Mechanically recycled glass fiber reinforced polymer (GFRP) has increasingly been reused in concrete, while its physicochemical properties need to be tailored for achieving effective reinforcement. To this end, fibers were carefully separated from three sources of GFRP recyclates via a process consisting of vibratory screening, followed by hydraulic selection and aerodynamic separation. The influence of the elaborate fiber selection on the physical-mechanical properties and microstructures of mortars were investigated with mechanical testing, X-ray micro-CT and Scanning Electron Microscopy (SEM) analysis. Results indicated that the fine selected GFRP fibers apparently enhanced the mechanical properties and reduced the shrinkage of mortars, with the highest compressive and flexural strength of 47.3 MPa and 9.83 MPa, respectively. The reinforcement mechanisms were mainly attributed to (i) the porosity of mortar ameliorated by the modified fiber uniformity; (ii) the increased fiber-cement adhesion thanks to the rough and hydrophilic surface of recycled GFRP fibers; and (iii) the protective resin coating of recycled GFRP fibers against alkali corrosion.

机械回收的玻璃纤维增​​强聚合物（GFRP）已越来越多地在混凝土中重复使用，而其理化特性需要进行调整以实现有效的增强。为此，通过振动筛选，水力选择和空气动力学分离等方法，将纤维与三种来源的GFRP回收物仔细分离。通过机械测试，X射线显微CT和扫描电子显微镜（SEM）分析，研究了精心选择的纤维对砂浆的物理力学性能和微观结构的影响。结果表明，精选的GFRP纤维明显增强了砂浆的机械性能并减少了砂浆的收缩，其最高抗压强度和抗弯强度分别为47.3 MPa和9.83 MPa。增强机理主要归因于（i）改性纤维均匀性改善了砂浆的孔隙度；（ii）由于再生的GFRP纤维粗糙而亲水的表面，增加了纤维与水泥的粘合力；（iii）再生的GFRP纤维的保护性树脂涂层，防止碱腐蚀。