摘要：Consideration of the durability of building materials from a thermal fluctuation position is the most difficult, but at the same time the most adequate method now. Since this concept is insensitive to changes in the physical structure, it becomes necessary to consider not only the material, but also the configuration of the structure. This will make it possible to bring the simplified theoretical ideas about the performance of a building material in a structure closer to real conditions. Thus, the aim of the work is to compare the destruction mechanism of PVC sheet elements of solid section and composite section from the thermal fluctuation position. To achieve this goal, the initial data for finding thermal fluctuation constants (durability of PVC plates at non-critical stress) were determined by an experimental method. Based on the initial data, the thermal fluctuation constants for each section were determined by the graphic-analytical method. During the comparative analysis, it is proposed to introduce a coefficient into the Zhurkov’s equation, which will consider the configuration of the section. It was also determined that for PVC sheet elements of composite cross-section in two layers, this coefficient iskc= 2. Considering the configuration of the cross-section when determining the thermal fluctuation dependences will increase the quality of predicting the durability of the building material.
