聚丙烯纤维水泥稳定碎石断裂能试验研究

为了研究聚丙烯纤维对水泥稳定碎石断裂韧性的影响，通过对84个尺寸为100 mm × 100 mm × 515 mm的聚丙烯纤维水泥稳定碎石和普通水泥稳定碎石三点弯曲试件断裂试验，测得了试件的断裂能(GF)、裂缝嘴张开位移(CMOD)和裂缝尖端张开位移(CTOD)，并探讨了试验龄期、聚丙烯纤维体积掺量以及水泥掺量对聚丙烯纤维水泥稳定碎石断裂能的影响，对聚丙烯纤维水泥稳定碎石的经济性和施工和易性进行了简要分析，给出了聚丙烯纤维体积掺量合适的建议范围为0.6‰ ～ 0.8‰。试验结果表明：聚丙烯纤维的掺入可以明显提高水泥稳定碎石的断裂能、极限裂缝嘴张开位移(CMODmax)和极限裂缝尖端张开位移(CTODmax)；随着试验龄期的增长，无论聚丙烯纤维掺入与否，水泥稳定碎石断裂能均呈增大趋势，但聚丙烯纤维水泥稳定碎石断裂能增大的速率较大；随着纤维体积掺量的增加，水泥稳定碎石断裂能、CMODmax和CTODmax逐渐增大，尤其是当纤维体积掺量大于0.6‰时，GF增大的效果更为明显；随水泥掺量的增加，聚丙烯纤维水泥稳定碎石试件的极限荷载逐渐增加，但断裂能却逐渐减小。

Experimental Study on Fracture Energy of Cement Stabilized Macadam Reinforced with Polypropylene Fiber

In order to study the effect of polypropylene fiber on the fracture toughness of cement stabilized macadam, the three-point bending experiments on 84 specimens of polypropylene fiber reinforced cement stabilized macadam and common cement stabilized macadam with the size of 100mm×100mm×515mm were carried out. The fracture energy (GF), crack mouth opening displacement (CMOD), and crack tip opening displacement (CTOD) of the specimens were measured. And the impacts of curing period, polypropylene fiber volume content and cement content upon fracture energy of cement stabilized macadam were studied. The economy and workability of cement stabilized macadam reinforced with polypropylene fiber were analyzed, and the appropriate volume content range of polypropylene fiber was suggested, which was 0.6‰ to 0.8‰. The test results indicate that the addition of polypropylene fiber can increase fracture energy (GF), ultimate crack mouth opening displacement (CMODmax) and ultimate crack tip opening displacement (CTODmax) of cement stabilized macadam. With the increase of curing period, fracture energy is increasing gradually, whether polypropylene fiber is added into cement stabilized macadam or not, however, the increasing rate of polypropylene fiber cement stabilized macadam is much higher. As the increase of polypropylene fiber volume content, fracture energy (GF), CMODmax and CTODmax are increasing gradually. Especially when the fiber volume content exceeds 0.6‰, the improving effect of GF will be more evident. As the increase of cement content, the ultimate load is increasing gradually, however, fracture energy decreasing gradually.