Acoustic testing of reinforced concrete structure corrosion: Fid-Bau Portal

Acoustic testing of reinforced concrete structure corrosion

Timcakova-Samarkova, Kristyna / Chobola, Zdenek / Stefkova, Daniela

The rebar condition influences profoundly die properties of horizontal structures. Note that the occurrence of corrosion in the bulk cannot be observed from the outside in many cases. This is why studies of non-destructive methods allowing the researchers to detect the degree of corrosion for the built-in rebars are being paid much attention currently. An acoustic method, known as Impact-Echo method, providing for die internal structure damage evolution and degree detection, appears to be a convenient method to monitor the building structure condition the defect detection, identification and location are constituents of the diagnosis of the object technical condition. The paper deals with die study of dominant frequencies of an Impact-Echo method response signal obtained from a reinforced concrete beam with a steel rod diameter of 8 mm. Tension pulse was produced in the centre of the concrete beam and detected in opposite position of the concrete beam. Dominant frequencies of the response signal will be the main criterions for the reinforced concrete rebar corrosion progress. The article presents the results of measurements obtained after 24 months controlled degradation in aqueous NaCl solution. The results were compared with measurements of electrical resistance of reinforcing steel by using the Thomson double bridge. It is obvious that die measurement of electrical resistance of reinforcement is a sensitive method for assessing the state of corrosion of reinforcing steel in reinforced concrete structures, and so it can be used to compare the results of corrosion monitoring using acoustic methods. We observed a strong correlation between these two changes. Based on the above results, the frequency inspection method can be recommended as an efficient tool to evaluate the steel rebar corrosion condition. The non-destructive testing methods make it possible to timely identify the occurrence and development of defects in materials and thus ward off the failure or even the breakdown of structural units consisting of mechanically or thermally stressed, or corrosion affected parts.