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为研究掺入短切纤维的纤维编织网增强混凝土(简称TRC)薄板的受弯承载能力及裂缝开展,对其进行了四点弯曲试验,对比分析了TRC薄板纤维编织网浸胶的处理、水灰比、短切纤维种类和掺量,以及钢纤维长径比等因素的影响。在此基础上,采用环境扫描电镜及能谱仪对短切纤维与纤维编织网在混凝土基体中的微观形貌进行观察。研究结果表明:对浸胶处理的TRC薄板、掺入碳纤维和聚丙烯纤维的试件的承载力提高幅度分别为16%和32%;掺入钢纤维并未提高薄板的承载力。未浸胶处理的TRC薄板,掺入短切碳纤维、钢纤维、聚丙烯纤维和掺入短切钢纤维与聚丙烯纤维混合纤维的试件,其承载力的提高幅度分别为132%、47%、27%和86%,且钢纤维和碳纤维掺量越多,薄板开裂后刚度越大,但聚丙烯纤维的掺量不宜偏高。短切碳纤维与钢纤维均能有效减缓裂缝的扩展,但在微观裂缝处两种纤维的交联作用机理不同;掺入短切纤维可使薄板裂缝数量增多。
In order to study the flexural load-bearing capacity and crack initiation of fiber-reinforced concrete braided wire mesh reinforced concrete (TRC) spun into short fibers, a four-point bending test was carried out. The treatment of TRC veneer fiber braided net dipped, water Ash ratio, the type and content of chopped fiber, and the aspect ratio of steel fiber and other factors. On this basis, the microscopic morphology of short-cut fiber and fiber braided net in concrete matrix was observed by using environmental scanning electron microscope and energy dispersive spectrometer. The results show that the load-carrying capacity of the dipped TRC sheet and the carbon fiber and polypropylene fiber-reinforced specimens are respectively 16% and 32%, respectively. The incorporation of steel fiber does not increase the bearing capacity of the sheet. The tensile strength of un-dipped TRC sheet, chopped carbon fiber, steel fiber, polypropylene fiber and mixed fiber with chopped steel fiber and polypropylene fiber increased by 132%, 47% , 27% and 86% respectively. The more the steel fiber and carbon fiber content, the greater the stiffness after cracking, but the content of polypropylene fiber should not be too high. Both chopped carbon fiber and steel fiber can effectively reduce the crack propagation, but the mechanism of cross-linking of the two fibers is different at the micro-cracks. The incorporation of chopped fibers can increase the number of cracks in the steel plate.