Presentation by Anna D'Angelo, Executive Director, Technology, of the Australian Flexible Pavements Association. Delivered at the California Asphalt Pavement Association "Where the Rubber Meets the Road" asphalt rubber educational workshop April 18, 2023 in Sacramento.

1. AfPA International
Knowledge Transfer
2023 USA
Overview of Australia’s sustainability
goals related to tires

2. • AfPA: Australian flexible Pavement
Association – previously AAPA
• Peak body representing all parts of the
flexible pavement industry in Australia
since 1969.
• AfPA memberships include bitumen
suppliers, asphalt producers, sprayed
surface operators and equipment
suppliers, all State Government Road
Authorities and many Local Governments
from across Australia.

3. AfPA IKT 2023
Sustainable, Smarter and safer construction works
1. Sustainable best practise for the selection, design and
construction of pavements (roads & airports)
2. Low carbon and reusable materials
3. Pavement preservation best practice to achieve lower
life cycle cost
4. Binder and asphalt characterization & performance
assessment
5. Sustainability in procurement practices

4. IKT2023 Delegates

5. Overview
• Tyre Stewardship Australia
• Waste tyres – the scale of the issue
• Why crumb rubber?
• CRB specification and use in roads
• Current focus & projects
• Summary

6. Who is Tyre Stewardship Australia? What is the purpose of the organization?
Who is TSA?
• An industry-led VOLUNTARY Product Stewardship Scheme.
• Three objectives:
1. Create and facilitate new markets from tyre derived material.
2. Ensure and mitigate against the mismanagement of end of life tyres
3. Raise awareness of the issues, solutions and opportunities
Who is TSA? What is the purpose?
$8M towards
new projects
Accreditation,
Compliance and
Audit
MyTyres
MyChoice
What is the purpose?
• To be the custodians of our own waste
• Drive sustainable outcomes for end of life tyres
• Facilitate the commercialization of opportunities

7. Source: TSA (2021). Australian Tyre Consumption and Recovery in 2019-2020.
OTR include tyres from
Tractors (agriculture, construction) 33.6%
Aircrafts (aviation) 2.9%
Fork lifts (manufacturing and trade) 2.3%
Earth movers (mining) 61.2%
459,000 tonnes of tyre waste generated annually
( 57 million EPU)
8

8. This is what 57 million used tyres look like 9
Tyre waste generated 459,000 tonnes per year

9. Source: TSA (2021). Australian Tyre Consumption and Recovery in 2019-2020.
Fate of Australian used tyres
Used whole in thermal
processing
Disposed to landfill or
buried
Dumped or stockpiled
Processed into TDPs
Reused
10
Total recovery rate

10. Source: TSA (2021). Australian Tyre Consumption and Recovery in 2019-2020
Fate of Australian used tyres
Out of the 72.5% ‘RECOVERED’ tyres (= 332,000 tonnes):
• only 21% (= 69,000 tonnes) is used for domestic market
• 79% is exported (= 263,000 tonnes)
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In 2019 Environment Ministers
agreed that waste tyres that
have not been processed
into a ‘value-added material’
should be banned from being
exported overseas

11. End-of-life tyres in New Zealand
12
• Tyrewise is the regulated product stewardship programme that will provide for the nationwide
resource recovery of end-of-life tyres in New Zealand.
• A report from Tyrewise (2020) indicated that New Zealand produces ~6.5 million EOLTs per
year – of these, ~ 4 million EOLTs ended up in landfill, stockpiled or dumped posing a threat to
the environment
In July 2020, the NZ Government declared tyres as a ‘priority product’ and as a
result, a regulated product stewardship is being implemented to improve the
environmental impact of end-of-life tyres.

12. Main CR sources
• Passenger tyres
• Truck tyres
• Off-road tyres
OTR include tyres from
Tractors (agriculture, construction) 33.6%
Aircrafts (aviation) 2.9%
Fork lifts (manufacturing and trade) 2.3%
Earth movers (mining) 61.2%

13. Why crumb rubber?
• Environmental benefits
• Reduction exposure to harms by illegal tyre dumping
and stockpiling
• Recovery of resources
• Energy and GHG emissions: Recycling end-of-life
tyres in roads can save 75% of CO2eq emissions
compared to sending them to landfill
• Technical benefits
• Enhanced elastic properties
• Anti ageing properties: “sunscreen effect”

14. TAS, Hobart (noon, cloudless)
VIC, Melbourne (noon, cloudless)
NSW, Sydney (noon, cloudless)
SA, Adelaide (noon, cloudless)
WA, Perth (noon, cloudless)
NT, Darwin (noon, cloudless)
Technical benefits – anti ageing
QLD, Brisbane (noon, cloudless)

