硅烷水解调控对钢纤维-水泥界面黏结及增韧效应的影响

李明华¹，王娜²，吴继囡¹，冯兆龙¹，谭旭翔^1,3，王彦敏^1,3，齐美丽^1,3*

1.山东交通学院交通土建工程学院，山东 济南  250357；2.济南黄河路桥建设集团有限公司，山东 济南  250000；

3.山东交通学院山东省智能建造装备关键技术与系统重点实验室，山东 济南  250357

摘要：为改善钢纤维–水泥基界面的黏结性能和复合材料的韧性，在钢纤维与水泥基体间构建化学–机械协同界面。以KH–550为偶联剂，设计醇水比、pH值和偶联剂在混合料中的质量分数三因素三水平正交试验（共9组），系统探讨硅烷水解–缩合历程对纤维表面形貌及纤维–水泥界面性能及弯曲韧性的影响；通过场发射扫描电镜观察钢纤维表面结构，对试件进行抗压、抗折及弯曲韧性试验。结果表明：在中性及弱碱性条件下，经优化水解的硅烷可在纤维表面构筑粗糙层，显著增大表面粗糙度；养护14 d时改性纤维的抗折强度比未改性组增大28.7%，等效初始弯曲韧度比与残余弯曲韧度比分别增大约33.0%与35.7%；超景深三维显微观测表明，改性纤维周围水泥界面致密、无可见缺陷，且纤维周围C—S—H凝胶质量分数显著增大，证实了硅烷诱导的水化强化-界面密实化协同增韧机制。

关键词：钢纤维；硅烷偶联剂改性；界面；增韧

The effect of silane hydrolysis regulation on the bonding and toughening of steel fiber-cement interface

LI Minghua¹, WANG Na², WU Jinan¹, FENG Zhaolong¹, TAN Xuxiang^1,3,WANG Yanmin^1,3, QI Meili^1,3*

1. School of Civil Engineering, Shandong Jiaotong University, Jinan 250357, China;

2. Jinan Huanghe Road and Bridge Construction Group Co., Ltd., Jinan 250000, China;

3. Shandong Provincial Key Laboratory of Key Technologies and Systems for Intelligent Construction Equipment,

Shandong Jiaotong University, Jinan 250357, China

Abstract: To improve the bonding performance of the steel fiber-cement matrix interface and the toughness of the composite material, a chemical-mechanical synergistic interface is constructed between the steel fiber and the cement matrix. Using KH-550 as the coupling agent, a three-factor and three-level orthogonal test (a total of 9 groups) is designed with the alcohol-water ratio, pH value and coupling agent mass fraction as factors to systematically investigate the influence of the silane hydrolysis-condensation process on the surface morphology of the fiber, the performance of the fiber-cement interface and the flexural toughness. The surface structure of the steel fiber is observed by field emission scanning electron microscopy, and the specimens are subjected to compressive, flexural and flexural toughness tests. The results show that under neutral and weakly alkaline conditions, the optimized hydrolyzed silane can form a rough layer on the fiber surface, significantly increasing the surface roughness; At 14 days, the flexural strength of the modified fiber is 28.7% higher than that of the unmodified group, and the equivalent initial flexural toughness ratio and residual flexural toughness ratio increase by approximately 33.0% and 35.7%, respectively; Ultra-depth-of-field three-dimensional microscopic observation shows that the cement interface around the modified fiber is dense and free of visible defects, and the mass fraction of C–S–H gel around the fiber significantly increases, confirming the synergistic toughening mechanism of silane-induced hydration strengthening and interface densification.

Keywords: steel fiber; silane coupling agent modification; interfacial zone; toughening