IPWEA SA 2016 – Conference Low Traffic Volume Asphalt Trial Rod Ellis 27 May 2016 Support From:

Introduction 2012 trials resulted in DPTI Specification for FineAC10 Characteristics of the mix include: Finer Grading then medium duty DPTI mixes Minimum binder content 5.7% Characteristic Field Air Voids 2.5% min 6% max specified Laboratory Voids Target 4% 2015/2016 trials were established to explore if the FineAC10 specification can be translated to the field

Mix Philosophy Refer Linden et al (1989) Asphalt pavement life is reduced by 10% for each % increase in voids above 7% Oliver 1992 “Ageing of binder greatly reduces for mixes that are compacted to 6% air voids and below” APRG Technical Note - light duty non structural asphalt surfaces and overlays (July 1997) Aims: Low air voids (density) High bitumen content (impermeability)

Goal Longer life asphalt for Lightly Trafficked roads that minimises whole of life cost and has environmental benefits Characteristics A fine, dense graded aggregate distribution in combination with a high binder content. Create mixes that are easy to compact, this to remedy the rapid cooling that takes place when mixes are constructed in thin layers Considers challenges such as stiffness of underlying pavement, Irregular shape of underlying pavement, Access for full size paving and compaction equipment. Mixes will be constructed to a low in-situ air voids content. This will reduce the permeability of the mixes, which helps to protect the underlying granular layers and limits oxidation aging of the binder. The high flexibility of the mixes will accommodate the relatively high deflections in residential street pavements

Aim to slow down aging process

Trial Sites The trial site should be an urban street carrying traffic that falls within the lowest category of Table A 2 of the Austroads ‘Guide to Pavement Technology Part 4B: Asphalt’, i.e.: A street that carries less than 100 commercial vehicles per lane per day The structural design level for the street should be less than 5 x 105 ESAs Light free flowing traffic For the purpose of the trial a street should be selected that does not include steep inclines or busy intersections

Project Financial Support and active involvement IPWEA led trials 2015 and 2016 with financial support and active participation of: City of Salisbury City of Playford City of Port Adelaide Enfield West Torrens City Council City of Mitcham Corporation of the City of Adelaide Corporation of the City of Marion City Of Unley Light Regional Council City Of Prospect

Project Team Project Sponsor– John Hutton IPWEA SA Board Project Lead – Rod Ellis Tonkin Consulting supported by Rodney Uebergang Technical Advisors on Reference Group – Hugo van Loon (DPTI) and Dr Erik Denneman (ARRB) AAPA Rep –Klinton Devenish Expert Panel – the above Contractors – Top Coat, Fulton Hogan, Boral and Downer Councils – 10 Councils ( Unley, ACC, Light no trial sites yet)

Project Scope so far Expert Reference Group (AAPA, DPTI, IPWEA, ARRB and Tonkin) Engagement with Industry ( Asphalt Companies) Development of protocol and trial requirements Establishing 8 trial sites from April – June 2015( air temps range degree C) Reference Group Review Modify Protocol for Summer trial Establishing 5 trial sites from Feb - April 2016 ( air temps above 25 degree C) Reference Group Review Next Steps to be determined

Site and Ambient Temps

Winter Trail Field Voids compared to previous trail Winter Trial 2015 (FineAC10) – 8 sites Any Binder Combination warm or hot bitumen ( 1 mix per site)

Key findings Winter Trail Ambient temperature deg C resulted in the question being asked - what can happen when Temps over 25 degree C? Is FineAC10 compacting better than lower binder mixes supplied by industry using lower up front cost alternatives? WMA with FineAC10 placed at cooler temperatures showed improved results for field voids from 2012 to 2015 Outcome New Protocol developed for summer and using 2 mixes per site (contractor mix and FineAC10)

Scope of mixes trials Summer Trial 2016 (FineAC10/LG Mix) – 5 sites Any Binder Combination warm or hot bitumen (2 mix per site, One Fine AC10 and One LG Mix)

Key findings Summer Trial Ambient temperature above 25 deg C using hot Fine AC10 resulted in field voids generally below 7 %. Only 2 sites demonstrate difference of Fine AC10 ( 5.8 Binder to LG Mix 5.2 Binder) results in upper field voids difference from to 9-10%. Can WMA with Fine AC10 placed at higher temperatures in Winter with Sasobit additive improve workability for ambient temps below 20 degrees C. Can WMA with Fine AC10 placed at lower temperatures in Summer with Sasobit or Foam improve workability for ambient temps above 25 degrees C

High Level Insitu Air Voids all trials 2012, 2015, 2016

Summary of all mix types 2015 and 2016 Fine AC10 – sorted by Temp

Summary of all mix types 2015 and 2016 Fine AC10 – sorted by voids

Key Findings so far FineAC10 can be placed with upper void limit below 7% when placed above 25 degree ambient temp with C170 (over 150 degree auger temp). FineAC10 WMA can be placed with upper void limit below 7.5% when placed below 20 degree ambient temp with C170 (below 140 degree auger temp). Next question to answer – Can Fine AC10 be placed consistently below 7% air voids for ambient temperatures below 20 degree C?

Next Steps Trials below 25 degrees ambient temperatures for WMA Additive but placed with auger temperature at or above 150 degrees. Trials above 25 degrees ambient temperatures for WMA Additive and place with auger temperature below 140 degrees. Test a range of durability tests – wheel tracking and tensile strength ratio subject to funding