再生混凝土压剪复合受力性能的试验研究

发布时间：2018-03-31 22:31

本文选题：再生混凝土　切入点：纯剪　出处：《哈尔滨工业大学》2014年硕士论文

【摘要】：本课题属于国家自然科学基金项目“再生混凝土构件复合受力性能和冻融环境下结构力学性能试验研究与设计方法”（项目批准号51278151）的子课题。对废弃混凝土进行处理制备成再生骨料，进而配制成再生混凝土用于建筑结构中，不仅缓解了天然骨料的需求压力，减少环境污染，同时也产生了良好的社会经济效益。在混凝土结构实际工程中，混凝土处于单轴受压（拉）或纯剪应力状态的情况较少，经常会处于复合的应力状态。因此研究再生混凝土在复合应力状态下的破坏准则具有重要意义。本文基于混凝土结构构件截面上受压应力和剪应力联合作用的情况，开展再生混凝土压剪复合受力相关性研究。试验中采用自主设计的加载装置对75根再生粗骨料取代率分别为0%，30%，50%，70%，100%的再生混凝土空心圆柱体试件进行了纯剪和压剪复合受力的试验研究。基于已有的混凝土强度准则，利用公式转换，获得了其各自对应的压剪复合受力的表达式。试验表明：在纯剪应力状态下，再生粗骨料的引入会降低混凝土的抗剪强度。不同取代率的再生混凝土试件在不同轴压比下具有相似的破坏形式和剪应力—剪应变曲线变化规律。在轴压比不超过0.6时，极限剪应力随着轴压比的提高而增大，超过0.6后，抗剪强度出现下降。采用多种强度准则转换后的表达式对压剪复合受力的试验值进行了误差对比分析，确立了以八面体应力理论抛物线拟合公式回归出的结果作为再生混凝土压剪复合受力的破坏准则曲线方程。通过获取的试件平面压剪复合受力破坏强度，，换算出了主应力空间下的双轴拉压破坏强度。通过给出的再生混凝土压剪复合受力的破坏准则方程进行了28根再生混凝土无腹筋梁的抗剪承载力试算，对偏压构件的斜截面承载力计算公式进行了探讨，验证了破坏准则的有效性和实用性，可为《再生混凝土结构技术规程》（编号：HB130928002）的编制提供依据。
[Abstract]:This subject belongs to the project of National Natural Science Foundation of China, "Test Research and Design method of Composite Mechanical Properties of recycled concrete members and structural Mechanical Properties under Freeze-thaw Environment" (Project Grant No. 51278151). Waste concrete is treated to produce recycled aggregate, and then recycled concrete is prepared to be used in building structure, which not only alleviates the demand pressure of natural aggregate, but also reduces environmental pollution. At the same time, it also produces good social and economic benefits. In the actual engineering of concrete structure, the concrete is in the condition of uniaxial compression (tensile) or pure shear stress. Therefore, it is of great significance to study the failure criterion of recycled concrete under composite stress. Based on the combination of compressive stress and shear stress on the section of concrete structural members, In the experiment, 75 recycled concrete hollow cylinder specimens with replacement ratio of 0 30% and 50% of recycled coarse aggregate were subjected to pure shear and compression shear by using a self-designed loading device. Experimental study of combined forces. Based on existing concrete strength criteria, The expressions of their respective compression-shear composite forces are obtained by means of formula transformation. The experimental results show that under the pure shear stress condition, When the recycled coarse aggregate is introduced, the shear strength of concrete will be reduced. The specimens with different replacement ratio have similar failure forms and shear stress-strain curves under different axial compression ratios. When the axial compression ratio is less than 0.6, The ultimate shear stress increases with the increase of axial compression ratio, and the shear strength decreases when the axial compression ratio exceeds 0.6. The results of the parabola fitting formula of octahedron stress theory are used as the failure criterion curve equation of recycled concrete. The failure strength of plane compression shear composite force is obtained. The failure strength of biaxial tension and compression under principal stress space is converted. The shear bearing capacity of 28 recycled concrete beams without web reinforcement is calculated by the failure criterion equation of composite compressive and shear forces of recycled concrete. The formulas for calculating the bearing capacity of oblique sections of eccentric compression members are discussed, and the validity and practicability of the failure criterion are verified, which can provide the basis for the compilation of the Technical Specification for recycled concrete structures (No.: HB130928002).
【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】：2014
【分类号】：TU528

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