Elucidating the influence of minimum environmental temperature on freeze-thaw damage behavior of concrete: Wave propagation technology assisted non-destructive structural performance testing

Traditional methods for monitoring and analyzing the concrete durability in cold climates are expensive and labor-intensive. For the purpose of solving this problem, a novel method based on the wave propagation (WP) technique was put forward to monitor the freeze-thaw damage (FTD). Time of Flight (TOF), Largest Peak to Peak Amplitude (LPPA), and Wavelet Packet Energy (WPE) were selected as damage assessment parameters for evaluating FTD evolution. Besides, the sensitivity of damage assessment parameters to the FTD stages was clarified. Results showed that the sensitivity of all the assessment parameters based on the WP test was higher than that of the conventional parameter named relative dynamic elasticity modulus (RDEM). Among the parameters, the LPPA and WPE exhibited higher sensitivity to FTD and were suitable for monitoring the damage during the early freeze-thaw (F-T) process. Since the TOF consistently identified the FTD within the specimen, it was suitable for evaluating the whole F-T process. Moreover, the sensitivity of the parameters to FTD can be effectively improved by increasing the input signal frequency. To make the WP test method better applied to practical engineering, the mathematical relationship between the novel damage assessment parameters and the RDEM was established.