持续载荷下氯离子对海洋基础设施用混凝土性能及结构的影响

Effects of Chloride Ions on the Performance and Structure of Concrete for Marine Infrastructure under Continuous Loading

海洋工程构筑物中的混凝土受海水侵蚀与潮汐作用,在频繁干湿交变环境导致的潮差区、浪溅区腐蚀最为严重。采用对干湿循环实验试样施加持续应力的方法,探究海水中Cl^(-)侵入与持续载荷对混凝土力学性能的影响。基于微米CT技术,从微观孔隙层面,持续载荷条件下Cl^(-)侵入对混凝土结构及单轴抗压强度的影响。力学性能测试表明:持续载荷条件对维持混凝土力学强度具有积极作用,而随着干湿循环周次的增加,混凝土单轴抗压强度缓慢衰退;结合孔隙分析可知,Cl^(-)不断侵入混凝土孔隙并沉积,但对混凝土力学性能劣化影响较小。

Concrete used in marine structures is corroded most seriously in tidal splash area caused by frequent dry-wet alternating environment.The influence of Cl^(-)invasion in seawater and continuous loading on the mechanical properties of the concrete was investigated by applying continuous stress to the dry-wet cycles test samples.By using the micro-CT technology,the influence of Cl^(-)invasion on concrete structure and uniaxial compressive strength under continuous loading was investigated from the micro-porous level.The results of mechanical property tests show that the continuous loading condition has a positive effect on maintaining the mechanical strength of the concrete,while the uniaxial compressive strength of concrete declines slowly with the increase of dry-wet cycles.Combined with pore size distribution analysis,it can be seen that Cl^(-)constantly invaded into concrete pores and deposited but has little influence on the mechanical property deterioration of concrete.