水化硅酸钙对加气混凝土干燥收缩的影响

2.河海大学淮安研究院，江苏 淮安  223001；3.盐城力通建材有限公司，江苏 盐城  224100）
 

    摘要：为揭示水化产物对加气混凝土（AAC）干燥收缩的影响规律，基于BET/XRD半定量水化硅酸钙组成建立了基材干燥收缩值随其水化硅酸钙胶体含量和托勃莫来石含量变化的等值线图，计算了水化硅酸钙对砂加气混凝土和粉煤灰加气混凝土干燥收缩的贡献率，观察了加气混凝土的微观形貌。结果表明，当晶体含量小于19%时，基体收缩值随胶体含量增加呈先减小后增大的趋势；当晶体含量大于19%时，基体收缩值随胶体含量增加而减小；砂加气混凝土和粉煤灰加气混凝凝土中胶体含量分别为41%和40%，而晶体含量及水化产物微观形貌差异明显，水化产物对加气混凝土干燥收缩的贡献率分别为57.4%和42.3%。

    关键词：加气混凝土；干燥收缩；水化硅酸钙；托勃莫来石

    中图分类号：TU528.2        文献标识码：A        文章编号：1001-702X（2018）06-0119-03

 

Effect of calcium hydrates on drying shrinkage mechanism of autoclaved aerated concrete

GAO Chao1，JIANG Yaqing1，2，WANG Yu1，PAN Yunfeng1，2，HUANG Wanming 3

（1.College of Mechanics and Materials，Hohai University，Nanjing 210098，China；

2.Huaian Research Institute，Hohai University，Huaian 223001，China；

3.Yancheng Litong Building Materials Company，Yancheng 224100，China）

    Abstract：In order to reveal the influence law of hydration products on dry shrinkage of autoclaved aerated concrete（AAC），the contour map of the dry shrinkage of matrix with C-S-H gel content and tobermorite content was established based on BET/XRD semi quantitative calcium silicate hydrate，and，contribution ratio of calcium silicate hydrates to dry shrinkage of sand based AAC and fly ash based AAC was calculated，microstructure of the two kind of AAC was observed. It is indicated that dry shrinkage of matrix decreases first and then increases with gel content increases when crystal content is less than 19%，but it decreases with gel content increases when crystal content is more than 19%. C-S-H gel content of sand based AAC and fly ash based AAC are 41% and 40% respectively. Distinct difference in tobermorite content and microstructure between sand based AAC and fly ash based AAC is observed. Contribution rate of hydration products to dry shrinkage of two kind of AAC is 57.4% and 42.3% respectively.

    Key words：autoclaved aerated concrete，dry shrinkage，hydrated calcium silicate，tobermorite