| 摘要: |
| 研究了受稀硫酸侵蚀后的混凝土试件表面腐蚀产物附面层成分及其对腐蚀速度的影响，同时结合不同试验控制条件下的长期浸泡试验，测定了硫酸消耗量曲线；通过扫描电镜(SEM)、能谱仪(EDS)和X射线衍射(XRD)，分析了附面层的形貌、元素组成和矿物成分.结果表明：附面层的化学成分及其对腐蚀速度的影响与试验过程中是否存在CaSO4的流失和试件表面的清洗作用有关，在置换浸泡液的情况下，附面层主要成分是SiO2等水泥石腐蚀后的残留矿物，在不置换浸泡液的情况下，附面层中含有石膏；2种类型的附面层均会降低腐蚀速度，其中以石膏附面层引起的降低程度更显著，石膏附面层是导致试验相似性破坏的重要原因. |
| 关键词: 硫酸 混凝土 腐蚀 石膏 附面层 |
| DOI：103969/j.issn.1007 9629201903004 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目(51078175) |
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| Corroded Product Surface Layer of Concrete Corroded by Sulfuric Acid and Its Effect on Corrosion Rate |
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SONG Zhigang, LI Xiansheng, XIE Shihua, QI Yangyan
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Institute of Architecture Engineering, Kunming University of Science & Technology, Kunming 650500, China
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| Abstract: |
| A product layer will form on the surface of the concrete after it is corroded by sulfuric acid and which will consequently decrease the corrosion rate. To investigate the chemical components and decelerating effect of the corroded concrete surface layer, a series of immersion tests under different control conditions and in different pH value of immersion acid were carried out. The acid consumption curve during the immersion tests was obtained and the morphology， elemental composition and mineral components of corroded concrete surface layer were analyzed by SEM, EDS and XRD tests. The results show that the lost of CaSO4 and the cleanout of the corroded concrete surface layer during the immersion process would significantly impact the chemical components and decelerate effect of the corroded concrete surface layers. In the condition of replacement of immersion sulfuric acid, the chemical products are SiO2 and other residue materials of cement stone after eroding. In those non replacement cases, the chemical products contain gypsum. Both types of corroded concrete surface layers can decrease the corrosion rate and the corroded concrete surface layer containing gypsum can decrease greatly. The corroded concrete surface layer with gypsum are the main factor that destroys the similarity between different experiments. |
| Key words: sulfuric acid concrete corrosion gypsum surface layer |
