Co-effect of carbon nanotube and nano-sized silica on dispersion and mechanical performance in cementitious system

Due to the advances in science and technology, the creation and application of nanomaterials are becoming more important in the building industry. The synergistic effect of carbon nanotubes (CNTs) with nano-sized silica particles was examined in this study. For the dispersion of CNTs, four different polymeric surfactants (Brij35, TritonX100, CTAB, and polycarboxylate-based super-plasticizer) were used. Among these, Brij35 was found most effective for CNT dispersion, which was confirmed using a combination of centrifugation and scanning electron microscopy (SEM) techniques. Furthermore, their impact on compressive strength, flexural strength, and microstructural development of cement matrix in the presence of nano-sized silica has been investigated. When compared to control cement paste, compressive and flexural strength improved by 12 to 15%. SEM micrographs confirm the bridging mechanism of CNTs with cement hydration products. They act as networks and bridges across pores and cracks, ensuring the load transfer in case of tension and certainly enhances the flexural toughness of the cement matrix. [Display omitted] •Effective dispersion of CNTs plays important role in improving hydration properties.•The centrifugation technique helps in observing effective dispersion.•Addition of nano silica further helps in carbon nanotubes dispersion.•CNTs act as networks and bridges across pores and cracks.