ASTM D4788-88(1997)
(Test Method)Standard Test Method for Detecting Delaminations in Bridge Decks Using Infrared Thermography
Standard Test Method for Detecting Delaminations in Bridge Decks Using Infrared Thermography
SCOPE
1.1 This test method covers the determination of delaminations in portland-cement concrete bridge decks using infrared thermography. This test method is intended for use on exposed and overlaid concrete bridge decks.
Note 1—This test method can be used on asphalt or concrete overlays as thick as 4 in. (100 mm).
1.2 This test method uses an imaging infrared scanner and video recorder, mounted on a vehicle, to detect delaminations and debonded areas on bridge decks and to record the information.
1.3 The values stated in inch-pound units are to be regarded as the standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D 4788 – 88 (Reapproved 1997)
Standard Test Method for
Detecting Delaminations in Bridge Decks Using Infrared
Thermography
This standard is issued under the fixed designation D 4788; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2 The conventional video image is used to edit the
infrared image and separate those patches or surface defects
1.1 This test method covers the determination of delamina-
that may be present and may appear as hot areas.
tions in portland-cement concrete bridge decks using infrared
3.3 The video recording is used to map the delaminated
thermography. This test method is intended for use on exposed
areas at a suitable scale.
and overlaid concrete bridge decks.
NOTE 1—This test method can be used on asphalt or concrete overlays 4. Significance and Use
as thick as 4 in. (100 mm).
4.1 This test method may be used in conjunction with other
1.2 This test method uses an imaging infrared scanner and
test methods in determining the general condition of a bridge
video recorder, mounted on a vehicle, to detect delaminations
deck.
and debonded areas on bridge decks and to record the
4.2 Areas indicated as delaminated on overlaid bridge decks
information.
may be an indication of lack of bond between the overlay and
1.3 The values stated in inch-pound units are to be regarded
the underlying bridge deck. This test method may be used in
as the standard.
determining specific areas of delaminations requiring repair.
1.4 This standard does not purport to address all of the
5. Apparatus
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5.1 General—In order to collect data on the areal extent and
priate safety and health practices and determine the applica- location of the delaminations, the following apparatus is
bility of regulatory limitations prior to use.
required:
5.1.1 Infrared Scanner— An imaging infrared scanner hav-
2. Referenced Documents
ing a minimum thermal resolution of 0.2 Celsius degrees under
2.1 ASTM Standards:
ambient air conditions. The scanner shall be mounted on the
D 4580 Practice for Measuring Delaminations in Concrete
front of the vehicle at a height sufficient to allow a minimum
Bridge Decks by Sounding
image width of 14 ft (4.3 m). The scanner shall be capable of
producing a television-compatible image.
3. Summary of Test Method
5.1.2 Video Recorders capable of reproducing a thermal
3.1 The vehicle-mounted infrared scanner and video re-
image or a conventional video image. Each device shall have at
corder is driven over the center of each lane of a bridge deck.
least one audio channel available and provide a minimum
The data from the scanner is recorded on video tape. Delami-
resolution of 240 lines per inch. Two are required.
nations appear as white or “hot’’ areas on a gray or “cooler’’
5.1.3 Video Camera— A conventional video camera capable
background in the video image on a monochrome scanner
of viewing a minimum image of 14 ft (4.3 m) and producing a
system during daytime testing. During nighttime testing, the
color video signal that can be recorded on a standard video
delaminations will appear as dark or “cooler’’ areas on a white
recorder.
or “warmer’’ background. Delaminations will appear as the
5.1.4 Distance Measuring Device having an accuracy of
warmer colors on color scanner systems during daytime
63 in. (76 mm) over the longest span in the deck. The output
testing. Calibration of thermal anomalies using sounding tech-
of this device shall be recorded by both the infrared video
niques are used to determine the colors associated with
recorder and the conventional video recorder.
delaminations.
5.1.5 Test Vehicle on which the imaging infrared scanner
and video recorder will be mounted. The vehicle shall be
capable of supporting the infrared scanner and the conventional
This test method is under the jurisdiction of ASTM Committee D-4 on Road
video camera at a height sufficient to allow a minimum width
and Paving Materials and is the direct responsibility of Subcommittee D04.32 on
of 14 ft (4.3 m) of pavement to be observed at one time. The
Bridges and Structures.
vehicle shall be capable of supplying the necessary electrical
Current edition approved Sept. 30, 1988. Published November 1988.
Annual Book of ASTM Standards, Vol 04.03.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 4788
power required for the instrumentation. 6.10 Should field confirmation of the existence of a delami-
5.1.6 Contact Thermometer having a minimum tempera- nated or debonded area be required, select a core location(s)
ture resolution of Celsius degrees. during the inspection. Mark the location(s) for coring either
during the survey or subsequent to the infrared survey.
6. Procedure
7. Interpretation and Plotting of Results
6.1 Prior to the survey remove any debris that has accumu-
7.1 Plot the delaminations on a scaled plan of the bridge
lated on the deck.
deck using either a manual o
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