Detection of near-surface reinforcement in concrete components with ultrasound

Abstract

Ultrasonic testing of concrete has grown in importance considerably in recent years in non-destructive testing in civil engineering (NDT-CE). In the past, the main focus was on the imaging of the internal construction of steel and prestressed concrete components. On the other hand, comparatively little attention was paid to the location of near-surface reinforcement and concrete cover measurement. In this research, it is shown to what extent ultrasound is suitable for the detection of near-surface reinforcement in addition to magnetic inductive methods. The measurements were carried out with the newly developed Pundit 250 Array from the company Proceq and with the measuring devices of the company Acsys, the A1220 Monolith and the A1040 Mira. The ultrasound data was analysed with the vendor-independent software InterSAFT of the University of Kassel. Systematic investigations were carried out on test specimens with a variety on the concrete cover, the diameter of the reinforcement and the reinforcement ratio in the form of mesh reinforcement close to the surface. The detectability and accuracy of the concrete cover were set in relation to the concrete cover, wavelength and reinforcement diameter, with the result that more detailed rules for the detection of reinforcement are formulated for the user, instead of the known λ/2-criterion.

Embedded system for ultrasonic imaging of under-water concrete structures

“…Some of the systems work purely on the principle of UPV, such as Canopus Instruments, India [10] make UPV instrument which operates in contact-method for the T-R mode of inspection and provides measurement of either acoustic velocity or depth of the concrete block under inspection, using 50-500 kHz user-selectable narrow-band contact transducers. The ultrasonic phased-array, imaging system of Russia [11][12][13] utilizes 12x4 array of contact, shearwave, 50 kHz (fixed frequency) broad-band and heavily damped transducers, having frequency range capability of 25-85 kHz, suitable for PE mode. Another ultrasonic phased-array, imaging system of Switzerland [14] utilizes 16 × 3 array of contact, shear-wave 40 kHz (fixed frequency) broad-band and heavily damped transducers, having frequency range capability of 20-80 kHz suitable for only PE mode.…”

Estimation Position and Diameter of Rebar by Modern Non-Destructive Techniques

“…Among the available non-destructive testing techniques, including the Ground-penetrating radar (GPR), X-rays, the Ultrasonic Tomographic Imaging based on shear wave pulse-echo technique becomes more and more demanding due to its feasibility to more accurate and effective detection of different defect types, higher resolution of testing and applicability for deeper thicknesses of testing object [3,4,5].…”