PSI - Issue 79

Naweed Ahmad Rabani et al. / Procedia Structural Integrity 79 (2026) 124–137

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Barite concrete’s performance is negatively impacted by high temperatures. KÖk et al. (2023) found that at 300  C, compressive strength decreased by 34%. In line with research by Luo et al. (2022), Sevinç et al. (2023), and Demir et al. (2020), Kanagaraj et al. (2023) noted that geopolymer concrete exhibited notable mechanical losses at 1029  C, indicating a general susceptibility to thermal stress. Reduced expenses, increased sustainability, and improved resilience to environmental elements like freeze-thaw cycles can result from combining barite with natural minerals like sunflower, wheat, and maize ash (Akso ğ an et al., 2016). A heavyweight material with a density of approximately 4.9 to 5.5 g/cm3, hematite significantly alters the properties of concrete by increasing its unit weight. It is advantageous for applications requiring higher density and specific performance characteristics. Based on the findings of multiple studies, this section summarizes the effects of hematite on concrete, with a focus on mechanical properties, radiation shielding, and other features. Overall, hematite improves concrete’s compressive strength. In comparison to pure concrete, Gencel et al. (2011) found that the high adhesion between cement paste and hematite aggregates resulted in an increase in compressive strength of 3.7% to 14.3%, with a hematite content ranging from 10% to 50%. Concrete using 100% hematite particles showed a 23% increase in compressive strength, according to Shams et al. (2018). Similarly, Ibrahim et al. (2021) discovered that the greater increase in compressive strength when compared to a control mix was achieved with a 30% hematite replacement. While it remained above 110MPa, Lv et al. (2022) observed a minor drop in compressive strength when hematite powder largely substituted river sand in ultra-high performance concrete (UHPC). A 30% hematite replacement had no discernible impact on splitting tensile strength, according to Ibrahim et al. (2021). On the other hand, Lv et al. (2022) discovered that hematite improves UHPC’s flexural and impact strength. Hematite inclusion affects workability. In UHPC, Lv et al. (2022) found that fluidity decreased as hematite replacement ratios increased; nonetheless, a 40% replacement kept fluidity above 170mm, suggesting reasonable workability. 3.2. Effect of Hematite on Concrete

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Concrete’s power to shield radiation is improved by hematite, especially when it comes to gamma rays. Gencel et al. (2011) found that while hematite did not affect neutron absorption, it enhanced gamma ray shielding. While Lv et al. (2022) observed a 43% rise at a 40% replacement ratio in UHPC, Ibrahim et al. (2021) reported an 11.90% increase with 30% hematite in the linear attenuation coefficient. Hematite performed better than barite in radiation attenuation, according to Shams et al. (2018), who also noted higher linear attenuation coefficients in concrete using 100% hematite aggregates. Additionally, Tekin et al. (2018) showed that adding Nano-sized WO3 and Bi2O3 to hematite-serpentine concrete greatly enhanced radiation shielding, suggesting possible uses in nuclear facilities. While iron slag aggregate did not improve thermal conductivity, Ibrahim et al. (2021) discovered that hematite aggregates could raise it by up to 8.95% when compared to a control mix. In contrast to barite aggregates, Shams et al. (2018) observed that hematite aggregates were compatible with the concrete environment, had no adverse effects on attributes such as efficiency or initial setting time, and supplied adequate slump. Figure 5:(a) Unit weights of the concretes; (b) Compressive strengths of the concretes; with a hematite content ranging from 10% to 50% (Gencel et al.., 2011); (c) Flexural strengths of the 28d hematite UHPC; (d)Compressive strengths of the UHPC with different (Lv et al. 2022)

3.3. Effect of Magnetite

The naturally occurring iron oxide mineral magnetite (Fe3O4) is categorized as a ferrite chemically and makes up about 72% of the mass of iron (Sun & Zeng, 2002). For specialized uses like radiation shielding, thermal stability, and electromagnetic absorption,