Field validation of constructed sub-grade and pavement

1
Field validation of constructed sub-grade and
pavement
September 21, 2006

• John S. Popovics
• Jeffery Roesler
• Marshall Thompson
• David Lange
• Robert Rodden
• Yi-Shi Liu
• Department of Civil Environmental Engineering

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Project Objectives
Obtain response data and non-destructive test
(NDT) test results from a test structure that
replicates the nominal design to be used in the
OHare modernization program.

• The output data from the sensors will be used to
  infer stress and movement of the slab owing to
  temperature and moisture gradients. Those
  responses will be used as input for other OMP
  research projects.
• The NDT findings will be used to develop new test
  methods that provide more appropriate and
  effective performance at the OMP site.

3
Work to date

• Pavement sensing (instrumented concrete slab)
• NDE tasks

Saw-cut joints
10 inch pcc slab
16 inch dense AC base
NDT applied to determine in place thickness
and/or material properties of pavement layers.
Impact-echo and surface wave methods (SASW, MASW)
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Concrete pavement instrumentation
Three types of sensors are embedded in the
concrete slab

• Relative humidity (RH) and temperature
• (at a range of depths though the slab)
• Slab lift-off (at slab corners)
• Joint opening

On-site battery-powered data logger collects data
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Sensor layout (plan view)
Instrumented concrete slab cast on June 22, 2006
at ATREL
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Joint Opening Data
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Lift-Off Data
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RH profile
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Temperature profile
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Non-destructive tests (impact-echo)
Expected resonance at 8000 Hz for 10 inch slab
Dis-bonded region
Bonded region
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Impact-echo thickness predictions
Data from bonded regions (hollow points)
Expected value
Data from dis-bonded regions (solid)
Inaccurate thickness predictions where pcc bonded
to ac
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Work to date Conclusions

• Useful data for field verification of the
  constructed pavement layer have been collected.
  The sensor layout was effective. Most sensors
  functioned adequately, but lift-off sensor design
  should be improved.
• Conventional NDT tests may not work suitably for
  OMP pavement structure (dense asphalt base)

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Future work

• Pavement sensing
• NDE tasks

Continue sensing and data collection in trial
slab to monitor longer term environmental
effects, and share data with other OMP projects
Incorporate sensors (similar layout) in actual
OHare slab cast in 2007 (R/W 9L section?)

• Modify or develop new NDT methods for estimation
  of
• layer properties and thickness that will work on
  OHare
• pavement modified impact-echo and MASW. Tests
• Developed at ATREL, verified at OHare