SIBIE application to detecting void at post-installed adhesive anchor in concrete

•Impact-echo tests are conducted in anchor-fixation stages of concrete specimens.•Anchors were fixed with mortar and epoxy, while the fixation have a void.•Elastic wave are aroused by various size steel balls' drop, or titanium impactor.•The magnitude change of amplitudes is investigated by FFT of the echo to detect void.•The decreased amplitude by the drilling of hole recovers after the fixing of anchor. Stack Imaging of spectral amplitude based on the Impact Echo so-called SIBIE is among the recent techniques of nondestructive inspection. The current study addresses its application to detect voids in anchor-bolts and its applicability for periodic inspection through the shift in the magnitudes of amplitudes. Anchor-bolts have extensive usage in concrete structures and their periodic inspection and maintenance are necessary. SIBIE post-analysis of Impact-echo data has been performed to detect the artificial voids in concrete specimens. The analyses were performed in three stages (intact, hole-drilled, and anchor-fixed) of the grout and epoxy-resin based fixed anchor fixations. Four methods (7.9 mm, 6.4 mm, and 4.6 mm steel balls' free drop, and spring impactor with titanium bullet) were used to generate elastic stress waves in concrete. The artificial voids of 4 cm and 5 cm depths were detected in grout and epoxy-resin based fixed anchors. The FFT analysis reveals the shift in the magnitude of amplitudes while SIBIE analysis provides a more comprehensive image of the scenario. The amplitudes’ shift indicates apparent effects of hole-drilled, and anchor-fixed stages from the intact. It was indicated that the amplitude intensity of reflecting frequencies is higher before the hole-drilled stage, it has decreased when the hole of anchor fixation has been drilled and recovered back as the anchor has been fixed.