Tahwia Ahmed M, Abdellatief Mohamed, Salah Aml, Youssf Osama
Department of Structural Engineering, Faculty of Engineering, Mansoura University, Mansoura, 35516, Egypt.
Department of Civil Engineering, Higher Future Institute of Engineering and Technology in Mansoura, Mansoura, Egypt.
Sci Rep. 2025 Apr 1;15(1):11049. doi: 10.1038/s41598-025-93598-x.
The use of recycled powder as a binder in geopolymer concrete (GPC) represents a promising approach to reducing construction waste and promoting the production of sustainable materials. This study examines the impact of recycled concrete powder (RCP), clay brick powder (CBP), and volcanic pumice powder (VPP) on the mechanical, durability, and thermal properties of GPC with fly ash and slag under water curing. Key mechanical properties, including compressive strength (CS), splitting tensile strength, and flexural strength, were evaluated, while durability was assessed through water absorption, water penetration, and resistance to sulfate and acid attacks. The thermal performance was tested by exposing the samples to elevated temperatures of 200 °C, 400 °C, and 600 °C. Results demonstrated that incorporating 25% RCP enhanced CS by 14.88% at 28 days compared to the control mixture, although higher replacement levels (50% and 75%) led to reduced CS due to increased porosity. Similarly, CBP at 25% substitution resulted in a 21.12% increase in CS, with declines observed at higher replacement levels. Conversely, VPP at 25% substitution decreased CS by 8.68% at 28 days, with further significant reductions at higher levels due to its high porosity. Sulfate resistance testing in a 5% MgSO₄ solution showed minimal mass loss for CBP mixtures (0.3-1.2%) and moderate CS reductions (5.7-29.6%). RCP mixtures exhibited low mass loss (0.3-1.7%) and CS reductions (8.7-15.8%), while VPP mixtures experienced the highest mass losses (1.36-3.4%) and CS reductions (20.5-31.3%). SEM analysis revealed that RCP and CBP mixtures exhibited denser microstructures, which contributed to their enhanced durability and thermal stability. Generally, optimizing the replacement levels of RCP, CBP, and VPP improves the durability, pore structure, and mechanical performance of GPC. Among the materials, CBP demonstrated superior resistance in acidic environments, while RCP excelled in thermal stability, demonstrating their potential for producing sustainable and durable geopolymer concrete.
在地质聚合物混凝土（GPC）中使用再生粉末作为粘结剂是一种减少建筑垃圾和促进可持续材料生产的有前景的方法。本研究考察了再生混凝土粉末（RCP）、粘土砖粉末（CBP）和火山浮石粉末（VPP）对水养护条件下粉煤灰和矿渣GPC的力学、耐久性和热性能的影响。评估了包括抗压强度（CS）、劈裂抗拉强度和抗弯强度在内的关键力学性能，同时通过吸水率、水渗透性以及抗硫酸盐和酸侵蚀性来评估耐久性。通过将样品暴露于200℃、400℃和600℃的高温下测试热性能。结果表明，与对照混合物相比，掺入25%的RCP在28天时使CS提高了14.88%，尽管更高的替代水平（50%和75%）由于孔隙率增加导致CS降低。同样，25%替代量的CBP使CS增加了21.12%，在更高替代水平下观察到CS下降。相反，25%替代量的VPP在28天时使CS降低了8.68%，由于其高孔隙率，在更高水平下CS进一步显著降低。在5%MgSO₄溶液中的抗硫酸盐测试表明，CBP混合物的质量损失最小（0.3 - 1.2%），CS有适度降低（5.7 - 29.6%）。RCP混合物的质量损失较低（0.3 - 1.7%），CS降低（8.7 - 15.8%），而VPP混合物的质量损失最高（1.36 - 3.4%），CS降低（20.5 - 31.3%）。扫描电子显微镜（SEM）分析表明，RCP和CBP混合物表现出更致密的微观结构，这有助于提高它们的耐久性和热稳定性。总体而言，优化RCP、CBP和VPP的替代水平可改善GPC的耐久性、孔隙结构和力学性能。在这些材料中，CBP在酸性环境中表现出优异的抗性，而RCP在热稳定性方面表现出色，证明了它们在生产可持续和耐用地质聚合物混凝土方面的潜力。
