摘要
研究了钢纤维掺量和强度等级对超高性能纤维增强水泥基复合材料(UHPFRCC) 宏观性能的影响及UHPFRCC 在荷载与环境因素耦合作用下的耐久性能. 制备了 3 组不同强度等级(100,150,200 MPa) 和不同纤维掺量 (0%,1%,2%,3%) 的高与超高性能水泥基复合材料,并且测试了其各项力学性能和短期耐久性能. 利用设计的预加载装置,在 UHPFRCC150 试件上施加了应力比为 0. 5 的四点弯曲荷载. 结果表明,随着强度等级的增加,在掺加适量钢纤维掺量的情况下,高与超高性能水泥基复合材料的强度和韧性均明显提高,同时其干燥收缩值降低. 对于加载的试件,钢纤维降低了拉应力对 UHPFRCC 抗氯离子渗透性能的不利影响,并且提高了材料的抗冻融性能.
This study aims to reveal the mechanism that how the content of steel fibers and strength grades affect the macro performance of the ultra-high performance fiber reinforced cementitious composite (UHPFRCC) and to study the UHPFRCC durability under the combined effect of loads and environments. Three types of high and ultra-high performance fiber reinforced cement composites with different strength grades (100, 150, 200 MPa) and different steel fiber volume fractions (0%, 1%, 2%, 3%) are prepared. The main properties of mechanical performance and short-term durability are studied. A preloading frame is designed to apply a four- point load external flexural stress with a stress selection ratio of 0.5 for UHPFRCC150 specimens. The results show that the growth in strength grade with a proper content of steel fiber greatly increases the strength and toughness of the HPFRCC and the UHPFRCC while decreasing the dry-shrinkage ratio. For the loaded specimens, the existence of steel fiber can reduce the negative influence of tensile stress on the Cl- penetration resistance of the UHPFRCC in addition to improving its ability to resist the freeze-thaw damage.
基金
The Technical Research Program from NV Bekaert SA of Belgium (No. 8612000003)
the National Natural Science Foundation of China (No. 50908047)
关键词
超高性能纤维增强水泥基复合材料
荷载与环境耦合作用
力学性能
耐久性
ultra-high performance fiber reinforced cementitious composite
couple effect of load and environment
mechanical properties
durability