Damage in infrastructure can be as a result of its degenerating state under service loads or after exposure to impact loads such as earthquakes. Early damage detection is essential to preventing failure and ensure the integrity and safety of structures. Damages lead to changes in the geometric and material properties like mass, stiffness, and damping, and influences the response behavior of the structure. It has been proven that vibration-based damage detection technique is an efficient means of damage identification and assessing structural integrity. This review article examines conventional vibration-based damage detection techniques. It highlights the importance of early damage detection as a means of ensuring infrastructural safety, reliability and maintenance. Damage detection techniques like the time domain methods, frequency domain and modal domain methods have been developed and constantly evolving to meet the existing challenge of identifying structural damages. The practical application is still minimal, hence more research works are necessary for damage detection in large civil engineering structures.

This study examines the residual strength of concrete produced with crushed discarded soda-lime glass as aggregates after exposure to elevated heating. The natural aggregates, which comprise both the coarse and fine aggregates were partially and completely replaced by 0, 25, 50, 75 and 100% of the discarded glass. The control and samples containing crushed discarded glass aggregates were prepared at constant water-cement ratio (w/c) of 0.50 and the cube samples were exposed to temperatures of 60, 150, 300 and 500°C after curing in water for 90 days. The heating was increased at a constant heating rate of 10°C/min. The strength of the concrete samples was measured before and after exposure to heating after air-cooling of the heated samples. Moreover, scanning electron microscope (SEM) examination was carried out on selected samples to investigate the extent of change in the concrete bonding, especially at higher heating. Test results depict reduction trend in the characteristic strength of the tested samples as the level of heating increases, while the SEM micrographs reveal clear decomposition in the concrete interfaces. However, it was noticed from the results that concrete containing crushed discarded glass show better performance in terms of strength compared to the reference concrete at certain temperature exposure indicating a modified concrete with improved post-fire resistance.