MWCNT and CNF Cementitious Nanocomposites for Enhanced Strength and Toughness

Abstract

Cementitious nanocomposites reinforced with carbon fibers at the nanoscale were fabricated and tested, exhibiting remarkably improved mechanical and fracture properties. The cementitious nanocomposites were reinforced with well dispersed multiwall carbon nanotubes (MWCNTs) and carbon nanofibers (CNFs). A dispersion method involving the application of ultrasonic energy and the use of a superplasticizer was employed to prepare the nanoscale fiber suspensions. Flexural strength and Young’s modulus were experimentally investigated and compared with similarly processed reference cement based mixes without the nano-reinforcement. The nanocomposites’ fracture properties were also determined using the two parameter fracture model (TPFM). The excellent reinforcing capability of MWCNTs and CNFs is demonstrated by a significant improvement in flexural strength (87 % for MWCNTs and 106 % for CNFs reinforcement), Young’s modulus (100 %), and fracture toughness (86 % for MWCNTs and 119 % for CNFs reinforcement).