Comparison of Different Sensors Used in the Assessment of Concrete Elements by Impact-Echo Method

Abstract

Testing methods used for assessment of buildings considered as a cultural heritage are focused mainly on non-destructive testing methods. Old buildings are usually sensitive to destructive in-situ testing, and a variety of non-destructive techniques (NDT) are frequently used. One of the most commonly used sensors are accelerometers, which can measure vibrations of different part of structures. These can be used in either continuous monitoring or in short-time assessment. Impact-Echo is a well-known method which can locate defects, caverns, or damaged parts not only in industry-level structures, but also in preservation of cultural heritage. This type of measurement requires attaching a sensor to the surface of the observed element. This is in most cases done by adhesives which can damage the more porous structures. In this paper a comparison of two different sensor types in testing of reference concrete elements is presented: contact piezoceramic accelerometer; non-contact MEMS type microphone. Signals recorded by each sensor type are assessed by the statistical method of feature extraction.