Use of Carbon Nanotubes in the Retrofitting of Reinforced Concrete Beams With an Opening and the Effect of Direct Fire on Their Behaviour

Hassan, Ahmed

doi:10.21660/2018.44.01175

Cited by 8 publications

(3 citation statements)

References 9 publications

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“…The unique features offered by CNTs provide an excellent opportunity to develop CNTs-reinforced structural concrete 27 . Addition of CNTs to the concrete mix and repair mixtures was studied in literature 28,29 . CNTs improve cement composites in tension due to its ability to prevent the initiation of micro cracks in the cement matrix 30 .…”

Section: Introductionmentioning

confidence: 99%

Effect of Adding Carbon Nanotubes on Corrosion Rates and Steel-Concrete Bond

Hassan

Elkady

Shaaban

2019

Sci Rep

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This paper presents a continuation of the evaluation of utilizing Nano Carbon Tubes (CNTs) in reinforced concrete (CNT-CRETE). The compressive, tensile and bond strengths of the samples with and without CNTs were investigated. Scanning Electron Microscope (SME) was utilized to study the microstructure of the prepared samples. In addition, the corrosion resistance of CNT-CRETE, was measured and compared to traditional concrete. Four mixes were prepared, with 0.01%, 0.02%, and 0.03%, CNTs by weight of cement, along with a control mix without CNTs. The results of the experimental work showed that adding CNTs led to an increase in the compressive, tensile and bond strengths of specimens compared to those of the control specimen. SEM examination for control and CNTs specimens showed that CNTs specimen were well structured compared with the control specimen and this affirms that CNTs act as bridges across micro cracks, which explains the improvement in mechanical properties. The diameter of steel bars played a significant role in failure mechanism for pull-out testing and corrosion resistance. In general, adding CNTs to the concrete mix increased the rate of corrosion for steel bars within the low risk limits. Benefits from using CNTs were limited to moderate. Mineral/chemical admixtures or fibers provide better improvements in the mechanical properties of concrete without the problems associated with dispersing CNTs and the health hazard of handling a Nano material.

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Section: Introductionmentioning

confidence: 99%

Effect of Adding Carbon Nanotubes on Corrosion Rates and Steel-Concrete Bond

Hassan

Elkady

Shaaban

2019

Sci Rep

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Section: Introductionmentioning

confidence: 99%

“…Carbon nanotubes (CNTs) are one of the most used reinforcement materials for the next generation of high-performance nanoparticles due to their remarkable mechanical properties [21]. CNTs offer various distinct advantages in applications as a reinforcing material compared with other fibers used due to their high strength in cemented composites and their remarkable physical properties [21][22][23]. CNTs have much greater strength and rigidity than traditional fibers; they thus have the potential to improve overall mechanical properties compared with composites, including traditional fibers.…”

Section: Introductionmentioning

confidence: 99%

Utilization of carbon nanotubes and steel fibers to improve the mechanical properties of concrete pavement

Hassan

Galal

Hassan

et al. 2022

Beni-Suef Univ J Basic Appl Sci

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Background Rigid pavements have become an urgent demand in recent years, as these pavements need less maintenance and renovation than other types. However, traditional rigid pavement faces various challenges and difficulties over its lifetime. It has a much higher initial erection cost than asphalt pavements, a greater sensitivity to dynamic stresses, and a highly susceptible to temperature variations causing cracking. Previous works dealt with these drawbacks by using effective materials as alternatives to cement and/or aggregates in pavements mixtures. In the last few years, much interest has been carried out in nanomaterial applications to improve the mechanical performance of construction materials, which can also be used for rigid pavement constructions. This improvement is due to nanomaterials' role in concrete as nanoreinforcements and nanofillers. On the other hand, various types of fibers have been used to improve the performance of concrete constructions. This study investigates the effect of adding carbon nanotubes (CNTs) and steel fibers (SFs) to concrete mixtures. A series of experiments on concrete mixes with various weight percentages of CNTs (0%, 0.025%, 0.050%, and 0.075%) were added to the mixtures to determine the best cost and amount of CNTs to add to a concrete mix. Compressive, tensile, and flexure strength characteristics are investigated. In the second experimental stage of this work, the effect of adding steel fibers to the mixture was investigated. Results According to the results, the optimal carbon nanotube content in concrete is 0.05%. Compared to other concrete combinations with varying proportions of CNTs, this quantity offers the maximum compressive, tensile, and flexural strength. Additionally, SFs can improve the mechanical properties of the mix as well as enhance its post-cracking and fatigue behavior. Adding both CNTs with SFs increased compressive, tensile, and flexural strength by 22.7%, 29.3%, and 70.8%, respectively, more than the traditional pavement. Conclusion This work found that combining SFs with CNTs improves the mechanical properties of the concrete mortar, resulting in a stronger mortar that can withstand more loads than the traditional one.

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