Characterizing cement paste containing SRA modified nanoSiO₂ and evaluating its strength development and shrinkage behavior

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• 作者：Yue Gu^a ; ^b ; ^c ; ¹ ; ^{gubetter@seu.edu.cn} ; Zhenhua Wei^d ; ¹ ; ^{zhenhuawei@ucla.edu} ; Qianping Ran^b ; ^c ; Xin Shu^b ; ^c ; Kai Lv^a ; Jiaping Liu^b ; ^c
• 关键词：NanoSio2 ; Surface modification ; Compressive strength ; Shrinkage-reducing ; Cementitious composites
• 刊名：Cement and Concrete Composites
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：75
• 期：Complete
• 页码：30-37
• 全文大小：1508 K
• 卷排序：75

文摘

In this study, shrinkage reducing admixture (SRA) was grafted on NanoSiO2 (NS) surfaces to synthesize novel core-shell (NS@SRA) particles and improve dispersion of NS in cement paste. The synthesized NS@SRA was characterized by Fourier transform infrared spectroscopy, dynamic light scattering, and thermogravimetric analysis. A series of tests were performed to investigate the effects of NS@SRA addition on the compressive strength and shrinkage of cement paste. It is found that NS@SRA increases the strength of cement paste, especially at later ages. Unlike conventional NS, which significantly increases autogenous shrinkage of cement paste, addition of NS@SRA does not appreciably affect autogenous shrinkage of the paste at early ages. Based on dispersion and zeta potential measurements of NS and NS@SRA particles in synthetic pore solution, we propose that hydration products around NS@SRA may result in gradual separation of SRA from the core. The released SRA may reduce shrinkage and mitigate cracking of cement composites at later ages.