在复杂拉压应力状态下再生混凝土动态力学性能研究

发布时间：2018-03-28 21:46

本文选题：再生混凝土　切入点：多轴　出处：《北方工业大学》2017年硕士论文

【摘要】：当前,我国基础设施正在加大发展完善,高速高铁正快速发展,大型市政的建设:如污水处理和河坝工程等,上述工程均需要大体积的混凝土。随着建筑物的使用年限的到达,一些建筑拆除而产生大量的废弃混凝土。将其渣块做为骨料搅拌制成再生混凝土(recycled aggregate concrete,RC)可以节约资源,减少垃圾处理费用。也可应用在大型构筑物之中。再生混凝土既然将应用于这些结构中,就必须研究其在多轴应力下的强度规律,研究的成果对于再生混凝土的设计、工程实际应用等有着重要意义。本人在本校结构实验室浇筑试件,然后运至大连理工大学结构试验室,采用混凝土动三轴试验机进行了多种应力比状态下的再生混凝土单轴和多轴拉压试验。应力组合包括:动态单轴拉伸、动态单轴抗压、动态双轴拉-压、动态三轴拉-压-压;加载速率为10-5/s,10-4/s,10-3/s,10-2/s。本文的主要研究工作具体如下:1.进行了强度为C20、C40、C60的再生混凝土动态单轴受拉试验。给出了再生混凝土在单轴受拉状态下的动态破坏形态为断裂破坏,给出了含1参数的破坏强度公式。再生混凝土动态单轴受拉破坏面更为错落不平。再生混凝土的单轴拉的应力应变曲线也与普通混凝土有所不同,下降段更为陡峭也与断裂破坏形态相吻合。2.进行了强度为C20、C40、C60的再生混凝土在不同应力比状态下(α=σ1:σ2:σ3=0.00:0.05:-1;0.00:0.1:-1;0.00:0.25:-1;0.00:0.50:-1、0.00:1:-1)的双轴拉压试验。根据试验结果得出了再生混凝土在双轴拉压应力状态下的破坏为拉断破坏,表现出一定的脆性,破坏的形态与应变速率有关,与应力比无关。破坏的宏观破坏形态与骨料替代率的无关。在双轴拉压下的强度值受加载动态速率的影响。加载速率越大抗拉强度越大。在平面坐标下,并建立2参数破坏准则。主拉方向的应力应变曲线也与试件的断裂相吻合。3.进行了强度C20、C40、C60的再生混凝土在不同替代率和不同应力比状态下(α=σ1:σ2:σ3=0.1:1:-1;0.25:-0.25:-1;0.25:-0.5:-1)的三轴拉-压-压试验。根据试验结果得出了其在三轴拉压压应力状态下的破坏形态均为断裂破坏,在三轴拉压压下,破坏形态为拉断破坏。强度也随应变率的提高而提高。应变率越高断裂面越齐整。根据试验结果在八面体应力空间状态下,建立2参数破坏准则公式。主拉方向的应力应变曲线与断裂破坏相吻合。
[Abstract]:At present, the infrastructure of our country is increasing and improving, high-speed high-speed rail is developing rapidly, and the construction of large-scale municipal projects, such as sewage treatment and river dam projects, all of which require large volume of concrete. With the arrival of the building's service life, Some buildings are demolished and a lot of waste concrete is produced. Mixing its slag as aggregate to make recycled aggregate concretes can save resources. Reducing the cost of garbage disposal. Can also be used in large structures. Since recycled concrete will be used in these structures, it is necessary to study its strength under multiaxial stress, and the results of the research can be applied to the design of recycled concrete. The practical application of the project is of great significance. I built the test pieces in the structural laboratory of our university and then transported them to the structural laboratory of Dalian University of Technology. Uniaxial and multiaxial tensile compression tests of recycled concrete under various stress ratios have been carried out by using a concrete dynamic triaxial tester. The stress combinations include: dynamic uniaxial tension, dynamic uniaxial compression, dynamic biaxial tension-compression, dynamic triaxial tension-compression; The main work of this paper is as follows: 1. The dynamic uniaxial tensile test of recycled concrete with strength C20 / C40 / C60 is carried out. The dynamic failure mode of recycled concrete under uniaxial tension is given as fracture failure. The failure strength formula with 1 parameter is given. The dynamic uniaxial tensile failure surface of recycled concrete is more uneven. The stress-strain curve of recycled concrete under uniaxial tension is also different from that of ordinary concrete. A biaxial compression test of recycled concrete with strength C20 / C40 / C60 under different stress ratios (伪 = 蟽 1: 蟽 2: 蟽 3: 0. 005: 1: 0.000. 1: 0. 1: 0. 25:-1: 0. 25: 0. 25:-1: 0. 50:-1: 0. 001: 1) was carried out. The results of the tests showed that the recycled concrete should be subjected to biaxial compression. The failure in the state of force is tensile failure, Showing a certain degree of brittleness, the form of failure is related to strain rate, The strength value under biaxial tension and compression is affected by the dynamic loading rate. The higher the loading rate, the greater the tensile strength. The stress-strain curve in the main tensile direction is also consistent with the fracture of the specimen. 3. The triaxial pull-compression compression compression test of recycled concrete with strength C20C40C60 under different substitution rates and different stress ratios (伪 = 蟽 1: 蟽 2: 蟽 3o 0.1: 0.1: 1-1: 0.25: -0.25: -1 0.25: -0.25: -0.5-1) has been carried out under different stress ratios and different substitution rates. (a = 蟽 1: 蟽 2: 0. 1: 0. 1: 0. 25: 0. 25:-0. 25: -0.5-1). According to the test results, it is concluded that the failure patterns of the specimens under triaxial tension and compression stress are fracture failure. Under triaxial tension and compression, the failure form is tensile failure, and the strength increases with the increase of strain rate. The higher the strain rate is, the more uniform the fracture surface is. According to the test results, under the octahedron stress space state, The formula of 2 parameter failure criterion is established. The stress-strain curve in the main tensile direction is in agreement with the fracture failure.
【学位授予单位】：北方工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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