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

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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

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Verifying theVV

CoCCFHWTechJulie

Neural Network Training Set

Fre

qu

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cy

(H

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Sample Sample Sample Sample Sample

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Test Site

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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.