超高分子量聚乙烯纤维混凝土抗多次冲击性能研究

工程上常设计混凝土棚洞结构抵抗山区落石的冲击,以此保护山区公路。棚洞结构面临落石多次冲击作用,本文在混凝土中引入超高分子量聚乙烯纤维(UHMWPE纤维),从而达到有效增强混凝土延性,并提高混凝土抗多次冲击能力的目的。对此,本文设计了5种纤维掺量的UHMWPE纤维混凝土,系统开展了抗压强度实验、抗折强度实验、抗多次冲击性能实验研究,分析了纤维掺量对混凝土基本力学性能的影响。结果表明：UHMWPE纤维对混凝土的抗压强度没有明显增强作用,但能提高混凝土的抗折强度,显著增强混凝土的抗多次冲击性能。当纤维掺量为1.2 kg/m3时,混凝土的抗压和抗折强度最高,并且抵抗落块多次冲击的性能最优,其承受抗冲击次数比素混凝土多12次。

Study on multiple impact resistance of UHMWPE fiber concrete

Concrete rock-shed structures are widely designed in engineering to resist the impact of falling rocks in mountainous areas, aiming to protect mountainous roads. The rock-shed structures generally undergo multiple rockfall impact. To enhance the ductility and improve the resistance to multiple impacts, ultra-high molecular weight polyethylene fiber (UHMWPE) is added into concrete. Then, UHMWPE fiber concrete with five types of fiber content was designed. On the basis of the experimental studies on compressive strength, flexural strength and multiple impact resistance, the effect of fiber content on the basic mechanical properties of concrete is analyzed. The results show that the effect of UHMWPE on the compressive strength of concrete can be ignored. However, UHMWPE can improve the flexural strength of concrete and significantly enhance the multiple impact resistance of concrete. Additionally, when the content of fiber is 1.2 kg/m3, the optimal mechanical properties of fiber concrete can be obtained. Especially in the multiple impact experiments, the resistance of the fiber concrete to impact is much greater than that of plain concrete.