Hybrid concretes: solutions for better bond and splitting tensile strength under elevated heat exposure
Journal of Structural Fire Engineering
ISSN: 2040-2317
Article publication date: 14 October 2021
Issue publication date: 22 February 2022
Abstract
Purpose
This paper presents the second part of the investigation on resistance to elevated temperatures of a proposed hybrid composite concrete (NCSF-Crete) mix. The composite including nano metakaolin (NC) and steel fibers (SF) in addition to regular concrete components has proven -in the first published part-earlier promoted fresh concrete behavior, and to have reduced loss in compressive strength after exposure to a wide range of elevated temperatures. This presented work evaluates another two critical mechanical characteristics for the proposed composite -namely- splitting and bond strengths.
Design/methodology/approach
A modified formula correlating splitting and compressive strength (28 days) based on experiments results for NCSF is proposed and compared to formulas derived for regular concrete in different design codes. Finally, both spitting and bond strengths are evaluated pre- and post-exposure to elevated temperatures reaching 600 °C for two hours.
Findings
The proposed NCSF-Crete shows remarkable fire endurance, especially in promoting bond strength as after 600 °C heat exposure tests, it maintained strength equivalent to 70% of a regular concrete control mix at room temperature. Improving residual splitting strength was very significant up to 450 °C exposure.
Research limitations/implications
Obvious deterioration is monitored in splitting resistance for all concretes at 600 °C.
Practical implications
This proposed composite improved elevated heats resistance of the most significant concrete mechanical properties.
Social implications
Using a more green and sustainable constituents in the composite.
Originality/value
The proposed composite gathers the merits of using NC and SF, each has been investigated separately as an addition to concrete mixes.
Keywords
Acknowledgements
The authors wish to thank the National Research Centre of Egypt for kind contribution by using its labs and facilities to support this research program.
Citation
Elkady, H.M., Shalaby, O.B., Kohail, M. and Nasr, E.A.R. (2022), "Hybrid concretes: solutions for better bond and splitting tensile strength under elevated heat exposure", Journal of Structural Fire Engineering, Vol. 13 No. 1, pp. 88-98. https://doi.org/10.1108/JSFE-02-2021-0010
Publisher
:Emerald Publishing Limited
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