Effect of Different Parameters on Properties of Multiwalled Carbon Nanotube-Reinforced Cement Composites

Abstract

The exceptional mechanical properties of carbon nanotube (CNT) such as high strength, elastic modulus and aspect ratio. reflect its potential to be used as reinforcements in cementitious materials. Nanotubes can be distributed on much finer scale and can act as bridge across void spaces and cracks. This in turn improves the overall mechanical properties of the composite. However, there are certain issues that need to be considered while producing CNT cement composites. With this end in view, an attempt has been made to summarize the effect of different parameters on properties of CNT-reinforced cementitious composites through interpretation of results obtained from a comprehensive study. Different sizes and dosage rates of MWNT were used to conduct parametric study. In addition, untreated and surface-treated commercially available MWNTs were used to make composites. Sonication was done for dispersion of nanotubes within cement matrix. An appropriate mixing technique was suggested after conducting a parametric study by varying the amplitude and time of sonication. In some cases, polycarboxylate-based superplasticizer was used as surfactant to disperse MWNTs in aqueous medium. It was observed that surface treatment of nanotubes and utilization of superplasticizer as surfactant enhance their solubility within water. It was also found that proper dispersion and dosage rates of MWNT have significant effect on composite behavior. A suitable mix proportion in terms of MWNT dosage rate, MWNT size and plasticizer proportion has been found. Moreover, it was suggested that flow values of composite paste is a good indicator of stability of the mix.