橡胶颗粒掺杂提高超高性能混凝土的抗冲磨性能及其机理

Mechanism of Enhancing Anti-Abrasion Performance of Ultrahigh-performance Concrete via Rubber Particles

针对我国西部洪水泥石流多发山区桥梁墩柱冲磨破坏问题,研制了一种具有高强、低收缩、高耐磨、抗冲击及耐久性能佳的橡胶颗粒抗冲磨超高性能混凝土(UHPC),并利用扫描电子显微镜、能谱仪和接触角仪探究了橡胶颗粒表面改性对UHPC性能的提升机理。结果表明:基准UHPC中掺入10%(体积分数)经NaOH+KH570硅烷偶联剂复合改性的粒径为1~3 mm的橡胶颗粒后,其抗冲磨强度和终裂冲击功分别提升了26%和72%;掺入15%(体积分数)饱水预湿高钛重矿渣砂和6%(质量分数)CaO型膨胀剂后,其收缩较基准UHPC降低了约50%。改性橡胶颗粒主要通过改变橡胶颗粒表面形貌、提升表面亲水性和改善橡胶颗粒–胶凝材料基体界面黏结性能提升UHPC各项性能。

A rubber particle anti-abrasive ultrahigh-performance concrete(UHPC) with a high strength, a low shrinkage, a high abrasion resistance, a high impact toughness and a high durability was developed to solve the problems of erosion damage of bridge pier in western mountainous areas with frequent floods. The mechanism of the surface modification of rubber particles to improve the properties of UHPC materials was investigated by scanning electron microscopy, energy spectroscopy and contact angle measurement. The results show that the anti-wearing strength and final crack impact energy are increased by 26% and 72%, respectively, after adding 10%(in volume fraction) NaOH + KH570 modified rubber particles with the sizes of 1–3 mm into UHPC. Also, the shrinkage is reduced by approximately 50% after adding 15%(in volume fraction) saturated pre-wet high-titanium heavy slag sand and 6%(in mass fraction) CaO type expansion agent into UHPC, compared to the reference UHPC. In addition, the modified rubber particles mainly improve the properties of UHPC material due to the improvements of the surface morphology of rubber particles, the surface hydrophilicity, and the interface properties of rubber particle-cementitious materials matrix.