The influence of multi-walled carbon nanotubes on various properties of cementitious materials

Abstract

This thesis presents the results of an experimental study on the effects of multi-walled carbon nanotubes on various properties of cementitious materials including cement paste and mortar. Normal multi-walled carbon nanotubes are added to ordinary Portland cement paste, with the expectation of improved mechanical performance and modified microstructures. The results are promising, with maximum improvement of 50% in compressive strength and fiber pullout load. In addition, multi-walled carbon nanotubes functionalized with -COOH or –OH groups are added to PVA latex modified mortar. With very low content of both CNTs (<0.15% of cement by weight) and PVA latex (<0.6% of cement by weight), mechanical properties, including compressive strength and flexural strength, are found to be improved significantly. Meanwhile, durability performances, including water absorption and chloride diffusivity, only exhibit mild improvements. The microstructure of both MWCNTs-OH/PVA latex solution and MWCNTs-COOH/PVA latex hybrid modified cement mortar are analyzed by Scanning Electron Microscopy (SEM) as well. Results reveal the formation of CNT/latex nanocomposite network inside the cementitious matrix, which is consistent with expectation from theoretical consideration.

Date of Award	2016
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology