氧化石墨烯接枝碳纤维增强体改性混凝土的力学性能

Mechanical properties of concrete modified by graphene oxide grafted carbon fiber reinforcement

为增强碳纤维/混凝土基体界面性能,探究氧化石墨烯接枝碳纤维增强体(CF-GO)对混凝土力学性能的影响规律,以氨基硅烷为桥接物,将碳纤维和氧化石墨烯通过化学键紧密结合,制备了CF-GO。利用扫描电子显微镜和红外光谱仪对CF-GO的微观形貌和官能团进行表征,确定了氧化石墨烯成功接枝到碳纤维表面,并测试了CF-GO的界面剪切强度。制备了CF-GO改性混凝土(CF-GO/C),测试了其力学性能,并与碳纤维改性混凝土进行了对比。此外,分析了CF-GO对混凝土力学性能的改性机制。结果表明:CF-GO的界面剪切强度较碳纤维增大了25.37%。随着CF-GO掺量的增大,CF-GO/C的抗折和抗压强度均先增大后减小。CF-GO的最佳掺量为0.3vol%,碳纤维的最佳掺量为0.2vol%。在最佳掺量下,CF-GO/C的抗折和抗压强度分别增大了33.21%、24.63%。CF-GO表面的氧化石墨烯通过提高CF-GO与混凝土基体的机械咬合力和促进水化产物在CF-GO表面的生成,从物理和化学两方面增强CF-GO/混凝土基体界面。

In order to enhance the interface properties of carbon fiber/concrete matrix,and investigate the effects of graphene oxide grafted carbon fiber reinforcement(CF-GO)on the mechanical properties of concrete,by using amino silane as bridge material,carbon fiber and graphene oxide were tightly bonded through chemical bonds and CF-GO was prepared.The microstructure and functional groups of CF-GO were characterized by scanning electron microscopy and infrared spectroscopy.Graphene oxide was successfully grafted to the surface of carbon fiber and the interfacial shear strength of CF-GO was tested.CF-GO modified concrete(CF-GO/C)was prepared,its mechanical properties were tested and compared with those of carbon fiber modified concrete.In addition,the modification mechanism of CF-GO on the mechanical properties of concrete was analyzed.The results show that the interfacial shear strength of CF-GO increases by 25.37%compared with that of carbon fiber.With the increase of CF-GO content,the flexural and compressive strength of CF-GO/C first increase and then decrease.The optimal content of CF-GO is 0.3vol%,and the optimal content of carbon fiber is 0.2vol%.The flexural and compressive strength of CF-GO/C increase by 33.21%and 24.63%respectively with the optimal CF-GO content.Graphene oxide on the surface of CF-GO enhances the interface of CF-GO/concrete matrix physically and chemically by improving the mechanical bite between CF-GO and concrete matrix and promoting the formation of hydration products on the surface of CF-GO.