关键词: 聚丙烯塑料颗粒, 混凝土, 切口梁, 损伤裂缝, 弯曲断裂特性

Abstract: To investigate the effect of plastic particles on the bending characteristics and fracture damage behavior of concrete， three-point bending fatigue fracture tests were conducted on the modified recycled polypropylene （PP） plastic particle concretes used for the concrete notched beams. The experimental results indicated that the load crack opening displacement curve of plastic particle concretes presented a single peak shape. With the addition of PP plastic particles， there is no change in the crack opening displacement. However， the downward section of the curve descended significantly， and the fatigue failure ductility of concrete was enhanced. The appropriate addition of PP plastic particles can effectively alleviate the fatigue damage of concrete； The shape of plastic particles has a significant impact on the fatigue performance of concrete. Short columnar PP particles play a bridging role in the tension， improving the toughness and deformation resistance of concrete. There is an increase in the fracture energy and energy absorption capacity of concrete after addition of PP plastic particles. This results in a significant extension in the fatigue life.

Key words: polypropylene plastic particles, concrete, cutting beam bending, damage crack, bending fracture characteristics