LASER-INDUCED ROUGHNESS-INDEX

ANOMALIES IN LONGITUDINAL BOXCAR AND

DRAG CONFIGURATIONSBernard Igbafen Izevbekhai P.E.

Bernard.izevbekhai@state.mn.usMinnesota Department of Transportation

Transportation Research Board Conference

January 2012

a)Ultimate Grind (Corrugated Box Car) a) Turf Drag (Hessian)

b) Conventional Grind (Square Wave) c) Innovative Grind (Box Car)

e) Configuration Nomenclature

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TEXTURES INVESTIGATED

TRIPLE LASER AND LINE (ROLINE) LASER

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a) Geometry of Lateral Wander Across an Ultimate Grind Configuration 2

3

b) Single Point Spatial Domain and Laser 10o Visualization of Texture 4 Configuration 5

LATERAL WANDER IN BOX-CAR CONFIGURATIONS

LATERAL WANDER IN BOX-CAR CONFIGURATIONS

LATERAL WANDER IN BOX-CAR CONFIGURATIONS

TriODs on a box car configuration Roline on a Boxcar Configuration

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VARIOUS OBSERVATIONS

VARIOUS OBSERVATIONS

VARIOUS OBSERVATIONS

VARIOUS OBSERVATIONS

VARIOUS OBSERVATIONS

Adjacent Lanes of the Same Cell

Cell Lane Laser

Mean Rank

Two-Tailed P-Value for Normal

Approximation

Difference with 95%

Confidence?

Difference with 99%

Confidence?

Cell 13 Turf Drag (TD)

Driving TriODs 24.7

0.926 no no Roline 24.3

Passing TriODs 27.4

0.6603 no no Roline 25.3

Cell 14 Broom Drag(BD)

Driving TriODs 24.3

0.9342 no no Roline 24.7

Passing TriODs 25.8

0.7345 no no Roline 27.2

Cell 71 UDG Driving, CDG Passing

Driving TriODs 21.5

0 yes yes Roline 7.5

Passing TriODs 18 0.0273 no no

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STATISTICAL ANALYSIS

Mann-Whitney Wilcoxon Method of Data Comparison

Cell Lane Laser

Mean Rank

Two-Tailed P-Value for Normal

Approximation

Difference with 95%

Confidence?

Difference with 99%

Confidence?

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Cell 5 (CDG)

Driving TriODs 26.7

0.2833 no no Roline 22.3

Passing TriODs 30.6

0.05 no no Roline 22.4

Cell 7 Innovative Grind (IDG)

Driving TriODs 32.8

0 yes Yes Roline 16.2

Passing TriODs 32.7

0.0032 yes Yes Roline 20.3

Cell 8 Conventional Grind (CDG) Driving

TriODs 28 0.0827 no no

Roline 21

Passing TriODs 29 0.245 no no

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STATISTICAL ANALYSIS

Mann-Whitney Wilcoxon Method of Data Comparison

CONCLUSION &RECOMMENDATION

• The innovative grind and most recently the ultimate grind configurations are widely accepted, sought after and used because of excellent acoustic properties.

• To a 95% confidence level, Innovative/ Ultimate grind line and triple laser data are different

•The different lasers may not be used interchangeably because of sensitive textures

•Use line laser for acceptance testing of all Innovative grinds

.