Feedback on HMA recycling task team

1
Feedback on HMA recycling task team
Trevor Distin RPF May 2008
2
Progress since last RPF

• Resolution passed at Nov 07 RPF that a task team
  be established to
• to develop best practice guidelines for the use
  of RAP in HMA
• this follows from 3 SAT seminars specialty
  session held at CAPSA07
• first task team meeting held 24 April

3
Task Team

• Manufacturers Contractors
• Bennie Greyling
• Herman Marais
• Wynand Nortje
• Gary Catin

• Client
• Dennis Rossmann
• Adreo Brits
• Rob Lindsay
• Eric Lathlief/ Krishna Naidoo
• Engineers
• Derick Pretorius
• Tony Lewis
• Nico vd Walt
• Benoit Verhaege

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Plan of action

• Use draft TRH 21 (1996) as working document
• Update with latest international best practice
• Identify appropriate documents
• Agree on content of new TRH 21
• Appoint a consultant/s to rewrite new document
• Identify specialists from task team to act as
  peer reviewers for each section
• Contract specifications to be incorporated into
  revised COTO document
• SANRAL to include in proforma project
  specifications

5
Proposed specification framework

• 3 classes of HMA
• lt 15 RAP
• gt 15 lt 30 RAP
• gt 30 RAP
• Prescribe same mix end properties irrespective
  of RAP within each class of HMA
• For each class identify
• risk/application/constraints/protocols

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Paradigm shift

• Treat RAP as a valuable asset of the State
• RAP to be regarded as an alternative aggregate
  source ie linear quarry
• Stockpile RAP for general use on future projects
• Optimise use of RAP
• RAP to be seen as competitive advantage

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Handling of RAP

• Develop protocol for reclaiming, stockpiling and
  processing RAP
• Milling of RAP
• Investigate insitu layers
• Selected premilling
• Stockpiling of RAP
• Demarcate dedicated stockpiles
• Minimise moisture content of RAP
• Avoid segregation and consolidation
• Processing of RAP
• Screen RAP into different sizes
• Fractionating of RAP when using gt15
• Plant limitations
• Type of plant
• Where the RAP is feed into mixing process

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Reference documents

• Brock D (2007), Milling recycling, Technical
  paper T-127
• Newcomb D (2007), Designing HMA mixtures with
  high RAP content, QIS 124
• Young T (2007), Processing handling of RAP, IS
  123
• EN 13108-8 (2005), Bituminous mixtures
  materials specifications for reclaimed HMA
• Austroads (2000), Framework specifications for
  HMA recycling, AP-T02
• Rebbechi J (2005), Austroads guide commentary
  series on HMA recycling
• PIARC (2007), Review of the growth development
  of recycling in pavement construction

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Content

1. Introduction
2. Pavement recycling
3. Use of RAP in HMA plant recycling
4. Feasibility of recycling
5. Mix design
6. Reclaiming of RAP
7. Stockpiling of RAP
8. Mixing plant

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Way forward

• Appoint consultant/s
• June 2008
• Complete first draft
• Nov 2008 RPF
• Publish best practice document
• Jan 2009
• Workshop best practice document
• Feb 2009