Nano-Silica Sol-Gel and Carbon Nanotube Coupling Effect on the Performance of Cement-Based Materials

Abstract

Carbon nanotubes (CNTs) have shown promise for improving the mechanical performance of cement composites through crack-bridging and frictional pull-out. The interactive behaviors between CNTs and cement matrix act are crucial in optimizing the reinforcement of CNTs in cement composites. This study investigates the effects of nano-silica (NS) sol-gel on the interactive behaviors of CNTs and the cement matrix through a series of experiments and analyses. UV-visible spectrometer results show that CNTs are well-dispersed in suspension and the addition of NS has a negligible effect on the stability of CNT dispersion. Calorimetry tests and dynamic mechanical analysis demonstrate the nucleation and frictional performance of CNTs in cement matrix, respectively. The paper shows that the physical adsorption of NS on the CNT surface could result in the acceleration of cement hydration. Morphology observation confirms that a denser interface between CNTs and cement hydrates is formed. Finally, the improved interaction between CNTs and cement hydrates leads to a substantial increase in friction between CNTs and the cement matrix under periodic loading. NS may act as an ideal admixture for improving both the interactive behaviors between CNTs and cement matrix and the damping properties of cement composite.

Modification Effects of Carbon Nanotube Dispersion on the Mechanical Properties, Pore Structure, and Microstructure of Cement Mortar

“…It can be seen that CNTs are cemented with the hydration products calcium silicate hydrates (C-S-H) gel and calcium hydroxide (CH), and CNTs cement with each other in the matrix to form a meshwork microstructure. Other research results [13,14,34] suggest that this meshwork microstructure can absorb energy when the cement-based materials are under stress, as pulling work of CNTs in the matrix when a crack develops. This indicates that CNT microfibers enhance the toughness of materials, which agrees with the results of the significantly improved flexural strength of C1 in this study.…”

High-Strength, Waterproof, Corrosion-Resistant Nano-Silica Carbon Nanotube Cementitious Composites

“…Nanomaterials possess small volume and adding nanomaterials such as nano-silica (NS), Sardon et al used (3-aminopropyl) triethoxysilane (APTES)-modified SiO 2 to reduce the agglomeration of NS significantly [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. The addition of nano-titanium dioxide (nano-TiO 2 ) [ 14 ], nano-iron (nano-Fe 2 O 3 ) [ 15 ], nano-alumina (nano-Al 2 O 3 ) [ 16 ], carbon nanotube (CNTs) [ 17 , 18 , 19 ], and nano-clay particles [ 20 ] into cementitious composite can improve its overall properties. Among these nanomaterials, NS and CNTs are particularly significant in cementitious composite [ 21 , 22 ].…”

The mechanical properties, microstructures and mechanism of carbon nanotube-reinforced oil well cement-based nanocomposites

“…Compared with other nano-materials, carbon nanotubes (CNTs) are considered one of the most ideal nanomaterials for nano-reinforcement, owing to their excellent mechanical, thermal and electrical properties. 29,30 CNTs are hollow tubular channels, which are commonly categorized as either single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs) based on the number of concentric tubes. 31 MWCNTs can have diameters ranging from 1 nm to 100 nm, while their lengths range from 0.1 to 100 mm.…”

“…34 Theoretically, the Young's modulus of MWCNTs approaches 1 TPa, 35 with an ultimate strain of up to 15%. 30 Different from microber reinforcements in cement matrices, which contribute to delays in the development of microcracks, MWCNTs, which are distributed on a much ner scale, prevent crack growth at the nanoscale and limit the initiation of micro-cracks. 36 In the last few years, many investigations 34,[37][38][39] have focused on adding MWCNTs into cement-based composites for the purpose of strength improvement and microstructure reinforcement.…”