论文部分内容阅读
通过不同钢纤维掺量RPC200的三点弯曲和断裂实验,研究了RPC的韧性机制与韧性特征,分析了梁不同变形方式下钢纤维对提高RPC抗裂能力、耗能能力和韧性所起的作用.根据RPC200初裂变形、峰值变形及其增幅随钢纤维含量增加而变化的事实,以及梁变形方式对初裂和峰值行为的影响,提出用素RPC200峰值变形作为初始参考变形来计算RPC200韧性.针对RPC200的P-δ和P-CMOD响应分别定义了韧性指标T2(n-1)(n)和FT2(n-1)(n),该指标以理想弹塑性材料的韧性水平2(n-1)为基准,表述了不同变形方式下相比理想弹塑性材料RPC的韧性水平.分析表明:韧性指标T2(n-1)(n)可以反映整体变形时钢纤维对提高RPC韧性的作用,但指标T2(n-1)(n)放大了钢纤维对提高RPC峰值后韧性的作用,未能反映出钢纤维对提高初裂至峰值阶段RPC韧性的贡献.韧性指标FT2(n-1)(n)反映了变形集中在断裂面上时钢纤维对阻滞RPC基体裂纹扩展而吸收能量的作用,较好地反映出钢纤维对提高RPC初裂至峰值阶段以及峰后阶段韧性的贡献.本文方法直观地反映了RPC的韧性特征与韧性水平,为建立统一的RPC韧性指标体系和方便工程应用提供了参考.
The toughness and toughness characteristics of RPC were studied by three-point bending and fracture tests of RPC200 with different steel fiber contents. The effect of steel fiber under different deformation modes on cracking resistance, energy dissipation and toughness of RPC was analyzed According to the fact that RPC200 primary crack deformation, peak deformation and its increase with the increase of steel fiber content, as well as the influence of beam deformation on primary cracking and peak behavior, RPC200 toughness was calculated by using peak deformation of RPC200 as initial reference deformation. The ductility indices T2 (n-1) (n) and FT2 (n-1) (n) are defined for the P-δ and P-CMOD responses of RPC200, 1) as the reference, the toughness of RPC is compared with that of ideal elastic-plastic material under different deformation modes.The results show that the toughness index T2 (n-1) (n) can reflect the effect of steel fiber on RPC toughness during the whole deformation, However, the index T2 (n-1) (n) magnifies the effect of steel fiber on the post-RPC peak toughness and does not reflect the contribution of steel fiber to improve the RPC toughness of the initial cracked to the peak stage toughness index FT2 (n-1) (n) shows that the steel fiber pairs block the RPC matrix when the deformation is concentrated on the fracture surface The effect of fiber extension and energy absorption can well reflect the contribution of steel fiber to improving the peak-to-peak and post-peak toughness of RPC.The method of this paper directly reflects the toughness characteristics and toughness of RPC and establishes a unified RPC Toughness index system and facilitate the application of engineering provides a reference.