Nanocomposites Prepared by a Dispersion of CNTS on Cement Particles (original) (raw)
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CARBON NANOTUBE CEMENT COMPOSITES
The carbon nanotubes are revolutionary material which has superior mechanical properties, which make them an ideal reinforcing material in polymer composites.The present paper is a comprehensive study of researches and developments in the field of Carbon nanotube cement composites. The carbon nanotube are nano scale particles, its additions in small amounts to the cement mortar and cement concrete mixtures improve their durability,flexural strength, compressive strength and reduce porosity. The additions of CNT in small amounts that is upto .5% by weight to cement mixture and its effects have been analysed. The study of synthesis of CNT and its dispersion methods have also been done.The challenges regarding production of CNT-cement compoites are posed by insoulubility of carbon nanotubes in any of the aqeous and organic solvents ordinarily. The dispersion of carbon nanotubes have been achieved by use of surfactants and other chemical compounds along with vigorous agitation by sonication. The various researches have reported varied results experimenting with different amounts of CNTs and different dispersion techniques leading to a conclusion that although .05 to .5% addition of CNTs to cement enhance the properties greatly, but the field still requires more research into the methods of dispersion and effects of carbon naontube on microstructure of cement and concrete mixes.
Properties of Carbon Nanotube (CNT) Reinforced Cement
Carbon nanotubes (CNTs) have great potential to improve the strength and toughness of traditional cement-based building materials. After effective dispersion in water with a surfactant, followed by separation using a centrifuge, multi-walled carbon nanotubes (MWCNTs) can be stored stably for over three months. Our study focused on the microstructure and compressive strength of Portland cement reinforced with MWCNTs. As the proportion of added MWCNTs was increased from 0% to 0.2% by weight of cement, the mechanical properties of the cement paste correspondingly improved. With the addition of 0.1 wt% MWCNT, the 7-day and 28-day compressive strengths increased by 22% and 15%, respectively. The cement paste flexural strength was also improved by addition of MWCNTs. Scanning electron microscopy (SEM) analysis showed that the carbon nanotubes were well dispersed in the cement hydration products. Debonding, bridging, and mesh filling were also observed by SEM. Pressured-mercury testing was used to measure pore distribution in the MWCNT-reinforced cement pastes, and it was found that the pore size distribution tilted in favor of gel pores, pores that have a positive influence on mechanical strength.
Dispersion of carbon nanotubes and its influence on the mechanical properties of the cement matrix
Cement and Concrete Composites, 2012
An appropriate dispersion of carbon nanotubes (CNTs) is a prerequisite for their use in improving the mechanical properties of cement-based composites. In this study two types of carbon nanotubes (CNTs) having different morphologies were investigated. To obtain a uniform distribution of CNTs in the cement matrix, the effect of sonication on the deagglomeration of CNTs in combination with anionic and nonionic surfactants in varying concentrations was quantitatively investigated when preparing aqueous dispersions of CNTs for the subsequent use in cement paste. The relationships between the quality of CNT-dispersion on the one hand and the sonication time and surfactant concentration on the other were determined using UV-vis spectroscopy. After dispersion, nitrogen-doped CNTs were found mostly as individual, broken CNTs. In contrast, after the treatment of the mixture of single-, double-, and multiwalled CNTs, a net-like distribution was observed where destruction of the CNTs due to sonication could not be distinguished. Modification of the cement pastes with dispersions of CNTs led to a pronounced increase, up to 40%, in compressive strength and, in some cases, to a moderate increase in tensile strength under high strain-rate loading. However, no significant improvement in strength was observed for quasistatic loading. Microscopic examination revealed that the bridging of the C-S-H phases differed depending on the type of CNT. This explained, at least partly, the observed effects of CNT-addition on the mechanical properties of hardened cement pastes.
