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Bituminous Stabilized Materials Guideline

Bituminous Stabilized Materials Guideline. RPF Feedback : K Jenkins May 2006. Background. South Africa’s road network is ageing Many designs use crushed stone But, difficult to open new quarries Increasingly inappropriate solution Need to rehabilitate with available materials

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Bituminous Stabilized Materials Guideline

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  1. Bituminous Stabilized Materials Guideline RPF Feedback : K Jenkins May 2006

  2. Background • South Africa’s road network is ageing • Many designs use crushed stone • But, difficult to open new quarries • Increasingly inappropriate solution • Need to rehabilitate with available materials • Use of foam and emulsion are appropriate solutions for many cases

  3. Guidelines • Emulsion materials • Sabita Manual 14 (1993) • Sabita Manual 21 (1999) • Foamed bitumen materials • TG2 Interim Guideline (2002) • Guidelines widely used, but need to • Modernize • Improve • Place foam and emulsion on equal footing • Create a single, combined guideline

  4. Current Project • Initiated and funded by Gautrans and SABITA • Update and produce a new, combined guideline document • Objectives • Improved mix and structural design • Use of real field data and HVS data to develop design method • Construction guidelines

  5. Project Structure Phase 1: Inception Study Structural Design (F Long) Mix Design (K Jenkins) Phase 2: Development of Design Guidelines Structural Design (F Jooste) Mix Design (K Jenkins) Selection Criteria Phase 3: Guideline Compilation & Review Mix Design Guidelines Structural Design Issues Construction Issues Guideline Finalization & Review

  6. Inception Study Results • Investigated aspects of mix design that need development, and planned these development activities • Proposed a structural design method • Investigated the type and quality of data from field pavements that can be used to develop design method

  7. Mix Design • Best tests to capture material properties • Durability test • Shear properties through triaxial test • Curing • Standardization • Specimen preparation • Mixing • Compaction • Curing • Testing • Interpretation

  8. Purpose of flexibility/fatigue tests • Flexibility increases with increasing binder content Flexibility Strength Cement/binder ratio

  9. Strain at Break comparison

  10. Fatigue Strain

  11. Flexibility vs Durability

  12. Recent curing protocols • 24 hours in mould and 72 hours at 40°C (unsealed)  Six months in road (Loudons, 1994) • 24 hours in mould and 72 hours at 40°C (sealed)  Six months in road (TG2, 2003) • 24 hrs at ambient (unsealed) + 48 hours at 40°C (sealed) + several hours cooling at ambient (unsealed)  Medium cure (Wirtgen, 2004) • 24 hours at ambient (unsealed) and 48 hours at 40°C (sealed)  Medium cure (Houston, 2004) • 20 hours at 30°C (unsealed) and 2x24 hours at 40°C & change bag (sealed)  Med cure (Univ Stell, 2004)

  13. Possible Curing Approach Foam Emulsion Active filler Inactive/no filler Active filler Inactive/no filler

  14. PERFORMANCE INFORMATION FWD Test Pits Emod1 Visuals Class B Nf DCP Class B Emod2 Field Performance LAB 3-10 Mesa Options Class A Long Term Field Performance Elastic Theory Emod3 RSD MDD Approaches to Structural Design BEHAVIOUR

  15. Traffic Class: 0 to 1 MESA 10 to 30 MESA 1 to 3 MESA 3 to 10 MESA       000 BS-B 000 BS-A  000 BS-C 000 BS-A 000 BS-B 000 BS-A 000 BS-B Subgrade Class A  000 SC-C 000 SC-B 000 SC-C 000 SC-C 000 SC-B 000 SC-B 000 SC-B        000 BS-A 000 BS-A 000 BS-A 000 BS-B 000 BS-A 000 BS-B 000 BS-B  Subgrade Class B 000 SC-A 000 SC-B 000 SC-B 000 SC-B 00 SC-B 00 SC-A 00 SC-A     000 BS-B  000 BS-B 000 BS-B 000 BS-A 000 BS-A 000 BS-A   000 SC-C 000 SC-B 000 SC-B 000 SC-A 000 SC-C 000 SC-C  000 BS-B   000 BS-A 000 BS-A Subgrade Class C Not Recommended Without Special Subgrade Preparation or Addition of Selected Layers 000 SC-B 000 SC-B 000 SC-A Legend and Notes:  = Structural Capacity validated through LTPP data (see Appendix A for Details)  = Structural Capacity validated through HVS testing (see Chapter 5 for Details) 000 BS-X Denotes 000 mm of Bitumen Stabilized Material, Class X = Structural Capacity estimated by interpolating between LTPP data and HVS testing 000 SC-X Denotes 000 mm of Class X support material Design Matrix

