基于氧化石墨/PVA纤维设计的高延性水泥基复合材料应变硬化研究

The unmatched property of interface between fiber and cement matrix lead to the fracture of fiber in the process of pulling out for the fiber reinforced cement-based composite materials. And for this reason, the strain hardening cannot form, which radically result in a lack of ductility of the fiber reinforced cement-based composites. The design principle and method of graphite oxide/PVA fiber which had a good consistency and low adhesive friction with cement matrix were proposed to control the interface property. And on this basis, the influence mechanism of surface microstructure of graphite oxide/PVA fiber to the interface structure was explored, the influence mechanism of interfacial shear slip of graphite oxide to the bridge effect of fiber during pulling out was put forward, the design and preparation technology based on interface optimization of high ductility cement-based composites were achieved through interface structure optimization and control of interaction between graphite oxide/PVA fiber and cement matrix. This research would be important and meaningful to the perfection of design and preparation of high performance cement-based composites, and the improvement of its ductility and structure safety which would increase the service life of cement-based composites.......

由于纤维-基体界面性能与基材特性不匹配，导致纤维增强水泥基复合材料在拉伸过程中纤维断裂，不能形成应变硬化，材料延性不足。为提高纤维增强水泥基复合材料延性，提出纤维-基体界面结构优化理念，并提出与水泥石相容性好且粘结摩擦力小的氧化石墨/PVA纤维的设计原理与方法；掌握氧化石墨/PVA纤维熔融包覆纺丝制备关键技术；探明氧化石墨/PVA纤维对界面结构影响机理；揭示氧化石墨层间滑移对纤维拔出桥接效应影响规律；提出基于界面结构优化设计的高延性水泥基复合材料设计理论及制备方法。研究对于丰富和完善高性能水泥基复合材料设计制备理论，提高水泥基复合材料的延性和结构安全性，延长水泥基复合材料生命周期具有重要意义。

针对水泥基复合材料延性不足，纤维表面浸润的油剂对基体水泥水化产生不良影响等问题，项目提出采用无机石墨类材料包覆PVA纤维，调控纤维与基体界面性能，提高高延性水泥基复合材料应变硬化性能。项目深入系统研究了高延性水泥基复合材料原料组成与制备工艺对其应变硬化特性的影响规律，研究了制备工艺条件对石墨与氧化石墨包覆PVA纤维包覆性能的影响，探明了纤维表面包覆石墨和氧化石墨对纤维/基体界面结构与性能的影响规律。通过纤维表面改性与基体性能调控，使高延性水泥基复合材料延性由3%提高至5.5%。研究对于丰富和完善高性能水泥基复合材料设计制备理论，提高水泥基复合材料的延性和结构安全性，延长水泥基复合材料生命周期具有重要意义。