The performance of concrete cover as a thermal insulation for BFRP bars in tension at early stage of fire

openaccess, Vol. 633 (5) 2025 / czwartek, 22 maja, 2025

Zastosowanie otuliny betonowej jako izolacji termicznej prętów BFRP podczas rozciągania we wczesnej fazie pożaru

(Open Access)

DOI: 10.15199/33.2025.05.02

citation/cytuj: Wydra M., Sadowski G., Dolny P., Turkowski P., Fangrat J. The performance of concrete cover as a thermal insulation for BFRP bars in tension at early stage of fire. Materiały Budowlane. 2025. Volume 633. Issue 05. Pages 10-15. DOI: 10.15199/33.2025.05.02

Despite multiple beneficial mechanical properties and low ecological impact, limited recognition of the properties of relatively new Basalt Fibre Reinforced Polymer (BFRP) reinforcement bars, especially at elevated and high temperature range, still limits the area of their potential applications in building structures. In this study the performance of such bars in tension during heating up to 200°C in steady state regime, and the performance of concrete cover were investigated. Due to limited data available in terms of elasticity modulus values changes for FRP at elevated temperatures, the Digital Image Correlation (DIC) was used for strain analysis in this study. There was no clearly positive influence of concrete cover on the maximum value of observed stresses. This may be attributed to the loss of bond between concrete and BFRP bars, as well as negligible values of registered strains at the concrete surface were registered.

Pomimo wielu korzystnych właściwości mechanicznych i niewielkiego wpływu na środowisko, niedostateczne rozpoznanie właściwości stosunkowo nowych prętów zbrojeniowych z polimeru wzmocnionego włóknem bazaltowym (ang. Basalt Fibre Reinforced Polymer – BFRP), szczególnie w podwyższonej i wysokiej temperaturze, nadal ogranicza obszar ich potencjalnego zastosowania w konstrukcjach budowlanych. W pracy prezentowanej w artykule zbadano charakterystykę takich prętów przy rozciąganiu podczas nagrzewania do 200°C w stanie ustalonym oraz skuteczność ich otuliny betonowej. Ze względu na ograniczoną liczbę dostępnych danych dotyczących zmian wartości modułu sprężystości BFRP w podwyższonej temperaturze, do analizy odkształceń w tym badaniu wykorzystano cyfrową korelację obrazu (ang. Digital Image Correlation – DIC). Nie zaobserwowano pozytywnego wpływu otuliny na maksymalną wartość naprężeń, co można przypisać utracie wiązania między otuliną a prętami BFRP. Ponadto zarejestrowano znikome wartości odkształceń na powierzchni betonu.
Basalt Fibre Reinforced Polymer; bars; temperature; fire.

polimer wzmocniony włóknem bazaltowym; pręty zbrojeniowe; temperatura; pożar.
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dr inż. Małgorzata Wydra, University of Michigan, Ann Arbor, United States of America
ORCID: 0000-0002-4629-9656
dr inż. Grzegorz Sadowski, Warsaw University of Technology, Faculty of Civil Engineering, Mechanics and Petrochemistry
ORCID: 0000-0001-6441-0875
dr inż. Piotr Dolny, Warsaw University of Technology, Faculty of Civil Engineering, Mechanics and Petrochemistry
ORCID: 0000-0002-5384-9257
dr inż. Piotr Turkowski, Building Research Institute
ORCID: 0000-0002-0020-0091
dr hab. inż. Jadwiga Fangrat, prof. ITB, Building Research Institute
ORCID: 0000-0002-7871-0032

dr inż. Małgorzata Wydra, University of Michigan, Ann Arbor, United States of America
ORCID: 0000-0002-4629-9656

Correspondence address: malgorzata.wydra@pw.edu.pl

Full paper:

DOI: 10.15199/33.2025.05.02

Article in PDF file

Received: 03.01.2025 / Artykuł wpłynął do redakcji: 03.01.2025 r.
Revised: 10.03.2025 / Otrzymano poprawiony po recenzjach: 10.03.2025 r.
Published: 22.05.2025 / Opublikowano: 22.05.2025 r.