Document Type : Research Article

Authors

• Pui-Lam Ng ^{1, 2}
• Jiajian Chen ³
• Albert K.H. Kwan ²

¹ Faculty of Civil Engineering, Vilnius Gediminas Technical University, Sauletekio al. 11, Vilnius LT-10223, Lithuania

² Department of Civil Engineering, University of Hong Kong, Pokfulam, Hong Kong SAR 999077, China

³ Department of Civil Engineering, Foshan University, No. 18 Jiangwan Road, Foshan 528000, China

Abstract

Nano silica sol is an aqueous solution containing colloidal nano-silica. From limited research in the literature, it has been reported to offer better effects on the cement-based materials compared with nano-silica powder, which is by far the most widely studied nano-material. In this research, the possible use of nano silica sol to improve the performance of marine cement-based mortar is investigated. The optimal type of nano silica sol among acidic, neutral, and alkaline pH is identified, followed by systematic experimentation of the flexural strength, compressive strength, chloride ion permeability, as well as Fourier-transform infrared (FTIR) spectrum and X-ray diffusion (XRD) pattern. It was found that alkaline nano silica sol outperformed acidic and neutral counterparts. Generally, the addition of nano silica sol increased the flexural and compressive strengths of marine mortar. Addition of 3% nano silica sol by volume of cement yielded remarkable effects, while further addition of nano silica sol yielded diminishing returns. The FTIR spectra and XRD patterns suggested the nano silica sol induced nucleation effect at relatively early age and pozzolanic reaction effect at relatively late age. These effects improved the performance of marine cement-based mortar.

Graphical Abstract

Keywords

• Colloidal nano silica,,
• ,،Chloride ion permeability,,
• ,،Marine cement-based mortar,,
• ,،Nano silica sol,,
• ,،Nucleation effect

Main Subjects

• Nanomaterials & Nanotechnology