Improving the mechanical performance of cement composites by carbon nanotubes addition

Gillani, Syed Shujat Ul Hussan; Khitab, Anwar; Ahmad, Sajjad; Khushnood, Rao Arsalan; Ferro, Giuseppe Andrea; Kazmi, Syed Minhaj Saleem; Qureshi, Liaqat Ali; Restuccia, Luciana

doi:10.1016/j.prostr.2017.04.003

Cited by 59 publications

(21 citation statements)

References 28 publications

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“…It reveals that the reduction of effective water content ultimately results into the improvement in compressive strength. Dispersion concerns and agglomeration sometimes cause a reduction in the strength with increase in the quantity of MWCNTs [39]. The three-point bending tests showed similar trend as produced by the splitting cylinder tensile tests.…”

Section: Performance Evaluation Of Samples In Tension and Flexuresupporting

confidence: 56%

Fracture toughness and failure mechanism of high performance concrete incorporating carbon nanotubes

Khitab

Ahmad

Khushnood

et al. 2017

Frattura Ed Integrità Strutturale

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ABSTRACT. Cement and concrete composites are inherently brittle and exhibit very less tensile/flexural strength capacity as compared to their compressive strength. Use of thoroughly dispersed carbon nanotubes in the concrete matrix is one of the possible solution for enhancing mechanical properties in tension/flexure. In the present research work, small fractions of multiwall carbon nanotube (MWCNTs) i.e. 0.05 and 0.10 wt% of cement have been integrated into the cement concrete to study their effect on the mechanical properties of the resultant concrete mixtures. The enhanced performance of the whole mix lies on a single point that MWCNTs must be thoroughly disperse in the mixture. Hence, special arrangement through usage of high energy sonication along with amended acrylic based polymer (performing as a surfactant) was made to have a uniform dispersion of MWCNTs in the concrete mix. The testing of concrete samples includes i.e., flexure, splitting tensile and compressive strengths after 3, 7, 28 and 56 days of curing. After having comparison with the control mix cured for 28 days, it was observed that the addition of 0.05 wt% MWCNTs increased the splitting A. Khitab et alii, Frattura ed Integrità Strutturale, 42 (2017) [238][239][240][241][242][243][244][245][246][247][248] 240 tensile strength by 20.58%, flexural strength by 26.29% and compressive strength by 15.60%. Through above results, which verify the increase in concrete mix strength after adding MWCNTs, these MWCNTs may be incorporated in the treatment of Nano/micro cracks completed through process of connecting, branching and pinning. Similarly, as proved in threepoint bending tests, MWCNTs also enhances the breaking strains as well as the fracture energy of the concrete mixes, besides, imparting increase to the strength. The investigations have shown that incorporating lesser amounts of MWCNTs i.e., 0.05 and 0.10 wt% of cement to the concrete mixes after insuring there complete dispersion, unusually improve their properties like mechanical strengths and fracture behavior.

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Section: Performance Evaluation Of Samples In Tension and Flexuresupporting

confidence: 56%

Fracture toughness and failure mechanism of high performance concrete incorporating carbon nanotubes

Khitab

Ahmad

Khushnood

et al. 2017

Frattura Ed Integrità Strutturale

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“…1,2 Numbers of studies have been carried out to improve the flexural strength, toughness, and decrease microcracks by adding nanomaterials in cement composites. 3,4 Owing to the distinctive physical and chemical properties, the materials effectiveness can be improved using nanomaterials. 5,6 Carbon nanotubes (CNTs) are one of appropriate cement nano-reinforcement, its have the ability to arrest propagating cracks owing to their high aspect ratio and large specific surface area.…”

Section: Introductionmentioning

confidence: 99%

Properties improvement of multiwall carbon nanotubes-reinforced cement-based composites

