SIBIE procedure for the identification of ungrouted post-tensioning ducts in concrete

SIBIE (Stack Imaging of Spectral Amplitudes Based on Impact-Echo) is an imaging procedure applied to the impact-echo data in the frequency domain. The procedure is developed to improve the impact-echo method and to visually identify locations of defects in concrete. SIBIE has been applied to identification of voids within post-tensioning tendon ducts in concrete. In order to investigate the effect of the distance between impact and detection points on SIBIE results and to improve the applicability of the procedure, a concrete slab containing post-tensioning tendon ducts of metal and plastic was tested. Locations of void within both metal and plastic ducts are identified visually by the SIBIE procedure.