intelligent compaction for subgrades and structural layers aashto rac high value research workshop...
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Intelligent Compactionfor Subgrades and Structural Layers
AASHTO RAC High ValueResearch WorkshopJuly 27, 2011
Intelligent Compaction for Subgrades and Structural Layers
Overview
Intelligent compaction is a promising construction technique under evaluation by several states
• Vibratory rollers are equipped to measure position, speed and drum vibration
• Data are processed and displayed in real time as a color-coded map of stiffness
Intelligent Compaction for Subgrades and Structural Layers
Goals and methods
• Evaluate IC on highway projects for bound and unbound layers– Low- and high-plastic clay subgrades– Silty sand subbases– Crushed aggregate and recycled
asphalt base courses– Asphalt overlays
• Determine accuracy ofIC measurements througha variety of field tests
Intelligent Compaction for Subgrades and Structural Layers
Findings
Results were promising• For unbound materials, IC is effective to map stiffness and
identify weak areas prior to placement of new layers• IC helps determine best rolling patterns for unbound layers
and avoid over-rolling
But challenges remain• IC is not used for hot-mix asphalt finishing rollers yet• Stiffness readings are influenced by supporting layers;
adjustment factors or other field controls are needed• Output values from different manufacturers’ equipment need
to become more uniform
Intelligent Compaction for Subgrades and Structural Layers
Outlook
With further research, IC has the With further research, IC has the potential to lower construction potential to lower construction
costs, improve the uniformity of costs, improve the uniformity of compaction, and increase pavement compaction, and increase pavement
performance and service life.performance and service life.
Intelligent Compaction for Subgrades and Structural Layers
For more information
• Wisconsin Highway Research Program project 0092-08-07, Evaluation of Intelligent Compaction Technology for Densification of Roadway Subgrades and Structural Layers
• http://www.whrp.org/research-areas/geotechnics/geotechnics_0092-08-07.html
• Daniel [email protected](608) 267-6977