Terence Milne

South AfricanRoad Pavement Forum

13 & 14 November 2002

South AfricanRoad Pavement Forum

13 & 14 November 2002

Conference Report Back:

ICAP 2002

17 – 22 AUGUST 2002

COPENHAGEN

AFRICON

ATTENDANCE

Over 40 countries represented by nearly 400 delegates

34 Delegates from South Africa

SCOPE OF CONFERENCE

Parallel Sessions Design

Construction and Maintenance

Performance

Environment

Accelerated testing

Plenum Sessions

www.asphalt.org

PRESENTATION

Examples of World Wide presentations

120 papers presented

PLENUMS

Perpetual Pavements Endurance of 50 years

Asphalt Pavement Alliance (USA) Guidelines for Design and Construction

UK: Long life pavements

Europe

10 Road Laboratories Project

PLENUMS (cont.)

e.g. Prof Per Ullidtz

Analytical tools for design of flexible pavements

- Analytical – empirical method of pavement design

Differences between the assumptions for analytical models vs the reality of pavement materials and behaviour

Keynote Addresses

Linear electric theory vs back calculated layer moduli

PLENUMS (cont.)

Keynote Addresses

Analytical tools for design of flexible pavements

Discrete element modeling deals with the forces on, and displacements of individual grains in a particulate medium

DESIGN

Binder Rheology Belgium:

Looking at reliable standard testing method

Bending Beam Rheometer or Dynamic Rheometer

Long term ageing

USA Uncertainty and appropriate use of CBR design of air fields

Japan Structural design of airport asphalt pavements on soil with

high water table

Design Parameters

DESIGN (cont.)

Material Models UK

Constitutive material modeling for asphalt mixes Elastic visco plastic model with input required from uniaxial

test data (3 temperature and 3 displacement rates)

Netherlands Design aspects for wearing courses on orthotropic steel

bridge decks

Development of a FEM based model going beyond linear elastic theory

FEM modeling of elasticity, plasticity, cracking

DESIGN (cont.)

Materials Models

Netherlands Tools developed for the better understanding of the interaction

between the different components of the structure

Permanent deformation of asphalt concrete pavement: development of a non-linear visco elastic model for mix design analysis

FE simulations compared to real pavement data

South Africa

Non-linear visco elastic constitutive model to describe the rutting behaviour of asphalt

PERFORMANCE

The design and performance of thin surfacing layers

Europe:

Role of the binder considered

Possible failure criteria considered

CONSTRUCTION AND MAINTENANCE

Towards a Performance Related Seal Design Method

South Africa:

Japan and USA: Compaction of HMA using a high frequency,

double drum vibrating roller Relationship between roller speed, vibrating frequency,

number of roller impacts per metre and its effect on density obtained on a HMA pavement layer

IMPRESSIONS Materials modeling based on fundamental materials

characteristics using both Theoretical and Empirical relationships (reality always differs from a model with its assumptions)

IMPRESSIONS

Papers content ranged from highly involved simulations to practical papers such as roller compaction

Cost of technology

Europe and USA not always agreeing on the way forward

South Africa to take the best from both groups

Risk assessment in design using probabilities and modeling

IDEAS FOR CAPSA

Good mix of plenaries and specialist parallel sessions

Include all events in conference price to keep affordable, and delegates involved

Good idea of display in lunch and tea area

CAPSA compares well, personal touch too