Automatic Pavement Cracking Distress Measurement System

Bugao Xu and Yaxiong HuangUniversity of Texas at Austin

bxu@mail.utexas.edu

(512) 471-7226

December 2004

Automated Pavement Distress Measurement Vehicle

Digital Line Scan Camera

System Specifications

• One linescan camera: 2k pixel, 37k scan/sec• One frame grabber: 4 taps, 40MB each• GSP: position and speed• LED or halogen linear lighting device (patent

pending)• Imaging Resolution: min 1.786 mm per pixel • Image capturing and processing: Real-time• Network support

System Capabilities

• Real-time inspection• Distance coverage: 100%• Lane coverage: Up to 12 feet (3.65 m)• Vehicle speed: 3-70 mile/hour (5 to 112 km/hour)• Pavement type :flexible and rigid pavements• Weather tolerance: cloudy or sunny• Night operation: same as in daytime

System Output

• Format: PMIS and ASSHTO protocols• Summary data: at a given interval • Crack map: continuous• Snapshot: at an interval• AVI images: saved up to one km• Compressed images: continuous

System Performance

• Repeatable over multiple runs: R2>0.8, CV 5.0~14%

• Repeatable over testing speeds• Repeatable under different cloud conditions• Reproducible (vehicle to vehicle)• Output data directly up-loadable input PMIS• Measurements correlate well with manual ratings

for flexible pavements

System Benefits

• Safety (removing raters for roadway)• Low cost compared to visual rating• High data Quality • Multiple data types with one pass of vehicle• Easy data management

Continuous Crack Maps (40ft)

Unsealed Crack Sealed Crack

Asphalt PavementCorrelation of Multiple Scans

Longitudinal Crack on SL360 R1 432 to 436.

R2 = 0.9519

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Multiple ScansLongitudinal Cracks on SL360 R1 432 to 436

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1 51 101 151 201stations

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Transverse Cracks on SL360 R1 432 to 436

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Weather Conditions

Transverse Cracks on SL360 R1 432 to 436

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Stations

Count\Station

Longitudinal Crack on SL360 R1 432 to 436

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1 51 101 151 201

Stations

May 8 (heavily cloudy)

May 9 (sunny)

May 20 (cloudy)

Feet\Station

Vehicle Speeds

Transverse Cracks on SL360 R1 432 to 436

Count\Station

Longitudinal Crack on SL360 R1 432 to 432+0.5

Feet\Station

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35 mph45 mph55 mph

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Long Distance Data (24 miles)

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Concrete PavementTransverse (Vehicles 1 and 2)

020406080

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1 5 9 13 17 21 25 29 33 37 41 45 49

0.1 Mile Segments

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Concrete Pavement Transverse Cracks

Vehicle V1 V2

R1-R2 0.884 0.963

R1-R3 0.960 0.964

R2-R3 0.908 0.966

ScanScan

Correlations of Different Runs Correlations of Different Runs (Transverse)(Transverse)

Concrete Pavement Transverse Cracks (V1 and V2)

R1 0.970

R2 0.897

R3 0.936

Correlations

Concrete Pavement AASHTO Left Wheel Path (V1)

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Concrete Pavement AASHTO RWP (V1)

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Concrete Pavement AASHTO Between Wheel Path (V1)

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101520253035

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R1

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Concrete Pavement AASHTO Outside Wheel Path (V1)

0102030405060

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R1

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Concrete Pavement AASHTO Correlations (V1)

LWP RWP BWP OWPR1-R2 0.9564 0.9071 0.9390 0.9701

R1-R3 0.9459 0.8324 0.9189 0.9427

R2-R3 0.9215 0.8263 0.9201 0.9293

Asphalt: Longitudinal Crack(2)

Asphalt: Longitudinal Crack (4)

Asphalt: Transverse Crack (1)

Asphalt: Transverse Crack (2)

Asphalt: Alligator Crack (2)

Asphalt: Alligator Crack (4)

Asphalt: Sealed Crack (2)

Asphalt: Sealed Crack (3)

Asphalt: Raveled Pavement

Asphalt: Patched Pavement

Asphalt: Dark Image (1)

Asphalt: Dark Image (2)

Asphalt: Bright & Fuzzy Image (1)

Asphalt: Bright & Fuzzy Image (2)

Concrete: No tinning (3)

Concrete: No tinning (4)

Concrete: No tinning (10)

Concrete: No tinning (11)

Concrete: Wide tinning (1)

Concrete: Wide tinning (2)

Concrete: Spalled (1)

Spalled crack