硫酸盐侵蚀-高温耦合作用下钢筋/BFRC界面劣化机理

Degradation Mechanism of Steel Bar and BFRC Interface under Coupled Action of Sulfate Erosion and High Temperature

摘要:

以受硫酸盐侵蚀的玄武岩纤维混凝土（BFRC）为研究对象，系统探究温度（20~700 ℃）与侵蚀龄期（0~210 d）对钢筋/BFRC界面黏结性能的影响，并建立了相应的黏结-滑移模型。结果表明：在耦合作用下，当温度低于300 ℃时，界面黏结强度随侵蚀龄期总体上呈先增后减趋势；当温度高于300 ℃时，界面黏结强度随侵蚀龄期持续下降。高温促使硫酸盐侵蚀产物分解，既抵消了侵蚀初期对钢筋与BFRC界面黏结性能的提升效应，又进一步加剧了钢筋与BFRC界面结构的劣化。

Abstract:

Basalt fiber reinforced concrete （BFRC） subjected to sulfate attack was taken as the research object. The effects of temperature （20-700 ℃） and exposure duration （0-210 d） on the bond performance at the steel bar and BFRC interface were systematically investigated， and a corresponding bond-slip model was established. The results show that under the coupled action， when the temperature is below 300 ℃， the bond strength generally first increases and then decreases with the increased exposure ages； when the temperature is above 300 ℃， the bond strength continuously declines with the prolonged exposure ages. High temperature promotes the decomposition of sulfate attack products， which not only offsets the enhancing effect on the interfacial bond performance in the initial stage of attack but also further exacerbates the deterioration of the interface structure between the steel bar and BFRC.