硫酸盐侵蚀下混凝土内腐蚀反应-扩散过程的实验研究

Experimental Study on Corrosion Reaction-Diffusion Process of Concrete under Sulfate Attack

通过开展硫酸盐腐蚀试验,研究了硫酸盐侵蚀环境下混凝土中内部硫酸盐浓度随时间和空间的变化规律,探讨了混凝土内部各组分浓度的变化与硫酸根离子浓度之间的关系。结果表明:随着侵蚀时间的增加,反应扩散不断进行,混凝土内部硫酸根离子浓度不断增加,越靠近侵蚀表面浓度越高;水泥水化产物中二水石膏、氢氧化钙和腐蚀产物的浓度变化与硫酸盐浓度变化之间存在一定的联系,随着二水石膏和氢氧化钙含量的减少,钙矾石含量前期增长较快,后期渐渐趋于稳定,硫酸盐浓度变化速率不断减小,直至混凝土内外环境中硫酸盐浓度差达到平稳状态。

By carrying out the experiment of sulfate corrosion,the evolution law of sulfate concentration in concrete subjected by sulfate attack was investigated.Meanwhile,the relationship of concentrations between the concrete constituents and sulfate ions in concrete was comprehensively discussed.The results show that the sulfate concentration in concrete increases with the corrosion time during the reaction-diffusion process of sulfate ions.However,it decreases with the diffusion depth increasing.Furthermore,it is found that with the decrease of the contents of gypsum and calcium hydroxide,the content of ettringite quickly increases at the earlier stage of the reaction-diffusion process,then close to stabilization,the change rate of sulfate concentration has decreased continuously until the sulfate concentration difference between the internal and external environment of concrete reaches a steady state.