High performance asphalt and binders Part 2

1. High performance asphalt and binders Part 2

2. 2012 Study Tour Key Topics • Long life pavements • Experience, design systems, use, durability & performance • High performance asphalt & binders • High modulus asphalt (EME, HiMA), modifiers • Sustainability • RAP/WMA, bitumen substitutes, carbon calculators & energy analysisclimate change impacts, societal concerns • Health & Safety • Construction of road works, health considerations for bitumen and asphalt products • Procurement Systems • Proprietary products (Avis Technique, HAPAS, etc.), “green” procurement, REACH, responsible sourcing, PPP and contract models

3. Topic 2: High performance asphalt & binders Overview of reasons • Bituminous binders  key component in the performance and service life of bituminous surfacings & asphalt pavements • About 90% of the Australian all weather road network length is surfaced with sprayed seals  about 50% of binder usage • Need to ensure optimum asphalt & seals performance in the field, and to promote best practices suitable to be adapted & adopted in Australia. Seeking details on: • new developments and test methods in high performance asphalt and bituminous materials (e.g. HiMA /EME, PMB, Emulsion) • actions taken by European and others (e.g. binder manufacturers, asphalt producers and researchers) to overcome field problems (e.g. climate change) • correlation between laboratory test results and field trials

4. Binder Specification and PMB Testing Khar Yean Khoo

5. European Specifications for Bituminous Binders

6. Bitumen industry position report (2012)

7. Binder standards 1st generation: harmonisation of national existing standards • based on conventional test methods, completed 2nd generation:development of performance-related standards • project started in 2000, in progress • under responsibility of CEN TC 336 Bituminous Binders.

8. European standard development CEN TC336 Bituminous binders

9. Task Groups TG1 High service temps TG2 Low service temps TG3 Ageing- conditioning BiTVal Project correlation with performance specification recommendations CEN TC336 Bituminous binders Data Collection new tests data on binders

10. First generation − bitumen based on conventional test methods PENETRATION. R & B

11. Framework Specification for PMB − EN 14023 (mandatory) • penetration • softening point • cohesion • force-ductility • tensile test at 5 C • Vialit pendulum (surface dressing) • durability (RTFOT or RFT) • mass loss, retained pen, increase in S Pt • flash point After long discussion, eventually agreed on:

12. Framework Specification for PMB − EN 14023 (optional) • Fraass breaking point • elastic recovery • plasticity range (S Pt – Fraass BP) • storage stability (delta S Pt & pen) • fundamental tests (to be reported) • DSR, BBR, deformation energy

13. Elastic recovery − not an Australian test • A bitumen test sample is stretched at a constant speed predetermined elongation (200 mm). • The thread of bitumen thus produced is then cut in the middle to obtain two halves. • After leaving for 30 min, the distance between the two ends of the threads is measured.

14. Future binder specifications Industry task force concluded in 2012: • a new specification is only required for rheologically complex materials such as: • PMBs • hard paving grade bitumen • rheologically simple bitumen meeting EN12591 does not require new specifications

15. Second Generation Standards these are needed because: • first generation specs based on traditional empirical tests • performance related specs required by Construction Products Directive • performance related standards will cover a broader range of products and stimulate new development Note: binder adhesion will not be addressed. It is important but no easy test method exists or will be developed soon.Need to cover under asphalt properties

16. Summary • Europeans began development of performance related specifications in 1995 • there was great diversity of test and specs among different countries • first generation specs (1999 – 2005) concentrated on harmonisation and simple, traditional test methods − these are considered unsuitable for PMBs • second generation specifications are required but need input from users

17. PMB Testing

18. PMB test methods • no really new tests • focus is on finding a PMB property related to asphalt rutting • SHRP used Dynamic Shear Rheometer (DSR) parameter: G*/sin  - but poor correlation • Europeans - Zero Shear Viscosity (ZSV) using DSR • then easier to obtain Low Shear Viscosity (LSV) • latest is U.S. DSR parameter: non recoverable creep compliance (Jnr) − from the Multiple Stress Creep Recovery (MSCR) test

