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Feedback on HMA recycling task team. Trevor Distin RPF May 2008. 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
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Feedback on HMA recycling task team Trevor Distin RPF May 2008
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
Client Dennis Rossmann Adreo Brits Rob Lindsay Eric Lathlief/ Krishna Naidoo Engineers Derick Pretorius Tony Lewis Nico vd Walt Benoit Verhaege Manufacturers & Contractors Bennie Greyling Herman Marais Wynand Nortje Gary Catin Task Team
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
Proposed specification framework • 3 classes of HMA • < 15% RAP • > 15 < 30% RAP • > 30 % RAP • Prescribe same mix end properties irrespective % of RAP within each class of HMA • For each class identify: • risk/application/constraints/protocols
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
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 >15% • Plant limitations • Type of plant • Where the RAP is feed into mixing process
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
Content • Introduction • Pavement recycling • Use of RAP in HMA plant recycling • Feasibility of recycling • Mix design • Reclaiming of RAP • Stockpiling of RAP • Mixing & plant
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