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<p>This study introduces a novel ultra-high-performance concrete (UHPC) formulation designed for integrated neutron and gamma radiation shielding, as it is an advancement not typically addressed in conventional UHPC research. By incorporating colemanite, a boron-rich mineral with high neutron absorption capacity, the concrete achieves multifunctionality for use in nuclear and medical infrastructure requiring both structural integrity and radiation protection. Three UHPC variants were developed: sand-based (S-UHPC), barite-based (B-UHPC), and magnetite-based (M-UHPC), each modified with 0–10% colemanite replacement. Their fresh, mechanical, and durability properties were evaluated, including compressive strength, ultrasonic pulse velocity, pore structure, and macroscopic removal cross sections. Polyvinyl alcohol (PVA) fibers were added at varying dosages and tested under elevated temperatures (400–800&#xa0;°C) to assess thermal resilience. The optimal mix (5% colemanite and 0.5% fiber) showed strong mechanical retention and enhanced shielding performance. Compared to unmodified UHPC, B-UHPC exhibited a 30.2% reduction in flexural strength and 23.9% in tensile strength, while M-UHPC showed only a 9.0% tensile reduction. S-UHPC recorded the highest wave velocity (4902&#xa0;m/s at 10% colemanite), indicating improved compactness. M-UHPC and B-UHPC showed moderate gains at 5% replacement, followed by slight declines at 10%. S-UHPC exhibited the lowest <i>∑</i><sub><i>R</i></sub>(<i>E</i><sub><i>n</i></sub>) value, which decreased further with fiber addition, dropping from 0.0329 to 0.0238&#xa0;cm<sup>−1</sup>, a reduction of 15.8–27.7%. Magnetite UHPC recorded the highest gamma attenuation coefficient (<i>µ</i>) of 0.2195&#xa0;cm<sup>−1</sup>, followed by barite UHPC at 0.2193&#xa0;cm<sup>−1</sup>, both about 19% higher than S-UHPC. At higher gamma energies, M-UHPC maintained the top <i>µ</i> value of 0.1491&#xa0;cm<sup>−1</sup>, corresponding to the most efficient thickness for 99% shielding. This research offers a pioneering UHPC formulation with validated neutron shielding capability, supported by experimental data and ANSYS–PHITS simulations, suitable for deployment in high-risk thermal and nuclear environments.</p>

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Experimental and Numerical Investigation of Ultra-high-Performance Concrete with Boron-Rich Colemanite for Enhanced Mechanical, Radiation, and Thermal Performance

  • 期刊论文

  • 发表日期：

    2026年3月2日

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  • M. A. H. Abdullah,
  • M. Amran,
  • Abdullah Alnutayfat

摘要

This study introduces a novel ultra-high-performance concrete (UHPC) formulation designed for integrated neutron and gamma radiation shielding, as it is an advancement not typically addressed in conventional UHPC research. By incorporating colemanite, a boron-rich mineral with high neutron absorption capacity, the concrete achieves multifunctionality for use in nuclear and medical infrastructure requiring both structural integrity and radiation protection. Three UHPC variants were developed: sand-based (S-UHPC), barite-based (B-UHPC), and magnetite-based (M-UHPC), each modified with 0–10% colemanite replacement. Their fresh, mechanical, and durability properties were evaluated, including compressive strength, ultrasonic pulse velocity, pore structure, and macroscopic removal cross sections. Polyvinyl alcohol (PVA) fibers were added at varying dosages and tested under elevated temperatures (400–800 °C) to assess thermal resilience. The optimal mix (5% colemanite and 0.5% fiber) showed strong mechanical retention and enhanced shielding performance. Compared to unmodified UHPC, B-UHPC exhibited a 30.2% reduction in flexural strength and 23.9% in tensile strength, while M-UHPC showed only a 9.0% tensile reduction. S-UHPC recorded the highest wave velocity (4902 m/s at 10% colemanite), indicating improved compactness. M-UHPC and B-UHPC showed moderate gains at 5% replacement, followed by slight declines at 10%. S-UHPC exhibited the lowest ∑R(En) value, which decreased further with fiber addition, dropping from 0.0329 to 0.0238 cm−1, a reduction of 15.8–27.7%. Magnetite UHPC recorded the highest gamma attenuation coefficient (µ) of 0.2195 cm−1, followed by barite UHPC at 0.2193 cm−1, both about 19% higher than S-UHPC. At higher gamma energies, M-UHPC maintained the top µ value of 0.1491 cm−1, corresponding to the most efficient thickness for 99% shielding. This research offers a pioneering UHPC formulation with validated neutron shielding capability, supported by experimental data and ANSYS–PHITS simulations, suitable for deployment in high-risk thermal and nuclear environments.