Effect of different particle sizes of nano-SiO 2 on the properties and microstructure of cement paste

Nanotechnology Reviews

article

Tao Meng¹  Kanjun Ying¹  Yongpeng Hong¹  Qinglei Xu¹ 

[1] Institute of Engineering Materials, College of Civil Engineering and Architecture, Zhejiang University

关键词: nano-SiO2;    particle size;    mechanical properties;    microstructure;    cement paste;   

DOI  :  10.1515/ntrev-2020-0066

学科分类：社会科学、人文和艺术（综合）

来源: De Gruyter

【 摘 要 】

Nano-materials modified cement-based materials have attracted wide attention due to their advantages of improving strength and durability. In this paper, the effect of nano-SiO 2 (NS) with particle sizes of 15 and 50 nm on the mechanical properties and microstructure of cement paste was studied. The results showed that 50 nm NS provided a greater compressive strength than that of 15 nm NS, while 15 nm NS afforded a denser microstructure than that of 50 nm NS. A fluctuation in the compressive strength was revealed using a physicochemical reaction equation, and the microstructure was interpreted by a pore structure analysis. In addition, the orientation index of calcium hydroxide (CH) with 15 nm NS could be reduced significantly in the early stages (the early stages refer to the first three days from the maintaining of specimens) compared with when the 50 nm NS was used. The experimental results also showed that NS helped increase the mechanical strength of cement paste, advance the endothermic peak of CH, and refine the size of the CH crystals. The microstructural changes at different stages of cement paste with different particle sizes of NS were investigated by X-ray diffraction, scanning electron microscopy, mercury intrusion porosimetry and differential thermal analysis. This study is expected to promote the research and application of nano-materials in the cement industry by clarifying the performance of NS with different particle sizes.

【 授权许可】

CC BY