Wang

Pang

2019

Journal of Composite Materials

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Multiwall carbon nanotubes with extraordinary mechanical properties have been widely used as effective nano-reinforcer of cement-based composites. In this research, multiwall carbon nanotubes were dispersed uniformly in aqueous solution using N,N-dimethylformamide as dispersant with ultrasonication. The structure and micromorphology of multiwall carbon nanotubes were characterized via X-ray photoelectron spectroscopy and transmission electron microscopy. The effect of N,N-dimethylformamide on multiwall carbon nanotubes dispersion was better than that of previous dispersants. The multiwall carbon nanotubes/cement composites with different multiwall carbon nanotubes contents were prepared and the mechanical performances of multiwall carbon nanotubes/cement composites were researched. Results showed that the flexural strength growth rate of multiwall carbon nanotubes/cement composites was 21.7% and the compressive strength growth rate of the multiwall carbon nanotubes/cement composites was 2.9% incorporating with 0.04 wt% multiwall carbon nanotubes at 28 days. The ratio of compressive strength to flexural strength of decline rate of multiwall carbon nanotubes/cement composites was 15.9% with 0.04 wt% multiwall carbon nanotubes at 28 days. The isothermal calorimetry (TAM Air) showed that multiwall carbon nanotubes could accelerate the hydration reaction. The X-ray diffraction and thermal gravity analysis (TG/DTG) suggested that multiwall carbon nanotubes could improve the hydration process and increase the number of hydration products. The mercury intrusion porosimetry revealed the porosity of multiwall carbon nanotubes/cement composites was decreased. There is an effect of multiwall carbon nanotubes on inhibiting the extension of cracks and promoting the degree of compactibility of the cement-based composites. The micromorphology of multiwall carbon nanotubes/cement composites was observed through scanning electron microscope.

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“…Recently, Mehta's group published a review on the consequences of CNTs on the properties of cement mortars, which evidently shows that numerous attempts have been made by various authors towards enhancing the compressive strength, flexural strength, microstructure, Young's modulus, and porosity of cement-CNT composites [12]. The effect of the addition of CNTs to cement-based materials was also investigated to effectively change their brittleness and developmaterialswith superlative mechanical properties [13][14][15][16][17]. Besides all the benefits, certain issues such as poor dispersion, high entanglement with matrix, agglomeration, interfacial strain transfer, lack of functional sites, etc., limit the global use of CNTs.…”

Section: Introductionmentioning

confidence: 99%

Hydration Phenomena of Functionalized Carbon Nanotubes (CNT)/Cement Composites

Balasubramaniam

Mondal

Ramasamy

et al. 2017

Fibers

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Abstract:The exciting features of carbon nanotubes (CNTs), such as high elastic modulus, high thermal and electrical conductivities, robustness, and nanoscopic surface properties make them attractive candidates for the cement industry. They have the potential to significantly enhanceengineering properties. CNTs play an important and critical role as nano-anchors in concrete, which enhance the strength by bridging pores in the composite matrix, thereby ensuring robust mechanical strength. The diameter, dispersion, aspect ratio, and interfacial surface interaction of CNTs affect the physical and mechanical properties of concrete, if due care is not taken. In this paper, the usable amount of CNT is scaled down considerably from 0.5% to 0.025% by weight of the cement and the fluctuation caused by these phenomena is assessed. It is observed that the properties and exact quantities of incorporated CNTs influence the hydration and consistency of the composites. In order to address these issues, the surface functionalization of CNTs and rheological studies of the composites are performed. The hydration products and functional groups are carefully optimized and characterized by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and a Zeta potential analyzer. For Mixes 6 and 7, the compressive and tensile strength of CNTs incorporated in mortar specimens caused 77% and 48% increases in split tensile strength, respectively, and 17% and 35% increases in compressive strength, respectively, after 28 days of curing and compared withthe control Mix.

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Improving the mechanical performance of cement composites by carbon nanotubes addition

Cited by 59 publications

References 28 publications

Fracture toughness and failure mechanism of high performance concrete incorporating carbon nanotubes

Fracture toughness and failure mechanism of high performance concrete incorporating carbon nanotubes

Properties improvement of multiwall carbon nanotubes-reinforced cement-based composites

Hydration Phenomena of Functionalized Carbon Nanotubes (CNT)/Cement Composites

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