40007 2015 eng 412 420 11 20 article NDT.net Kirchwald 0 -- -- -- Dense GPR measurements of rebar reflection amplitudes Show relative variations, which can be in the order of more than 10% - 20%. Former investigations demonstrated that these variations are caused by the heterogeneity of concrete, i.e. due to the inclusion of aggregates in concrete. These amplitude variations make it difficult to analyse single reflection amplitudes in order to determine the rebar diameter or to estimate the concrete deterioration state. In a systematic study we have quantified the statistical variation of the rebar reflection amplitude for concrete covers of 6 cm, 9 cm, 12 cm, 15 cm and 18 cm, for two different grading curves and for the rebar diameters 12 mm and 28 mm. Also the influence of the wavelength has been investigated by using antennas with different centre frequencies in relation to the aggregate size. The results are discussed with regard to a quantitative amplitude evaluation of GPR measurements and also the potential of using these variations for a characterization of concrete material properties. The e-journal of nondestructive testing & ultrasonics 1435-4934 http://www.ndt.net/?id=18402 NDT-CE 2015 - International symposium non-destructive testing in civil engineering Berlin, Germany 15.09.2015 17.09.2015 Thomas Kind eng uncontrolled Ground penetrating radar eng uncontrolled Concrete eng uncontrolled Rebar eng uncontrolled Aggregate scattering Analytische Chemie Ingenieurwissenschaften und zugeordnete Tätigkeiten Ingenieurbau Datei im Netzwerk der BAM verfügbar ("Closed Access") Graue Literatur