硫酸镁侵蚀后碱矿渣水泥中C(N)-A-S-H(I)组成-结构梯度变化  

Compositional-structural Gradient Change of C(N)-A-S-H(I)Gel in Alkali-activated Slag after Magnesium Sulphate Attack

作　　者：朱效宏 李青 熊德意[3] 杨凯 杨长辉[3] 刘荣进[1] ZHU Xiaohong;LI Qing;XIONG Deyi;YANG Kai;YANG Changhui;LIU Rongjin(College of Civil and Architectural Engineering,Guilin University of Technology,Guilin 541004,Guangxi,China;School of Civil Engineering,University of Leeds,Leeds LS29JT,UK;College of Materials Science and Engineering,Chongqing University,Chongqing 400045,China)

机构地区：[1]桂林理工大学土木与建筑工程学院,广西建筑新能源与节能重点实验室,中国桂林541004 [2]利兹大学土木工程学院,英国利兹LS29JT [3]重庆大学材料科学与工程学院,中国重庆400045

出　　处：《硅酸盐学报》2021年第10期2276-2285,共10页Journal of The Chinese Ceramic Society

基　　金：广西创新驱动重大专项(2018AA23004);广西建筑新能源与产能重点实验室开放基金(桂科能19–J–22–3);广西建筑新能源与节能重点实验室开放基金(桂科能19–J–21–12);广西科技重大专项子课题(桂科AA18242007–3)。

摘　　要：通过^(29)Si魔角自旋核磁共振及高分辨透射电镜-能谱方法,研究了10%(质量分数)硫酸镁溶液侵蚀后碱矿渣水泥(AAS)砂浆中C(N)-A-S-H凝胶结构梯度变化。结果表明:侵蚀表层(0.5~3.0mm)主要为硅铝凝胶;侵蚀中层(3~6mm)主要为M/C(N)-A-S-H凝胶;内部(6~9mm)主要为C(N)-A-S-H凝胶(几乎未受到侵蚀);在硫酸盐侵蚀后仍会有稳定的类托贝莫来石(Ca/Si摩尔比为0.98)/类水滑石(Mg/Al摩尔比为2.39)晶体存在,但C(N)-A-S-H凝胶主链中,位于桥氧四面体(BT)位置的铝氧四面体受硫酸盐侵蚀影响更大。同时,硫酸镁侵蚀首先造成脱钙现象发生(其位置将会由Mg补充),而后产生脱铝现象,当C-A-S-H完成脱Ca及部分脱Al后,形成Al-Si凝胶且凝胶中存在大量Mg平衡离子(即最外层产物)。This paper presented the gradient changes of the characteristics of C(N)-A-S-H(Calcium(Sodium)-Aluminium-Silicate Hydrates)gel in alkali-activated slag(AAS)mortars subjected to sulphate attack in 10%(in mass fraction)MgSO_(4) solution by ^(29)Si solid-state magic-angle Spinning nuclear magnetic resonance(SS MAS-NMR),and high-resolution transmission electron microscopy-energy dispersive X-ray spectroscopy(HR TEM-EDX).The results show that the outer layer with the thickness of 0.5-3 mm after attack is mainly composed of Si-Al gel,the middle-level layer with the thickness of 3-6 mm is M/C(N)-A-S-H gel,and the internal layer with the thickness of 6-9 mm is mainly composed of C(N)-A-S-H gel which was almost not attacked.The stable crystal tobermorite(Ca/Si ratio=0.98)and hydrotalcite-like phase(Mg/Al ratio=2.39)could not be destroyed by sulphate attack.However,the main chain of C(N)-A-S-H gel is readily attacked by sulphate at[AlO4]bridging tetrahedra(BT).Meanwhile,the magnesium sulphate initially results in de-calcium phenomenon(Mg will replace Ca),and then generates the de-aluminium phenomenon,finally forming the Si-Al gel(main product in the out layer)when removing Ca and partial Al from the gel and charge-balancing the gel by abundant Mg ions.

关 键 词：硫酸镁 C(N)–A–S–H凝胶 硅氧四面体 结构演变 梯度 

分 类 号：TU528[建筑科学—建筑技术科学]