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Reinforced impermeability of cementitious composites using graphene oxide-carbon nanotube hybrid under different water-to-cement ratios
Highlights GO/MWCNTs enhance impermeability and refine pore structures of cement pastes. High W/C ratios hinder the reinforcing effects of GO/MWCNTs in cement pastes. There is a linear correlation between fractal dimensions and permeability. Analytical models and SEM unveil the mechanism of impermeability enhancement.
Abstract The prominent dispersibility of graphene oxide (GO) and superior mechanical properties of multi-walled carbon nanotubes (MWCNTs) make them potential materials for reinforcing cementitious composites. The aims of this study were to investigate the effectiveness and mechanisms of GO/MWCNT admixtures on the impermeability of cementitious composites. Comparative tests concerning the transport properties between plain cement pastes and GO/MWCNT-OPC pastes at different water-to-cement (W/C) ratios were conducted in this study. Mercury intrusion porosimetry (MIP) tests were carried out to characterize the pore structures of the cement pastes, and the fractal dimensions were utilized to exploit the relationship between the pore structures and permeability-related properties. Power’s model, general effective media (GEM) theory, and scanning electron microscopy (SEM) images were used to illustrate the mechanism of pore structure enhancement. The results imply that mixing GO/MWCNTs into cementitious composites enhances the impermeability of hardened pastes, and the reinforcing efficiency rate in impermeability decreases linearly with the increment of W/C ratio. The fractal dimensions based on the MIP data characterized the pore structures and predicted the transport properties with considerable accuracy. Furthermore, the role of GO/MWCNTs as nucleating sites for hydration reaction and net-like distribution in the composites may explain the impermeability enhancement mechanism induced by the additional GO/MWCNTs. However, GO/MWCNTs tend to re-agglomerate due to the longer setting times at high W/C ratios and lead to a nonuniform distribution of hydration products, which is responsible for the incompetent reinforcing effects.
Reinforced impermeability of cementitious composites using graphene oxide-carbon nanotube hybrid under different water-to-cement ratios
Highlights GO/MWCNTs enhance impermeability and refine pore structures of cement pastes. High W/C ratios hinder the reinforcing effects of GO/MWCNTs in cement pastes. There is a linear correlation between fractal dimensions and permeability. Analytical models and SEM unveil the mechanism of impermeability enhancement.
Abstract The prominent dispersibility of graphene oxide (GO) and superior mechanical properties of multi-walled carbon nanotubes (MWCNTs) make them potential materials for reinforcing cementitious composites. The aims of this study were to investigate the effectiveness and mechanisms of GO/MWCNT admixtures on the impermeability of cementitious composites. Comparative tests concerning the transport properties between plain cement pastes and GO/MWCNT-OPC pastes at different water-to-cement (W/C) ratios were conducted in this study. Mercury intrusion porosimetry (MIP) tests were carried out to characterize the pore structures of the cement pastes, and the fractal dimensions were utilized to exploit the relationship between the pore structures and permeability-related properties. Power’s model, general effective media (GEM) theory, and scanning electron microscopy (SEM) images were used to illustrate the mechanism of pore structure enhancement. The results imply that mixing GO/MWCNTs into cementitious composites enhances the impermeability of hardened pastes, and the reinforcing efficiency rate in impermeability decreases linearly with the increment of W/C ratio. The fractal dimensions based on the MIP data characterized the pore structures and predicted the transport properties with considerable accuracy. Furthermore, the role of GO/MWCNTs as nucleating sites for hydration reaction and net-like distribution in the composites may explain the impermeability enhancement mechanism induced by the additional GO/MWCNTs. However, GO/MWCNTs tend to re-agglomerate due to the longer setting times at high W/C ratios and lead to a nonuniform distribution of hydration products, which is responsible for the incompetent reinforcing effects.
Reinforced impermeability of cementitious composites using graphene oxide-carbon nanotube hybrid under different water-to-cement ratios
Gao, Yuan (author) / Jing, Hongwen (author) / Zhou, Zefu (author) / Chen, Weiqiang (author) / Du, Mingrui (author) / Du, Yue (author)
Construction and Building Materials ; 222 ; 610-621
2019-06-22
12 pages
Article (Journal)
Electronic Resource
English
Carbon nanotube reinforced cementitious composites: An overview
| British Library Online Contents | 2016