分形理论在混杂纤维轻骨料混凝土力学性能及耐久性能研究的应用
发布时间：2019-05-14 06:09
【摘要】：混凝土作为土木工程材料被广泛的应用在国民经济建设之中。混凝土有着来源丰富、经济性好、可塑性强等优点。然而自重较大、抗拉性能差等缺点一直限制着混凝土的发展。为了改善这些缺点,人们长久以来不断寻找将新的材料加入到混凝土中。大量研究表明,在以天然浮石作为混凝土粗骨料的轻骨料混凝土中掺入纤维不但可以增强混凝土的韧性,而且可以改善其耐久性能并且减轻混凝土的自重。本论文将结合内蒙古自治区丰富的天然浮石储备这一地区资源优势,使用内蒙古自治区乌兰察布市集宁地区的天然浮石作为轻骨料的混杂纤维轻骨料混凝土,着重研究混杂纤维(聚丙烯纤维和玄武岩纤维)的掺入对于轻骨料浮石混凝土的宏观性能和微观性能间的关系。在宏观方面,本文通过混凝土抗压强度试验来研究混杂纤维轻骨料混凝土。而冻融循环破坏试验,对于质量损失率和相对动弹性模量这两个参数作了具体的分析。并且探讨纤维对于混凝土宏观性能方面增强的机理在微观方面,本论文在不同尺度利用不同方式,观测并且计算了混凝土的孔结构参数。并且讨论了不同的分形维数的计算对于模型的影响,最终选择了两种方法对于两个尺度分别计算出分形维数。并利用该分形维数与之前的试验参数和结果做了进一步的讨论和研究。最终利用将分形维数与冻融损伤模型相结合,得到了基于分形维数的混杂纤维轻骨料混凝土的冻融损伤模型。研究结果表明:在混杂纤维轻骨料混凝土中,当玄武岩纤维和聚丙烯纤维的掺量在一个合理的范围之内时,混杂纤维轻骨料混凝土的力学性能和抗冻耐久性能将会有一定的提升。且聚丙烯-玄武岩纤维的最佳掺量为:聚丙烯纤维0.6κg/m3,玄武岩纤维0.7kg/m3。
[Abstract]:Concrete, as a civil engineering material, is widely used in national economic construction. Concrete has many advantages, such as rich source, good economy, strong plasticity and so on. However, the development of concrete has been limited by the shortcomings of large self-weight and poor tensile performance. In order to improve these shortcomings, people have been looking for new materials to add to concrete for a long time. A large number of studies have shown that the addition of fiber into lightweight aggregate concrete with natural pumice as coarse aggregate can not only enhance the toughness of concrete, but also improve its durability and reduce the weight of concrete. In this paper, combined with the rich natural pumice reserve in Inner Mongolia Autonomous region, the mixed fiber lightweight aggregate concrete is used as lightweight aggregate, which is based on the natural pumice in Jining area of Wulanchabu City, Inner Mongolia Autonomous region. The relationship between the macroscopic and microscopic properties of lightweight aggregate pumice concrete with the addition of hybrid fiber (polypropylene fiber and basalt fiber) is studied in detail. In macroscopical aspect, this paper studies hybrid fiber lightweight aggregate concrete through concrete compressive strength test. In the freeze-thaw cycle failure test, the two parameters of mass loss rate and relative dynamic elastic modulus are analyzed in detail. The mechanism of strengthening the macro performance of concrete by fiber is discussed in the microscopic aspect. In this paper, the pore structure parameters of concrete are observed and calculated by using different methods at different scales. The influence of different fractal dimensions on the model is discussed. Finally, two methods are selected to calculate the fractal dimensions for the two scales. The fractal dimension is further discussed and studied with the previous experimental parameters and results. Finally, the freeze-thaw damage model of hybrid fiber lightweight aggregate concrete based on fractal dimension is obtained by combining fractal dimension with freeze-thaw damage model. The results show that in hybrid fiber lightweight aggregate concrete, when the content of basalt fiber and polypropylene fiber is within a reasonable range, The mechanical properties and frost durability of hybrid fiber lightweight aggregate concrete will be improved to a certain extent. The optimum content of polypropylene-basalt fiber is as follows: polypropylene fiber 0.6 kg 鈮，
本文编号：2476487
[Abstract]:Concrete, as a civil engineering material, is widely used in national economic construction. Concrete has many advantages, such as rich source, good economy, strong plasticity and so on. However, the development of concrete has been limited by the shortcomings of large self-weight and poor tensile performance. In order to improve these shortcomings, people have been looking for new materials to add to concrete for a long time. A large number of studies have shown that the addition of fiber into lightweight aggregate concrete with natural pumice as coarse aggregate can not only enhance the toughness of concrete, but also improve its durability and reduce the weight of concrete. In this paper, combined with the rich natural pumice reserve in Inner Mongolia Autonomous region, the mixed fiber lightweight aggregate concrete is used as lightweight aggregate, which is based on the natural pumice in Jining area of Wulanchabu City, Inner Mongolia Autonomous region. The relationship between the macroscopic and microscopic properties of lightweight aggregate pumice concrete with the addition of hybrid fiber (polypropylene fiber and basalt fiber) is studied in detail. In macroscopical aspect, this paper studies hybrid fiber lightweight aggregate concrete through concrete compressive strength test. In the freeze-thaw cycle failure test, the two parameters of mass loss rate and relative dynamic elastic modulus are analyzed in detail. The mechanism of strengthening the macro performance of concrete by fiber is discussed in the microscopic aspect. In this paper, the pore structure parameters of concrete are observed and calculated by using different methods at different scales. The influence of different fractal dimensions on the model is discussed. Finally, two methods are selected to calculate the fractal dimensions for the two scales. The fractal dimension is further discussed and studied with the previous experimental parameters and results. Finally, the freeze-thaw damage model of hybrid fiber lightweight aggregate concrete based on fractal dimension is obtained by combining fractal dimension with freeze-thaw damage model. The results show that in hybrid fiber lightweight aggregate concrete, when the content of basalt fiber and polypropylene fiber is within a reasonable range, The mechanical properties and frost durability of hybrid fiber lightweight aggregate concrete will be improved to a certain extent. The optimum content of polypropylene-basalt fiber is as follows: polypropylene fiber 0.6 kg 鈮，
本文编号：2476487
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