玄武岩纤维自密实混凝土的力学及耐久性能试验研究

发布时间：2018-10-05 07:11

【摘要】：建筑业对国家的发展功不可没。作为建筑业中应用最广泛的材料之一的混凝土近年来出现了多种新品种,如沥青混凝土,橡胶混凝土,纤维混凝土,自密实混凝土等。其中自密实混凝土由于其在施工时不需要人工振捣,减少噪声污染越来越受到专家学者的青睐。然而自密实混凝土存在着抗拉性能差,韧性差等缺点,这也在一定程度上阻碍了其推广应用。有关研究表明纤维混凝土能够增强混凝土的力学和耐久性能,于是在自密实混凝土中掺加纤维成为科学家关注的焦点话题。玄武岩纤维较其它纤维具有熔点高,耐酸碱,抗拉强度高等优良特性。所以本文将探究玄武岩纤维自密实混凝土的力学和耐久性能,相关结论可以为有关规范的制定提供参考和借鉴。首先,采用全体积法计算,试配并调整配合比,同时结合纤维混凝土的有关配合比计算经验,通过测试新拌混凝土的坍落扩展度,J环扩展度,坍落扩展时间等工作性能指标,获得该种混凝土原材料组合比例。其次,分别研究玄武岩纤维掺量,混凝土标号等参数对玄武岩纤维自密实混凝土的标准立方体承压强度,劈裂强度,棱柱体承压强度,棱柱体承压强度与立方体承压强度比,弹性模量等力学性能的影响规律。建立玄武岩纤维自密实混凝土立方体标准承压强度拟合公式,玄武岩纤维自密实混凝土劈裂强度与立方体标准承压强度之间的拟合公式。通过试验得出:伴随纤维所加比例的增加,玄武岩纤维自密实混凝土的立方体承压强度先变大而后逐渐降低,在纤维含量为2.2kg/m~3时,各基准配合比的玄武岩纤维自密实混凝土抗压强度达到最大值。再次,分别探究玄武岩纤维含量和混凝土强度等级对玄武岩纤维自密实混凝土抗冻融耐久特性的影响规律。分别测试玄武岩纤维自密实混凝土不同冻融循环次数作用下的的动弹性模量和质量。通过试验得出:随着冻融循环次数的累加,其质量损失率变大,相对动弹性模量变小。最后研究纤维掺量对玄武岩纤维自密实混凝土的抗氯离子渗透性能影响规律,测试各种纤维掺量的自密实混凝土的氯离子电通量。通过试验得出:各种基准强度的自密实混凝土的六小时总电通量均随其纤维掺量的增加先减小而后增大。
[Abstract]:The construction industry has contributed to the development of the country. As one of the most widely used materials in the construction industry, concrete has emerged a variety of new types in recent years, such as asphalt concrete, rubber concrete, fiber concrete, self-compacting concrete and so on. The self-compacting concrete is more and more popular with experts and scholars because it does not need artificial vibration to reduce noise pollution. However, self-compacting concrete has some disadvantages, such as poor tensile performance and poor toughness, which hinder its popularization and application to some extent. Some studies have shown that fiber reinforced concrete can enhance the mechanical and durability of concrete, so adding fiber to self-compacting concrete has become the focus of attention of scientists. The basalt fiber has higher melting point, higher resistance to acid and alkali and higher tensile strength than other fibers. Therefore, this paper will explore the mechanical and durability of basalt fiber self-compacting concrete, the relevant conclusions can provide reference and reference for the formulation of relevant specifications. First of all, the whole volume method is used to calculate and adjust the mixing ratio. At the same time, combined with the relevant calculation experience of fiber reinforced concrete (FRC), the performance indexes of freshly mixed concrete (FRC), such as the collapsing extension degree and the collapse propagation time and so on, are tested. The ratio of the concrete raw material combination is obtained. Secondly, the ratio of standard cube compressive strength, splitting strength, prism compression strength to cube compressive strength of basalt fiber self-compacting concrete is studied. The influence of elastic modulus and other mechanical properties. The fitting formula of the cubic compressive strength of basalt fiber self-compacting concrete and the fitting formula between the splitting strength of basalt fiber self-compacting concrete and the cube standard compressive strength are established. The experimental results show that the cube compressive strength of basalt fiber self-compacting concrete increases first and then decreases with the increase of fiber ratio, and the fiber content is 2.2 kg / m ~ 3. The compressive strength of basalt fiber self-compacting concrete with reference ratio reaches the maximum. Thirdly, the effects of basalt fiber content and concrete strength grade on the freeze-thaw resistance of self-compacting basalt concrete are studied. The dynamic elastic modulus and mass of basalt fiber self-compacting concrete under different freeze-thaw cycles were measured. The results show that the mass loss rate increases and the relative dynamic elastic modulus decreases with the accumulation of freeze-thaw cycles. Finally, the effect of fiber content on chloride permeation resistance of basalt fiber self-compacting concrete is studied, and the chloride ion flux of self-compacting concrete with various fiber content is tested. The experimental results show that the total electric flux of self-compacting concrete of various standard strength decreases first and then increases with the increase of fiber content.
【学位授予单位】：沈阳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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