高延性水泥基复合材料的断裂性能分析

实验测试了不同纤维掺量下的高延性水泥基复合材料的载荷—挠度曲线,并对试件加载过程中的声发射信号进行收集,分析了试件断裂后的裂纹分布及纤维在基材中的破坏形式。结果发现:(1)当纤维体积掺量2.0%时,水泥基材的极限挠度、极限抗弯承载力分别可达20.16mm、19.47MPa;(2)高延性水泥基复合材料破坏主要来自于微裂纹的萌生、扩展以及损伤积累过程,试件从加载至完全破坏的时间为素水泥基复合材料破坏持续时间的2~5倍;(3)高延性水泥基复合材料中纤维的破坏以纤维被拔出和纤维被拉断两种模式,试件表现出明显的多缝开裂特征。

Analysis of the fracture properties of high ductility cementitious composites

Tested the load-deflection curves of high ductility cement-based composite materials with different content of fiber, and collected the acoustic emission signal in loading process, analysed the crack distribution and fiber failure modes in the broken samples. The results show as follows：（1） when the fiber volume rate is over 20%, the ultimate deflection and flexural capacity of the ce- ment-based composite can reach 20.16 mm and 19.47 MPa;（2） the failure of high ductility cement-based composite was mainly caused by the accumulation process of crack＇s emerging, expanding and damaging, as the time trom loading to complete destroy was 2~5 times of that of pure cement-based composite material; （3） the destroy of fiber in high ductility cement-based composite has two kinds of mode--one is ＂be pulled＂ out and the other is ＂be broken＂, the sample shows multiple cracking obviously.