The basics of a system for evaluation of fiber-cement materials based on acoustic emission and time-frequency analysis.

Fiber-cement building products are increasingly used in construction. They are used as building and finishing material for facades, internal walls and roofs. Numerous advantages such as relatively low weight, low absorbability and relatively high strength allow to use these materials in bulky constructions and in buildings which are commonly considered tall. Safety reasons, however, point to the need to control the condition of materials used to erect such structures. It is also in line with the more and more widely implemented concept of monitoring the state of the structure and its components over their entire period of use (SHM). The article presents the results of experimental tests on flexural strength of cement-fiber boards in an air-dry state, which have been soaked in water for 24 hours and subjected to high temperature. The paper also presents a possibility to use a non-invasive method of acoustic emission and wavelet analysis for testing cement boards reinforced with cellulose fibers. Obtained results allow to track the change of mechanical parameters in boards subjected to environmental and exceptional factors. These results also confirm the applicability of the presented methods as instruments for observing the condition of the panels used.