HMA Mix Design Process
Progress Report
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
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.
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
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
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
Conclusions
• User Guide Available Soon
• Highlights problems and identifies areas for research and investigations
• Will need supplementary work to actually improve criteria and procedures