Interim Guidelines: The Design and Use of Foamed Bitumen Treated Materials Kim Jenkins, Dave Collings Hechter Theyse, Fenella Long Road Pavements Forum 6 – 7 May 2002

Where are we? u Guideline prepared and reviewed u Finalizing document in light of reviews u Thank you, don’t stop now!

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

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

Chapter 2.Selection Criteria u Project Selection u Risk Assessment u Recycling Process u Environmental Advantages u Traffic Delay Advantages u Economic Considerations

Chapter 2.Selection Criteria

Chapter 3.Mix Design u 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

Aggregate Selection, Magic Triangle % of STONES % OF FILLER % OF SAND FILLER SKELETON STONE SKELETON SAND SKELETON High optimum binder content foamed bitumen mix Ideal foamed mix grading Suitable foamed mix grading

Chapter 3.Mix Design (cont.) u Mix design procedure –Mix design philosophy –Mix constituents –Sample preparation –Curing –Mechanical testing

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

Material Classification u Interim foamed bitumen treated material classification

Chapter 4.Structural Design u Research based on –HVS tests –Laboratory tests u Distress modes –Effective fatigue –Permanent deformation resistance –Balance the distress modes

Chapter 4.Structural Design u New pavements –Catalogues u Deep in situ recycling –Design charts u Materials –FB2, FB3 only

New Construction, Catalogue

Deep In Situ Reycling, Design Charts

Chapter 5. Construction Aspects u General u Basic requirements –Quality of foamed bitumen –Material being mixes u Before starting –Planning the recycling work –Equipment selection –Logistical planning –Trial sections

Equipment Selection

u Working with foamed bitumen –Mixing process –Moisture content –Placing and compaction –Surfacing Chapter 5. Construction Aspects

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

Recommendations for Future Work u 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

Recommendations for Future Work u Structural design –FB1, FB4 materials –Wider range of parent materials –Mix behaviour/performance with no active filler –Erodibility, permeability, durability –More advanced material models

Recommendations for Future Work u HVS testing