Measurement of shear wave velocity in concrete using embedded piezoelectric transducers

Context of the master thesis

The mechanical properties of concrete are commonly measured using static traction/compression tests following different available standards. Such tests require to have access to an adequate testing machine and to design a specific concrete sample with given shape and dimensions. An alternative is the use of dynamic testing techniques which can be split in two categories: resonant methods are low frequency methods which also require having a concrete sample with a simple shape and known dimension, while ultrasonic methods do not suffer from such limitations but work at much higher frequencies. At BATir-ULB, we have developed embedded piezoelectric sensors for ultrasonic testing of concrete. These have been used to measure the traction-compression wave velocity (P-wave) [1]. The P-wave velocity can be used to estimate the Young’s modulus if a hypothesis is made on the Poisson’s ratio. An alternative is to measure both the P-wave and the shear wave velocities (S-wave). Knowing the S- and P-waves velocities, both the Young’s modulus and the Poisson’s ratio can be calculated.

 References

[1] Dumoulin C., Karaiskos G., Carette J., Staquet S. and Deraemaeker A.. Monitoring of the ultrasonic P-wave velocity in early-age concrete with embedded piezoelectric transducers. Smart Materials and Structures, 21(4), (2012)

Objectives of the master thesis

The main objective is to assess the possibility to measure the S-wave velocity using embedded piezoelectric transducers developed at BATir-ULB. Two approaches will be followed. In the first one, the possibility to measure the S-wave velocity using adequate signal processing techniques will be assessed for the existing sensors. In the second one, new sensors based on piezoelectric shear actuation mechanisms will be manufactured and tested in order to compare their performance to measure the S-wave velocity compared to the existing sensors.

Arnaud Deraemaeker (aderaema@ulb.ac.be)

Co-Supervisor

Cédric Dumoulin (cedumoul@ulb.ac.be)

English/French

Architectural Engineering/Civil Engineering/Mechanical Engineering

The student must have an interest in Structural Dynamics, Cementitious materials and Concrete behavior, basic programming skills in Matlab and an interest in experimental testing.