Title:	Role of Carbon Nanomaterials as Reinforcing Phase in Improvement of Physico-Chemical Properties of Pozzolana Portland Cement Mortar
Authors:	Bhatrola, Kanchna
Keywords:	Department of Chemistry
Issue Date:	2024
Publisher:	NIT Jalandhar
Abstract:	Cement mortar is a common building material used all over the world and is the foundation of many civil engineering infrastructures. However, it is subject to a number of constraints, some of which include low physico-mechanical strength, quasi brittleness, the cracking phenomena, high permeability, and porous microstructural characteristics. Researchers in the past have used steel fibres, glass fibres, polypropylene fibres, carbon fibres, and other common materials as reinforcing agents in the cement mortar to avoid these problems. But these materials only work to strengthen up to the micro-level, or marco-level, and cracks continue to form at the nano-level in the cement mortar matrix. Nanotechnology has become an interesting way to use nano-sized reinforcements in cement-based materials. Extraordinary mechanical properties can be found in carbon nanomaterials (CNMs), such as one￾dimensional functionalized multiwalled carbon nanotubes (FMWCNTs) and two￾dimensional graphene oxide (GO). CNMs, with their high surface area, high aspect ratio, and exceptional mechanical potential, add new dimensions at the interface to the cementitious matrix. Despite these benefits, there are several drawbacks to using CNMs in the cementitious matrix. One of these is the difficulty of uniform distribution of CNMs throughout the alkaline cement pore solution. In light of these observations, it is possible that CNMs can be covalently functionalized and that CNMs can be dispersed by a superplasticizer to improve their dispersion. Another option is to incorporate hybrid CNMs (i.e., FMWCNTs and GO) as nano￾reinforcements into the cementitious matrix to take advantage of their synergistic impact. Cement manufacturing seems to be a major contributor to the release of the greenhouse gas carbon dioxide. Using pozzolana portland cement has the potential to reduce cement consumption and consequently cement-related CO2 emissions. The results of the thesis show that CNMs and hybrid CNMs play a role as reinforcing phases in making pozzolana portland cementitious nanocomposites (CNCMs) stronger. The CNCMs were made with Graphene Oxide (GO), Functionalized Multiwalled Carbon Nanotubes (FMWCNTs), and a hybrid of GO and FMWCNTs. Graphite Powder (GP) was converted into Milled Graphite Powder (MGP) with the help of a planetary ball milling machine (Retsch PM100) ball mill. Using Hummer's ABSTRACT Method, the MGP was subjected to an oxidative treatment in order to produce the GO. Through exposure to nitric acid, the MWCNTs were converted into FMWCNTs. UV Visible Spectroscopy was utilized to observe the enhanced dispersion of or GO or FMWCNTs. The CNMs were structurally investigated using FE-SEM/EDS, FT-IR, HR-TEM, RAMAN Spectroscopy and PXRD. For CNMs dosages ranging from 0.0015% to 0.012% (by weight of cement), the impact of CNMs and HCNMs on the compressive and tensile strength of the CNCMs was assessed. Microstructural investigations, crystalline behaviour, and durability (electrical resistivity, capillary water absorption, and acid-sulfate attack) were investigated as additional features of CNCMs. The effects of varying CNMs and HCNMs concentrations and cure times (7, 28, 56, and 90 days), on these characteristics were investigated. After incorporating CNMs/HCNMs, the characteristics of CNCMs were compared to those of Control samples, where no carbon nanomaterial was added. The results demonstrated that HCNMs improved physico-mechanical strength more than CNMs applied alone (i.e., GO or FMWCNTs). In terms of compressive strength, 0.0015% HCNMs-CNCMs obtained maximum values of 21.32%. However, at 90 days of curing, tensile strength values were discovered to be greatest for 0.0015% HCNMs-CNCMs with respect to control samples, by 35.27%. With the help of microstructural and crystalline studies, it was found that the hydration reactions of CNMs/HCNMs that included CNCMs were better. Electrical resistivity, capillary water absorption, and acid-sulfate attack verify the cementitious matrix improved compactness and finer pore structure. The current research aimed to improve the physico-mechanical properties of pozzolana portland cementitious nanocomposites by using sterically stabilized CNMs and HCNMs so that safer and sustainable construction materials can be produced with reduced costs and desirable longevity. The results obtained from this study were quite encouraging.
URI:	http://localhost/xmlui/handle/1/67
Appears in Collections:	PHD - Thesis

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