Experimental Study on Mechanical Properties of Polyurethane Cement Composite (PUC) Under Various Temperatures

This paper aims to investigate the mechanical properties of polyurethane cement (different ratios) at different ambient temperatures. The temperature and proportion which affect the constitutive relation of the material were analyzed by axial tensile test. The microstructure and failure mode of polyurethane cement were studied using scanning electron microscope technology. At -40 degrees C similar to 40 degrees C, the stress-strain curves of polyurethane cement with different proportions were roughly similar. When the temperature was higher than 40 degrees C, with the rise of temperature, the ultimate tensile strength of polyurethane cement specimens would decrease but the ultimate strain would increase. When the temperature was lower than -40 degrees C, with the decline of temperature, the ultimate strain and tensile strength of polyurethane cement specimens would decrease. The ultimate stress of polyurethane cement with different ratios was different. With the rise of the proportion of polyurethane components, the ultimate stress would increase but the elastic modulus would decrease. Macroscopically, the failure modes of polyurethane specimens were different with the change of temperature. Brittle fracture occurred at low temperatures. At high temperatures, the specimen did not fracture, but a large number of "V"shaped cracks appeared at the edge. The higher the temperature, the more obvious this phenomenon was. At the microscopic level, the fibers didn't break at high temperatures, and there were obvious cracks and more stubble on the surface of cracks at room temperature.