Zhang Ge, Shi Huawei, Li Kunpeng, Li Jialing, Jiang Enhui, Yuan Chengfang, Chen Chen
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.
Nanomaterials (Basel). 2025 Jul 6;15(13):1051. doi: 10.3390/nano15131051.
To address the demands for resource utilization of Yellow River sediment and the durability requirements of engineering materials in cold regions, this study systematically investigates the mechanisms affecting the frost resistance of slag-Yellow River sediment geopolymers through the incorporation of mineral admixtures (silica fume and metakaolin) and fibers (steel fiber and PVA fiber). Through 400 freeze-thaw cycles combined with microscopic characterization techniques such as SEM, XRD, and MIP, the results indicate that the group with 20% silica fume content (SF20) exhibited optimal frost resistance, showing a 19.9% increase in compressive strength after 400 freeze-thaw cycles. The high pozzolanic reactivity of SiO in SF20 promoted continuous secondary gel formation, producing low C/S ratio C-(A)-S-H gels and increasing the gel pore content from 24% to 27%, thereby refining the pore structure. Due to their high elastic deformation capacity (6.5% elongation rate), PVA fibers effectively mitigate frost heave stress. At the same dosage, the compressive strength loss rate (6.18%) and splitting tensile strength loss rate (21.79%) of the PVA fiber-reinforced group were significantly lower than those of the steel fiber-reinforced group (9.03% and 27.81%, respectively). During the freeze-thaw process, the matrix pore structure exhibited a typical two-stage evolution characteristic of "refinement followed by coarsening": In the initial stage (0-100 cycles), secondary hydration products from mineral admixtures filled pores, reducing the proportion of macropores by 5-7% and enhancing matrix densification; In the later stage (100-400 cycles), due to frost heave pressure and differences in thermal expansion coefficients between matrix phases (e.g., C-(A)-S-H gel and fibers), interfacial microcracks propagated, causing the proportion of macropores to increase back to 35-37%. This study reveals the synergistic interaction between mineral admixtures and fibers in enhancing freeze-thaw performance. It provides theoretical support for the high-value application of Yellow River sediment in F400-grade geopolymer composites. The findings have significant implications for infrastructure in cold regions, including subgrade materials, hydraulic structures, and related engineering applications.
为满足黄河泥沙资源利用需求以及寒冷地区工程材料耐久性要求，本研究通过掺入矿物掺合料（硅灰和偏高岭土）和纤维（钢纤维和聚乙烯醇纤维），系统研究了影响矿渣 - 黄河泥沙地质聚合物抗冻性的机制。通过400次冻融循环并结合扫描电子显微镜（SEM）、X射线衍射仪（XRD）和压汞法（MIP）等微观表征技术，结果表明，硅灰含量为20%的组（SF20）表现出最佳抗冻性，在400次冻融循环后抗压强度提高了19.9%。SF20中SiO₂的高火山灰反应活性促进了连续二次凝胶的形成，生成低钙硅比的C-(A)-S-H凝胶，并使凝胶孔隙率从24%增加到27%，从而细化了孔隙结构。由于聚乙烯醇纤维具有高弹性变形能力（伸长率6.5%），能有效减轻冻胀应力。在相同掺量下，聚乙烯醇纤维增强组的抗压强度损失率（6.18%）和劈裂抗拉强度损失率（21.79%）显著低于钢纤维增强组（分别为9.03%和27.81%）。在冻融过程中，基体孔隙结构呈现出“先细化后粗化”的典型两阶段演化特征：在初始阶段（0 - 100次循环），矿物掺合料的二次水化产物填充孔隙，使大孔隙比例降低5 - 7%，增强了基体致密化；在后期阶段（100 - 400次循环），由于冻胀压力和基体相（如C-(A)-S-H凝胶和纤维）之间热膨胀系数的差异，界面微裂纹扩展，导致大孔隙比例回升至35 - 37%。本研究揭示了矿物掺合料与纤维在增强冻融性能方面的协同作用。为黄河泥沙在F400级地质聚合物复合材料中的高值应用提供了理论支持。研究结果对寒冷地区的基础设施，包括路基材料、水工结构及相关工程应用具有重要意义。
