TxDOT 3-D Pavement Survey Technology

Dr. Yaxiong (Robin) Huang, Robin.Huang@txdot.gov Texas Department of Transportation, Construction Division

New Technologies for Pavement Evaluation

For 86th Annual Transportation Short Course at Texas A&M University, 2012

What is High Speed Pavement Evaluation A combination of following pavement condition measurement 1. Ride quality IRI by longitudinal profiler

2. Rutting by five-point rut measurement device

3. Surface distress (cracking) by downward surface image

4. Surface texture by high speed laser sensor

New Technology for 3-D pavement structure A combination of surface image and surface elevation data 1. Rutting by high speed continuous transverse profile

2. Surface distress (cracking) by downward surface image and depth imformation

3. Surface texture by high resolution surface 3-D structure

4. Cross slope, faulting, marking thickness, pothole, and other features

TxDOT 3D Rutting system, VRUT

• Based on high speed 3D technology

• Samples 1536 points of profile for every 1 inch of travel

• Covers 14’ (4.26m) wide surface

• .025” (0.65 mm) rut resolution

• .093” (2.38 mm) transverse resolution

• Works on any type of pavement

• 0 to 70 mph (112 km/h) speed

• Straight edge, string line, and 5 point rut measurement methods

14 feet laser line, 1500/2300 data points

Image capability

Surface (intensity) image:

Range (elevation) image:

Surface Intensity Image and Elevation Image capable

Rut Measurement

String Line Rut Measurement

Six feet Straight Edge Rut Measurement

Based on continuous transverse profile Lane width detection for correct rut locations String line and straight edge rut algorithms

Rut Location and Spacing

US0183 major highway FM2239 county road

Only measured rut deeper than 1/8” are shown on maps

Rut spacing is calculated only when left and right rut is measured

Rut trace changes with distance

Rut space changes with different traffic patterns

Accuracy: Manual vs. 3D Rut Data Comparison

Manda Rd Left Wheelpath Rut R²=0.939

0

0.5

1

1.5

2

1 11 21 31 41 51 61 71 81 91 101Measurement (Count)

Rut

val

ue in

Inch

Manual 3D Rut

Manda Rd Right Wheelpath Rut R²=0.948

0

0.5

1

1.5

2

1 11 21 31 41 51 61 71 81 91 101Measurement (Count)

Rut

Val

ue in

Inch

Manual 3D RUT

ACP S

mooth

FM165 Left Wheelpath Rut R²=0.423

0.0

0.5

1.0

1.5

2.0

1 21 41 61 81 101 121 141

Measurement (count)

Rut

(in

inch

)

Manual 3D Rut

FM165 Right Wheelpath Rut R²=0.910

0.0

0.5

1.0

1.5

2.0

1 21 41 61 81 101 121 141

Measurement (Count)

Rut

in in

ches

Manual 3D Rut

Seal coat G

3 rough

Repeatability Test, Multiple Runs

Each test was conducted:

On same test section

At posted speed

Three trial runs

left and right rut on ever 10 ft

VRUT Repeatability Test, FM165, Right Wheelpath

0

0.2

0.4

0.6

0.8

1

1.2

1 21 41 61 81 101 121 141Measurement Count

Rut V

alue in

inch

RUN#1RUN#2RUN#3

VRUT Repeatability Test, FM967, Right Wheelpath

0

0.2

0.4

0.6

0.8

1

1.2

1 11 21 31 41 51 61 71 81 91 101Measurement count

Rut V

alue in

inch

RUN#1RUN#2RUN#3

Excellent correlation between different runs.

TxDOT 3D Texture system Technology for texture survey has moved to 3D for reliable data!

TxDOT 3D Texture System • Based on high speed 3D technology

• Samples 2048 points for every 2 inches of travel

• Covers 12” (304 mm) wide surface, 100%

• 10 µm texture resolution

• .007” (0.2 mm) spatial (x, y) resolution

• Works on any type of pavement

• Very high resolution 3D texture image for project level test

• Speed independent data.

Longitudinal Scanning Unit

Network level

Survey

Transverse Scanning Unit

Project level

Survey

Accurate, Repeatable, Speed Independent

1. Scan on test targets with known depth at different speed from 0 to 70 mph.

2. Reproduce each target profile accurately 3. Speed independent MPD data

VTexture Errors in %

VTexture errors in % at 0 to 70 mph

-10.0

10.0

30.0

50.0

0 10 20 30 40 50 60 70

Speed in MPH

Erro

r in

%

2.5 mm Target 3 mm Target 5.5 mm Target 8 mm Target

VTexture system errors in %

Targets 2.5 mm 3 mm 5.5 mm 8 mm

Travel Speed (mph)

0 -0.1 1.0 2.2 0.8

10 3.0 2.1 2.0 0.1

20 4.3 2.9 2.1 1.1

30 6.6 0.7 1.5 1.0

40 6.6 2.1 2.4 1.4

50 9.6 3.0 2.3 1.2

60 9.8 2.6 2.5 1.8

70 9.2 4.1 0.5 -2.1

1. Produce high accurate MPD data on different targets

2. Very low error on large target

3. Acceptable accuracy on small target

Comparison to other Texture Methods 3D vs Sand Patch in MPD R2 = 0.9907

0.000

0.500

1.000

1.500

2.000

2.500

3.000

0.00 0.50 1.00 1.50 2.00 2.50 3.00

Section Sand Patch CTM 3D

A 1.31 1.28 1.284

B 1.26 1.40 1.367

C 1.71 1.91 1.936

D 1.23 1.18 1.380

E 0.51 0.48 0.570

F 0.65 0.77 0.779

G 2.56 2.81 2.883

H 0.42 0.46 0.455

I 0.94 1.17 1.078

J 1.19 1.50 1.371

K 1.02 1.37 1.181

3D vs CTM in MPD R2 = 0.9742

0.000

0.500

1.000

1.500

2.000

2.500

3.000

0.00 0.50 1.00 1.50 2.00 2.50 3.00

1. Tested on 11 different pavement surface

2. VTexture shows very high correlations to sand patch and CTM data

3. VTexture works on concrete surface

Network Level Data

1. During network level survey, VTexture gives am MPD for every 2” of travel

2. Statistical summary reported every 0.1 mile, includes average, minimum, maximum MPD values and standard deviation.

3. Fully automated, no operator assistance is needed.

Texture MPD Mopac N.

0

1

2

3

4

5

1 2001 4001 6001 8001 10001 12001 14001

Bridge joints on ACP

Bridge joints on concrete

ACP on MoPac Smooth Street

Texture profile on ACP Texture Profile on tined concrete

Project Level Application 1. Three scan direction at Longitudinal, transverse, and 45 degree mount 2. 5 to 10 mph speed, continuous data collection. 3. High density data at 256 profile per foot of travel 4. Different display images for better analysis

Asphalt Intensity Range Image Concrete Intensity Range Image

3-D Display

TxDOT 3-D Cracking System

Built on true 3-D technology High speed 0 to 70 mph Fully automated Works on different pavement 2350 Data point 10000 scan/sec 8.11 profiles/inch 3.13 x 1.81 mm resolution

Surface and Depth Image Capable

Intensity and range Images 3-D Display

Automated Image Processing

Intensity Image Processed Range Image

Crack Detection Result

Pavement Image in 3D Display

Cracks Displayed in Range Image

Crack map

Crack Map

Thank You!

All systems were developed by TxDOT 3-D development team: Dr. Robin Huang, Todd Copenhaver, Phillip Hempel, P.E. and others from Construction Division, Pavement and Material Branch under the leadership of branch manager Dr. Magdy Mikhail, P.E.