This article discusses the degradation of concrete materials in post-fire conditions by examining the mechanical properties and damage mechanisms of concrete reinforced with polypropylene (PP) fibers. The tested material is offered as a construction product and approved for sale. The effect of different fire temperatures on the material's performance was analysed in laboratory tests using acoustic emission (AE) technology. The analyses show that PPR exhibits ductile fracture under bending loads, whereas PPF undergoes brittle fracture. AE ringing counts strongly correlate with loading conditions. The b-value effectively reflects damage characteristics, providing early warning indicators. AF-RA images suggest that fire temperatures accelerate and intensify shear cracking. The acoustic emission method has potential as a diagnostic technology for PP-reinforced concrete in post-fire conditions.