Steel detection in reinforced concrete wall by microwave infrared thermography

The Use of Non-destructive Methods to Detect Non-metallic Reinforcement in Concrete and Masonry

“…A thermal image (thermogram) is the result of tests capturing temperature distribution over the area of the tested body. Non-destructive tests using infrared thermography can be classified into procedures of passive and active tests [14,19]. Passive thermography analyses heat emitted by material without any additional thermal simulation, whereas active thermography is based on thermal analyses of the material response after its exposure to heat.…”

Development of Infrared Techniques for Practical Defect Identification in Bonded Joints

“…In vibrothermography the structure is subject 33 to a mechanical vibration load that causes any defect or crack surfaces to vibrate relative to each other causing a localised heating which may then be detected on the surface over the defect [83]. Microwave radiation has been used to stimulate larger concrete structures to detect steel reinforcement when considering the use of thermography in civil engineering applications [84].…”

“…The main disadvantage of x-ray stimulation is the health and safety issues associated with the use of such radiation, involving the use of shielding as in [84] or an exclusion zone being enforced, which impacts on other work being carried out. Eddy currents have been used as a heating source that does not rely on just surface heating but rather penetrates to the skin depth, which is dependent on the strength of the eddy current [85], which was found to increase the temperature contrast between defective and defect free regions [86].…”

Cooling analysis of welded materials for crack detection using infrared thermography

“…The heat source varies according to the technique employed. So far active thermography has been implemented with surface heating by pulsed laser [10,11] and flashlamps [11][12][13][14][15][16]; also no optical heat sources [12] like mechanical vibration [13,14], acoustic wave excitation [15] and microwaves [17] have been applied in active thermography. Regarding its application as NDT method, active thermography not only allows the detection and characterization of pathologies and flaws in materials [18,19], but also enables obtaining thermophysical parameters of the objects such as thermal diffusivity and thermal effusivity [20,21].…”

“…However, recent studies have discussed the possibility of applying the heat source in the weld installation place. [17] have researched the application of heat with a microwave open source directly in the weld. It is a high thermal efficiency source, portable and which allows heating in a short time, but it is also an expensive resource, which requires a rigorous security study and presents difficulties to be used in Europe due to the safety standards for microwave heating systems [24].…”