MgO活性对无机聚合物硬化浆体体积变形及微观结构的影响
|
摘要
无机聚合物胶凝材料是一种新型胶凝材料,具有早期强度快硬、结构致密的特点,且抗腐蚀性能优异,可应用于滨海和海洋工程基础设施建设。但该类材料存在收缩大、易开裂的缺陷,严重影响了其工程应用。结合无机聚合物快硬早期强度的特点,研究了高活性(60 s)、中活性(150 s)及低活性(220 s)氧化镁(Mg O)对无机聚合物硬化浆体的体积变形及微观结构的影响。结果表明:Mg O活性对无机聚合物性能影响显著,60 s活性Mg O促进无机聚合物的水化放热,提高了无机聚合物硬化浆体的早期强度,且硬化浆体的早期收缩值最低,硬化浆体的改善效果也最好;150 s和220 s活性Mg O延缓了无机聚合物水化放热,但改善了无机聚合物长龄期的体积收缩;Mg O加入到无机聚合物中与水反应生成了Mg(OH)2,从而改善无机聚合物的体积收缩。
Geopolymer,a novel cementitious material of superb corrosion resistance and quick setting and big strength in early stage,is applied to offshore and coastal projects. It is also,however,subject to cracking and large volume shrinkage which limit its engineering application. In this paper,the effects of Mg O of high activity(60 s),medium activity( 150 s) and low activity( 220 s) on the volumetric shrinkage and microstructure of hardened geopolymer pastes were examined respectively. Results revealed remarkable influence of Mg O activity on geopolymer performance: Mg O of high activity could improve the early-stage strength of hardened geopolymer pastes by enhancing hydration heat release,and the early shrinkage value of the hardened pastes were the lowest; on the contrary,Mg O of medium activity and low activity postponed the hydration heat release,and alleviated the volumetric shrinkage by acting with water in the geopolymer.
Geopolymer,a novel cementitious material of superb corrosion resistance and quick setting and big strength in early stage,is applied to offshore and coastal projects. It is also,however,subject to cracking and large volume shrinkage which limit its engineering application. In this paper,the effects of Mg O of high activity(60 s),medium activity( 150 s) and low activity( 220 s) on the volumetric shrinkage and microstructure of hardened geopolymer pastes were examined respectively. Results revealed remarkable influence of Mg O activity on geopolymer performance: Mg O of high activity could improve the early-stage strength of hardened geopolymer pastes by enhancing hydration heat release,and the early shrinkage value of the hardened pastes were the lowest; on the contrary,Mg O of medium activity and low activity postponed the hydration heat release,and alleviated the volumetric shrinkage by acting with water in the geopolymer.
引文
[1]杨南如.碱胶凝材料形成的物理化学基础(Ⅰ)[J].硅酸盐学报,1996,24(2):209-215.
[2]王小萍,殷素红,赵三银,等.碱激发碳酸盐矿-矿渣复合灌浆材料流变性能的研究[J].长江科学院院报,2006,23(6):80-83.
[3]李珍,韩炜,邵晓妹.地质聚合物在材料领域的应用及其发展方向[J].长江科学院院报,2008,25(4):93-95.
[4]WANG S D,PU X C,SCRIVENER K L,et al.Alkali-activated Slag Cement and Concrete:A Review of Properties and Problems[J].Advances in Cement Research,1995,7(27):93-102.
[5]黄科,马玉玮,郭奕群,等.碱激发粉煤灰/矿渣复合体系的性能研究[J].硅酸盐通报,2015,34(10):2769-2774.
[6]李兆恒,陈晓文,张君禄,等.Na OH激发无机聚合物的水热合成及其性能研究[J].广东水利水电,2016,(8):7-12.
[7]乔飞,余其俊,赵三银,等.适应于碱激发碳酸盐矿-矿渣胶凝材料的缓凝剂研究[J].长江科学院院报,2007,24(1):36-39.
[8]郑娟荣,姚振亚,刘丽娜.碱激发胶凝材料化学收缩或膨胀的试验研究[J].硅酸盐通报,2009,28(1):49-53.
[2]王小萍,殷素红,赵三银,等.碱激发碳酸盐矿-矿渣复合灌浆材料流变性能的研究[J].长江科学院院报,2006,23(6):80-83.
[3]李珍,韩炜,邵晓妹.地质聚合物在材料领域的应用及其发展方向[J].长江科学院院报,2008,25(4):93-95.
[4]WANG S D,PU X C,SCRIVENER K L,et al.Alkali-activated Slag Cement and Concrete:A Review of Properties and Problems[J].Advances in Cement Research,1995,7(27):93-102.
[5]黄科,马玉玮,郭奕群,等.碱激发粉煤灰/矿渣复合体系的性能研究[J].硅酸盐通报,2015,34(10):2769-2774.
[6]李兆恒,陈晓文,张君禄,等.Na OH激发无机聚合物的水热合成及其性能研究[J].广东水利水电,2016,(8):7-12.
[7]乔飞,余其俊,赵三银,等.适应于碱激发碳酸盐矿-矿渣胶凝材料的缓凝剂研究[J].长江科学院院报,2007,24(1):36-39.
[8]郑娟荣,姚振亚,刘丽娜.碱激发胶凝材料化学收缩或膨胀的试验研究[J].硅酸盐通报,2009,28(1):49-53.