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<p>This study addresses the critical gap in fire safety standards for rubber-modified concrete (RMC) by developing the&#xa0;first fully coupled thermo-mechanical model&#xa0;that integrates rubber pyrolysis kinetics with interfacial stress evolution—a critical advancement over existing uncoupled frameworks that neglect phase-change interactions. Unlike conventional concrete models (e.g., Eurocode 2), our framework uniquely captures void-induced thermal insulation effects and CTE mismatch mechanisms specific to rubber decomposition. The research investigates how rubber content, particle size, and decomposition kinetics influence structural integrity under fire exposure, aiming to balance sustainability (waste tire reuse) with fire resistance thresholds. Experimental validation included ISO 834 fire tests, thermogravimetric analysis (TGA), and compressive strength measurements on RMC specimens (0–30% rubber replacement). Parametric studies evaluated thermal conductivity, porosity evolution, and interfacial stress development across 20–1000&#xa0;°C. Rubber content exceeding 20% accelerated porosity growth (28% at 600&#xa0;°C), causing 55% compressive strength loss. Smaller rubber particles (1–3&#xa0;mm) delayed decomposition but exacerbated interfacial cracking due to thermal expansion mismatch. The model demonstrated high predictive accuracy, with temperature and stress RMSD &lt; 10% and R<sup>2</sup> &gt; 0.94. Optimal performance was achieved at 10–15% rubber replacement, limiting strength loss to ≤ 40% at 600&#xa0;°C while repurposing 130–195&#xa0;kg/m<sup>3</sup> of waste tires. The validated framework provides actionable guidelines for fire-safe RMC design, emphasizing ≤ 15% rubber content and 1–3&#xa0;mm particles for structural elements. Results advocate code updates to address rubber-specific degradation, enabling sustainable construction aligned with UN SDGs. This work resolves bidirectional thermo-mechanical coupling in RMC—unachieved in Ozbakkaloglu et al.’s (2017) uncoupled model—reducing failure time errors from ± 25 to ± 8% while enabling fire-safe repurposing of 130–195&#xa0;kg/m<sup>3</sup> waste tires at 10–15% rubber content.</p>

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Thermo-mechanical modeling of rubber-modified concrete at elevated temperatures: predictive framework for structural fire safety and sustainability

  • 期刊论文

  • 发表日期：

    2025年11月23日

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  • George Gershom Christopher,
  • Monkam Ngameni Huguette Maeva,
  • Olajide Rasheed Olalekan,
  • Butera Hassan,
  • Hassan A. A. Sayed

摘要

This study addresses the critical gap in fire safety standards for rubber-modified concrete (RMC) by developing the first fully coupled thermo-mechanical model that integrates rubber pyrolysis kinetics with interfacial stress evolution—a critical advancement over existing uncoupled frameworks that neglect phase-change interactions. Unlike conventional concrete models (e.g., Eurocode 2), our framework uniquely captures void-induced thermal insulation effects and CTE mismatch mechanisms specific to rubber decomposition. The research investigates how rubber content, particle size, and decomposition kinetics influence structural integrity under fire exposure, aiming to balance sustainability (waste tire reuse) with fire resistance thresholds. Experimental validation included ISO 834 fire tests, thermogravimetric analysis (TGA), and compressive strength measurements on RMC specimens (0–30% rubber replacement). Parametric studies evaluated thermal conductivity, porosity evolution, and interfacial stress development across 20–1000 °C. Rubber content exceeding 20% accelerated porosity growth (28% at 600 °C), causing 55% compressive strength loss. Smaller rubber particles (1–3 mm) delayed decomposition but exacerbated interfacial cracking due to thermal expansion mismatch. The model demonstrated high predictive accuracy, with temperature and stress RMSD < 10% and R2 > 0.94. Optimal performance was achieved at 10–15% rubber replacement, limiting strength loss to ≤ 40% at 600 °C while repurposing 130–195 kg/m3 of waste tires. The validated framework provides actionable guidelines for fire-safe RMC design, emphasizing ≤ 15% rubber content and 1–3 mm particles for structural elements. Results advocate code updates to address rubber-specific degradation, enabling sustainable construction aligned with UN SDGs. This work resolves bidirectional thermo-mechanical coupling in RMC—unachieved in Ozbakkaloglu et al.’s (2017) uncoupled model—reducing failure time errors from ± 25 to ± 8% while enabling fire-safe repurposing of 130–195 kg/m3 waste tires at 10–15% rubber content.