The Influence of Diurnal and Seasonal Variations of Relative Humidity and Temperature on Coal–Plastic Moisture Saturation in Open Climatic Conditions

Strength Characteristics of Carbon Fiber Reinforced Plastic in Shear and Cyclic Extension-Compression after 7 Years of Climate Exposure

“…If the PCM is under the influence of direct solar radiation, then the processes of binder destruction are activated in the thin surface layer, forming a gradient of properties along the thickness of the plates [3]. Overheating of the surface contributes to the desorption of water molecules from the volume of the material [16] and a decrease in the plasticizing effect of moisture, thereby increasing the complex of deformation and strength parameters of the PCM [28].…”

“…Plate 2 was under a canopy and was exposed to temperature and natural humidity. According to [16], 0.3 ± 0.05% of moisture accumulated in it. The same amount of moisture was contained in plates 1 and 3.…”

“…Due to daily and seasonal fluctuations in air temperature under the influence of solar radiation, the plate was heated to 25 °C and conditions were formed for more intensive moisture transfer (sorption at high humidity and rains and desorption during heating) and the formation of micro-cracks due to different values of the coefficients of linear thermal expansion of the polymer matrix and reinforcing fibers [12]. Under the influence of the ultraviolet component of solar radiation, the destruction of the thin surface layer of plate 3 occurred, over 7 years of climatic tests, and its mass decreased by 0.5 ± 0.05% [16].…”

“…By adjusting the reinforcement scheme [13] and pressing modes [14], it is possible to achieve the levels of indicators necessary for the construction of loaded structural elements. In the works [15,16], it was reported on the levels of moisture saturation of CFRP based on Cycom 977-2, including during 6 years of exposure of this material in a warm humid climate [16].…”