Embedding ultrasonic transducers in concrete: A lifelong monitoring technology

Abstract

This paper deals with lifelong monitoring of concrete structures using embedded piezoelectric transducers. Thanks to such transducers, monitoring of the concrete can be automated both at the early age, right after the concrete is cast, and over the long term, until the end of the lifetime of the structure. For long term monitoring, the wave velocity variations introduced by operational factors effects should be filtered out. In the present study, we introduce a new technique called the Direct Wave Interferometry (DWI) which uses time stretching only on the early part of the recorded wave. This appears to be a good tradeoff between the high resolution of the Coda Wave Interferometry (CWI) for low velocity variations and the reliability of the measurement of the time of flight (TOF) for large velocity variations.

Influence of Glass Silica Waste Nano Powder on the Mechanical and Microstructure Properties of Alkali-Activated Mortars

“…Thus, within the concrete industry, OPC is currently the main binding agent [1][2][3]. However, the production of OPC is associated with high emissions of carbon dioxide, with one ton of carbon dioxide emitted for each ton of OPC that is produced [4][5][6]. Given that carbon dioxide contributes massively to the formation of greenhouse gases that promote global warming, OPC is not a sustainable material [7].…”

Entwicklung und Anwendung der Ultraschalltechnik zur Qualitätssicherung von Beton

“…Beispielhaft seien hier zwei Entwicklungen erwähnt. Seit etwa zehn Jahren entwickelt die Gruppe um Prof. Deraemaeker (Freie Universität Brüssel) Ultraschallverfahren zur Untersuchung von Frisch‐ und Festbeton mit eingebetteten Sensoren . Die Firma Giatec (http://www.giatecscientific.com) bietet demgegenüber Messgeräte an, welche die Daten drahtlos an einen Empfänger senden.…”

Automated crack evaluation of a high‐rise bridge pier using a ring‐type climbing robot

“…To tackle the aforementioned technical issues, a number of contact‐type nondestructive evaluation (NDE) techniques have been proposed. Ultrasonic techniques have been widely accepted due to their high sensitivity to cracks (An et al., 2014; Deraemaeker & Dumoulin, 2019). However, ultrasonic waves inherently have high attenuation characteristics especially in concrete materials, which are the main components of the bridge pier.…”