Document Type : Research Paper
Authors
1
Department of Mechanical Engineering, Payame Noor University, P.O. Box 19395-3697, Tehran, Iran
2
Department of Civil Engineering, Tarbiat Modares University, Tehran, Iran
10.22124/jcr.2026.27719.1662
Abstract
The use of in situ synthesized carbon nanotubes, using chemical vapor deposition in the cement production process, to improve the durability of concrete has attracted the attention of many researchers. In this study, the appropriate range of use of these nanotubes under freeze-thaw cycle conditions and tensile strength was investigated. After adding cement containing in-situ synthesized carbon nanotubes at different percentages (0, 4, 6, 8, 10, and 12) to concrete samples, the weight loss of the samples under freeze-thaw cycle conditions was measured as a factor to determine the effect of this cement. The weight loss in the control sample (without nanotubes) was 5.82%, and for the cement samples containing 4, 6, 8, 10, and 12% nanotubes, the weight loss was 1.74, 1.75, 1.38, 1.02, and 1.68%, respectively, after 300 freeze-thaw cycles. Adding 10% of cement containing in-situ synthesized carbon nanotubes to concrete samples resulted in the lowest weight loss. The indirect tensile strength of the samples, as an important parameter in the design of concrete structures, was also measured using indirect tensile testing. Samples containing 8% of this cement had the highest tensile strength, which is approximately 24% higher than the control sample. In order to better understand the desired cement and also the microstructure of the samples, Field Emission Scanning Electron Microscopy (FESEM) observations were also performed. The FESEM results indicated that the nanotubes were properly dispersed and did not aggregate in the cement matrix.
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