Hybrid Nano Intruded Cement Paste System With Intrusions Of Carbon Nanotubes(CNTs) And Graphene Nanoplatelets(GNPs)

Cementitious materials are extensively and frequently used for numerous types of infrastructure by the construction industry worldwide.They.Still have inadequate tensile strength.and tensile strain capacity,despite their exceptional compression strength.Various kinds of fibers have been studied over the last fifty years to strengthen the cementitious matrix against tensile failures and to provide ductility.Recently,advancements in technology have produced many nanomaterials(e.g.,carbon nanotubes(CNTs)and graphene nanoplatelets(GNPs)that can be used as reinforcements at nanoscale so that crack initiation and propagation can be stopped before it grows to macro/micro level.There are three main forms of engineered nanomaterials zero dimensional(0D)nanoparticles,one dimensional(1D)nanofibers and two dimensional(2D)nanosheets.The application of 1D nanofibers,2D nanosheets such as carbon nanotubes(CNTs),graphene nano platelets(GNPs)respectively,has been described in the existing literature.Because of excellent intrinsic properties and large aspect ratio,carbon nanotubes(CNTs)were magnificently examined as a reinforcing filler to enhance the mechanical strength of cementitious composites.However,CNTs are difficult to be dispersed,and problems associated bonding with host matrix due to low surface friction and the Van der Waals’ force between them cause the CNTs to agglomerate.rather than bonding with the cement matrix and limit its wide applications on a large scale.Researchers have tried many methods to improve CNTs dispersion in aqueous as well as in the cementitious matrix.In order to overcome the issues mentioned above regarding the dispersion and bonding of nano-reinforcing materials within the host matrix,graphene nanosheets were explored for the first time as a dispersant for CNTs in this research.Graphene nano sheets are free to form entanglement problems and hence require smaller energy for proper dispersion.CNTs and GNPs were improved by the surfactant Gum Arabic(AG).1D CNTs and 2D GNPs resulted in the CNTs making a bridge between adjacent GNP sheets,effectively preventing the restacking of GNPs and the agglomeration of MWCNTs,resulting in more excellent dispersion.UV–vis spectroscopy and scanning electron microscopy(SEM)result revealed that GNPs highly dispersed CNTs with the help of surfactant rather than individual CNTs and GNPs.Foremost,the reinforcing capabilities of the hybrid CNTs/GNPs were revealed by the enhanced mechanical properties of the cementitious matrix.It was analyzed that at a very low content of addition graphene nanoparticles into carbon nanotubes resulting in outstanding improvements in the flexural strength and compressive strength can be attained.The hybrid CNTs/GNPs C6G2(0.06 wt%CNTs and 0.02 wt% GNPs by weight of cement)aged for 28 day with surfactant Gum Arabic(CNTs: GNPs=1:1)enhanced the flexural strength and compressive of cement paste by 22.76% and 17.55%,respectively,higher than that obtained upon addition of GNPs or CNTs individually.Surface morphology,bonding and interaction of nanomaterials with the surrounding cement matrix was visualized by using Scanning Electron Microscope(SEM)and results confirmed the strong bonding with the cement matrix which ultimately resulted in improved mechanical properties.