Using modal-parameter-based analysis of the behaviour of alkali-activated material with surface degraded by ultraviolet radiation

Monitoring the behaviour of constructions, building structures, and materials caused by degradation processes is the main purpose of non-destructive testing methods. Most building materials are exposed to the action of environment. As some parts of building structures come into contact with external effects such as sunshine, they may be altered by ultraviolet radiation. For building materials, monitoring their structure degradation is a much more difficult task than for metal structures mostly due the non-homogeneity. Since, for homogeneous structures, impulse (acoustic) methods can be used to advantage particularly because the monitoring they enable is non-destructive, they were used in this case, too. To monitor the degradation caused by ultraviolet radiation, the impact echo method was employed [1-4].