Hybrid effect of carbon nanotubes and polypropylene fibers on mechanical properties and fire resistance of cement mortar

The hybrid effect of multi-walled carbon nanotubes (MWCNTs) and polypropylene (PP) fibers on the mechanical properties and fire resistance of Portland-cement-based mortar was experimentally investigated in this study. MWCNTs of 0.1%, 0.25%, and 0.5% by weight were added, and PP fibers were added at a constant dosage of 0.2% by volume. The strength of the mortar exposed to various temperatures up to 1,000 degrees C was determined. It was found that the addition of 0.1% MWCNTs improved the compressive strength and permeability of the mortar. Furthermore, the study showed that cement mortar with a high fire resistance could be developed by adding 0.25% MWCNTs and 0.2% PP fibers in the composite. After being heated to 1,000 degrees C, the mortar produced with this optimal mix exhibited a residual compressive strength of approximately 40%, which was 19% higher than that observed using plain mortar. Microstructure observations indicated that bridging effect of MWCNTs and melting of PP fibers work together for improving the fire resistance of mortars. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

The experimental study demonstrated that the addition of multi-walled carbon nanotubes and polypropylene fibers can enhance the mechanical properties and fire resistance of Portland-cement-based mortar. The optimal mix of 0.25% MWCNTs and 0.2% PP fibers showed a significant increase in residual compressive strength at high temperatures, indicating improved fire resistance.