Autogenous Shrinkage Property of High-Performance Multi-Walled Cement-Based Carbon Nanotubes Composites.

Abstract

High-performance cement-based materials have been widely used and are sensitized to early cracks because of high autogenous shrinkage stress. In this study, the uniformly dispersed MWCNTs were added into high-performance cement-based materials. The autogenous shrinkage of high-performance cement-based composites with different contents of MWCNTs was also investigated at the water to cement ratio of 0.35, 0.30 and 0.25. It was proved that moderate incorporation of MWCNTs decreased the autogenous shrinkage of cement-based composites. With addition of 0.05 wt.% MWCNTs, the value of autogenous shrinkage was minimal after treatment for 7 days at the water to cement ratio of 0.35, with depressed percentage of autogenous shrinkage even reaching 46.74%. The value of autogenous shrinkage increased significantly decreased water to cement ratio, at the same addition of MWCNTs. The mechanism for autogenous shrinkage was also explored according to hydration property, porosity and microstructure of cement-based materials.