Abstract
Steel corrosion is one of the main pathological manifestations found in reinforced concrete. Its early detection can avoid costly repairs and damage to users. This paper proposes using infrared thermography and ultrasound to detect corrosion in reinforced concrete. The methodology consisted of preparing six specimens of 30x20x10 cm each including three 12.5-mm steel bars inserted and 2.5, 5.0 and 7.5-cm coatings. Those are the most commonly used and and recommended types of coating for reinforced concrete structures. The test specimens were subjected to an accelerated corrosion process, in a differentiated manner, in order to analyze three different degrees of corrosion. Subsequently, the specimens were submitted to infrared thermography tests and finally, ultrasound tests. The results showed that infrared thermography has many limitations regarding corrosion detection, but those limitations are reduced during the morning period; in very advanced conditions of deterioration, and on steel covered with only limited coating. On the other hand, the ultrasound showed a clear distinction in the results for the specimens, since wave propagation speed varies according to the corrosion degree and the quality of the concrete. Even though both tests present some limitations, using them in combination is a more effective way to detect the problem, since thermography can locate affected areas and ultrasound can better characterize any problems by comparing these areas against other intact concrete areas.
Keywords:
Corrosion; Infrared thermography; Ultrasound; Reinforced concrete
