Study On Stress Corrosion And Corrosion Fatigue Of High Performance Concrete

Due to the long-term action of corrosion medium under the effects of load including still load and live load, the performance of concrete structure becomes inferior, which decreases its durability and leads it to damage in advance. At present, it has become an important problem for stress corrosion and corrosion fatigue causing durability degradation of concrete structure in the field of civil engineering, and thus become a hot topic to study. On the basis of systematically summarizing the international and domestic research of concrete corrosion, taking high performance concrete (HPC) as study subject, adopting the technology route of corrosion effect of environment media to cement concrete, test and physical phase analysis, stress corrosion of HPC, corrosion fatigue of HPC and corrosion damage mechanism of HPC under load effects, the paper studies the characters of stress corrosion and corrosion fatigue of HPC and achieves satisfactory results.The physical and mechanical properties of concrete corrosion are studied, and the expansion corrosive damage to concrete of environment media and the stress of expansion action are analyzed. According to elastic theory, the calculation model of expansion stress in concrete caused by corrosive media is established, which provides theoretical foundation for the further study of establishment of concrete constitutive model and mechanical performance of concrete corroded.Using physical phase analysis technology, the component and shape of fly ash cement hardened paste and the offspring of HPC bearing load faction is researched. Through studying the hydration mechanism of fly ash cement, the anti-corrosion performance of HPC to environment corrosion media is analyzed.Through studying stress corrosion of HPC with the equipment designed by the author, the targets of stress corrosion factor and environment corrosion factor are set up to evaluate the damage of environment corrosion media to concrete under load faction. The influencing regularity of the factors of mix design parameter, corrosion media type, stress level, corrosion time and dry and wet circle to HPC stress corrosionare systematically studied, and the damage mechanism of stress corrosion is also analyzed.On the ground of corrosion fatigue character, the load equipment and test program is designed. The fatigue character of HPC under the effect of corrosion medium of Na2SO is approached and the durability and corrosion fatigue damage mechanism of HPC on the condition of corrosion fatigue is analyzed.With the component structure analysis of HPC hardened cement paste, the influence of pore structure and transition region structure of HPC to its stress corrosion and corrosion fatigue character is discussed. The penetration performance and damage mechanism of HPC under effects of corrosion and load is analyzed, which can be theoretically significant for the safety evaluation of concrete structure.