玄武岩纤维和纳米材料对轻骨料混凝土力学性能影响研究

发布时间：2018-06-12 09:45

本文选题：轻骨料混凝土 + 玄武岩纤维　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：混凝土是当今世界应用最广的建筑材料,其中结构轻骨料混凝土(SLWAC)在相同强度下降低其密度,可以减少基础和结构构件的尺寸,从而减轻结构自重并降低成本、提高抗震能力,在大跨和高层结构中具有广泛应用价值与前景。该论文研究轻骨料混凝土的配比设计、性能及通过掺加玄武岩纤维和纳米材料的改性方法,进行了72批次的性能测试及微观结构观测分析,主要内容如下:(1)采取膨胀页岩陶粒代替普通骨料,设计了不同配合比的结构轻骨料混凝土(SLWAC),以实现坍落度、抗压强度、劈裂抗拉强度、抗折强度、剪切强度、干密度、空气含量、孔结构测定和微观结构细化的设计值。确定了粉煤灰、硅灰或矿渣替代普通硅酸盐水泥的优化比例。制备的轻骨料混凝土表观密度约为1643 kg/m3至1935 kg/m3,根据轻骨料混凝土表观密度的不同,轻骨料混凝土的强度在27.3 MPa到61.7 MPa之间变化。轻骨料混凝土的延性和弹性都发生了显著变化。在相同的抗压强度下,轻骨料混凝土与普通混凝土相比,其弹性模量显著降低并表现出明显的脆性。但是轻骨料混凝土的泊松比与普通混凝土相比变化不大。(2)纳米二氧化硅和纳米二氧化钛可以显著提高轻骨料混凝土的抗渗性。使用压汞法和SEM扫描电镜分析了其耐久性、渗透性和微观结构。在轻骨料混凝土中引入纳米材料可以显著改善低水灰比的轻骨料混凝土的耐久性。另外在特定的水灰比下,纳米二氧化硅可以优化孔结构,从而提高基体的抗渗性,纳米二氧化硅或纳米二氧化钛的添加对混凝土微观结构细化的影响提高混凝土的力学性能和长期耐久性。(3)研究了在轻骨料混凝土中掺加纤维解决其任性差的问题。研究掺加纤维对膨胀页岩为轻骨料的不同混凝土力学性能的影响,包括工作性、抗压强度、应力应变特性、抗拉强度、弹性模量和压弯韧性等等。在轻骨料混凝土中以单一或复合的形式掺加纤维,可以提高其力学性能,并显著改善其韧性、延性和吸能能力,但同时也会降低它的工作性能。对于劈裂抗拉强度和弯折强度,在轻骨料混凝土中掺加纤维明显比在普通混凝土中掺加纤维有效。
[Abstract]:Concrete is the most widely used building material in the world. The structure of lightweight aggregate concrete (SLWAC) reduces its density at the same strength and reduces the size of the basic and structural components, thus reducing the weight of the structure and reducing the cost and improving the seismic capacity. It has a wide application value and Prospect in the large span and high level structure. After studying the proportioning design of lightweight aggregate concrete, performance and the modification method of adding basalt fiber and nanomaterial, 72 batches of performance testing and microstructure observation are carried out. The main contents are as follows: (1) taking the expansion shale ceramsite instead of ordinary aggregate, the structure of lightweight aggregate concrete (SLWAC) with different mix ratio is designed to realize it. Slump, compressive strength, splitting tensile strength, flexural strength, shear strength, dry density, air content, pore structure determination and microstructure refinement. The optimum proportion of fly ash, silica fume or slag to replace ordinary portland cement is determined. The apparent density of the prepared lightweight aggregate is about 1643 kg/m3 to 1935 kg/m3, according to light bone. The strength of lightweight aggregate concrete varies from 27.3 MPa to 61.7 MPa. The ductility and elasticity of lightweight aggregate concrete have been significantly changed. Under the same compressive strength, the elastic modulus of lightweight aggregate concrete is significantly lower than that of ordinary concrete and shows obvious brittleness. The Poisson ratio of concrete has little change compared with that of ordinary concrete. (2) nano silica and nano titanium dioxide can significantly improve the anti permeability of lightweight aggregate concrete. The durability, permeability and microstructure of the lightweight aggregate concrete can be analyzed by using the mercury injection method and SEM scanning electron microscope. The introduction of nano materials in the lightweight aggregate concrete can improve the low water ash significantly. In addition, under specific water cement ratio, nano silica can optimize the pore structure and improve the permeability of the matrix, and the effect of nano silica or nano titanium dioxide on the concrete microstructure refinement can improve the mechanical properties and long-term durability of concrete. (3) study on the lightweight aggregate. The problem of adding fiber in concrete to solve its poor wayward problem. The study of the effects of adding fiber on the mechanical properties of different concrete with expanded shale as light aggregate, including workability, compressive strength, stress-strain characteristics, tensile strength, elastic modulus and bending toughness, etc.. In light aggregate concrete, a single or compound form of fiber can be added to the lightweight aggregate concrete. In order to improve its mechanical properties and significantly improve its ductility, ductility and energy absorption capacity, it will also reduce its working performance. For splitting tensile strength and bending strength, fiber reinforced in lightweight aggregate concrete is obviously more effective than the addition of fiber in ordinary concrete.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

【相似文献】