The propagation and attenuation of medium-frequency ultrasonic waves in concrete: a signal analytical approach

Abstract

The manner in which medium-frequency ultrasonic pulses travelling through concrete are generated, received, digitized and analysed is described. Due to the highly attenuating nature of this medium and its differential effects on the frequency composition of broad-band signals, signal analysis was performed by partitioning the signal into discrete windows in the time domain, corresponding to the emergence of individual wave phenomena within the medium. These windows were then transformed to the frequency domain for subsequent filtering and interpretation. Experimentation combined with theoretical modelling has shown that the appearance and decay of discrete frequency bands depends on both the composition of the concrete, termed the resonance phase, and its external importance with respect to the ultrasonic inspection of concrete and other such inhomogeneous materials.

Ultrasonic monitoring on glass fiber reinforced cement (GRC) bending test

“…An ultrasonic through-transmission setup was selected because it offers good penetration and good accuracy for velocity and attenuation estimation [6,[13][14][15]. The layout of the equipment is shown in Figure 1.…”

Ultrasonic characterization of GRC with high percentage of fly ash substitution

“…10. For frequencies over 550kHz (diffusion region, [15,24]), both specimens converge with a similar linear positive dependence.…”

The Effect of Moisture on the Strength of Concrete Sample by using Ultrasonic Device

“…Machines for making and receiving ultrasonic waves have a digital monitor to show the results. As per Gaydecki (1992) using low frequencies in the area of 40 to 80 KHz to assess the concrete. We used 54 KHz frequency that in this research.…”

“…These parameters must be considered by the researchers (Facaoaru, 1970). Gaydecki (1992) examined the propagation and attenuation of waves in concrete at different frequencies. Malhotra (1976) studied the velocity of waves in concrete samples with different ratios of waterand types of different aggregates.Factory with multiple tests on made concrete samples with a variety of aggregates usually offered the ranges of waves' speed depending on the type of aggregate (Facaoaru, 1970).…”