纳米粒子-长-短纤维协同改性碱激发材料的弯曲韧性及多缝开裂机理研究-中国材料进展

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Title:: Study on Bending Toughness and Multi-Crack Cracking Mechanism of NanoParticle and Long-Short Fiber Co-Modified Alkali-Activated Material

作者:: 何小军; 高承基; 何怡媚; 李黎; 1. 陕西省宝鸡峡工程局，陕西宝鸡 721001 2. 西北农林科技大学水利与建筑工程学院，陕西杨凌 712100

Author(s):: HE Xiaojun; GAO Chengji; HE Yimei; LI Li; 1. Baoji Gorge Engineering Bureau, Baoji 721001, China 2. College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling 712100, China

Keywords:: alkali-activated material; nano CaCO3; PP fiber; bending toughness; multicrack opening; hybrid effect

摘要:: 为提高灌区渠道修复材料的抗变形、抗裂和抗渗性能，研究了纳米碳酸钙与聚丙烯（PP）纤维混杂对碱激发材料弯曲韧性、裂缝演变及微观机理的影响。结果表明：纳米碳酸钙（质量分数为1%）与长短PP纤维（0.4% 6 mm+0.8% 12 mm，体积分数）混掺可显著提升弯曲韧性（较对照组提高42.9倍），改性后碱激发材料达到荷载峰值后荷载下降速率减缓，载荷达峰值前呈现挠曲硬化行为。裂缝演变和SEM微观分析表明，纳米碳酸钙通过增强纤维基体界面化学粘结与物理摩擦，结合纤维桥联与拔出机制，显著延长裂缝扩展路径、增加了裂缝数量，提高能量耗散，从而改善弯曲韧性。混杂效应分析显示，纤维因子为38710且纳米碳酸钙掺量为1%时，正混杂效应最显著（S=0.596），验证了多尺度协同增韧机制的有效性。

Abstract:: To enhance the deformation, crack resistance and impermeability of channel repair materials in irrigation districts, the hybridization effects of nano CaCO3 and polypropylene (PP) fibers on the flexural toughness, crack evolution and micromechanism of alkaliactivated material were investigated. The results show that the hybridization of 1wt% nano CaCO3 and 0.4vol% 6 mm+0.8vol% 12 mm long-short PP fibers can significantly improve the flexural toughness (42.9 times higher than the control group). The post-peak load drop rate is slowed down, and the flexural hardening behavior is present before the peak. Crack evolution and SEM microstructure analysis indicate that nano CaCO3 significantly extends the crack propagation path, increases the number of cracks, and enhances energy dissipation by strengthening the chemical bonding and physical friction at the fiber-matrix interface, and combining the fiber bridging and pull-out mechanism, thereby improving the flexural toughness. The hybrid effect analysis shows that when the fibro factor is 38710 and the nano CaCO3 dosage is 1wt%, the positive hybrid effect is the most significant (S=0.596), verifying the effectiveness of the multi-scale synergistic toughening mechanism.