Extruded polystyrene (XPS) and polystyrene (EPS) are widely used as insulation materials in cold regions, mainly to prevent ice damage to projects. However, the degradation of polymer material performance caused by freeze-thaw cycles has not been fully quantified. To fill this gap, XPS boards were tested in a series of experiments. After several XPS board tests, volumetric water absorption, thermal conductivity, uniaxial compressive strength, Young's modulus and creep strain were measured and analyzed. The results show that water absorption and thermal conductivity change slightly with FTC. The increase in volumetric water absorption is less than 0. In addition, the increase in uniaxial compressive strength and Young's modulus increases and FTC decreases. The influence of FTC on Young's modulus is mainly concentrated at 50 times. The creep behavior of XPS boards belongs to attenuated creep, and the exponential function can describe the creep process. The results of this study can help us understand the degradation of XPS boards, to understand the damage caused by control in cold regions and provide reference for engineering design.
Practical application of XPS in railway engineering. To evaluate and ensure the cold and insulation effect of XPS boards in engineering construction, it is necessary to study the performance of XPS boards under freeze-thaw conditions. For example, the compressive strength and shear strength, thermal conductivity and water absorption rate of extruded boards. Unfortunately, most studies have focused on positive temperature changes or the performance of higher thicknesses or how to improve the performance of XPS boards with additives. However, a key problem is the performance decline of XPS boards, except for some studies. In short, XPS performance still has three aspects that need further research. The quantity is too small to reflect the performance of XPS boards; second, the temperature range and quantity during the experiment are limited, insufficient to meet the use needs of most cold regions; third, there are few physical and mechanical performance studies on the performance decline of XPS boards. How to quantitatively evaluate the physical and mechanical properties of XPS boards after repeated and extensive alternating freeze-thaw temperatures is unclear.
Combined with the above background, systematic experiments were carried out: (1) revealed the variation laws of thermal conductivity, volumetric water absorption, uniaxial compressive strength, Young's modulus and creep strain; (2) quantitatively analyzed the performance decline of XPS boards; (3) discussed the influence of density on thermal conductivity and volumetric water absorption; (4) creep strain of XPS boards. This study can provide some valuable references for the application of XPS boards in engineering construction in cold regions and help us more effectively deal with the damage of FTC engineering.
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