文章摘要
何真,李洋,蔡新华,陈晓润.Na+和K+对水泥基材料早期收缩性能的影响[J].水利学报,2016,47(11):1345-1351
Na+和K+对水泥基材料早期收缩性能的影响
Influence of Na+ and K+ on the early-age shrinkage properties of cement-based materials
投稿时间:2015-12-25  
DOI:10.13243/j.cnki.slxb.20151409
中文关键词: 收缩  碱类型  孔结构  水化硅酸钙  纳米压痕  核磁共振
英文关键词: shrinkage  alkali type  pore structure  calcium silicate hydrate  nanoindentation  nuclear Mag-netic Resonance
基金项目:国家自然科学基金项目(51379163);科技部973项目(2013CB035901,2015CB655101)
作者单位
何真 武汉大学水资源与水电工程科学国家重点实验室, 湖北 武汉 430072 
李洋 武汉大学水资源与水电工程科学国家重点实验室, 湖北 武汉 430072 
蔡新华 武汉大学水资源与水电工程科学国家重点实验室, 湖北 武汉 430072 
陈晓润 武汉大学水资源与水电工程科学国家重点实验室, 湖北 武汉 430072 
摘要点击次数: 2826
全文下载次数: 294
中文摘要:
      利用压汞、纳米压痕以及27Al固体核磁共振方法,系统研究了不同碱金属离子(Na+和K+)与含量对水泥基材料早期自收缩和干燥收缩性能的影响规律。结果表明,超量的Na+或K+均促进了水泥基材料早期自收缩和干燥收缩,但K+的促进作用明显大于Na+,其机制在于:(1)K+比Na+更易促进水泥基材料中小于50 纳米孔数量的增加,这使得超量K+水泥基材料在干燥时具有更大的收缩驱动力;(2)虽然K+比Na+更易促进水泥基材料生成高密度水化硅酸钙(HD C-S-H),但同时超量K+水泥基材料中C-S-H总量也较高,大量的C-S-H是导致较高早期收缩的根源;(3)与Na+相比,K+更明显地阻碍了钙矾石(AFt)晶体的形成,削弱了AFt的骨架作用,且K+可促使AFt向单硫型水化硫铝酸钙(AFm)转变,因而导致超量K+水泥基材料更易发生收缩变形。
英文摘要:
      The influence of the different metal ions (K+ and Na+) and alkali content on autogenous shrink-age and drying shrinkage at early age has been investigated through mercury intrusion porosimetry (MIP), nanoindentation and 27Al magic angle spinning nuclear magnetic resonance (27Al MAS NMR). The results in-dicate that the autogeneous and drying shrinkage of cement-based materials are increased by K+ or Na+, whereas the effect of K+ is much more obvious. The mechanisms of these phenomena are attributed to three reasons:(1) the capillary pores less than 50nm in cement-based material with high K+ content are more than those with high content Na+, leading to a higher driving force when shrinkage occurs;(2) K+ tends to promote the formation of high density calcium silicate hydrate (HD C-S-H), but the total content of C-S-H in cement-based material with high K+ content is higher than the one with high Na+ content, and the large amount of C-S-H is primary cause of high early-age shrinkage; and (3) K+ is easier to hinder the formation of AFt and accelerate the transformation of AFt to AFm than Na+ at early age, leading to the weak framework function of AFt. The cement-based material with high K+ content has more shrinkage values at early-age.
查看全文   查看/发表评论  下载PDF阅读器
关闭