Mahmoud Alaa A, El-Sayed Alaa A, Fathy Islam N, Fawzy Samer, Alturki Mansour, Elfakharany Maged E, Abouelnour Mohamed A, Mahmoud K A, Dahish Hany A, ElTalawy Soliman M, Nabil Islam M
Construction and Building Engineering Department, October High Institute for Engineering & Technology, Giza, Egypt.
Civil Engineering Department, Faculty of Engineering, Fayoum University, Fayoum, Egypt.
Sci Rep. 2025 Jul 26;15(1):27229. doi: 10.1038/s41598-025-11987-8.
This study investigated the viability of rice husk-derived biochar (RHB) as a partial substitute for cement in concrete. The used RHB, characterized by a novel chemical composition abundant in silicon and aluminum oxides, was incorporated into ordinary concrete at increasing substitution ratios up to 25% by cement weight. A comprehensive evaluation was conducted to assess the influence of RHB on various properties of concrete, including physical (setting time, standard consistency, workability), mechanical (compressive and tensile strength), microstructural (XRD, and EDX), and radiation shielding characteristics. The results indicated that RHB marginally increased cement setting time, with a maximum 7.14% increase observed at a 25% replacement level. However, it significantly increased water demand for standard consistency, reaching 35.7% at 25% replacement. The increased water demand correlated with a reduction in workability, with a maximum slump reduction rate of 57.3% at a 25% replacement level. The optimal replacement levels for mechanical strength enhancement were at 10% for compressive strength and 15% for tensile strength, achieving improvements of 13.74% and 9.48%, respectively. Additionally, Monte Carlo simulation code and PhyX software were employed for assessing gamma and fast neutron radiation attenuation characteristics of concrete. Gamma-ray attenuation tests revealed moderate improvements in the concrete's gamma-ray shielding capacity. Interestingly, the 15% RHB sample demonstrated a higher linear attenuation compared to the other samples, a result of its increased density. On the contrary, the 25RHB sample is less valuable. The 15RHB sample had the highest value for FCS (0.090 cm) indicating its efficacy as a neutron shield.
本研究调查了稻壳衍生生物炭（RHB）作为混凝土中水泥部分替代品的可行性。所使用的RHB具有富含硅和铝氧化物的新型化学成分，以水泥重量计，按递增的替代率掺入普通混凝土中，最高可达25%。进行了全面评估，以评估RHB对混凝土各种性能的影响，包括物理性能（凝结时间、标准稠度、工作性）、力学性能（抗压强度和抗拉强度）、微观结构性能（XRD和EDX）以及辐射屏蔽特性。结果表明，RHB使水泥凝结时间略有增加，在25%替代水平下观察到最大增加7.14%。然而，它显著增加了标准稠度的需水量，在25%替代时达到35.7%。需水量的增加与工作性的降低相关，在25%替代水平下最大坍落度降低率为57.3%。增强力学强度的最佳替代水平是抗压强度为10%，抗拉强度为15%，分别提高了13.74%和9.48%。此外，采用蒙特卡罗模拟代码和PhyX软件评估混凝土的伽马射线和快中子辐射衰减特性。伽马射线衰减测试表明混凝土的伽马射线屏蔽能力有适度提高。有趣的是，15%RHB样品与其他样品相比表现出更高的线性衰减，这是其密度增加的结果。相反，25%RHB样品价值较低。15%RHB样品的FCS值最高（0.090厘米），表明其作为中子屏蔽的有效性。
