Pavement Research Advisory Committee (PRAC) 13 th Meeting of the RPF 8 May 2007

Slide 2 © CSIR Purpose of PRAC Partnered initiative between the public and private sector to Identify and prioritise immediate and future R&D needs in pavement engineering Coordinate and avoid duplication of R&D activities Promote a Team SA approach with the objective to fast track R&D activities and the entrenchment in practice of their outcomes (T’T, guidelines, specifications) Role of the PRAC Advise on R&D needs and priorities Advise on development of strategic plans and research portfolios Assist with technology foresight studies Assist in the review of outcomes Assist in assessing impact of R&D activities

Slide 3 © CSIR Partnered initiatives Bituminous Stabilisation Gautrans, Sabita, SANRAL MAS, US, AsAc SA Pavement Design Method SANRAL CSIR, Consultants, UP, US, AsAc Ultra-Thin Continuously-Reinforced Concrete SANRAL UP, CSIR, C&CI, Consultants Rutting Resistance of HMA Gautrans, Sabita, Akasia, Much Asphalt CSIR, ITT, Consultants, Suppliers

Slide 4 © CSIR Resolution of the 12 th meeting of the RPF “That PRAC assumes leadership and implements a systematic approach for the updating and standardisation of our engineering practices, and aligns its research agenda to support the above” Extensively debated at the 5 th PRAC meeting Role of PRAC vis-à-vis other bodies (RMC, RPF WG, etc) Does the PRAC have the powers & mandate to enforce decisions? Recommendation of PRAC Best practice documents: SANS/CIDB/other public bodies? Standards & specifications: SANS Feedback by Kobus van der Walt after tea

Slide 5 © CSIR Research Priorities Bituminous stabilisation Gravel roads and their upgrading Thin bituminous surfacings Structural design & performance Thin concrete layers Quality control & quality assurance Lime & cement-treated materials Hot-mix asphalt Materials classification Performance specifications for bituminous binders Long-life pavements Replacement of tar-based products

Slide 6 © CSIR Progress Bituminous stabilisation Main drive: Guideline document capturing best practice in bituminous stabilisation using both bitumen-emulsion and foamed-bitumen Progress: Structural design & mix design guidelines to be completed in early 2008 after which TG2 will be updated Gravel roads and their upgrading Need to upgrade Sabita Manual 10 (Appropriate Stds for bituminous surfacings) and TRH20 (Structural design, construction and maintenance of unpaved roads) taking cognisance of: New TRH12 Recent experiences gained on the upgrading of gravel roads to paved standards SADC guidelines on low volume roads Labour-based maintenance & construction techniques

Slide 7 © CSIR Progress Thin bituminous surfacings Agrément SA guideline for certification of proprietary thin-layer asphalt mixes accepted by Board of Agrément & one product has been submitted for certification (feedback by Joe Odhiambo) Seal design guideline (TRH3) currently in process of being finalised (feedback by Gerry van Zyl on issues raised at last RPF) Aggregates for ultra-thin asphalt (feedback by Alex Weideman) Structural design and performance Good progress made since May 2006 on the Development of a Framework for the revision of the SA Pavement Design Method Mapped out research needs and identified & drafted 22 Project Briefs Workshop held in April 2007 Inception reports due in June 2007 Projects to be initiated in November 2007 (Feedback by Louw Kannemeyer)

Slide 8 © CSIR Progress Hot-mix asphalt Laboratory and APT study into HMA rutting initiated in October 2006 Laboratory study almost completed Binder studies Laboratory compaction methods Wheel tracking tests Mechanical Properties (ITT, ITS, dynamic creep) APT study Heavy Vehicle Simulator & MMLS Progress will be fed back at a Symposium on 24 May (CSIR ICC) Industry meeting to be held on 23 May to discuss evaluation of rut- resistant mixes

Slide 9 © CSIR Permanent deformation of HMA (Hamburg wheel tracking test) 40  C 45  C 50  C 55  C 60  C

Slide 10 © CSIR HVS results

Slide 11 © CSIR CSIR ThermalPADS Based on locally developed asphalt pavement temperature prediction algorithms Uses daily maximum and minimum air temperature to calculate: Maximum and minimum surface temperature, Temperature at depth, Diurnal temperature profile Currently contains weather data from 65 SA weather stations Can be used to select Performance Grade (PG) binder

Slide 12 © CSIR Weather station selection

Slide 13 © CSIR PG binder selection 7-day average maximum temperature at 20mm depth Average minimum surface temperature

Slide 14 © CSIR Progress Performance specifications for bituminous binders TG1 “The Use of Modified Bituminous Binders in Road Construction” currently being reviewed by the RPF Task Group (feedback by Dennis Rossmann) Appropriate long-term durability (ageing) tests for bituminous binders currently being researched at US and the CSIR Website: