Enhancing Post-Fire Residual Performance of Concrete: A Comprehensive study on the Synergistic Effects of Multiwalled Carbon Nanotubes and Nano Clay at Elevated Temperatures

Badawy, Amr H.; El-hadad, Areej S.; El-Hariri, Mohamed O.R.; Gamal, Amr A.; El-Gammal, M.A.; El-Feky, M.S.

doi:10.21608/ejchem.2025.374446.11576

Enhancing Post-Fire Residual Performance of Concrete: A Comprehensive study on the Synergistic Effects of Multiwalled Carbon Nanotubes and Nano Clay at Elevated Temperatures

Document Type : Original Article

Authors

¹ National Research Centre, Giza, Egypt

² Faculty of Engineering at Shoubra, Banha, Egypt

10.21608/ejchem.2025.374446.11576

Abstract

When a reinforced concrete structure is exposed to elevated temperatures, an assessment of its residual capacity is needed. This article addresses the study of various nanomaterials in concrete to investigate their influence on enhancing the mechanical properties of concrete after exposure to different temperature levels. In this article, the compressive strength, splitting tensile strength, and bond strength of concrete were measured at elevated temperatures (200°C, 400°C, and 600°C) for 1 hour and 2 hours. The influence of multiwalled carbon nanotubes and nano clay on the properties of concrete post-heating was investigated. The carbon nanotubes and nano clay were used at 0.01% and 3%, respectively, for 550 kg/m³ cement content. The results showed that the residual compressive strength of the control and nano clay samples increased at 200 °C when compared to the unheated mix. Nevertheless, the residual compressive strength of CNTs and hybrid composite mixes was reduced at 200 °C. At 200 °C, the residual splitting tensile of control samples and nano clay increased. At 200 °C, CNT samples and hybrid composites had lower residual splitting tensile strength compared to the unheated mix. The residual bond strength increased up to 200 °C in the control sample. The residual bond strength of hybrid composite samples in concrete decreased dramatically between 200°C and 600 °C. The results of the statistical analysis, which evaluated the compressive strength, tensile strength, and bond strength, along with the effect of different elevated temperatures (200 °C, 400 °C and 600 °C) and different period (60 min and 120 min). Finally the statistical analysis were used to which evaluated the compressive strength, tensile strength, and bond strength, along with the effect of different elevated temperatures (200 °C, 400 °C and 600 °C) and different period (60 min and 120 min).

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