Recent Trends of Reinforcement of Cement with Carbon Nanotubes and Fibers
InTech eBooks, 2016
Recent achievements in the area of formation of carbon nanotubes (CNTs), nanocomposites, with cement are reviewed. The peculiarities of dispersion of CNTs in cementitious matrices are discussed, paying major attention to the CNT diameter, length and length-to-diameter ratio, concentration, functionalization, annealing, combination with other nanomaterials, and water-cement ratio. Several effects upon dispersion of carbon allotropes in concrete-water media are emphasized. It is also pointed out that the health impact should also be considered in further experiments on construction materials reinforced with CNTs.
Sustainability
Excellent mechanical properties and chemical stability make carbon nanotubes (CNTs) some of the most promising nanomaterials that can be used in cementitious composites to improve their performance. However, the difficulty of CNTs’ dispersion within the cementitious structure still exists and thus prevents the homogeneous distribution of CNTs. The homogeneous distribution of CNTs within a composite structure plays an essential role that can have a positive effect on the mechanical performance of CNT-cement composites. This paper introduces the methods for the production of CNTs and provides useful information about the influence of CNTs on the flowability, mechanical performance, microstructural changes and hydration of cement composites. The influences of water-cement ratio, used surfactants and various doses of CNTs on the properties of cementitious composites were also studied.
Evaluation of Carbon Nanotube Incorporation in Cementitious Composite Materials
Materials
Over the last decades, new materials with outstanding performance have been introduced in the construction industry. Considering these new technologies, it is worth mentioning that nanotechnology has revolutionized various areas of engineering. In the area of civil engineering and construction, cement is used for various purposes and the search to improve its performance has been receiving growing interest within the scientific community. The objective of this research was to evaluate the behavior of cement mortar produced by the addition of multi-walled carbon nanotubes (MWCNTs) in different concentrations by comparing their physical and mechanical properties with the properties of the nanotube-free composite. Motivated by the lack of consensus in the literature concerning to the optimal dosage of CNTs in cementitious matrices, three different carbon nanotube ratios, 0.20, 0.40 and 0.60 wt % Portland cement, were investigated with the aim of evaluating the mechanical properties. De...
Scientific.net, 2023
Carbon nanotubes (CNTs) have been studied as a reinforcement material for cementitious composites, with promising results. Incorporating CNTs into cement-based materials enhances the composites' mechanical, thermal, and electrical properties, as cementitious materials have limited applications due to their strain capacity and less tensile strength. CNTs have high tensile strength and modulus, along with excellent electrical conductivity. These features make them ideal for construction materials. Using CNTs in cement-based composites can improve the durability and sustainability of construction materials and provide new opportunities for advanced applications in the construction industry. The addition of CNTs to cement-based materials can improve mechanical performance, improve fire resistance and reduce carbon dioxide emissions. The incorporation of CNTs in cementitious composites is a promising area of research with significant potential for use in the construction industry. The current study's findings are expected to provide insight into the new material and its glamorous scopes for application as construction materials.
2018
Cement has been largely used in the construction industry, specifically as a matrix for concrete. Recently, a new generation of cement-based composite that greatly increases mechanical properties is replacing conventional concrete. With periodic advances in the field, researchers considered particles with highaspect ratios such as Carbon Nanotubes (CNTs) to reinforce cement matrices. Although there is not much literature to draw upon in research, some research on improving tensile strength of cementitious composite incorporating with CNTs does exist. However, there had been no evidence of investigation into impact strength until this study. Most papers presented examined the effect of multi-walled carbon nanotubes, but very few investigated single-walled carbon nanotubes (SWCNTs), and none of the research compared SWCNTs with multiwalled carbon nanotubes (MWCNTs), and hybrid CNTs (50% of MWCNTs and 50% SWCNTs) in cementitious composites. The aim of this research is to assess and compare the effect on tensile and impact strength of cementitious composite of reinforcing cement with functionalized (-COOH) SWCNTs, MWCNTs, and hybrid CNTs. Additionally, the lack of standard mixing and test procedures for nanomaterials with cement is considered.