Interim Guidelines:The Design and Use of Foamed

Bitumen Treated Materials

Kim Jenkins, Dave Collings Hechter Theyse, Fenella Long

Road Pavements Forum6 – 7 May 2002

Where are we?

Guideline prepared and reviewed Finalizing document in light of reviews Thank you,

don’t stop now!

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

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

Chapter 2. Selection Criteria

Project Selection Risk Assessment Recycling Process Environmental

Advantages Traffic Delay Advantages Economic Considerations

Chapter 2. Selection Criteria

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

Aggregate Selection, Magic Triangle

0 20 40 60 80 100

100

80

60

40

20

0 100

80

60

40

20

0

% o

f STO

NE

S%

OF FILLE

R

% OF SAND

FILLER SKELETON

STONESKELETON

SANDSKELETON

High optimum binder content foamed bitumen mix

Ideal foamed mix grading

Suitable foamed mix grading

Chapter 3. Mix Design (cont.) Mix design procedure

– Mix design philosophy– Mix constituents– Sample preparation– Curing– Mechanical testing

Mix Design Philosophy

Improved flexibility

Gre

ater

per

man

ent

def

orm

atio

n r

esis

tan

ce

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

High

Intermediate

Intermediate

Low

Low

None

None

Bituminous binder0% 7%

0%

Catalyst

Stren

gth

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 Interim foamed bitumen treated material classification

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 100 200 300 400 500 600

ITS (kPa)

UC

S (

kPa)

FB4

FB2 FB1

FB3

Chapter 4. Structural Design

Research based on– HVS tests

– Laboratory tests Distress modes

– Effective fatigue

– Permanent deformation resistance

– Balance the distress modes

Chapter 4. Structural Design New pavements

– Catalogues Deep in situ recycling

– Design charts Materials

– FB2, FB3

only

PAVEMENT CLASS AND DESIGN BEARING CAPACITY (80 kN AXLES/LANE)

DATE: January 2002

FoundationROAD CATEGORY

A: Major interurbanfreeways and roads.(95 % approximatedesign reliability)

B: Interurbancollectors and majorrural roads.(90 % approximatedesign reliability)

C: Lightly traffickedrural roads andstrategic roads.(80 % approximatedesign reliability)

D: Light pavementstructures, ruralaccess roads.(50 % approximatedesign reliability)

ES0,01

0,3-1,0x10 4ES0,03

1,0-3,0x10 4ES0,1

3,0-10x10 4ES0,3

0,1-0,3x10 6ES1

0,3-1,0x10 6ES3

1,0-3,0x10 6ES10

3,0-10x10 6ES30

10-30x106ES100

30-100x10 6ES0,003

0,1-0,3x10 4

A0, AP may be recommended as a surfacing measure for improved skid resistance when wet or to reduce water spray. SYMBOL A DENOTES AG, AC, OR AS. SYMBOL S DENOTES S2 OR S4

S

100 FB3

100 G8

S

125 FB3

125 G9

S

125 FB3

125 G8

100 FB3

S

100 FB3

S

150 G7

125 FB3

S

150 G7

S

100 C4

100 FB3

150 FB2

S

150 G7

S

100 C4

100 FB3

S

100 C4

100 FB3

125 FB3

S

150 G6

S

125 C4

125 FB3

30 AC

150 FB3

200 C4*150 FB3

S

200 G6

150 C4

125 FB3

S

175 FB3

30 AC

175 C4175 FB3

175 G6

S

NEW CONSTRUCTION : FOAMED BITUMEN BASE (FB3)

150 G9

G10

150 G7

150 G9

G10

* Minimum thickness for structural capacity. Construct in two lifts increasing thickness for ease of construction, if necessary.

30 AC

125 FB3

150 C4

New Construction, Catalogue

Deep In Situ Reycling, Design Charts

75

100

125

150

175

200

225

250

275

300

0 50 100 150 200 250 300

Support (MPa)

Th

ick

ne

ss

(m

m)

10 000

30 000

100 000

300 000

1 000 000

3 000 000

Category A, FB2

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

Equipment Selection

Working with foamed bitumen– Mixing process

– Moisture content

– Placing and compaction

– Surfacing

Chapter 5. Construction Aspects

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

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

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

Recommendations for Future Work HVS testing