Effect of Nanotube Geometry on the Strength and Dispersion of CNT-Cement Composites

Abstract

This study investigated the effect of multiwalled carbon nanotubes' geometry on the dispersion and strength of cement composites. Mixes with CNTs contents ranging from 0.03 to 0.25% were prepared and tested using CNTs' diameters of 10-20, 20-30, and 30-50 nm and lengths of 0.5-2 and 10-30 m. The samples' microstructures were then examined using a scanning electron microscope. After that, Response Surface Methodologies techniques were implemented to determine the strength functions' response to the aspect ratio and weight fraction variables. The results showed that CNTs of smaller diameters and longer lengths resulted in the highest strength values in batches having CNT contents of up to 0.15%. At 0.25% CNTs, the results showed that those CNTs of shorter lengths attained higher strengths than those of longer ones. SEM images showed better dispersion properties at lower CNTs' contents regardless of their geometry. The analysis also indicated that short CNTs of 0.5-2 m length have better dispersion properties compared to long ones of 10-30 m length. The RSM model confirmed this finding. Furthermore, the model showed that the CNTs with the lowest aspect ratio of 83 and highest weight fraction of 0.25% provided the highest strength response among all batches.

Carbon Nanotube Effect on the Ductility, Flexural Strength, and Permeability of Concrete

“…This improvement resulted in a flexural strength increase of about 100% compared to a plain cement paste. Also, the researchers conducted a set of experiments that investigated the effect of several parameters on the dispersion of CNTs in cement paste, such as CNT weight fractions, diameters, and lengths [23,24].…”

The Effect of Carbon Nanotubes on the Flowability, Mechanical, Microstructural and Durability Properties of Cementitious Composite: An Overview

“…The geometry of CNTs is also considered to be an influential factor in terms of dispersion and mechanical performance. Mohsen et al [60] reported that a cementitious composite containing CNTs with the lowest diameter and a high aspect ratio achieved higher mechanical strength when compared to CNTs with a medium or larger diameter (Figure 18). Besides, a cementitious composite containing longer CNTs achieved a slightly higher flexural strength.…”

Rheological behaviors and viscosity prediction model of cementitious composites with various carbon nanotubes

“…Owing to their excellent physical and mechanical properties, carbon nanotubes (CNTs) are favorable nano-fillers for cementitious composites [1,2] and has received extensive attention from researchers and engineers [3,4]. For example, compressive, flexural, tensile, and splitting strengths of cementitious composites can be increased by 50 %, 269 %, 19 %, and 86 %, respectively [3,5,6], due to the addition of CNTs. Meanwhile, the incorporation of CNTs endows cementitious composites with excellent piezoresistive properties [7,8], electromagnetic interference shielding properties [9] and damping performances [10,11].…”