纤维再生微粉水泥基复合材料断裂性能分析

基于三点弯曲试验，研究水胶比、再生微粉取代率、纤维种类对纤维再生微粉水泥基复合材料(FRPCC)断裂性能的影响.根据双K断裂参数分析各因素对FRPCC的增韧效果，并结合微观形貌分析各因素对FRPCC韧性的改善机制.结果表明：水胶比增大使纤维再生微粉水泥基复合材料失稳韧度先升高后降低；断裂韧度随着再生微粉取代率提升呈现先增后减的趋势；单掺玄武岩纤维(BF)会使FRPCC脆性增加，聚乙烯醇纤维(PVA纤维)占比增大能够明显提升FRPCC的断裂韧度；当水胶比为0.28、再生微粉取代率为45%、复掺0.2%玄武岩纤维和1.7%PVA纤维时，微观结构紧密，断裂韧度最优.

Fracture properties of fiber recycled powder cementitious composites

Based on the three-point bending test, the influence of water-binder ratio, recycled powder content, fiber type on the fracture performance of the fiber recycled powder cementitious composites (FRPCC) was studied. According to the double K fracture parameters, the toughening effect of each factor on the fiber recycled powder cementitious composites was analyzed, and the improving mechanism of each factor on the cementitious composites toughness was illustrated combined with the microscopic morphology. The results show that: with the increase of the water-binder ratio, the instability toughness of the fiber recycled powder cementitious composites increases first and then decreases. The fracture toughness shows a trend of increasing first and then decreasing with the improvement of recycled powder content. The single basalt fiber will increase the brittleness of the cementitious composites, and the increase in proportion of PVA fibers can significantly improve the fracture toughness of the cementitious composites. When the water- binder ratio is 0.28, the replacement rate of recycled powder is 45%, and mixed with 0.2% basalt fiber and 1.7% PVA fiber, the fracture toughness is optimal, and the microstructure is compact.