Assessment of the Destruction of a Fibre Cement Board Subjected to Fire in a Large-Scale Study.

This article presents the results of a study involving the assessment of the structural destruction of fibre cement boards taken from a large-scale model subjected to fire. These were subjected to a three-point bending test using the acoustic emission method. The analysis of the obtained results took into account the course of bending stresses σ m , the modulus of rupture (MOR), the number of acoustic emission events N zd and the sum of EA events ∑N zd . The conducted tests showed that the samples subjected to fire exhibited a clear decrease, up to 72%, in the recorded sum of EA events compared to a reference board (not subjected to fire). The analysis of the obtained modulus of rupture (MOR) values showed a similar trend-the reduction of the modulus of rupture for the degraded samples was in the range of 66-96%. In order to illustrate the changes taking place in the structure of the tested plates more precisely, analyses were carried out using the optical method and a digital microscope. This method may be sufficient for the final evaluation of degraded samples.