混杂纤维活性粉末混凝土力学性能及抗渗性能研究

发布时间：2018-01-28 10:08

  本文关键词： 混杂纤维 活性粉末混凝土 力学性能 抗渗性 SEM　出处：《内蒙古工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着科技不断进步,高强混凝土和纤维混凝土有了良好发展。活性粉末混凝土(RPC)作为高强混凝土和纤维混凝土的完美结合应运而生。RPC因其具有良好的力学性能和耐久性能,而被广泛使用在桥梁、隧道工程中。由于传统RPC中添加钢纤维具有易锈蚀、造价高等缺点,因此本论文利用玄武岩纤维替代钢纤维,并与聚丙烯纤维混掺,配制成混杂纤维活性粉末混凝土(HFRPC),研究了HFRPC的力学性能和抗渗性能。具体工作如下:1通过正交试验进行HFRPC配合比设计,选取水胶比、砂胶比、水泥/粉煤灰、减水剂、玄武岩纤维掺量为因素,根据试验精度要求设定相应的水平。并依据抗压强度和抗折强度,通过极差法得出RPC基体的最优配比。2.在基体最优配比基础上,研究混掺玄武岩纤维和聚丙烯纤维、单掺玄武岩纤维、单掺聚丙烯纤维各自的力学性能。当高弹性模量纤维掺量较少时,低弹性模量纤维掺量的增加不会引起强度的大幅增长。在抗压强度增长上,高弹性模量纤维起到主导作用。在抗折强度增长上,低弹性模量纤维单位体积数量较多,纤维均匀分布在基体内部,有效阻碍微裂缝的发展,细小的纤维还能跨越裂缝,继续承担剪力,使基体的抗折强度增长明显。3.在标准养护条件和90℃热水养护条件下分别对混杂纤维RPC试件的抗压强度进行研究,得出标准养护条件下混杂纤维RPC试件在28d强度达到最大,而90℃热水养护条件下混杂纤维RPC试件7d就能达到最终强度的95%以上。90℃热水养护可以缩短养护时间,为今后RPC的大规模普及和实现现场浇筑奠定一定的理论基础。4.选取混杂玄武岩和聚丙烯纤维、单掺玄武岩纤维、单掺聚丙烯纤维活性粉末混凝土,利用电通量法进行抗渗性能试验,研究其抗渗性能的优劣性。得出混杂纤维RPC的抗渗性能不及单掺纤维RPC的抗渗性能,其中单掺聚丙烯纤维RPC的抗渗性能最佳。5.通过电镜扫描,从微观角度研究影响RPC抗渗性能好坏的因素,并通过对RPC渗前、渗后SEM图片的对比,利用微观形态对混杂纤维RPC和单掺纤维RPC的抗渗性能优劣进行论证。
[Abstract]:With the progress of science and technology. High strength concrete and fiber reinforced concrete have developed well. Reactive Powder concrete (RPC). As the perfect combination of high strength concrete and fiber concrete, RPC has good mechanical properties and durability. It is widely used in bridge and tunnel engineering. Because the steel fiber added in traditional RPC has the disadvantages of easy corrosion and high cost, basalt fiber is used to replace steel fiber and mixed with polypropylene fiber in this paper. The mechanical properties and impermeability of hybrid fiber reactive powder concrete (HFRPC) were studied in this paper. The results are as follows: 1. The design of HFRPC mixture ratio is carried out by orthogonal test. The water / binder ratio, sand / binder ratio, cement / fly ash, water reducer, basalt fiber are selected as factors, and the corresponding level is set according to the requirement of test precision, and according to the compressive strength and flexural strength. The optimum ratio of RPC matrix was obtained by the range method. Based on the optimum ratio of matrix, the mixed basalt fiber and polypropylene fiber were studied, and the basalt fiber was only doped. When the content of high elastic modulus fiber is small, the increase of low elastic modulus fiber content will not cause the strength to increase substantially. The high elastic modulus fiber plays a leading role. In the increase of flexural strength, the low elastic modulus fiber has more unit volume, and the fiber distributes evenly in the matrix, which effectively hinders the development of micro-cracks. Fine fibers can also cross cracks and continue to bear shear forces. The flexural strength of the matrix increased obviously. 3. The compressive strength of hybrid fiber RPC specimens was studied under standard curing conditions and 90 鈩，

本文编号：1470464