One of the leading causes of reinforced concrete degradation is chloride attack. It occurs due to the penetration of chlorides through pores and cracks into the concrete cover. This phenomenon becomes more dangerous if reinforced concrete elements are subjected to cyclic temperature changes. The concrete cover protects against corrosion. This paper presents research, the primary purpose of which was to determine the effect of the addition of steel fibers to concrete on the development of corrosion of the main reinforcement. The tests were carried out on three types of reinforced concrete specimens made of ordinary concrete and concrete with different amounts of steel fibers (0.25% and 0.50%). In order to initiate corrosion processes, specimens were partially submerged in a 3% sodium chloride solution and were subjected to freeze–thaw cycles. The electrochemical polarization galvanostatic pulse method was used for analyzing the reinforcement corrosion activity. Moreover, it was verified whether the corrosion of reinforced concrete elements affects the acoustic emission wave velocity. The addition of steel micro-reinforcement fibers increases the corrosion resistance of reinforced concrete. In addition, a strong linear correlation between the AE wave velocity and the values of the corrosion current density was revealed.

This paper compares three nondestructive methods used to detect and locate defects such as delaminations or voids in externally bonded fiber reinforced polymer (FRP) concrete structures: infrared thermography, ground-penetrating radar, and measurement of acoustic wave velocity. One of the main goals was to check whether it was possible to distinguish overlapping defects. For this purpose, eight concrete samples were made with a bonded carbon fiber reinforced polymer (CFRP) strip with the following dimensions 100 × 100 × 500 mm. Two samples had no defects, four had single defects varying in location (at the edge of the strip or in the centre) simulating delamination or voids in the concrete cover, and the remaining samples had overlapping defects. Both infrared thermography and acoustic wave velocity measurement methods allow the detection of defects/voids in the adhesive layer and a concrete defect (void in the concrete cover). However, ground penetration failed to detect defects in the adhesive layer. Only infrared thermography allows for the differentiation of overlapping defects. On the basis of the conducted research, the methodology, differences, advantages, and limitations of each method were described, along with recommendations based on the authors’ experience.

Numerous artificial sources of acoustic waves have been described in the literature, which are designed to replicate the process by which actual damage occurs in a given material. Knowledge of the velocity with which an acoustic wave propagates is important here, both in order to correctly locate the signal source and to determine the degree of material degradation or the location of damage that has already occurred in the medium. This work presents the results of laboratory tests comparing two sources of artificial waves in terms of determining their parameters: the Hsu–Nielsen source and a sensor with the Auto Sensor Test function. The AST function allows the sensors to send and receive an elastic wave and is used to calibrate the sensor before, during, or after the test. In this study, the impact of the positioning of the sensors on the element being tested, their spacing, and the distance of the wave source from the sensor on selected parameters of the recorded waves are analyzed: velocity, amplitude, energy, rise time, waveform shape, and wavelet maps. This work demonstrates that a sensor with the AST function can be an effective alternative for the Hsu–Nielsen source in diagnostic studies.

Residential buildings near transport corridors are exposed to traffic-induced vibrations that can affect their safety. This paper presents a dynamic diagnosis of a masonry building located near a grade-separated junction. The study aimed to determine whether traffic-induced vibrations were responsible for the diagonal cracking of plaster observed in a dormer wall. The methodology included simultaneous acceleration measurements on the ground and building, traffic recording, 3D laser scanning for geometric reconstruction, and finite element modelling with soil–structure interaction. Time history and modal analyses were performed for various soil stiffness values. The results show that vibrations are predominantly attenuated at the soil–building interface, whereas soil flexibility markedly lowers the fundamental (lowest) natural frequencies of the building. The effect of soil stiffness on wall shear stress was more significant than that of dynamic action in load combinations. A comparison of the principal stress trajectories with the observed cracking patterns suggests that the damage was primarily due to the support condition of the wall. Traffic-induced vibrations are not the main cause of the observed damage. The integrated diagnostic procedure was effective in distinguishing vibration effects from other structural factors and was useful in assessing building safety.

The article presents experimental research and numerical analysis of a building partition in frame construction. The subject of the analysis were sections of the building partition consisting of cold-bent steel profiles and plasterboard cladding. The experiment was carried out using a four-point bending test and recording a continuous load-displacement curve until failure. Next, a computational model based on the finite element method was developed to simulate the experiment. The results from the experimental tests were then compared with that obtained from the numerical analysis. The validation of the numerical model demonstrated a high level of agreement in terms of load-displacement characteristics. The use of numerical analyses provides an alternative to time-consuming experimental tests for estimating displacements of building partitions in frame construction