Effect of Surface-Modified Carbon Nanotubes on Intrinsic Properties and Microstructures of Cement Composites

Multi-walled carbon nanotubes (MWCNTs) modified by gum arabic (GA) were incorporated into cement matrix composites to investigate their effect on intrinsic properties. Their ability to disperse the surface-modified MWCNTs uniformly in the cement matrix was also assessed using transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The intrinsic mechanical properties of the cement composites were investigated using Nano Indenter. Results showed that the addition of treated nanotubes significantly improved the intrinsic properties of cement matrix composites. The porosity and pore size distribution of the composites were measured using mercury intrusion porosimetry (MIP), and the results indicated that cement paste containing MWCNTs had lower porosity and a more uniform pore size distribution. The morphological structure of samples was investigated using field emission scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and X ray diffraction analysis (XRD), which showed that the MWCNTs acted as bridges across cracks and voided and formed a network that transferred the load in tension.