HMA Mix Design Process

1
HMA Mix Design Process

• Progress Report

2
Activities

• HMA User Guide Available at month end
• Need to consider roll-out
• Mix Design Activities
• Forensic Studies contemplated
• APT considering some testing
• HVS
• MMLS
• Sabita Research Needs

3
HMA Users Guide

• Highlight important issues and content given in
  the IGHMA
• Caution the reader against certain pitfalls or
  gaps in the IGHMA
• Provide some guidance on supplementary procedures
  to achieve a sound and workable mix design and
• Provide comment and guidance on issues that have
  arisen since the IGHMA was launched in 2001.

4
Chapters (1)

• Chapter 1 - Introduction
• 1.1 General issues related HMA design
• Chapter 2 Mix Design Procedures
• Phase 1 Evaluate Design Situation and Identify
  Objectives
• Phase 2 Mix Type Selection
• Phase 3 Component Selection
• Phase 4 Volumetric Mix Design
• Phase 5 Performance testing

5
Chapters (2)

• Chapter 3 - Discussions on different mix types
  and specific design considerations
• Sand-Skeleton mixes
• Stone mastic asphalt
• Open-graded mixes
• Large aggregate mixes for bases (LAMBS)
• Semi open-graded mixes

6
Chapters (3)

• Chapter 4 Design Implementation Construction
  and Quality Assurance aspects
• Segregation
• Compaction and layer thickness
• Temperature control
• Binder variation
• Joints
• Trial sections
• Sampling and testing
• Statistical judgement plans

7
Conclusions

• User Guide Available Soon
• Highlights problems and identifies areas for
  research and investigations
• Will need supplementary work to actually improve
  criteria and procedures