基于“同质梯度协同”仿生结构的聚酯纤维/沥青混合料界面设计及与其路面性能强化研究

Polyester fiber reinforced asphalt concrete (AC) has been widely studied. But, the fiber dispersion and the interface strength between fiber and AC, which have the strong relationship with the AC pavement performance, are the most important science problems in the fiber reinforced AC composite. To solve these two problems, the theory of gradient transition interface base on homogeneous is put forward from the point of view of bionic composite structure in this project. Homogeneous-reinforced layer, that is the coordination of homogeneous and modulus gradient is formed on the surface of polyester fiber. The polyester matrix fiber is coated by the solution of polyester and asphalt and then homogeneous coating layer is formed on the surface of polyester fiber through dry-wet spinning process. The gradient transition interface can be controlled through the adjustment of solution composition and the technology of phase inversion spinning process. The relationship between the structure of the homogeneous layer with the fiber dispersion coefficient, interface bonding strength and pavement performance will be discussed. Quantitative analysis of dispersion coefficient, interlayer cohesion strength and modulus of the interlayer, can reveal mechanism about the homogeneous-reinforced layer improving the fiber dispersion and the adhesion between the fiber and asphalt. The theory of gradient transition interface base on homogeneous would rich composite interface design theory. Under this theory, high performance polyester fiber for AC with the characters of higher fiber dispersion coefficient and good interface bonding strength has been designed. Therefore, it has important theoretical significance to study the technology of high performance polyester fiber and mechanism of gradient transition interface base on homogeneous.

从复合材料结构仿生和新方法角度出发，根据热力学相容性和复合材料界面理论，创新地提出“同质梯度协同”界面调控机理，采用同质纺丝液（聚酯和沥青共混溶液）与聚酯纤维共挤出的皮/芯复合纺丝技术，在纤维表面形成同质修饰层，达到同时解决纤维增强沥青混凝土中纤维分散性差、纤维与沥青界面结合力弱的两个关键科学问题。通过对同质纺丝液组成和凝固浴双扩散条件进行精确控制，得到化学组成、多孔结构及聚集态结构可调的同质层修饰聚酯纤维，从而在纤维沥青混合料中建立化学组成和模量梯度协同强化的同质界面层。进一步通过同质层中化学组成和模量变化的定量分析，探寻新型皮/芯复合纺丝工艺条件—同质层组成和结构—纤维分散性能和界面粘结性—沥青混合料路用性能的关系和控制规律，建立“同质梯度协同”增强机理。研究内容丰富了复合材料界面设计理论和制备方法，为开发集高分散、与沥青粘结好于一体的沥青混合料用高性能聚酯纤维提供科学依据。

本项目从纤维增强复合材料的细观力学理论出发，综合纤维强度、纤维直径、纤维/基体界面剪切强度和纤维长度的协同增效的因素，设计并采用了熔融纺丝-溶液共挤出的同质层纤维成形路线，研究了纤维的成形工艺、高强纤维的机理、纤维表面粗糙度调控及纤维/基体界面结构等与纤维增强混凝土的性能关系。基于目前沥青混凝土增强纤维具有较细直径、难以分散且难以与基体形成有效界面的不足，申请人提出制备高强度、大直径的，高界面粘结性的结构型纤维的新增强纤维。初步阐明了细观力学理论设计思路，建立了纤维成形工艺条件—纤维大分子凝聚态结构—纤维力学性能的关系，得到了纤维大分子非晶区取向是控制纤维力学性能的关键。设计了基于溶剂诱导结晶、静电喷涂及聚吡咯修饰的方法来调控纤维表面粗糙度，积累了相应设计方法和表征的经验。探讨了纤维/基体的界面结构表征和分析，建立了双界面的界面粘结机理，对界面粘结力可有效调控。系统分析了纤维增强混凝土和纤维增强沥青混凝土的性能。获得了具有高强度、高模量、易于分散、具有高界面粘结力的沥青混凝土用增强纤维。该纤维增强的混凝土具有较好的韧性。高强度高模量聚酯纤维对于提高级配为AC-20I型的沥青混合料的高温抗车辙性能尤为明显，动稳定次数提高了252.78%。 在国际上有影响的学术刊物发表3篇SCI收录论文，1篇EI收录论文，已授权1件中国发明专利。