Asphalt pavement stands out as a widely adopted form of paving due to its superior performance, ease of rehabilitation, and driving comfort. When it reaches the end of its design life and becomes non-functional, the restoration, maintenance, or reconstruction processes necessitate the use of essential raw materials such as aggregates and bitumen binders.
Asphalt, though not inherently environmentally friendly, is commonly recycled to minimize asphalt waste, positioning it as one of the most recycled aggregate materials. The utilization of Recycled Asphalt Pavement (RAP) is deemed environmentally sustainable, serving as a significant motivation for the recycling and reusing of asphalt. As per Inkwood Research, the global recycled asphalt market is expected to project a CAGR of 4.98% during the forecast period, 2023-2032. The incorporation of RAP proves to be highly cost-effective for both clients and contractors, especially in expansive projects located in remote areas.
This blog examines the design & development policies on recycled asphalt across the globe.
Recycled Asphalt Market: Design & Development Policies Across the World
The US Federal Highway Administration (FHWA)’s Support Toward Using Recycled Highway Materials
Environmental stewardship stands out as a pivotal focus area within the strategic plan of the United States Department of Transportation (DOT). According to the Environmental Protection Agency (EPA), environmental stewardship involves the collective responsibility for environmental quality among those whose actions impact the environment. Aligning with this commitment, the Federal Highway Administration (FHWA) actively endorses the incorporation of recycled materials in pavement construction to champion environmental preservation, waste reduction, and the provision of cost-effective materials for highway development. The primary aim is to foster the extensive use of recycled materials in highway construction, maximizing economic and practical viability while ensuring equal or enhanced performance. Adhering to the FHWA recycled materials policy, the FHWA takes proactive measures to advance asphalt pavement recycling and technology.
The success of asphalt pavement recycling relies on satisfying three key requirements:
- Demonstrating cost-effectiveness,
- Upholding environmental responsibility
- Ensuring optimal performance
To fulfill these criteria, the FHWA has outlined specific objectives to promote asphalt pavement recycling, including:
- Encouraging the utilization of recycled materials in highway construction to the fullest extent feasible, ensuring equal or improved performance
- Advocating for the use of Reclaimed Asphalt Pavement (RAP), recognizing its significant economic, environmental, and engineering impact on pavement recycling
The FHWA has set explicit goals, such as increasing the incorporation of RAP in highway construction and rehabilitation projects and augmenting the utilization of RAP in designated projects.
The Japanese Policy Development
Japan relies on importing aggregates from Russia, and oil is also a key import. Therefore, for both economic and environmental benefits, the recycling of pavement material is imperative. The development of RAP-HMA technology in Japan has been ongoing since 1970.
In 1982, the Ministry of Construction, Japan, executed a trial pavement utilizing RAP material. The initial RAP Pavement Guide was published in 1984. By 1992, it was evident that the recycled pavement’s performance equaled that of virgin pavement, leading to the approval of the guidelines for public works. The guidelines underwent further enhancements in 2004, culminating in the publication of the comprehensive RAP Pavement Handbook. A revision in 2010 incorporated a higher RAP content to achieve superior quality. Recent studies indicate an increased mixing ratio of RAP to 70%–75%, surpassing the national average of around 50%. Presently, the focus is on integrating high RAP content into WMA technology.
The Indian Design Policy
In 1948, India witnessed the construction of its inaugural recycled pavement, a resilient infrastructure that endured for three decades without interruption. The progress of recycling technology in the early 20th century was impeded by economic factors and the high cost of equipment. However, over the past decade, leading research and development institutes, including the Central Road Research Institute (CRRI), the Indian Institute of Technology (IIT), and the National Institute of Technology (NIT), have actively explored the performance of high reclaimed asphalt pavement (RAP) mixtures. Noteworthy contributions have been made by both the central and state government highway agencies, which have issued technical circulars advocating for recycling initiatives.
Further, in 2015, the Indian Roads Congress (IRC) introduced a critical technical specification, IRC:120 (IRC, 2015b), delineating standards for the hot and cold recycling of RAP material. The evolving landscape in developing nations such as India reflects a gradual shift towards hot mixture recycling. The National Highway Agency of India (NHAI) recommends the incorporation of up to 30% RAP in the construction of new flexible pavements, assuring that this approach maintains pavement functionality and performance. Previous studies confirm the successful utilization of up to 30% RAP in several Indian states.
Notably, the Gujarat state in India readily offers modified batch mix plants designed to accommodate RAP material. Presently, the Ministry of Road Transport and Highways is steadfast in its commitment to implementing waste management practices, signaling a potential industry-wide adoption of high RAP content in hot mix recycling as a standard practice by 2030.
The Way Forward for Global Recycled Asphalt Market
As the global recycled asphalt market continues to evolve, proactive collaboration between industry players, governments, and research institutions will be crucial. A holistic approach that considers economic, environmental, and performance aspects will shape future design and development policies, fostering a sustainable and resilient infrastructure landscape. Similarly, embracing sustainable practices and aligning design policies internationally will pave the way for a resilient and environmentally responsible infrastructure future.
By Akhil Nair
Recycled asphalt is a sustainable paving material created by reusing and reprocessing old asphalt pavement. The process involves milling and crushing existing asphalt surfaces, then mixing the resulting material with a rejuvenating agent to restore its binding properties. This recycled asphalt mix is commonly used in road construction and maintenance.
Recycled asphalt promotes sustainability by reducing the need for virgin materials, minimizing waste in landfills, and lowering energy consumption compared to traditional asphalt production. Its use significantly decreases the environmental impact of road construction, aligning with global efforts to achieve eco-friendlier infrastructure solutions.