冲击荷载作用下锈蚀钢纤维混凝土构件破坏机制及评估方法研究

Steel fiber reinforced concrete (SFRC) is a new type of composite material, which has been widely used in engineering structure. when the carbonation front of concrete reaches the surface of steel bars or the concentration of chloride ions on the surfaces of steel bars reaches a critical value, depassivation of the oxide film of steel bars may occur and corrosion may be initiated. The probability of SFRC structures exposed to the impact loading, explosion shock and other non-design loadings is increasing. Therefore, to carry out the study of the impact resistance of corroded steel fiber RC structures is very important and necessary. To evaluate the mechanical behavior of corroded steel fiber RC structures, corroded steel fiber bars and corroded RC members should be studied primarily, and the analysis method for mechanical behavior of corroded members under impact load should be developed. The main research work are as follows: Compress and tensile tests of corroded steel fiber concrete and corroded steel fiber under various strain rates were carried out to investigate the impact of corrosion on the mechanical properties of steel fiber and concrete under different strain rates. Pull-out tests were carried out to study the effects of strain rate, corrosion degree on bond behavior between corroded rebars and corroded steel fiber concrete. Drop hammer impact tests and numerical simulation were used to study the failure mechanism of corroded RC members under impact loading. Finally, a safety assessment method of corroded RC members under impact loading will be proposed. The object of this study is to reveal the mechanical behavior of corroded steel fiber RC structures under impact loading. It will also provide the necessary scientific basis for the structure design, maintenance, safety evaluation and the durability design.

钢纤维混凝土是一种广泛应用于工程结构的新型多相复合材料。由于混凝土碳化或氯离子侵蚀等因素的影响，钢筋、钢纤维锈蚀等耐久性问题较为常见。作为普遍采用的工程结构，面对冲击、撞击等非设计荷载的可能性日益增加，因此开展锈蚀钢纤维混凝土结构抗冲击性能的研究十分必要。本项目以冲击荷载作用下锈蚀钢纤维混凝土构件为研究对象，对其抗冲击性能进行基础研究。具体内容包括：通过试验研究锈蚀钢纤维受拉性能、锈蚀钢纤维混凝土受压性能、锈蚀钢筋与锈蚀钢纤维混凝土间粘结性能及锈蚀钢纤维混凝土构件在冲击荷载作用下的受力机制；通过理论分析建立钢纤维混凝土和锈蚀钢纤维动力本构关系模型和锈蚀钢筋与锈蚀钢纤维混凝土间粘结滑移本构关系模型；建立相应的锈蚀构件受力性能的定量评估方法。本项目旨在揭示冲击荷载作用下锈蚀钢纤维混凝土材料和构件锈蚀后的退化规律，将为结构设计、维护方法、服役结构的安全性评估及耐久性设计提供必要的科学依据。

钢纤维混凝土是一种广泛应用于工程结构的新型多相复合材料。由于混凝土碳化或氯离子侵蚀等因素的影响，钢筋、钢纤维锈蚀等耐久性问题较为常见。作为普遍采用的工程结构，面对冲击、撞击等非设计荷载的可能性日益增加，因此开展锈蚀钢纤维混凝土结构抗冲击性能的研究十分必要。本项目以冲击荷载作用下锈蚀钢纤维混凝土构件为研究对象，对其抗冲击性能进行基础研究。具体内容包括：通过试验研究锈蚀钢纤维受拉性能、锈蚀钢纤维混凝土受压性能、锈蚀钢筋与锈蚀钢纤维混凝土间粘结性能及锈蚀钢纤维混凝土梁构件在冲击荷载作用下的受力机制；通过理论分析建立钢纤维混凝土和锈蚀钢纤维动力强度模型和锈蚀钢筋与锈蚀钢纤维混凝土间粘结强度模型；建立相应的锈蚀梁构件受力性能的定量评估方法。本项目研究成果揭示了冲击荷载作用下锈蚀钢纤维混凝土材料和梁构件锈蚀后的退化规律，将为结构设计、维护方法、服役结构的安全性评估及耐久性设计提供必要的科学依据。