Title: Monitoring Concrete Curing by Linear and Nonlinear Ultrasonic Methods

Author(s): H. N. Alnuaimi, S. Sasmal, U. Amjad, A. Nikvar-Hassani, L. Zhang, and T. Kundu

Publication: Materials Journal

Volume: 118

Issue: 3

Appears on pages(s): 61-69

Keywords: curing stage; fast Fourier transform; guided waves; linear and nonlinear ultrasonic techniques; nondestructive testing; sideband peak count; time and frequency domain analysis; transmission mode

DOI: 10.14359/51730412

Date: 5/1/2021

Abstract:
Cement paste is the primary constituent of concrete that keeps all other constituents together and gives concrete its strength. During curing, the cement is developed as a binder by going through various chemical reactions. In the present study, ultrasonic testing is carried out on concrete samples during curing in transmission mode. The acoustic signals are generated using lead zirconate titanate (PZT) transducers which are excited by a sweeping frequency signal. Nondestructive testing and evaluation were carried out at various stages of curing for concrete with two different watercement ratios (w/c). The obtained signals were processed to analyze the change in signal characteristics during the different stages of curing. It was found that the nonlinear ultrasonic technique called the side band peak count (SPC) index, which is derived from the frequency spectra, exhibits a clear distinction among various concrete specimens at different stages of curing. Linear ultrasonic parameters, however, do not show such consistency. Therefore, the nonlinear ultrasonic technique provides an easy and effective way for monitoring the degree of concrete curing.