腐蚀环境中混凝土桩基耐久性研究进展

腐蚀环境中地下混凝土结构的耐久性问题一直是国内外研究的热点问题之一.针对海洋和近海氯盐侵蚀环境与内陆盐湖和盐碱地硫酸盐侵蚀环境中地下混凝土结构的耐久性问题,分别从混凝土侵蚀机理、侵蚀性离子扩散机制、钢筋锈蚀机理、混凝土强度和刚度损伤等几个方面总结和归纳了当前国内外的研究现状,探讨了氯盐侵蚀环境和硫酸盐侵蚀环境中地下混凝土结构的损伤特性和劣化机制.在此基础上,考虑PHC预制管桩和现浇钻孔灌注桩的制作养护工艺,分别论述了海工环境中水平受荷PHC管桩和盐渍土环境中竖向受荷钻孔灌注桩的侵蚀劣化机理,进而结合海工环境中水平受荷PHC管桩和盐渍土环境中竖向受荷钻孔灌注桩的承载机制,探讨了各自承载特性的退化规律,总结了海工环境中水平受荷PHC管桩和盐渍土环境中竖向受荷钻孔灌注桩寿命的预测方法.最后,基于当前腐蚀环境中钢筋混凝土桩基耐久性研究现状,笔者根据自己的见解提出了今后的研究思路和方向,以期为腐蚀环境中和复杂应力条件下钢筋混凝土桩基的耐久性研究以及今后相应规范的制定提供一定参考.

Advances in concrete pile durability in corrosive environment

The durability of underground concrete structures in corrosive environments is one of the hottest issues. The current research works on the durability of underground concrete structures in marine and offshore chlorine salt erosion environment and saline lake and inland saline sulfate environment were summarized based on concrete corrosion mechanism, erosive ion diffusion mechanism, rebar corrosion mechanism, concrete strength and stiffness damage and other aspects, respectively, and the damage characteristics and degradation mechanisms of underground concrete structures under chloride and sulfate corrosion environment were discussed. Considering the production technology of the PHC pipe pile and the bored pile, the deterioration mechanism of horizontally loaded PHC pipe pile in marine environment and vertically loaded bored pile in saline soil environment were discussed, respectively. The degradation laws of their load-bearing characteristic were investigated by considering the loading mechanism of bored piles and PHC pipe piles, and the methods for predicting the service life of horizontally loaded PHC pipe pile in marine environment and vertically loaded bored pile in saline soil environment were proposed. Finally, based on the current study, the further research ideas and directions were proposed to provide references for the durability research of reinforced concrete pile in corrosive environment and complicated stress conditions, and as well as the formulation of relevant standards.