RFID Applications for Asphalt Pavements Charles W. Schwartz

University of Maryland

AASHTO Subcommittee on Materials Anchorage, AK August 2009

Radio Frequency Identification (RFID)

Tag ID Power to Transmitter

Antenna

Tag ID from Receiver Antenna

RF Power

Tag ID

Tag Activated by Transmitter

RF

RFID Reader

Passive RFID Tag

Antenna Computer

Application Areas

Inventory Control – Tools/Equipment – Vehicles

Material Tracking – Test Specimens – Stockpiles – In-place

Sensing – Temperature – Strain – Others

Detection – Cracking

Application Areas

Inventory Control – Tools/Equipment – Vehicles

Material Tracking – Test Specimens – Stockpiles – In-place

Sensing – Temperature – Strain – Others

Detection – Cracking

Tracking: The Problem

Lot

AC

Lot

AC

Lot

AC Milepoint

Dis

tres

s

Pavement Construction Pavement Management

Link??

HMA from Plant

Paver Haul Truck

Tags scanned when convenient after construction

Finished Pavement

Encapsulated RFID Tag

Vehicle with RFID Reader and GPS

Compaction

The Solution?

Selected RFID Technology

Passive UHF (~900 MHz) Tags

– 2x2 inch Alien

– 1x1 inch Alien

– 1x2 inch UPM Raflatac

Tag Encapsulation

CPVC pipes (11/16” internal diameter)

Tags placed along inside of pipe wall

Pipe filled with high-temperature epoxy

Cost ~$1 each

Epoxy-filled CPVC pipe

Hollow CPVC pipe

Epoxy Tag along inner

surface of pipe wall

Laboratory Evaluation Gyratory Plug

Containing Encapsulated Tags

Antenna

• 67% survival rate • Some degradation over time • Read range: ~1 meter • Encapsulation process later improved

Pre-Positioned Tags Through-Paver Tags

Field Trials: UMD Lot EE

12.5 mm HMA surface, 50 mm thick 19 mm HMA base, 100 mm thick

1x1 tag (20 total) 2x2 tag (10 total)

2x2 tag (20 total) 1x1 tag (10 total)

UMD Field Trial Results

1x1 Base

1x1 Surface

1x1 All

2x2 Base

2x2 Surface

2x2 All

All

0%

20%

40%

60%

80%

100%

Detection on basis of Layer/Course

Rea

d Su

cces

s R

ate

Lot EE 10” antenna height

2x2 Tag

2x2 Tag

1x1 Tag

Tag Surfacing

Tag surfacing in Lot EE: • 1x1 tags: 20% • 2x2 tags: 40% (Surface lift tags only)

Hampstead Bypass Field Trial • MD 30 NW of Baltimore • New alignment: 4.4 miles, 2 lanes • 2” surface lift over two 4” base lifts (19 mm) • Staged construction

Hampstead Bypass Field Trial November 2007

• Lower 4” base lift (19 mm) • 40 UPM Raflatac 1x2 tags, 60 Alien 2x2 tags (10/truck) • No MTV

C.J. Miller Paving

• Vehicle speed: < 5 mph • Antenna height: 3” and 12” • Other variables: - Vehicle speed - Antenna height - Antenna configuration

Read Success Rate

3in12in

1x2

2x2

56.7%66.7%

17.5%17.5%

0%

20%

40%

60%

80%

100%

Perc

enta

ge o

f Tag

s R

ead

Antenna Height

Tag Dimension

Hampstead Bypass

Tag Surfacing Rates:

• 1x2: 0%

• 2x2: 15%

Hampstead Bypass Field Trial April 2008

• Upper 4” base lift (19 mm) • 32 Alien 2x2 tags (8/truck) • MTV

Tag Spatial Sequence

• Variable (unknown) spatial lag • Mixing in MTV surge hopper

Read Success vs. Speed

0%

20%

40%

60%

80%

100%

0 10 20 30 40 50

Vehicle Speed (mph)

Rea

d Su

cces

s (R

elat

ive

to 0

mph

)

