A Portable Low-Cost Ultrasound Measurement Device for Concrete Monitoring

Daniel Fontoura Barroso,Niklas Epple,Ernst Niederleithinger

doi:10.3390/inventions6020036

Daniel Fontoura Barroso, Niklas Epple + Show 1 more

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https://doi.org/10.3390/inventions6020036

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Abstract

This paper describes a new ultrasonic measuring device called “W-Box”. It was developed based on the requirements of the DFG Forschergruppe (research unit) CoDA for a portable device for monitoring of concrete specimens, models and actual structures using embedded ultrasonic transducers as well as temperature and humidity sensors. The W-Box can send ultrasonic pulses with a variable frequency of 50–100 kHz to one selectable transducer and records signals from up to 75 multiplexed channels with a sample rate of 1 MHz and a resolution of 14 bits. In addition, it measures temperature and humidity with high accuracy, adjustable amplification, restarts automatically after a power failure and can be fully controlled remotely. The measured data are automatically stored locally on-site data quality checks and transferred to remote servers. The comparison of the W-Box with a laboratory setup using commercial devices proves that it is equally reliable and precise, at much lower cost. The W-Box also shows that their measurement capacities, with the used embedded ultrasonic transducers, can reach above 6 m in concrete.

Highlights

This paper describes a new ultrasonic measuring device called “W-Box”
Monitoring and non-destructive testing (NDT) has become a major topic in civil engineering (CE) in recent decades, as safety and environmental issues have shown the need for methods to ensure the structural integrity and increase the lifespan of constructions such as bridges
As several sensors are usually required for monitoring, the W-Box should be capable of connecting to at least 20 ultrasonic transducers, all operating as transmitters and receivers, adjustable signal amplification, switching between them using multiplexers and sending variable pulses of up to 300 Vpp

Summary

Introduction

Monitoring and non-destructive testing (NDT) has become a major topic in civil engineering (CE) in recent decades, as safety and environmental issues have shown the need for methods to ensure the structural integrity and increase the lifespan of constructions such as bridges. One of the most researched and widely spread methods of NDT is measuring with ultrasound. With the increasing demand for ultrasound measurements— especially for long-term monitoring—the need for a cost efficient, easy to build, and reliable measurement system has been identified by researchers at the NDT-CE department of the German Federal Institute for Materials Research and Testing (BAM). Ultrasound transmission experiments for concrete are considered as a standard procedure for quality assessment. Time of flight (TOF) measurements with compressional waves are applied in a standardized manner to estimate concrete strength using ultrasonic velocity as a proxy [1]. Ultrasound is used to monitor changes in concrete in controlled experiments by following changes certain features such as velocity and/or amplitudes, e.g., to assess fatigue strength [3]

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