无水石膏对化学激发固硫灰性能的影响  

The Effect of Anhydrite on the Property of Chemico-Activated CFBC Ash

作　　者：宋学锋[1] 王鑫 郭渊飞 李鑫艳 魏逸明 Song Xuefeng;Wang Xin;Guo Yuanfei;Li Xinyan;Wei Yiming(College of Materials Science and Engineering,Xi’an University of Architecture and Technology,Xi’an,Shaanxi 710055)

机构地区：[1]西安建筑科技大学材料科学与工程学院,陕西西安710055

出　　处：《非金属矿》2020年第4期33-36,共4页Non-Metallic Mines

基　　金：陕西省科技厅资助项目(2018SF-367)。

摘　　要：为抑制循环流化床燃煤固硫灰(简称固硫灰)的有害膨胀,研究了Ⅱ-CaSO4(无水石膏)含量对化学激发固硫灰强度、体积稳定性的影响,并结合XRD、SEM分析了水化产物和影响机理。结果表明:随Ⅱ-CaSO4含量增加,NaOH激发固硫灰抗折、抗压强度均先增大后减小,Na2Si O3、Na2CO3激发固硫灰的抗压强度减小,抗折强度分别呈现出先增后降、降低的整体变化趋势。标准养护下,3种激发体系硬化体的线性膨胀率均随Ⅱ-CaSO4的增加而增大;3种激发剂中Na2SiO3对抑制固硫灰有害膨胀最有效。采用X射线衍射(XRD)、扫描电镜(SEM)对化学激发固硫灰水化产物进行了分析,结果表明,NaOH激发固硫灰体积膨胀主要由水化产物钙矾石引起,Na2SiO3激发固硫灰无钙矾石生成,硬化体膨胀主要由水化硅酸钙(C-S-H)吸水膨胀引起,Na2CO3激发固硫灰体积膨胀由水化产物钙矾石或碳硫硅钙石引起。To inhibit the volume expansion of CFBC ash,the effect of anhydrite content on the strength and volume stability of chemico-activated CFBC ash was studied,its mechanism and the hydration products were analyzed combined with XRD and SEM.With the increase of anhydrite content,the flexural and compressive strength of CFBC ash activated by NaOH increases at first and then decreases,and the compressive strength of CFBC ash activated by Na2SiO3 or Na2CO3 tends to decrease,the flexural strength of CFBC ash activated by Na2SiO3 increases at first and then decreases,the flexural strength of CFBC ash activated by Na2CO3 tends to decrease.Under standard curing,the linear expansion ratio of hardened bodies in the three activation systems increases with the addition of anhydrite.The main reason for the volume expansion of CFBC ash activated by Na OH is ettringite,expansion of CFBC ash activated by Na2SiO3 is mainly due to water absorbed by C-S-H and the formation of no ettringite in the hydration products,the volume expansion of CFBC ash activated by Na2CO3 is caused by ettringite or thaumasite.Among the three activators,Na2SiO3 is the most effective activator to inhibit the volume expansion of CFBC ash.

关 键 词：固硫灰 无水石膏 化学激发 强度 体积稳定性 

分 类 号：TU528[建筑科学—建筑技术科学]