硅灰对混凝土碳硫硅钙石侵蚀的抑制作用  

Inhibitory Effect of Silica Fume on Thaumasite Formation in Concrete

作　　者：张立刚 ZHANG Li-gang(China Railway Urumqi Group Co.,Ltd.,Urumqi 830011,China)

机构地区：[1]中国铁路乌鲁木齐局集团有限公司,新疆乌鲁木齐830011

出　　处：《化工管理》2023年第25期148-153,共6页Chemical Engineering Management

基　　金：中国铁路乌鲁木齐局集团有限公司重点项目(WLMQ-JGBM-GWB-GTK-2022-0004)。

摘　　要：硫酸盐侵蚀会引起混凝土膨胀开裂等现象,其可分为物理侵蚀和化学侵蚀两个方面。化学侵蚀主要是由于侵蚀产物中生成大量石膏和钙矾石所致。为了降低侵蚀产物中石膏、钙矾石以及碳硫硅钙石的生成量,文章从降低系统中可用钙(氢氧化钙含量、C-S-H凝胶Ca/Si)的角度出发,掺入高硅质活性掺合料(硅灰)对系统中的钙源进行调控。通过XRD、BSE-EDS、29SiNMR、FT-IR测试,研究不同pH值侵蚀液的低温环境下,水泥基材料的抗碳硫硅钙石侵蚀能力。研究结果表明,掺入不含Al相的高硅质活性掺合料,能够显著提高水泥基材料的抗硫酸盐侵蚀能力,侵蚀产物中无碳硫硅钙石生成,侵蚀后期,C-S-H凝胶层间钙很难继续脱钙。Sulfate attack can cause expansion and cracking of concrete,which can be divided into physical attack and chemical attack.Chemical attack is mainly caused by the formation of a large number of gypsum and Ettringite in the corrosion products.In order to reduce the formation of gypsum,ettringite and thaumasite in the corrosion products.From the perspective of reducing the available calcium(the content of Portlandite and the Ca/Si of C-S-H gel)in the system,high activity siliceous admixture is added to regulate the calcium source in the system.The sulfate resistance of cement-based materials under different pH of sulfate solutions during the low temperature condition was analyzed by the XRD,BSE-EDS,29Si NMR,and FT-IR analysis.Results indicated that the addition of high activity siliceous admixtures without Al phase can significantly improve the sulfate resistance of cement-based materials,and no thaumasite formed in the corrosion products.In the later stage of sulfate attack,the interlayer calcium of C-S-H gel is difficult to be decalcified.

关 键 词：硫酸盐 PH值 钙硅比 碳硫硅钙石 

分 类 号：TU528.44[建筑科学—建筑技术科学]