掺加聚丙烯纤维对路面混凝土抗冲击韧性的影响

水泥混凝土是一种典型的脆性材料,如何改善承受车辆动荷载作用下的水泥混凝土路面板结构的抗冲击性能,是改善水泥混凝土路面使用性能的关键问题之一。参照美国混凝土协会混凝土抗冲击韧性试验方法,自制落锤冲击试验装置,在混凝土中掺加不同掺量的聚丙烯纤维,在满足工作性能的条件下,成型制作掺量不同的聚丙烯纤维混凝土进行冲击试验。采用初裂次数、终裂次数等指标对聚丙烯纤维混凝土的抗冲击韧性进行评定,并与基准混凝土试验结果进行对比。结果表明:当纤维掺量由0、0.6 kg/m30、.9 kg/m3增加到1.2 kg/m3时,其抗冲击韧性最大增长4.3倍。聚丙烯纤维大大提高混凝土抗冲击韧性的特性,对于承受动荷载的路面结构是非常有利的。

Adding Polypropylene Fiber to Pavement Concrete and its Influence on Shock Resistance Toughness

Because cement concrete typically is a fragile material,raising the shock resistance toughness of cement concrete pavement structures under vehicular loads is a key challenge for improving the service performance of cement concrete pavement.The concrete test method developed by ACI to gauge shock resistance toughness was adopted.By using homemade drop hammer test equipment,adding different doses of polypropylene fiber to concrete,and molding concrete specimens,shock resistance toughness tests were carried out on specimens with required workability.The shock resistance toughness of polypropylene fiber concrete was evaluated by examining indicators such as first crack time and final crack time.The test results were compared with those of normal concrete.The results show that when the polypropylene fiber content varies from 0 g/m3,0.9g/m3 to 1.2g/m3,the maximal shock resistance toughness increases by 4.3 times.The ability of polypropylene fiber to increase greatly the shock resistance toughness of concrete is favorable for its use in pavement structures under vehicular loads.