钢筋钢纤维纳米混凝土粘结及梁受弯性能计算方法

发布时间：2018-01-12 05:11

本文关键词：钢筋钢纤维纳米混凝土粘结及梁受弯性能计算方法　出处：《郑州大学》2017年博士论文　论文类型：学位论文

【摘要】：随着我国水利水电、海岸海洋、土木建筑、道路桥梁等工程建设的深入,对混凝土材料及其结构性能提出了更高的要求。混凝土复合化是提高混凝土结构性能、满足现代化工程建设需要的有效方法。本文通过钢纤维与混凝土细观复合以及纳米材料与混凝土微观复合,形成钢纤维纳米混凝土,进一步研究钢筋与钢纤维纳米混凝土粘结性能以及钢筋钢纤维纳米混凝土梁正截面受弯性能,建立相应的计算模型和公式。主要内容如下:(1)通过164个粘结试件的粘结试验,探讨了基体强度、钢纤维体积率、纳米材料(纳米SiO_2和纳米CaCO_3)掺量、钢筋类型和试件形式对粘结破坏形态、粘结滑移曲线和粘结强度的影响,分析了钢纤维以及纳米材料的作用机理。(2)根据钢纤维纳米混凝土具有较大变形和裂缝扩展能力的特点,建立了钢纤维纳米混凝土环向应变和环向伸长的表达式。在此基础上,将弹性力学理论、虚拟裂缝理论与钢纤维纳米混凝土软化模型相结合,提出了钢筋与钢纤维纳米混凝土粘结强度的计算方法。利用本文及相关文献试验得到的粘结强度结果对提出的方法进行了验证,同时分析了保护层厚度、裂缝数量和钢筋直径对粘结强度的影响。(3)通过对钢筋纵向开槽,槽内均匀粘贴应变片的局部粘结试验结果的分析,建立了三次多项式表达的粘结应力分布函数,得到了各级荷载作用下钢筋与钢纤维纳米混凝土粘结应力和相对粘结滑移沿粘结区段的分布。在此基础上,提出了能够较好反映钢筋与钢纤维纳米混凝土受力过程的粘结应力-滑移关系模型。(4)通过12根钢筋钢纤维纳米混凝土梁的正截面受弯性能试验,分析了基体强度、钢纤维体积率和纳米材料(纳米SiO_2和纳米CaCO_3)掺量对梁开裂弯矩、裂缝发展、跨中截面混凝土应变和挠度的影响;考虑梁开裂后钢纤维对开裂截面的作用,提出了钢筋钢纤维纳米混凝土梁正截面承载力的计算方法及公式;同时,结合国内外现行规范,建立了基于有效惯性矩法和解析法的梁截面刚度的计算方法及公式。
[Abstract]:With the development of water conservancy and hydropower, coastal ocean, civil construction, road and bridge construction in China, the concrete material and its structure performance are required higher. Concrete compounding is to improve the performance of concrete structure. In this paper, steel fiber nano-concrete is formed by micro-composite of steel fiber and concrete and micro-composite of nano-material and concrete. The bond behavior of steel fiber reinforced nanocrystalline concrete and the flexural behavior of steel fiber reinforced nanocrystalline concrete beams are further studied. The main contents are as follows: 1) through the bond tests of 164 bonded specimens, the matrix strength and the volume ratio of steel fiber are discussed. The effects of nano-materials (nanometer SiO_2 and nano-CaCO3), type of steel bar and specimen form on bond failure, bond-slip curve and bond strength. The mechanism of action of steel fiber and nano-material is analyzed. According to the characteristics of steel fiber nanocrystalline concrete with large deformation and crack propagation ability. The expressions of circumferential strain and circumferential elongation of steel fiber nanocrystalline concrete are established. On this basis, elastic mechanics theory, virtual crack theory and softening model of steel fiber nanocrystalline concrete are combined. The calculation method of bond strength between steel and steel fiber nanocrystalline concrete is put forward. The method is verified by the bond strength results obtained in this paper and related literature tests, and the thickness of protective layer is analyzed at the same time. The effect of crack number and steel bar diameter on bond strength. (3) through the analysis of the local bond test results of longitudinal slotted steel bar and uniformly bonded strain gauge in the slot. The bond stress distribution function expressed by cubic polynomial is established, and the distribution of bond stress and relative bond-slip between steel fiber nanocrystals and steel fiber nanocrystals under various loads are obtained. The bond stress-slip relation model of steel fiber nanocrystalline concrete (SFNRC) is proposed, which can better reflect the stress process of steel fiber nanocrystalline concrete (SFNRC). The flexural behavior of normal section of 12 steel fiber reinforced nano-concrete beams (SFNCs) is tested. The effects of matrix strength, volume ratio of steel fiber and content of nano-material (nano-#en0# and nano-CaCO3) on crack moment, crack development, strain and deflection of mid-span concrete were analyzed. Considering the effect of steel fiber on the crack section after beam cracking, the calculation method and formula of normal section bearing capacity of reinforced steel fiber nanocrystalline concrete beam are put forward. At the same time, the calculation method and formula of beam section stiffness based on effective moment of inertia method and analytical method are established in combination with the current codes at home and abroad.
【学位授予单位】：郑州大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TU528;TU37

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