Gao Shuling, Xie Puxu
School of Civil and Transportation Engineering, Hebei University of Technology, Tianjin 300401, China.
Civil Engineering Technology Research Center of Hebei Province, Tianjin 300401, China.
Materials (Basel). 2022 Apr 1;15(7):2604. doi: 10.3390/ma15072604.
This research will help to improve our understanding of the fracture properties of ECC at low temperatures (long-term low temperatures, freeze-thaw) and evaluate the safety properties of ECC under low-temperature conditions. Three levels of saturation (saturated, semi-saturated, and dry), four target temperatures (20, 0, -20, and -60 °C), and the effect of the coupled of the two on the mode I fracture properties of ECC were investigated. Then, we compared and analyzed the fracture properties of ECC loaded at 20 and -20 °C, after different freeze-thaw cycles (25, 50, 100 cycles), which were compared with saturated specimens without freeze-thaw at the four target temperatures to analyze the differences in low-temperature and freeze-thaw failure mechanisms. Temperatures and saturation have a significant effect on the fracture properties. Low temperatures and freeze-thaw treatments both decreased the nominal fracture energy of ECC. Distinct differences in matrix and fiber-matrix interface damage mechanisms have been discovered. Low temperatures treatment transforms ECC from a ductile to a brittle fracture mode. However, even after 100 freeze-thaw cycles, it remains ductile fractured. This study complements the deficiencies of ECC in low-temperature theoretical and experimental applications, and it sets the stage for a broad range of ECC applications.
本研究将有助于提高我们对工程水泥基复合材料（ECC）在低温（长期低温、冻融）下的断裂性能的理解，并评估ECC在低温条件下的安全性能。研究了三种饱和度水平（饱和、半饱和和干燥）、四个目标温度（20、0、-20和-60°C）以及两者耦合对ECC的I型断裂性能的影响。然后，我们比较并分析了在20和-20°C下加载的ECC在不同冻融循环次数（25、50、100次循环）后的断裂性能，并将其与在四个目标温度下未进行冻融的饱和试件进行比较，以分析低温和冻融破坏机制的差异。温度和饱和度对断裂性能有显著影响。低温和冻融处理均降低了ECC的名义断裂能。已发现基体和纤维-基体界面损伤机制存在明显差异。低温处理使ECC从延性断裂模式转变为脆性断裂模式。然而，即使经过100次冻融循环，它仍保持延性断裂。本研究弥补了ECC在低温理论和实验应用方面的不足，并为ECC的广泛应用奠定了基础。
