PC with Superior Ductility Using Mixture of Pristine and Functionalized Carbon Nanotubes

Abstract

Polymer concrete (PC) replaces cement hydration with polymerization by utilizing epoxy polymer binders as a substitute of cement creating impermeable and highly durable concrete. It has been reported that the tensile properties of PC can be significantly improved by incorporating multi-walled carbon nanotubes (MWCNTs) at 2.0 wt.% content. In this work, pristine and carboxyl functionalized MWCNTs are mixed together to investigate the effect of functionalization as well as to engineer PC mechanical performance. Results show that hybrid mixes outperform plain mixes of either type of MWCNTs achieving strains at failure up to 5.5% and improvements in toughness up to 184%. The resultant PC also offers tensile strength in the range of 10 MPa. Microstructural analysis using scanning electron microscope (SEM) and dynamic modulus analyzer (DMA) reveals proper dispersion of MWCNTs and increased cross-linking density due to functionalization. Furthermore, it is evident that functional group concentration of 0.001–0.018 wt.% maximizes PC ductility. The proposed PC is an attractive alternative for concrete joints under extreme loading events such as earthquakes and hurricanes.