  16. Key Aspects of the Method • Focus on materials investigation • Some results to come from mix design • Specific guidelines for materials classification • Directly linked to observed field performance • Limited intermediary analysis steps • Yes / no system, limited scope to manipulate or misinterpret • Suitable for all levels of practitioners

  17. Emulsion (13) N1 Section 1 (Kraaifontein) N1 Sections 13 and 14 (Springfontein and Trompsburg) N2 Section 16 (Kwelera, East London) N3 Section 4 (near Mooi River) N4 Section 1 (Scientia to Pienaars River) N4 Section 5X (2 sections) (Wonderfontein to Crossroads) N7 Section 7 (near Kammieskroon) N12 Section 19 (Exp 1&2) (near Daveyton) MR27 (near Stellenbosch) P23/1 (Kroonstad to Steynsrus) D2388 (Cullinan) LTPP Sections Foamed bitumen (7) • P24/1 (near Vereeniging) • MR504 (A, B, C) (near Shongweni) • Same-Himo (1, 2, 3) (Tanzania)

  18. HVS Sections • N3 near Pietermaritzburg (4 ETB) • N2-16 near East London (1 ETB) • P9/3 near Heilbron (6 ETB) • D2388 near Cullinan (4 ETB) • P243/1 near Vereeniging (2 ETB,2 FTB) • N7 (TR11/1) near Cape Town (2 FTB) • N12-19 near Daveyton (1 ETB)

  19. Synthesis of observed performance

  20. LTPP Age Years MESA Accommodated to Date Section 3 6 9 12 15 18 21 24 30 N12-19 (1) 30 N12-19 (2) SUBBASE N1-13&14 25 N2-16 Crushed stone 25 N1-1 20 CTB N7-7 19 Natural gravel N3-4 17 MR27 17 ETB 13 P23/1 8 D2388 PARENT MATERIAL N4-5X (20-25) 8 N4-5X (27-30) 8 6 N4/1 Cemented crushed stone 11 Same-Himo (1) 11 Same-Himo (2) Recycled BTB Same-Himo (3) 11 10 MR 504 (1) 10 MR 504 (2) Crushed stone 10 MR 504 (3) P24/1 6 Natural gravel

  21. HVS MESA Accommodated Age Years Section 3 6 9 12 15 18 21 24 3 6 9 12 15 18 21 24 90 Surfacing 200 ETB 150 Lime stabilized base 150 Lime stabilized base N3 HVS (1) 0 N3 HVS (2) 0 SUBBASE N3 HVS (3) 0 N3 HVS (5) 0 Crushed stone N2-16 (322A2) 8 P9/3 (372A3) 0 CTB P9/3 (373A3) 0 Natural gravel P9/3 (374A3A) 0 P9/3 (374A3B) 0 LTB P9/3 (375A3) 0 PARENT MATERIAL P9/3 (376A3) 0 D2388 (397A4) 0 D2388 (403A4) 1 D2388 (407A4) Cemented crushed stone / natural gravel 2 D2388 (408A4) 3 P243/1 (409A4) 0 P243/1 (410A4) 0 Recycled BTB P243/1 (411A4) 1 P243/1 (412A4) 1 Crushed stone N7 (415A5) 0 N7 (416A5) 0 N12-19 (415A5) Natural gravel 30

  22. Key Trends: Support & Thickness • Subbase • Majority ETB sections have cemented subbase • Majority foam sections have gravel subbase • Base thickness: majority 100 - 200 mm thick • > 3 MESA even on thin bases • Subbase thickness: majority  150 mm • In TRH4, no sections for 3 to 10 MESA have subbases < 200 mm. Significant savings possible?

  23. Section N1 Section 13 & 14 TRH4 Traffic (MESA) 10 - 13 10 - 30 Pavement Structure 50 mm Surfacing 38 mm Surfacing 150 mm G1 160 mm ETB 150 mm ETB 250 mm C3 Key Trends: Traffic accommodated • Traffic accommodated exceeds expectations • Emulsion example:

  24. Section MR 504 (1) TG2 TG2 Traffic (MESA) 0.9 - 1.8 0.1 – 0.3 1 - 3 Seal 30 AC Pavement Structure 125 mm FB2 125 mm FB2 Slurry 125 mm FTB 150 mm G6 200 mm C4 150 mm G6 Key Trends: Traffic accommodated • Foam example:

  25. Tasks for Next Phase • Mix Design • Develop triaxial test and classification limits • Includes standardizing testing protocols • Develop durability test and classification limits • Standardize specimen preparation, particularly curing and compaction • Structural Design • Expand LTPP database • Develop and calibrate material classification method and design matrix

  26. Where are we now? • Submitted proposals for Phase 2 • Final approval pending • Thereafter we will be forging ahead with further investigation (test methods and protocols) and materials classification

  27. We hope to find a good marriage between cold materials and performance… Thank you

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