Durability and debond evaluation of high-rise concrete buildings using infrared thermography

The paper presents the development of a passive infrared thermography (IRT) method as a screening tool to indicate and measure the size of debonds in external wall envelop of building structures. The underlying principle of this method is the comparison of the surface temperature at areas with heat trapped by air (debond) during and after exposure to sunlight with the cooler areas (without debond). Mathematical inversion of the heat distribution over an external wall surface enables the measurement and calculation of debond size and boundary. It has been proven that the proposed methodology and algorithm are accurate, and can be used generally because they are not affected by factors like depth of debond, sizes of debond, surface temperatures, temperature scales set in the infrared camera and time when the thermograms are taken. This quantitative method allows the evaluation of the long term durability and facilitates planning of rehabilitation of tall buildings.