Here are some references to look at:
D4788-03 Standard Test Method for Detecting Delaminations in Bridge Decks Using Infrared Thermography
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.
See http://www.astm.org/cgi-bin/SoftCart.exe/STORE/filtrexx40.cgi?U+mystore+imnk2662+-L+D4788NOT:(STATUS::REPLACED)+/usr6/htdocs/astm.org/DATABASE.CART/REDLINE_PAGES/D4788.htm
Infrared Thermography, or thermal imaging as it is sometimes known, provides a cost effective and accurate method of detecting delamination and debonding in concrete structures. It works because the delaminations or voids are filled with air or water, each of which has a different density and thermal conductivity to the surrounding concrete.
See http://www.infratech.ltd.uk/concrete.pdf
The use of Infrared Thermography is based on the poor thermal conductivity of concrete. This characteristic of concrete is such that on a sunny day, significant temperature differences exist throughout the pavement. Consequently, any discontinuity parallel to the surface inhibits the transfer of heat to the concrete.
See http://www.gietech.com/Thermo.htm
This paper explores the possibility of detecting geometrical defects in concrete specimens using thermal imaging. The method is based on the characteristics of heat flow phenomenon, in a conductive medium of specific geometry, which is intended to model predetermined boundary conditions. A range of crack widths, representing mechanical damage, has been induced under controlled laboratory conditions. In all cases the cracks have been located successfully.
See http://www.ndt.net/article/v05n02/shih/shih.htm
Nondestructive Evaluation of Bridges and Highways
See http://www.spie.org/web/meetings/programs/ss99/confs/3587.html
Infrared thermography has the potential to size defects, to evaluate the quality of the adhesive bonds remotely and to cover a large area per scan. In this paper, a feasibility study was carried out to evaluate bonded and hollow areas between tile and concrete substrate. A locked-in thermography system was used. The study shows that there is a distinct difference in thermographic phase patterns. This is a possibility of using this technique when there is complete disbond (hollow area) between tile and concrete substrate.
See http://www.mod.com.bn/editor_4_12.htm
Gary Orlove
Infrared Training Center |
