Roads & Infrastructure breaks down SAMI Bitumen Technologies’ recent attendance and exhibitor booth from the latest Australian Flexible Pavement Association International Flexible Pavement Conference.
The 20th AfPA (Australian Flexible Pavement Association) International Flexible Pavement Conference, themed “Future-Ready Roads”, brought together the road industry’s leading professionals to Adelaide Convention Centre.
SAMI Bitumen Technologies stood out as a Gold Sponsor, showcasing its leadership through an interactive booth, four poster presentations, one oral paper, and multiple award nominations culminating in state and national award wins. The company’s vibrant presence reflected a unified commitment from the SAMI team to support the conference’s vision of sustainability and performance in modern road construction.
Under the motto “Driving Innovation and Sustaining the Planet”, SAMI reaffirmed its core principle – innovation as a path to sustainability. For SAMI, sustainability is not merely about lowering initial carbon emissions but also about designing pavements that last longer, perform better, and require less maintenance.
As R&D and Technical Support Manager Dr Hamidreza Sahebzamani explained, “The most sustainable road is the most durable one.” This philosophy guides SAMI’s R&D direction in developing low-carbon, high-performance binders, emulsions, and asphalt technologies that balance environmental responsibility with engineering resilience.
Research, the heart of sustainability
Among the technical highlights of the conference was Hamidreza Sahebzamani’s paper “The Effect of Biogenic and Recycled Oils on Binder Durability.” The study compared the effects of biogenic oils (derived from biogenic feedstocks) and re-refined engine oil bottoms (REOB) on the long-term performance of bituminous binders.
This work aligns with SAMI’s ongoing mission to understand how alternative feedstocks can be used responsibly, where recycled materials reduce waste and bio-based components capture carbon, without compromising performance.
ΔTc — A measure of durability
ΔTc (Delta Tc) parameter now recognised globally as an indicator of binder relaxation and cracking resistance after aging. Derived from Bending Beam Rheometer (BBR) tests, ΔTc is the temperature difference between the binder’s stiffness failure (Ts) and relaxation failure (Tm).
In practice, ΔTc quantifies how well a binder can relieve stress and resist brittle cracking after long-term oxidation. Generally a ΔTc value higher than -5°C indicates good durability; values more negative than -5°C suggest brittleness and poor long-term flexibility, however this limit is different in various jurisdictions.
This parameter has been proven to correlate closely with field cracking and the Glover-Rowe parameter, linking laboratory data directly to pavement performance.
Biogenic Oils vs. REOB
The research revealed a contrast between the two additive types. Binders modified with REOB, even at low levels, showed a drop in ΔTc to below -5°C after aging, indicating loss of stress-relief capacity and higher cracking potential.
Conversely, biogenic binders maintained or improved their ΔTc values even after 40 hours of aging, reflecting better durability and oxidation resistance. In field and laboratory evaluations, asphalt made with biogenic binders displayed excellent fatigue life, rutting resistance, and moisture stability all while offering a significantly lower carbon footprint and full recyclability.
Emulsion behaviour — A practical test of compatibility
Another key outcome came from SAMI’s emulsion testing. While bio-based binders emulsified easily, maintaining stability over several weeks, REOB-modified binders failed even at two per cent concentration, with emulsions separating within days of storage.
This confirmed that REOB hinders emulsification, whereas biogenic oils integrate seamlessly into spray seal and cold-mix applications.
Recognition, collaboration, and the road ahead
SAMI’s scientific achievements at AfPA 2025 were complemented by national recognition for outstanding project, innovation and safety. The company’s ongoing investments in research and development, including the SAMI Technical Centre in Sydney, ensure that future generations of binders and asphalts are designed around performance-based durability and carbon-aware materials science.
Through collaboration with partners across Australia, SAMI continues to help lead the industry toward sustainable, circular, and future-ready roads.
Future-ready roads through science and stewardship
As the pavement industry evolves toward net-zero and circular construction, SAMI’s work exemplifies how scientific research and industrial practice can merge to create tangible progress.
By focusing on materials that not only reduce emissions but also extend pavement life, SAMI is proving that the path to sustainability is paved with durability, responsibility, and innovation truly Driving Innovation and Sustaining the Planet.
This article was originally published in the December edition of our magazine. To read the magazine, click here.
