Linear and nonlinear resonant ultrasonic techniques applied to assess delayed ettringite formation on concrete samples

This study investigates the application of different ultrasonic Non-Destructive tests to assess Delayed Ettringite Formation, in concrete samples exhibiting low kinetic expansions (and up to 0.21%). Linear and nonlinear Resonant Ultrasonic Spectroscopy and Acoustic Emission tests were used. Scanning Electron Microscopy and optical microscopy observations were conducted at the end of the monitoring tests. The results showed a slight increase of the dynamic modulus and Quality factor while nonlinear hysteretic parameters remained constant over the test duration. Acoustic Emission tests attested the occurrence of events. However, the microscopic observations did not reveal meaningful differences in microcracking extent between the samples. (C) 2020 Published by Elsevier Ltd.

Automated summary

This study explores the application of various ultrasonic Non-Destructive tests to evaluate Delayed Ettringite Formation in concrete samples with low kinetic expansions. The results indicate a slight increase in dynamic modulus and Quality factor, with Acoustic Emission tests confirming the occurrence of events. However, microscopic observations did not reveal significant differences in microcracking extent between the samples.