Zhang Ge, Jiang Enhui, Li Kunpeng, Shi Huawei, Chen Chen, Yuan Chengfang
Yellow River Institute of Hydraulic Research, Yellow River Water Conservancy Commission, Zhengzhou 450003, China.
Key Laboratory of Lower Yellow River Channel and Estuary Regulation, Ministry of Water Resources, Zhengzhou 450003, China.
Polymers (Basel). 2025 Apr 16;17(8):1072. doi: 10.3390/polym17081072.
Steel fibers (STs), polyvinyl alcohol fibers (PVAs), and polyethylene fibers (PEs) were selected to systematically investigate the effects of different fiber types and dosages on the workability (slump and spread) and mechanical properties (compressive strength and splitting tensile strength) of slag-Yellow River sand geopolymer eco-cementitious materials. By combining microstructural testing techniques such as thermogravimetric-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), the influence mechanisms of fibers on the characteristic products and microstructure of the matrix were thoroughly revealed, and the role of fibers in the strength development of Yellow River sediment-based geopolymers was elucidated. The results show that as the fiber content increases, the workability of the mixture significantly decreases. The appropriate incorporation of steel fibers and PVAs can significantly enhance the strength and toughness of the matrix. When the fiber dosage is 1%, the 28-day compressive strength of specimens with steel fibers and PVAs increased by 25.93% and 21.96%, respectively, compared to the control group, while the splitting tensile strength increased by 50.00% and 60.34%, respectively. However, the mechanisms of action differ significantly; steel fibers primarily enhance the compressive performance of the matrix through their high stiffness and strength, whereas PVAs inhibit crack propagation through their flexibility and excellent bonding properties. In contrast, the strength improvement of PEs is mainly reflected in toughening. When the fiber dosage is 1.5%, the 28-day splitting tensile strength of PE specimens increased by 72.61%, and the tensile-to-compressive ratio increased by 92.32% compared to the control group. Microstructural analysis indicates that the incorporation of different types of fibers does not alter the types of characteristic products in alkali-activated cementitious materials, but excessive fiber content affects the generation of gel-like products and the distribution of free water, thereby altering the thermal decomposition behavior of characteristic gel products. Additionally, the matrix incorporating PEs forms a honeycomb-like amorphous gel, resulting in weak interfacial bonding between the fibers and the matrix. This is one of the main reasons for the limited reinforcing effect of PEs at the microscopic scale and a key factor for their inferior long-term performance compared to steel fibers and PVAs. This study provides theoretical foundations and practical guidance for optimizing the performance of fiber-reinforced geopolymer materials.
选取钢纤维（STs）、聚乙烯醇纤维（PVAs）和聚乙烯纤维（PEs），系统研究不同纤维类型和掺量对矿渣-黄河砂地质聚合物生态胶凝材料工作性能（坍落度和扩展度）及力学性能（抗压强度和劈裂抗拉强度）的影响。通过结合热重-差热分析（TG-DTA）、X射线衍射（XRD）和扫描电子显微镜-能谱分析（SEM-EDS）等微观结构测试技术，深入揭示了纤维对基体特征产物和微观结构的影响机制，阐明了纤维在黄河泥沙基地质聚合物强度发展中的作用。结果表明，随着纤维含量的增加，混合物的工作性能显著降低。适量掺入钢纤维和PVAs可显著提高基体的强度和韧性。当纤维掺量为1%时，钢纤维和PVAs试件的28天抗压强度分别比对照组提高了25.93%和21.96%，而劈裂抗拉强度分别提高了50.00%和60.34%。然而，其作用机制差异显著；钢纤维主要通过其高刚度和强度提高基体的抗压性能，而PVAs则通过其柔韧性和优异的粘结性能抑制裂纹扩展。相比之下，PEs的强度提高主要体现在增韧方面。当纤维掺量为1.5%时，PE试件的28天劈裂抗拉强度比对照组提高了72.61%，拉压比提高了92.32%。微观结构分析表明，掺入不同类型的纤维不会改变碱激活胶凝材料中特征产物的类型，但纤维含量过高会影响凝胶状产物的生成和自由水的分布，从而改变特征凝胶产物的热分解行为。此外，掺入PEs的基体形成蜂窝状非晶凝胶，导致纤维与基体之间的界面粘结较弱。这是PEs在微观尺度上增强效果有限的主要原因之一，也是其长期性能不如钢纤维和PVAs的关键因素。本研究为优化纤维增强地质聚合物材料的性能提供了理论基础和实践指导。