15. Test conditions
Duration: approx. 36 days (to simulate 1 year
of UV radiations in Melbourne)
Internal Temp: 30 °C
The complete set of experiments can be found at:
Muhammad Jamal, Michele Lanotte, Filippo Giustozzi (2022)
“Exposure of crumb rubber modified bitumen to UV radiation: A
waste-based sunscreen for roads,” Journal of Cleaner Production,
Volume 348, doi: 10.1016/j.jclepro.2022.131372

16. Carbon black as a 'sunscreen’
• Crumb rubber can reduce UV-related ageing of the road infrastructure
• Preliminary results showed crumb rubber can halve the rate of sun damage to roads
(extended service life and cost savings)
• Particularly suitable for local roads or roads where the primary deterioration mechanism is
non-load related

17. Specification for Crumb rubber #30 mesh

18. Specification for
Crumb rubber
modified
bitumen (ATS3110)
Polymer Modified Binders for Sprayed Sealing Applications

19. Specification for
Crumb rubber
modified
bitumen (ATS3110)
Polymer Modified Binders for Asphalt Applications

20. Specification for
Crumb rubber
modified
bitumen (ATS3110)
Properties of Field-Produced Crumb Rubber Binders

21. Spray sealing
• 341,000km of surfaced roads
• > 80% surfaced with spray seals
• 1951: first recorded use of CRB (NSW)
• 1970: field blending 5 -18% (VIC)
• 1990s: factory blended >10% developed

22. Sprayed sealing
• 1950s – NSW
• 1960’s – VIC
• 1980’s – WA
• 1992 – First national spec
• 2000’s – SA
• 2010’s - QLD
1950’s
1960’s
First National Specification 1992
1980’s
2000’s
2010’s
24
Base image: AUSLIG

23. Field blending
• Blending methods employed either in
line or dedicated mixing unit, 5 – 18%
• 5 – 10% rubber to bitumen to improve
early aggregate adhesion
• Allows new seal to be opened to traffic
with reduced risk of stone loss
• 15 – 18% rubber used to treat cracking
and in high stress and high temperature
environments

24. Factory blending
• The challenge is to prevent the
undigested rubber particles from
falling out of suspension during
transport
• Improvements have been made to
allow preblended CRB to be
transported up to 2000km

25. Dry process used for decades in:
• VIC
• NSW for wearing courses to retard reflective cracking
Wet process
• Open graded asphalt as a PMB substitute to improve durability
• Gap graded asphalt to prevent crack reflection in concrete pavements
• Dense graded asphalt in Council Roads
Crumb rubber in asphalt

26. Crumb rubber in asphalt
Australian experience
• 2018 NACOE Research Projects – collaboration with AfPA
• TMR draft specification PSTS112
• AfPA Pilot spec OGA/GGA - based on Arizona/California specification
• Demonstration trials to validate specification & monitor emissions
Crumb rubber OGA Bli-Bli trial Crumb rubber GGA – Gold Coast trial
Hot mix rubber OGA10/Warm mix rubber OGA10
SBS modified OGA10 (control)
Warm mix rubber GGA14
AC14 with SBS / AC14 with C320

27. • Western Australian Road Research and Innovation Program (WARRIP) Projects
on Crumb Rubber Binders (OGA/GGA)
• Draft MRWA specification 516 and 517 (updated 2020)
• DoT Victoria East Boundary Rd Crumb Rubber Asphalt Trial (SMA/GGA/DGA)
Crumb rubber in asphalt
Australian experience
CRM GGA mixes on Marmion Avenue CR OGA Kwinana Freeway East Boundary Rd

28. Crumb rubber used in roading applications

29. Current & Future focus
With almost 400 mines operating across Australia,
mining consumes almost 85,000 tonnes of OTR tyres
annually - the most of any OTR sector.
The agriculture sector consumes on
average over 37,000 tonnes of tyres,
second only to the mining sector

31. Current projects
OTR tyres in spray
sealings – S45 R
OTR tyres in asphalt
A18 R GGA
Passenger car tyres in
asphalt – several mixes
Passenger car and OTR tyres
in asphalt – S45 R in DGA
Passenger car tyres in
asphalt – several mixes

32. Summary
• CRMB is used extensively in sprayed seals
• In line field blending allows greater flexibility for spray sealing contractors to
adjust rubber between 5 – 18%
• Increasing use of crumb rubber in asphalt (wet method)
• New crumb rubber binder grades in specification for use in asphalt and in sprayed
sealing
• There is greater awareness of environmental and performance benefits derived
from use of CRMB in spray seals and asphalt

33. AfPA Conference 30 October – 1 November 2023

34. Thank you for listening
36
anna.d’angelo@afpa.asn.au

35. AfPA International
Knowledge Transfer
2023 USA
Thanks