Editor’s Note: Roads & Bridges does not usually give asphalt plants editorial space to express its vision like this. But recycling and sustainability are crucial, hot-button topics to the asphalt industry, and because of this, Green Asphalt in New York has become an industry leader. With the intention of moving this conversation forward, we asked Green Asphalt’s Kerianne Melillo to write the following article.
By Kerianne Melillo, Contributing Author
In a world that is increasingly focused on sustainability, the asphalt industry is no exception.
The need to reduce carbon emissions and enhance sustainability has spurred innovation, and the New York City-based asphalt producer Green Asphalt is at the forefront of this transformation.
Utilizing 100% recycled asphalt pavement (RAP), Green Asphalt demonstrates how low-carbon asphalt can pave the way for a greener future. Since its founding in 2009, the company has paved over two million tons of 100% RAP on city streets, showcasing the feasibility and benefits of sustainable road construction.
New York projects like Pelham Parkway and the Federal Plaza on Long Island exemplify the real-world applications of this groundbreaking approach and what it can mean for the future of low-carbon transportation materials.
How Green Asphalt is Made
Traditional asphalt production involves significant use of virgin materials with recycled materials averaging only about 23% of each mix nationally, but Green Asphalt leverages RAP to create high-quality asphalt.
The process begins with fractionation, which is when RAP is crushed and screened to appropriate sizes. The RAP stockpile created by this action becomes Green Asphalt’s quarry and undergoes similar stringent quality assurance (QA)/quality control (QC) requirements, such as daily gradations, moisture contents, asphalt cement (AC) contents and regular binder extraction testing. This ensures that the gradation and asphalt cement (AC) content of Green Asphalt’s finished mixes align with stringent city specifications.
Green Asphalt’s patented baghouse system is a notable innovation. This air filtration unit captures and treats blue smoke emissions, ensuring that the production process remains environmentally friendly.
The RAP heating process also is distinctive: larger RAP aggregate is added to the back of the drum where the coarse virgin aggregate would normally go. The fine RAP is added through a RAP collar that is placed before the combustion flights, allowing additional time for the material to heat in front of the flame without allowing too much time that the material runs the risk of over oxidation.
From there, the production process is relatively unchanged, with a rejuvenating oil added at the end of the mixing process, coating the RAP aggregates and mixing on its way up to the silos.
Green Asphalt currently produces 6F top and 3A binder mixes, employing rigorous testing to refine their products further. These mix designs effectively use RAP with AC contents ranging from 4.1% AC to 6.4% AC. This eliminates the need for the use of any virgin aggregates or AC.
This process is repeatable, and it has the potential to redefine the industry.
Economic Advantages
A major advantage of 100% RAP is cost-effectiveness. While RAP processing costs may increase slightly due to the fractionation process and rigorous QA/QC, the use of this RAP eliminates the need for even more costly quarrying and oil refining, allowing the producer to offer competitive pricing on their mixes.
In general, the cost per ton of 100% RAP is approximately 20-30% less expensive when compared to a traditional asphalt mix.
Transitioning to 100% RAP production might seem daunting, particularly for traditional asphalt plants. Currently, the only 100% RAP hot-mix solutions outside of Green Asphalt’s technology require erecting an entirely new plant, which comes with space, cost and permitting concerns.
Green Asphalt’s bolt-on solution offers an alternative, allowing producers to convert their existing plant with some additional equipment. However, Green Asphalt’s system can be integrated into existing setups with minimal disruption. Necessary upgrades, such as the baghouse installation, additional RAP collars and conveyors, are tailored to existing machinery, ensuring a smooth transition.
For instance, a plant currently producing 35% RAP can recoup an approximate $1 million investment in equipment after selling just 23,400 tons of 100% RAP.
These cost savings can be applied by the producer to reinvest back into other aspects of their business or can be passed on to project owners as a competitive advantage. A 30% reduction in mix cost could result in a 30% savings on a pavement project or could provide 30% more lane miles of paving to a community that needs it.
Additionally, it should be noted that several areas of the country have an excess of RAP that remains piled on producer properties, taking up valuable real estate. Utilizing this RAP to its full potential could allow a producer to clean out their RAP pile, making space for another business venture or even possibly leasing or selling a part of their property that was previously unusable.
These RAP piles have an inherit value and can be utilized for profit, rather than becoming an eye-sore or hinderance to business practices.
Reducing Carbon Emissions
Sustainability is a key driver behind this innovation. By prioritizing high RAP content, critical environmental concerns are addressed. Quarrying and oil refining—two major contributors to carbon emissions—are minimized, leading to a substantial reduction in the carbon footprint of asphalt production.
Using the National Asphalt Association’s Emerald Eco Label tool, 100% RAP has impressively low, almost-zero A1 (materials) and A2 (transport) scores. This limits embodied carbon to only include their production process.
These metrics reflect the ability to reduce emissions while also maintaining high product quality. Green Asphalt has calculated that a plant that adopts its technology could reduce its Environmental Product Declarations (EPDs) by up to 70% and can contribute heavily to a project’s LEED or En-Vision goals.
The Federal Highway Administration’s Balanced Mix Design Resource Guide ensures that mixes meet rigorous performance standards. Pre-pavement installation performance testing has been implemented, and required gradations and asphalt content requirements are followed. The asphalt that is produced is not only sustainable but also reliable and durable.
Real-World Applications
One of the biggest hurdles Green Asphalt faced was skepticism about the performance of 100% RAP compared to traditional asphalt.
However, with nearly two million tons of 100% RAP used on New York City streets and other projects, Green Asphalt’s track record speaks for itself.
Best practices, such as keeping RAP covered and dry and using appropriate crushing and screening techniques, enhance mix performance. Quality of the produced mixes is tested daily by Green Asphalt’s QA/QC lab using industry standard testing, such as Ideal-CT’s, high temperature IDT’s and flow and stability tests.
High-profile projects like Pelham Parkway, where 7,000 tons of recycled asphalt were successfully applied, highlight durability and quality. Pelham Parkway is a major semi-arterial thoroughfare through the Bronx in New York City and contains express and local lanes and a multitude of traffic lights.
Additionally, Pelham Parkway is a major bus route. Paved in May 2023, the 100% RAP provided by Green Asphalt has held up to the high daily use and is being monitored over the next several years for performance and marks an important high-profile use of 100% recycled asphalt.
Similarly, the Federal Plaza project—completed in collaboration with Suffolk Paving in the fall of 2024—saw over 10,000 tons of recycled top and binder mixes applied to a General Services Agency (GSA)-owned parking lot.
Green Asphalt’s 100% RAP mixes were selected for the project based on its ability to score in the top 20% of EPDs in the area. The project’s success displays Green Asphalt’s ability to deliver economic and environmental value.
The Road Ahead
As the asphalt industry continues to evolve, Green Asphalt offers a compelling vision for the future. By combining sustainability, innovation and economic feasibility, 100% recycled asphalt is not just a possibility but a necessity.
Projects like Pelham Parkway and Federal Plaza prove that 100% RAP can perform as well as—if not better than—traditional asphalt, making it an attractive option for contractors, government agencies and industry organizations alike.
The question is not whether this will play a role in the asphalt industry’s future, but rather how quickly it will become the standard. RB
Kerianne Melillo is the chief marketing officer at Green Asphalt.
