Valizadeh Kiamahalleh Mohammad, Gholampour Aliakbar, Rezaei Shahmirzadi Mohsen, Ngo Tuan D, Ozbakkaloglu Togay
College of Science and Engineering, Flinders University, Tonsley, Adelaide, SA 5042, Australia.
Department of Infrastructure Engineering, University of Melbourne, Parkville, Melbourne, VIC 3052, Australia.
Materials (Basel). 2024 May 28;17(11):2608. doi: 10.3390/ma17112608.
This study evaluates the potential use of discarded plasterboard paper as fibers from buildings to reinforce concrete. Various concentrations of wastepaper fibers (0.5%, 1%, 1.5%, 2%, and 2.5% by weight of the binder) were investigated in this research. To mitigate the water absorption effect of the paper fibers, metakaolin was employed as a partial cement replacement. The results demonstrate that the inclusion of the wastepaper fiber enhances the mechanical and durability performance of the concrete. The optimal fiber proportion was identified as 1%, leading to a 29% increase in the compressive strength, a 38% increase in the splitting tensile strength, a 12% decrease in the water absorption, and a 23% decrease in the drying shrinkage with respect to the concrete containing 20% metakaolin. However, exceeding this optimal fiber content results in decreased mechanical and durability properties due to the fiber agglomeration and non-uniform fiber distribution within the concrete matrix. Based on the microstructural analysis, the improved performance of the concrete is ascribed to decreased porosity, more refined pore structure, and reduced propagation of microcracks within the concrete matrix in the presence of wastepaper fiber. According to the results, concrete containing 20% metakaolin and 1% wastepaper fiber exhibits durability and mechanical properties comparable to those of the traditional concrete. This finding highlights the significant promise of reducing dependency on conventional cement and incorporating suitable recycled materials, such as discarded plasterboard, and secondary by-products like metakaolin. Such a strategy encourages the preservation of resources, reduction in carbon dioxide emissions, and a decrease in the ecological footprint resulting from concrete production.
本研究评估了废弃石膏板纸作为建筑纤维用于增强混凝土的潜在用途。本研究调查了不同浓度的废纸纤维（按粘结剂重量计为0.5%、1%、1.5%、2%和2.5%）。为减轻纸纤维的吸水效应，采用偏高岭土作为部分水泥替代品。结果表明，掺入废纸纤维可提高混凝土的力学性能和耐久性。确定最佳纤维比例为1%，相对于含20%偏高岭土的混凝土，抗压强度提高了29%，劈裂抗拉强度提高了38%，吸水率降低了12%，干燥收缩率降低了23%。然而，超过这一最佳纤维含量会导致力学性能和耐久性下降，这是由于混凝土基体中纤维团聚和纤维分布不均匀所致。基于微观结构分析，混凝土性能的改善归因于孔隙率降低、孔隙结构更细化以及在废纸纤维存在下混凝土基体中微裂纹扩展的减少。根据结果，含20%偏高岭土和1%废纸纤维的混凝土表现出与传统混凝土相当的耐久性和力学性能。这一发现凸显了减少对传统水泥的依赖并纳入合适的再生材料（如废弃石膏板）以及偏高岭土等二次副产品的巨大前景。这样的策略有助于资源保护、减少二氧化碳排放以及降低混凝土生产产生的生态足迹。