Tag Longevity 2x2 Tags - Lower Base Lift (November 2007)

0%

20%

40%

60%

80%

100%

Nov 07 - 3" Nov 07 - 12" Apr 08 - 3"

Read Date and Antenna Height

Rea

d Su

cces

s R

ate

Surfaced Tags

106 density measurements

for 7 tag (July 29, 2009)

(Permeability still TBD)

Technology Advances Small size – 1.5 x 0.44 x 0.11 inches

Durable – FR4 flame retardant PCB

laminate – Up to 200oC, 200+ psi, high

humidity, mechanical shock – No need for encapsulation

Survives paving simulation in lab Read range/performance?

Titan Tag (Summer 2008)

Related Applications

Field trials with NYDOT planned for this fall.

Sensing: Temperature

Intelligent Compaction

Surface Acoustic Wave (SAW) RFID

(Animation at http://www.rfsaw.com/animation/index.html)

2”

Tag 0443

0

20

40

60

80

100

120

140

0 1 2 3 4 5 6

Time (mins)

Deg

. Cel

cius

Tag

Fluke

Tag 09FE

0

10

20

30

40

50

60

70

80

90

0 1 2 3 4 5 6

Time (mins)

Deg

. Cel

cius

Tag

Fluke

Monopole Patch

Patch Monopole

Laboratory Evaluation

Field Trials

US15 / US340 SW of Frederick MD July 21-22, 2009

Field Trials

Group B - E - G - I Temp. Profile, Bottom of Mat

40

50

60

70

80

90

100

0 10 20 30 40 50

Distance Along Test Alignment (Feet)

Tem

pera

ture

(Deg

. Cel

cius

)

Pass 1Pass 2Pass 3Pass 4

Group B - E - G - I Temp. Profile, Middle of Mat

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40 45 50

Distance Along Test Alignment (Feet)

Tem

pera

ture

(Deg

. Cel

cius

)

Pass 1Pass 2Pass 3Pass 4

Group B - E - G - I Temp. Profile, Top of Mat

40

50

60

70

80

90

100

110

0 2 4 6 8 10 12 14 16

Distance Along Test Alignment (Feet)

Tem

pera

ture

(Deg

. Cel

cius

)

Pass 1Pass 2Pass 3Pass 4

(Very) Preliminary

Results

Temperature readings from ~60% of tags

Detection: Reflection Cracking

Frangible Conductive Links

Work is in very preliminary stage

Conclusions HMA production tracked successfully in field using RFID technology – Minimal interference with paving operations – No projection of tags above mat surface – Surfacing of tags being investigated further

Adequate to good read success rate – Range sufficient for bumper-mounted antenna array – 2x2 tags: 60-80% read success rate or higher – Need improvement for smaller tags

Ongoing Work Evaluation of surfaced tags – Local density – Local permeability

Evaluation of smaller format Titan tags Tracking of PCC placement Sensor applications – Temperature – Mechanical strains

Detector applications – Reflection cracking

Guidance on data integration

Benefit:

Added Value

to Data

0.00

0.05

0.10

0.15

0.20

1.0 1.2 1.4 1.6 1.8 2.0

MilepointR

ut D

epth

(in)

3.0

4.0

5.0

6.0

7.0

1.0 1.2 1.4 1.6 1.8 2.0

Milepoint

AC

(%)

0.00

0.05

0.10

0.15

0.20

1.0 1.2 1.4 1.6 1.8 2.0

MilepointR

ut D

epth

(in)

3.0

4.0

5.0

6.0

7.0

1.0 1.2 1.4 1.6 1.8 2.0

Milepoint

AC

(%)

0.00

0.05

0.10

0.15

0.20

1.0 1.2 1.4 1.6 1.8 2.0

MilepointR

ut D

epth

(in)

3.0

4.0

5.0

6.0

7.0

1.0 1.2 1.4 1.6 1.8 2.0

Milepoint

AC

(%)

Pavement Management

Construction

Contact Info:

Dr. Charles W. Schwartz University of Maryland schwartz@umd.edu +1.301.405.1962