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Title: Using emissivity-corrected thermal maps to locate deep structural defects in concrete bridge decks

Abstract

Dual-band infrared (DBIR) thermal imaging is a promising, non-contact, nondestructive evaluation tool to evaluate the amount of deteriorated concrete on asphalt-covered bridge decks. We conducted proof-of-principle demonstrations to characterize defects in concrete structures which could be detected with DBIR thermal imaging. We constructed two identical concrete slabs with synthetic delaminations, e.g., 1/8-in. thick styrofoam squares, implanted just above the 2-in.-deep steel reinforcement bars. We covered one of the slabs with a 2-in. layer of asphalt. We mounted the DBIR cameras on a tower platform, to simulate the optics needed to conduct bridge-deck inspections from a moving vehicle. We detected 4-in. implants embedded in concrete and 9-in. implants embedded in asphalt-covered concrete. The midday (above-ambient) and predawn (below-ambient) delamination-site temperatures correlated with the implant sizes. Using DBIR image ratios, we enhanced thermal-contrast and removed emissivity-noise, e.g., from concrete compositional variations and clutter. Using the LLNL/VIEW code, we removed the asphalt thermal-gradient mask, to depict the 4-in. deep, 9-in. square, concrete implant size. We plan to image bridge deck defects, from a moving vehicle, for accurate estimations of the amount of deteriorated concrete impairing the deck integrity. Potential longterm benefits are affordable and reliable rehabilitation for asphalt-covered decks.

Authors:
;
Publication Date:
Research Org.:
Lawrence Livermore National Lab., CA (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
61691
Report Number(s):
UCRL-JC-120545; CONF-9506126-3
ON: DE95011516; TRN: 95:004310
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: Conference on nondestructive evaluation of aging infrastructure, Oakland, CA (United States), 6-8 Jun 1995; Other Information: PBD: 5 Apr 1995
Country of Publication:
United States
Language:
English
Subject:
44 INSTRUMENTATION, INCLUDING NUCLEAR AND PARTICLE DETECTORS; 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; BRIDGES; NONDESTRUCTIVE ANALYSIS; DEFECTS; REINFORCED CONCRETE; INFRARED THERMOGRAPHY; USES; CRACKS

Citation Formats

Del Grande, N K, and Durbin, P F. Using emissivity-corrected thermal maps to locate deep structural defects in concrete bridge decks. United States: N. p., 1995. Web.
Del Grande, N K, & Durbin, P F. Using emissivity-corrected thermal maps to locate deep structural defects in concrete bridge decks. United States.
Del Grande, N K, and Durbin, P F. Wed . "Using emissivity-corrected thermal maps to locate deep structural defects in concrete bridge decks". United States. https://www.osti.gov/servlets/purl/61691.
@article{osti_61691,
title = {Using emissivity-corrected thermal maps to locate deep structural defects in concrete bridge decks},
author = {Del Grande, N K and Durbin, P F},
abstractNote = {Dual-band infrared (DBIR) thermal imaging is a promising, non-contact, nondestructive evaluation tool to evaluate the amount of deteriorated concrete on asphalt-covered bridge decks. We conducted proof-of-principle demonstrations to characterize defects in concrete structures which could be detected with DBIR thermal imaging. We constructed two identical concrete slabs with synthetic delaminations, e.g., 1/8-in. thick styrofoam squares, implanted just above the 2-in.-deep steel reinforcement bars. We covered one of the slabs with a 2-in. layer of asphalt. We mounted the DBIR cameras on a tower platform, to simulate the optics needed to conduct bridge-deck inspections from a moving vehicle. We detected 4-in. implants embedded in concrete and 9-in. implants embedded in asphalt-covered concrete. The midday (above-ambient) and predawn (below-ambient) delamination-site temperatures correlated with the implant sizes. Using DBIR image ratios, we enhanced thermal-contrast and removed emissivity-noise, e.g., from concrete compositional variations and clutter. Using the LLNL/VIEW code, we removed the asphalt thermal-gradient mask, to depict the 4-in. deep, 9-in. square, concrete implant size. We plan to image bridge deck defects, from a moving vehicle, for accurate estimations of the amount of deteriorated concrete impairing the deck integrity. Potential longterm benefits are affordable and reliable rehabilitation for asphalt-covered decks.},
doi = {},
url = {https://www.osti.gov/biblio/61691}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1995},
month = {4}
}

Conference:
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