engleski

The Role of Infrared Thermography in Nondestructive testing of Civil Engineering Structures

Infrared thermography is becoming ever more popular in nondestructive testing of materials and structures since it is completely noncontact and may be faster than many other techniques that are being used. The analysis of heating and cooling processes during and after warming up with an internal or external heat source is well established technique for the characterization of composites and metallic materials. In Civil Engineering, the application of infrared thermography is not limited to passive investigations of the quality of thermal insulation of building envelopes. Defects like voids in concrete or masonry, delaminations at interfaces of composites which have different density, heat capacity and/or heat conductivity in comparison to the bulk material can be localized and characterized. Basic principles of the two main techniques of active infrared thermography, which are pulse thermography (PT) and Lock-in thermography (LT), are briefly recalled. Active thermography by inducing a non-stationary temperature distribution in combination with the analysis of temporal data in frequency domain is very well suited for the visualization of inhomogeneities and defects close to the surface of building and reinforced concrete structures. In this paper, the use of passive infrared thermography technique for detecting defects in reinforced concrete structures and possible use of active thermography with post processing techniques that can be applied for characterization of defects in near surface region of reinforced concrete structures.

Infrared thermography; Hidden defects; Nondestructive testing; Civil Engineering; Reinforced concrete

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