钢纤维混凝土的优化研究

发布时间：2019-05-26 23:54

【摘要】：人类第一次使用钢纤维混凝土作为普通钢筋混凝土的替代品可以追溯到上世纪六十年代。自那以后,研究人员和工程师对对这种新型复合材料进行了大量深入的研究。在过去的几十年里,各个行业对钢纤维混凝土构筑物的需求呈上升趋势,尤其是在地下建筑结构领域,钢纤维混凝土更受到工程人员的青睐。在隧道及立井衬砌管片中使用钢纤维混凝土具有很多优点,诸如：提高管片力学性能,增强耐久性、耐火性以及抗疲劳能力等。另外,通过在衬砌管片中加入适量的钢纤维,可以部分甚至全部移除原有管片设计所需要的普通钢筋。在进行钢纤维混凝土结构构件的设计时,有两个很重要的问题必须提及。首先,设计者必须先根据相关规范制作试件进行相应的实验测试,但这些测试往往因为很高的离散结果而不尽如人意；其次,对于随着钢纤维在不同种类混凝土中的单位含量的增加,其利用效率的研究也还基本处于空白阶段。本论文将试图通过对普通钢纤维混凝土以及自密实钢纤维混凝土试件进行抗压测试,三点弯曲测试,巴塞罗那测试,多轴抗压测试以及电感应测试等一套完整的试验测试及数据分析来解决以上两个问题。在制备普通钢纤维混凝土及自密实钢纤维混凝土试件时,分别添加了单位体积为30、45和60千克每立方米的钢纤维。通过三点弯曲测试,单位体积钢纤维的含量和变异系数之间的关系可以得到很好的确定。此外,钢纤维利用效率与纤维含量之间的显著关系也可以通过在普通钢纤维混凝土及自密实钢纤维混凝土各自提升50%和100%来明确体现。尽管导致混凝土材料使用效率的原因是复杂多变的,但通过不同的测试结果归纳起来主要有以下三个：纤维分布及倾向特定方向优先原则,特定情况下出现纤维球以及不同混凝土拌合物的粘度差异。通过对巴塞罗那Sabadell隧道使用纤维利用率优化案来看,管片不仅可以完全不用使用钢筋,而且还可以减小衬砌管片的厚度。对于普通钢纤维混凝土衬砌管片,其厚度可以降低12%；而对于自密实钢纤维混凝土来说,在保证其各种力学性能的情况下,其管片厚度则可以降低达40%。另外,在不考虑劳务费节省的情况下,仅因管片厚度减小所带来的直接经济效益,普通钢纤维混凝土和自密实钢纤维混凝土可以分别降低31.60%,和35.81%。
[Abstract]:The first use of steel fiber reinforced concrete as a substitute for ordinary reinforced concrete can be traced back to the 1960 s. Since then, researchers and engineers have done a lot of in-depth research on the new composite. In the past few decades, the demand for steel fiber reinforced concrete structures in various industries has shown an upward trend, especially in the field of underground building structures, steel fiber reinforced concrete is more favored by engineers. The use of steel fiber reinforced concrete in tunnel and shaft lining segments has many advantages, such as improving the mechanical properties of segments, enhancing durability, fire resistance and fatigue resistance. In addition, by adding proper amount of steel fiber to the lining segment, the ordinary steel bar needed for the original segment design can be removed partly or even completely. In the design of steel fiber reinforced concrete structural members, there are two very important problems that must be mentioned. First of all, the designer must first make the specimens according to the relevant specifications to carry out the corresponding experimental tests, but these tests are often not satisfactory because of the high discrete results. Secondly, with the increase of the unit content of steel fiber in different kinds of concrete, the study of its utilization efficiency is still in the blank stage. In this paper, we will try to test the compression, three-point bending and Barcelona test of ordinary steel fiber reinforced concrete and self-compacting steel fiber reinforced concrete specimens. A complete set of test tests and data analysis, such as multiaxial compression test and electric induction test, are used to solve the above two problems. In the preparation of ordinary steel fiber reinforced concrete and self-compacting steel fiber reinforced concrete specimens, 30, 45 kg and 60 kg steel fiber per cubic meter were added respectively. Through three-point bending test, the relationship between the content of steel fiber per unit volume and the coefficient of variation can be well determined. In addition, the significant relationship between the utilization efficiency of steel fiber and the fiber content can also be clearly reflected by increasing the utilization efficiency of steel fiber and self-compacting steel fiber reinforced concrete by 50% and 100% respectively. Although the reasons for the efficiency of concrete materials are complex and changeable, there are three main test results: fiber distribution and preference for specific directions. In specific cases, the viscosity of fiber ball and different concrete mixtures is different. Through the optimization of fiber utilization ratio in Barcelona Sabadell tunnel, the segment can not only use steel bar at all, but also reduce the thickness of lining segment. For ordinary steel fiber reinforced concrete lining segments, the thickness can be reduced by 12%, while for self-compacting steel fiber reinforced concrete, the thickness of segments can be reduced by 40% under the condition of ensuring all kinds of mechanical properties of steel fiber reinforced concrete. In addition, without considering the saving of labor expenses, ordinary steel fiber reinforced concrete and self-compacting steel fiber reinforced concrete can be reduced by 31.60% and 35.81% respectively because of the direct economic benefits caused by the decrease of segment thickness.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528

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