19. Concept of ZSV and LSV ZSV LSV Source: ‘Austroads 2010, ‘Laboratory study on relationship between binder properties and asphalt rutting’, AP-T164/10

20. Papers reviewed • results from Argentinian and German papers presented at the 5th Eurobitume & Eurasphalt Congress • these relate asphalt laboratory wheel tracking with binder tests: • Zero Shear Viscosity ZSV • Low Shear Viscosity LSV • Multiple Stress Creep Recovery MCSR • then will compare with Australian Consistency correlations

21. Argentinian LSV vs. WT − paper 410 • 3 asphalt types • dense 20 mm (D-20) • micro 10 mm (M-10) • SMA 10 mm (SMA-10) • 3 binder types • conventional bitumen (C) • Multigrade (M) • SBS PMB (PM) • Testing • Binders: DSR testing to get LSV at 60 C • Asphalt: Wheel tracking (rutting rate at 60 C shown)

22. R2 = 0.87

23. BP German study – paper 402 Binders • 5 normal paving grade (NPG) • 11 PMBs • 7 < 4% additive • 4 > 4% additive • 2 low viscosity wax modified (NV) • 2 special bitumens (SP) – Multigrade (MG) and Phosphoric acid modified • Asphalt • 50 mm slabs of hot rolled asphalt (6.9% binder content） • Wheel tracked at 45 C and 60 C

24. German study R2 values for three tests

25. MSCR test conditions (for Jnr) • load applied for 1 s, recover for 9 s • further 10 creep/recovery cycles • repeated for 4 stress levels (30, 100, 300, 1,000 Pa) PMB CRMB Hv PMB

26. Wheel tracking rut rate vs. Jnrof RTFOT aged bitumen at 45 C and 60  C R2 = 0.90

27. Consistency (Oliver 1998) R2 = 0.89

28. Reciprocal plot (Urquhart 2010)

29. Consistency @ 5% strain (Choi 2010)

30. Conclusions • DSR parameters used to predict rut resistance: • Jnr from MCSR best (using aged binders) • LSV satisfacotry (reciprocal relationship) • ZSV poor in reported study • Elastometer Consistency gave good prediction and will be improved by • using Consistency 5% or 6% (Choi & Urquhart) • reciprocal relationship (Urquhart) • Consistency reciprocal plot is useful for developing specification limits

31. Thank You

32. Problems / challenges Adhesion Constancy / consistency of quality (ITT) Long Term Ageing

33. TG’s • Which test for which property? • TG1 – High Service Temperatures • TG2 – Low Service Temperatures • TG3 – Ageing-conditioning • Challenges • Takes a lot of time • Moving forward (very slowly) • Good test methods are needed

34. Source: Egbert Beuving, AAPA 2012 study tour PowerPoint presentation TG1 HIGH SERVICE TEMP

35. Source: Egbert Beuving, AAPA 2012 study tour PowerPoint presentation TG2 Low Service temp/cracking

36. Source: Egbert Beuving, AAPA 2012 study tour PowerPoint presentation TG3 Ageing-conditioning

37. Source: Egbert Beuving, AAPA 2012 study tour PowerPoint presentation Other requirements

38. Consistency correlation: R2 summary for 4 mix designs

39. Consistency 6% correlation (Urquhart − BSWG, Feb 2012) Choi 10 mm mix Urquhart 10 mm mix Fitted curve: Wheel tracking = A / (Consistency 6%) + B

40. Consistency 6% correlation (Urquhart − BSWG, Feb 2012) Remtulla 10 mm mix Urquhart 14 mm mix Fitted curve: Wheel tracking = A / (Consistency 6%) + B

41. Elastometer a) 50/100 method: conventional Consistency b) 20/40 method: Underlying Viscosity (UV) over 20-40% strain c) Consistency at 5% strain