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Need for InnovationProper compaction of newly applied asphalt helps ensure a crack-free paved surface and longer lasting
roadway. But if compaction levels do not meet the design requirements it can result in early degradation of
the pavement. Currently, compaction is verified by testing core samples extracted from the hardened
asphalt. Low compaction will result in either reduced payment or no payment for the sections. The
Intelligent Asphalt Compaction Analyzer (IACA) is a device mounted to vibratory compactors to provide
real-time data so compaction inconsistencies can be remedied while asphalt is still pliable. Replacing the
time-consuming manual process will reduce construction time and make pavements last longer.
Project Overview
The IACA estimates the density of asphalt pavement in real time so workers can detect and fix compaction problems during the paving process, saving time and money. The components consist of a GPS receiver (not shown, but mounted on the roof of the compactor) and an embedded computer/display which mounts on the vibratory compactor.
Changes in the compaction are displayed left to right based on the number of passes.
The IACA is a device based on an artificial neural network technology that can estimate the density of an
asphalt pavement continuously in real-time during its construction. Early field trials demonstrated that, after
calibration, the accuracy of the IACA is comparable to a nuclear density gauge or a non-nuclear density gauge.
Haskell Lemon Construction Company and the University of Oklahoma refined the technology, developed
commercial prototypes, and conducted extensive field testing. Recent enhancements extend the ability of the
IACA to estimate the stiffness of the pavement layer during its construction.
Test Site : I-35 Norman, Oklahoma• Subgrade: 200 mm @ 10% cement kiln dust (CKD)• Aggregate Base: 200 mm • Asphalt Layers: Two 100-mm asphalt layers S3 PG 64- 22 OK and 3rd lift of 75-mm S3 PG 76-28 OK
Intelligent Asphalt Compaction Analyzer (IACA)InteHighways for LIFE Technology Partnerships 2008 Award $200,000
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R2= 0.7086
Core Density (%MTD)
IACA
Est
imat
ed D
ensi
ty (%
MTD
)
Comparison of IACA estimated Density with
Density of roadway cores at 180 test locations
(MTD - Maximum Theoretical Density)
T1 T2 T3 T4 T5 T6 T7
3500
3000
2500
2000
1500
1000
500
0
Mod
ulus
(MPa
)
IACA Estimated Modulus
FWD Back Calculated Modulus
Comparison of IACA estimated modulus with
the modulus back calculated from FWD test
measurements at 7 random test locations on
I-35
Results
ConclusionsThe results obtained during field compaction
agree with FWD measurements from the
completed pavement. Empirical calculations of
the modulus in the laboratory provide
significantly higher values of the modulus and
are not suited for quality control during
compaction. On the other hand, the IACA can
estimate the modulus in real-time during the
compaction process and can be used to ensure
uniform compaction of the asphalt pavement.
Project TeamHaskell Lemon Construction Company
University of Oklahoma
Volvo Construction Equipment
CoCCThe r
agree
comp
th
Roller Vibrations
Mat Properties
SensorModule
Feature Extractor
CompactionAnalyzer
Measure of Compaction
(density/stiffness)
Collectvibration
data
Extract SalientFeatures from
Vibrations
Use training data to classify
the features
Maps the NeuralNetwork Output
to Density
Temperature Sensor Asphalt Base
Accelerometer
Drum withEccentric Weights
IACA
IACADisplay
GPS Antenna
Rover Radio GPS Base Stationand Radio
Neural Output
Principles of Operation
Verifying the seating and location of the test site.
Contact InformationFHWA, Highways for LifeTechnology Partnerships ProgramJulie Zirlin, 202-366-9105www.fhwa.dot.gov/hfl
Haskell Lemon Construction Companywww.haskelllemon.comTechnical Contact: Sesh Commuri, University of Oklahoma, 405-325-4302
98.00
97.00D)
RReRR
Verifying theVV
CoCCFHWTechJulie
Neural Network Training Set
Fre
qu
en
cy
(H
z)
Sample Sample Sample Sample Sample
L0 L1 L2 L3 L4
Test Site
PPPrPPP oHask
Unive
Volvo
Test S• Subg• Aggre
Ten prototype units were developed for installation
on vibratory compactors, and the technology was
validated during the construction of both full-depth
and overlays of asphalt pavements. The performance
of the IACA during the construction of the HMA
pavement was evaluated by independent users at
sites across the country during 2009-2010.
Project Status
FWD Testing
The final report and a video is available at
http://www.fhwa.dot.gov/hfl/partnerships/
haskell.cfm.