Dispersion of Multi-Walled Carbon Nanotubes in Portland Cement Concrete Using Ultra-Sonication and Polycarboxylic Based Superplasticizer

Abstract

The potential properties of carbon nanotube-cement based materials strongly depend on the dispersion of carbon nanotubes (CNTs) within the cement matrix and the bonding between CNTs and the hydrated cement. The homogeneous dispersion of CNTs in the cement matrix yet is one of the main challenges due to strong van der Waals forces between nanotubes. In this study, a polycarboxylic ether based superplasticizer and ultra-sonication technique was used for dispersion of multi-walled carbon nanotubes (MWCNTs). Portland cement concrete specimens with different concentrations of MWCNTs (0.04 and 0.1 % by the weight of cement), with and without the presence of superplasticizer were investigated. Compressive strength test results revealed a significant improvement in mechanical properties of sample containing 0.1 % MWCNTs and 0.2 % superplasticizer. Moreover, field emission scanning electron microscopy (FESEM) images of fractured surfaces of hardened specimens showed a good dispersion of MWCNTs within the cement matrix. This method was developed to facilitate the uniform dispersion of MWCNTs in the cementitious concrete for better reinforcement in nanoscale and mechanical properties enhancement by transfer of load between the nanotubes and matrix.