杂砂岩碱集料反应特征  

CHARACTERISTECS OF ALKALI AGGREGATE REACTION

作　　者：莫祥银[1] 景颖杰[1] HUNGER Klaus-Jurgen 康彩荣[3] 沈健[1] 

机构地区：[1]南京师范大学分析测试中心＆江苏省生物功能材料重点实验室,南京210097 [2]Faculty for Architecture, Civil Engineeringnd Urban Planning, Brandenburg University of Technology Cottbus, Cottbus 03046, Germany [3]南京工业大学材料科学与工程学院,南京210009

出　　处：《硅酸盐学报》2008年第10期1385-1389,共5页Journal of The Chinese Ceramic Society

基　　金：江苏省自然科学基金项目(2007191SB90098);德意志学术交流基金(DAADSection423–China,Mongolia);教育部留学回国人员南京师范大学科研启动基金(2006191XLH0132)资助项目。

摘　　要：杂砂岩集料所含的石英组分是引起碱集料反应的主要活性来源,研究该集料中的石英溶出及其在碱溶液中的行为特征,结果发现:石英颗粒尺寸和相应的硅溶出速度之间存在着一定的相关性,即:石英颗粒尺寸越小,其比表面积越大,同等条件下相应的硅溶出速度越大;石英颗粒的结构特征变化规律与杂砂岩试样本身的碱活性大小之间不存在相关性。集料中的铝主要来源于γ-Al2O3纳米相、黑云母和白云母,其对溶液中硅溶出的影响机理不同。集料中的铝溶出生成铝硅酸盐从而引起溶液中溶出硅含量的降低,砂浆或混凝土碱集料反应膨胀率的大小与溶液中所谓的"自由硅"含量有关,即"自由硅"含量越大,同等条件下的碱集料反应膨胀越大。这些相关性对于实际工程应用非常重要,由此可望建立评价杂砂岩碱活性敏感性的直接测试方法。研究还发现通过添加高铝粉可抑制碱集料反应产生的膨胀。The quartz constituent of greywacke is suspected to be the main causer of a damaging alkali aggregate reaction （AAR） in concrete. By studying silica dissolution of the aggregate and its behavior in an alkaline solution, it was found that a relation between the grain sizes of quartz and the silica releasing rate exists. That is, the smaller the size of the quartz particle, the larger its corresponding surface area, thus, the quicker the speed of silica dissolution at the same conditions. There are no relations between the characteristics of quartz and the alkali sensitivities of greywacke samples investigated. Aluminum in the aggregate comes from biotite and muscovite, but especially from a so called nano crystalline γ-Al2O3-phase. And this aluminum released affects the silica concentration by different mechanisms. The result is a decrease of the silica concentration in the solution caused by an aluminosilicate formation. The damaging process （expansions of concrete samples and mortar bars） can now be described much better as a function of so called ＂free＂ silica in the alkaline solution. The more the content of＂free＂ silica is, the bigger the AAR expansion will be at the same conditions. Based on the mechanisms discussed, possibilities for inhibiting the AAR by addition of highly aluminum containing dusts were shown and first results were presented.

关 键 词：碱集料反应 砂岩 铝溶出过程 化学测试方法 

分 类 号：TQ172[化学工程—水泥工业]