混杂纤维增强高性能混凝土(HFHPC)高温力学性能及微观分析

High temperature mechanical properties and microscopic analysis of hybrid fiber reinforced high performance concrete(HFHPC)

研究了混杂纤维增强高性能混凝土(HFHPC)与普通混凝土(NC)的高温力学性能,测试了两种混凝土试件在承受常温及200、400、600、800℃高温后的抗压、劈裂抗拉和抗折强度及试件烧失量,采用SEM观察高温后的混凝土微观组织变化。结果表明:混杂纤维可显著提高混凝土的常温及高温力学性能。在所试验温度下的HFHPC混凝土的抗压、劈裂抗拉和抗折强度均高于NC混凝土,且在400℃时,达到最大值。400℃以后,HFHPC混凝土的力学性能随着温度升高而降低,但仍显著高于同温度时NC混凝土的强度值,特别是劈裂抗拉强度的提高尤为明显,至800℃时HFHPC混凝土的抗压、劈裂抗拉、抗折强度分别为同温度时NC混凝土的1.24、4.5和1.61倍。

Investigated the high temperature mechanical properties of the hybrid fiber reinforced high performance concrete（HFHPC） and normal concrete（NC）.After being subjected to different elevated heating temperatures,two kinds of concretes have been tested for the compressive strength,splitting tensile strength,flexural strength and the ignition loss of test specimen at room temperature and 200,400,600, 800 ℃.Microstructure changes of concrete were also observed by using Scanning Electron Microscopy（SEM） after high temperature.The results show that the hybrid fiber can significantly increase mechanical properties of the concrete at room temperature and high temperature.The compressive strength,splitting tensile strength and flexural strength of HFHPC are better than the properties of NC In the test temperatures,and reach maximum at 400 ℃.From 400 ℃ on,the mechanical properties of HFHPC will decrease with the temperature increasing,but still be significantly higher than the strength of NC at same temperature,with the performance of resistant to high temperatures of HFHPC was better than that of NC.At 800 ℃,the compressive strength,splitting tensile strength,flexural strength of HFHPC are 1.24,4.5 and 1.61 times those of NC respectively.