Sustainable Development Goals
PROJECT INFORMATION AT A GLANCE:
Project Status:
Road-trial and laboratory evidence established; product and application underway.
Organizations Involved:
Confidential partners; Klean Industries
Services / Equipment:
Design & Engineering, Feasibility Studies, Packaged Solutions
Recovered carbon black is the one recycled additive that strengthens asphalt and shields it from the sun at the same time. Carbon is why a tire stays black and survives years of sun and weather: it absorbs ultraviolet light and reinforces against tensile stress. Recovered carbon brings that same engineering to a road, lifting tensile strength and building in UV protection, so the pavement performs long term through sun, rain, freeze and thaw in a way other recycled-content additives cannot match.
The endurance shows up in the numbers: a water-conditioned mix kept 67.3% of its compressive strength with recovered carbon against 48.9% without it, independent Australian work measured it 31% stiffer under load, and a carbon-enhanced section held up far better under repeated wheel loading. Klean's work in recovered carbon black for asphalt connects carbon-upgrading technology with application development and testing alongside confidential partners, and our public announcement in 2005 already linked carbon upgrading to asphalt modification.
Give recovered carbon a job an asphalt buyer values. A pyrolysis plant produces a carbonaceous residue whose commercial value depends on what happens next. Raw char varies in particle size, residual contaminants, mineral content and surface properties, while an asphalt producer needs a material it can handle, disperse and incorporate consistently into a specified mix.
The pavement must also balance competing demands: resistance to deformation under traffic at high temperatures, while retaining the behaviour that resists cracking, water and ageing. Increasing stiffness alone does not establish a better road. The development challenge therefore connects two industrial processes: producing a suitable recovered-carbon product, and incorporating it into asphalt that meets the buyer's performance requirements.
Connect carbon upgrading to asphalt performance. Klean's work combines carbon-upgrading technology with application development and testing, working with confidential partners to examine the integration of recovered carbon into asphalt and the results achieved in relevant formulations.
Why recovered carbon is different from every other recycled additive. Carbon black earns its place in a tire for two reasons: it absorbs ultraviolet light, stopping sun-driven breakdown of the surrounding material, and it reinforces against tensile stress. Recovered carbon carries both functions into asphalt. The earlier research behind this application found the recovered material reinforced bitumen, increased high-temperature viscosity and elasticity, and reduced temperature susceptibility, with strong surface interaction between the carbon and the bitumen. That means a road built with recovered carbon gains tensile strength and UV protection together, the combination that keeps a pavement performing long term through sun, rain, freeze and thaw.
Test the binder, the mixture and the road. The development record spans three levels of evidence. Binder tests examine the modified bitumen, asphalt-mixture tests evaluate the combined binder, aggregate and filler, and road observations show how selected sections perform under actual exposure. The historical studies use the terms pyrolytic or pyrolyzed carbon black, often abbreviated CBp or PCB; those names refer to the particular materials tested, and our present-day approach starts by characterising the available carbon and matching its upgrading requirements to the intended application.
A road trial with markedly less recorded cracking. The historical road-trial record compared conventional asphalt, a modified-binder asphalt and a carbon-enhanced version of the modified binder. The recorded crack lengths within the selected 500-foot surveyed sections were:
| Asphalt section | Recorded crack length |
|---|---|
| Conventional asphalt | 96 linear feet |
| Modified binder without recovered carbon | 66 linear feet |
| Modified binder with recovered carbon | 12 linear feet |
The carbon-enhanced section's recorded cracking was one reflective crack. These are observed crack lengths from the trial record, not a claim of proved maintenance savings or quantified life extension, and the trial predates Klean's involvement in this application.
Associated laboratory wheel tracking gives a second comparison: the carbon-enhanced formulation reached approximately 5 mm of permanent deformation after 20,000 wheel passes, while its modified-binder comparator reached approximately 19 mm before 14,000 passes. These are approximate readings from the recorded test curve, showing resistance to repeated loading under those conditions.
Improved resistance to water damage. A separate asphalt-mixture study compared an unmodified binder with a formulation containing 10% pyrolytic carbon black in the binder. After water conditioning, the index of retained compressive strength rose from 48.9% to 67.3%, meaning the modified mixture kept a greater share of its dry strength after exposure to water.
Independent Australian research reinforces the application. Subsequent work by the Australian Road Research Board, now the National Transport Research Organisation, evaluated Australian-produced recovered carbon in separate programmes. Its plant-mix tests recorded:
| Resilient modulus | Control asphalt | Asphalt containing rCB |
|---|---|---|
| Before laboratory ageing | 6,400 MPa | 8,400 MPa |
| After laboratory ageing | 7,200 MPa | 9,000 MPa |
These are approximately 31% and 25% higher resilient modulus, respectively, with an improved fatigue response after simulated ageing. NTRO's public account of a separate Australian programme using recovered carbon black and tire-derived fuel oil also cited 5 to 8 years of additional road life and an estimated 24% carbon reduction; those programme-level assessments cover both recovered products, complementing the laboratory evidence rather than constituting an audited lifecycle model.
A product market built around performance. For Klean the commercial connection runs from the carbon-recovery plant to the asphalt customer, with the upgrading system, finished-product properties, handling method and application working together. Asphalt offers a further route to market alongside rubber and other recovered-carbon applications, and the opportunity becomes investable through repeatable quality, demonstrated performance and an agreed commercial route to the customer.
Three priority lessons selected from the wider experience behind this work. Through a defined engagement, we apply our broader technology and delivery experience to your project's requirements, risks and opportunities.
1. Performance gives recovered carbon a commercial purpose. The historical cracking and water-conditioning results show why an asphalt buyer may value the material. Develop the product around the pavement property it can improve and the specification the customer must meet.
2. Upgrading and application development belong in the same project. Carbon properties, dispersion and binder compatibility drive the result, so define the intended asphalt application before fixing the carbon-finishing equipment and product specification.
3. An asphalt outlet broadens the project's market options. Independent Australian testing supports the application's technical relevance. Translate that into project-specific qualification, delivered-cost analysis and customer acceptance before committing production volumes.
The road industry could be the next customer for your recovered carbon. The results in this study show why: carbon that improves asphalt performance gives an asphalt producer a reason to buy, and realising that opportunity takes a product suited to the mix and evidence that supports its use.
If you have tire-derived carbon to commercialise, or an asphalt mix you want to improve, bring the challenge to Klean. We combine carbon-upgrading technology with asphalt application experience to develop the material and testing programme around your intended customer.
Let's turn your carbon stream into an asphalt product worth specifying.
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ABOUT THE INFORMATION PRESENTED
These case studies present selected information authorised for public disclosure. Client identities, operating practices, process details and proprietary know-how may remain confidential. The historical road-trial and research results are attributed to their documented sources and do not assert that Klean built or conducted the 1993 trial. An enquiry, NDA or paid engagement does not automatically grant access to restricted information, client facilities or site visits.
This project addresses the United Nations Sustainable Development Goals (SDGs) by considering the goals and associated targets illustrated by the WBCSD's Tire Industry Project (TIP). TIP provides a framework for action that outlines impactful pathways for the tire sector to contribute to achieving the Sustainable Development Goals (SDGs). To learn more about how our approach, solutions, and technologies contribute to advancing the SDGs, please review the report “Sustainability Driven: Accelerating Impact with the Tire Sector SDG Roadmap”.
