According to WPB, a new study published on October 8, 2026, has demonstrated a chemical recycling process capable of transforming severely aged bitumen recovered from asphalt roofing shingles into reusable binder suitable for roofing and potentially road paving applications. Using renewable fatty amines, researchers achieved chemical changes in the asphaltene-rich material rather than merely softening it, opening a potential pathway toward replacing 100% of virgin bitumen at the binder level.
The research introduces a chemical upcycling approach for recycled asphalt shingles (RAS), a material that contains highly aged and oxidized bitumen. Unlike reclaimed asphalt pavement (RAP), which is recovered from existing roads, RAS originates from asphalt-based roofing products. Its binder is typically much harder and more heavily aged, making it difficult to incorporate into new paving materials without compromising performance.
Conventional recycling methods often rely on adding softer bitumen, oils, or rejuvenating agents to reduce the stiffness of aged binder. Although these treatments can improve workability and certain rheological properties, they do not necessarily reverse the chemical changes associated with aging. The new study takes a different approach by using renewable fatty amines that react with asphaltenes, altering their chemical structure and converting part of the asphaltene-rich fraction into maltene components.
The researchers examined the process using air-blown asphalt, binder extracted from recycled roofing shingles, and a laboratory-produced RAS binder obtained by artificially aging air-blown asphalt. The results showed that changing the treatment conditions could produce materials with different properties. Limited softening generated a chemically rejuvenated binder with characteristics similar to virgin air-blown asphalt, while further treatment produced a binder suitable for paving-grade applications. More extensive softening could generate a liquid product.
Chemical analysis provided evidence that the treatment involved more than physical dilution. Results from the Saturates, Aromatics, Resins–Asphaltene Determinator (SAR-AD) method showed that part of the asphaltene fraction was transformed into lighter aromatic and resin fractions, particularly the Aromatics 3 category. Size exclusion chromatography also revealed a substantial reduction in associated asphaltene molecular species.
Additional experiments using asphaltenes extracted from RAS and coco amine provided further evidence of chemical modification. Nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), and gas chromatography–mass spectrometry (GC-MS) indicated the attachment of alkyl groups and alkyl amines to aromatic structures within the asphaltenes. Together, these findings supported the researchers' conclusion that the treatment chemically modified the aged binder rather than simply diluting it.
The changes were also reflected in the binder's mechanical behavior. Rheological testing showed that chemically treated binders exhibited improved relaxation properties at low temperatures, an important factor in reducing susceptibility to thermal cracking. Dynamic shear rheometer measurements further indicated improved ductile behavior compared with binder treated through physical dilution using the same fatty amine.
One of the study's most important findings concerns the possibility of repeated recycling. After the chemically rejuvenated binder was subjected to another aging cycle, researchers successfully applied the treatment again. This suggests that chemical upcycling could potentially support repeated recovery of roofing and paving binders rather than limiting recycled material to a single additional use.
However, the demonstration of repeatability after re-aging should not be interpreted as proof that the process can be repeated indefinitely without performance losses. The longer-term behavior of materials subjected to multiple recycling cycles still requires further evaluation.
The most significant industrial implication is the possibility of completely replacing virgin bitumen with chemically recovered RAS binder. Based on binder-level characterization, the researchers concluded that the process could potentially enable aged and oxidized materials to replace 100% of virgin binder while achieving properties appropriate for selected applications.
This finding represents a potential advance beyond conventional blending approaches, where aged binder is often combined with virgin material to achieve the required specifications. Nevertheless, 100% virgin-binder replacement is not equivalent to demonstrating a commercially produced asphalt mixture containing 100% recycled materials, nor does it establish equivalent pavement durability under real traffic and environmental conditions.
For the petroleum and bitumen industries, the technology could create a higher-value use for bitumen recovered from roofing waste. If successfully developed for industrial applications, chemical upcycling could reduce dependence on newly produced petroleum bitumen while creating new opportunities for manufacturers of rejuvenating agents and recycled binders.
The potential commercial benefits, however, depend on several factors that require further assessment, including the availability and consistency of RAS feedstock, binder extraction, chemical consumption, processing costs, quality control, and performance after long-term aging. The published binder-level findings do not establish the economics of large-scale commercial production or quantify environmental savings.
The research highlights a possible shift in asphalt recycling technology: from softening aged bitumen for limited reuse toward chemically modifying it to recover higher-value binder properties. For bitumen producers, roofing manufacturers, and road construction companies, the significance lies in the possibility of transforming a difficult-to-recycle petroleum-derived waste into a reusable material.
Although commercial-scale validation remains necessary, the study provides evidence that severely aged bitumen may retain greater recovery potential than conventional physical rejuvenation methods can achieve.
By WPB
Chemical Upcycling, Recycled Asphalt Shingles, RAS Binder, Virgin Bitumen Replacement, Renewable Fatty Amines, Asphaltenes, Maltenes, Chemical Rejuvenation, Asphalt Recycling, Circular Bitumen, Roofing Asphalt, Paving Grade Bitumen, SAR-AD, Sustainable Asphalt Technology
