) for accurate prediction of field performance based on laboratory data.
4. Field Validation Studies:
o Case histories and experiments that identify and reduce discrepancies between laboratory and field performance, offering practical solutions for highway agencies.

By facilitating interdisciplinary collaboration and showcasing cutting-edge research, this Topic aims to advance the reliable use of recycled materials in asphalt pavements, promoting sustainable, high-performing, and scientifically robust infrastructure for the future.

Keywords: Reclaimed Asphalt Pavement (RAP), Recycled Plastics, Asphalt Mixture Design, Field Performance, Laboratory Evaluation, Performance Gap, Sustainable Pavement, Binder Modification, Balanced Mix Design (BMD), Pavement Recycling, Mechanistic-Empirical Design

Important note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.