Interim Guidelines: The Design and Use of Foamed Bitumen Treated Materials

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Interim GuidelinesThe Design and Use of Foamed
Bitumen Treated Materials
Kim Jenkins, Dave Collings Hechter Theyse,
Fenella Long Road Pavements Forum 6 7 May 2002
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Where are we?

• Guideline prepared and reviewed
• Finalizing document in light of reviews
• Thank you,
• dont stop now!

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Reviewers

• Elzbieta Sadzik, Theuns Lewis and Enrico
  Fletcher, Gautrans
• Les Sampson, Asphalt Academy
• Piet Myburgh, SABITA
• Wouter Schreuder and Joe Grobler, VKE
• Mervyn Henderson and Rassie Otte, PAWC
• Wolf Reusch, Rumdel
• Dieter Vietze and Philip Kuun, Blitz Asphalt
• Jop du Plessis, AA Loudon and Partners
• Ian van Wijk and Johan Calitz, Africon
• Nicol van der Walt, Gibb Africa
• Andre Ungerer, Keeve Steyn
• Mike White, UWP Engineers

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Table of Contents

• 1. Introduction
• 2. Selection criteria for identification of
  suitable projects
• 3. Mix design
• 4. Structural design
• 5. Construction aspects
• Appendices
• Test procedure for measuring foamed bitumen
  characteristics
• Laboratory test methods and specimen preparation
• Mechanistic-empirical pavement design for foamed
  bitumen treated layers

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Chapter 2. Selection Criteria

• Project Selection
• Risk Assessment
• Recycling Process
• Environmental
• Advantages
• Traffic Delay Advantages
• Economic Considerations

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Chapter 2. Selection Criteria
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Chapter 3. Mix Design

• Important considerations in the mix design
  process
• Design constraints
• Aggregate selection
• Binder selection
• Fluid considerations
• Mixing techniques
• Compaction (mod AASHTO)
• Curing
• Moisture susceptibility
• Appropriate surfacings

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Aggregate Selection, Magic Triangle
High optimum binder content foamed bitumen mix
0
100
Ideal foamed mix grading
Suitable foamed mix grading
20
80
40
60
of STONES
OF FILLER
FILLER SKELETON
60
40
20
80
SAND SKELETON
STONE SKELETON
100
0
0
20
40
60
80
100
OF SAND
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Chapter 3. Mix Design (cont.)

• Mix design procedure
• Mix design philosophy
• Mix constituents
• Sample preparation
• Curing
• Mechanical testing

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Mix Design Philosophy
Bituminous binder
7
0
5
High
Intermediate
Low
None
Strongly cemented material C2 to C1
Stiff, brittle behaviour
Presumed economically not viable
High
Strength
Lightly cemented material C4 to C3
Intermediate
Foamed bitumen and emulsion treated material
containing cement
Cement
Catalyst
Low
Greater permanent deformation resistance
Unbound material, High quality crushed stone and
aggregate Moderate quality natural gravel Low
quality natural gravel
0
Foamed bitumen and emulsion treated material
without cement
Asphalt concrete
None
Improved flexibility
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Material Classification

• Interim foamed bitumen treated material
  classification

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Chapter 4. Structural Design

• Research based on
• HVS tests
• Laboratory tests
• Distress modes
• Effective fatigue
• Permanent deformation resistance
• Balance the distress modes

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Chapter 4. Structural Design

• New pavements
• Catalogues
• Deep in situ recycling
• Design charts
• Materials
• FB2, FB3
• only

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New Construction, Catalogue
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Deep In Situ Reycling, Design Charts
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Chapter 5. Construction Aspects

• General
• Basic requirements
• Quality of foamed
• bitumen
• Material being mixes
• Before starting
• Planning the recycling work
• Equipment selection
• Logistical planning
• Trial sections

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Equipment Selection
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Chapter 5. Construction Aspects

• Working with foamed bitumen
• Mixing process
• Moisture content
• Placing and compaction
• Surfacing

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Chapter 5. Construction Aspects

• Quality control aspects
• Thickness
• Quality of foamed bitumen
• Application of stabilising
• agents and quality of mixing
• Compaction
• Level and surface shape

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Recommendations for Future Work

• Mix design
• Build up database of shear parameters to move
  away from UCS
• Replace ITS test for assessing flexibility
  (beam?)
• Compaction specifications, Mod AASHTO versus BRD,
  build up experience and establish limits
• Laboratory versus field mixing
• Curing
• Water sensitivity

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Recommendations for Future Work

• Structural design
• FB1, FB4 materials
• Wider range of parent materials
• Mix behaviour/performance with no active filler
• Erodibility, permeability, durability
• More advanced material models

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Recommendations for Future Work

• HVS testing