干湿循环对混凝土在高浓度卤水中氯离子扩散行为的影响

Effect of Drying-wetting Cycles on Chloride Diffusion in Concrete Exposed to High Concentration Brine

中文关键词:  混凝土  氯离子扩散  干湿循环  表观扩散系数  表面氯离子浓度

英文关键词:Concrete,Chloride diffusion,Drying-wetting cycle,Apparent diffusion coefficient,Surface chloride concentration

中文摘要:

      在高浓度盐湖卤水中，采用自然扩散法进行了混凝土的Ⅲ维氯离子扩散实验，研究了普通混凝土（Ordinary Portland cement concrete, OPC）、高强混凝土（ High strength concrete, HSC ）、高性能混凝土（ High performance concrete, HPC）、钢纤维增强高性能混凝土（Steel fiber reinforced high performance concrete, SFRHPC）和高强高模聚乙烯纤维增强高性能混凝土（High elasticity module Polyethylene fiber reinforced high performance concrete,HEMPFRHPC）的氯离子扩散行为，探讨了干湿循环对混凝土氯离子扩散行为的影响。结果表明，干湿循环作用加快了OPC、HSC和HPC的氯离子扩散速度，而且毛细管作用对OPC、HSC、HPC和SFRHPC的氯离子扩散行为有一定程度的影响，从而导致混凝土表面氯离子浓度的富集现象更加明显。进一步研究发现，干湿循环降低了OPC的表观氯离子扩散系数，但是对HSC、MPC和HEMPFRHPC的表观氯离子扩散系数则没有明显的影响。

英文摘要:

      Diffusion of chloride in ordinary Portland cement concrete(OPC),high strength concrete(HSC),high performance concrete(HPC),steel fiber reinforced high performance concrete(SFRHPC) and high elasticity module polyethylene fiber reinforced high performance concrete(HEMPFRHPC),which were exposed to high concentration brine,were investigated by three dimensional diffusion experiment via natural diffusion,and the effect of drying-wetting cycling on chloride diffusion were discussed.Results show that drying-wetting cycles can accelerate chloride diffusion in OPC,HSC and HPC.Capillarity during drying-wetting cycling promotes chloride concentration on concrete surfaces for OPC,HSC,HPC and SFRHPC.Further research shows that drying-wetting cycles diminish the apparent diffusion coefficient in OPC,while exhibiting little influence on those in HSC,HPC and HEMPFRHPC.