钢纤维混凝土单轴受压本构关系试验研究

发布时间：2018-03-24 06:03

本文选题：钢纤维　切入点：混凝土　出处：《郑州大学》2017年硕士论文

【摘要】：钢纤维加入到混凝土中可以起到增强增韧的效果,虽然钢纤维混凝土已经应用于水利水电、海岸海洋、土木建筑、道路桥梁等工程建设中,但作为钢纤维混凝土结构设计和数值计算依据的钢纤维混凝土受压本构关系,相关研究还十分有限,限制了钢纤维混凝土的进一步推广和应用。本文通过钢纤维混凝土单轴受压试验,研究了钢纤维混凝土的抗压强度和受压本构关系。主要研究内容如下:(1)通过90个150mm×150mm×150mm的钢纤维混凝土立方体试件的抗压强度试验,研究了不同混凝土基体强度下,钢纤维体积率和钢纤维强度对混凝土立方体试件破坏形态和抗压强度的影响。结果表明,钢纤维使混凝土的破坏形态由脆性破坏转变为塑性破坏;混凝土基体强度在C30/CF30~C60/CF60时,钢纤维体积率在0%~2%范围的增大,立方体抗压强度可提高2.5%~41.66%,高强度钢纤维对混凝土立方体抗压强度的增强效果优于低强度钢纤维。(2)基于试验机自身刚度的情况下,通过90个150mm×150mm×300mm的钢纤维混凝土棱柱体单轴受压试验,研究了钢纤维体积率、基体混凝土强度和钢纤维强度对钢纤维混凝土单轴受压破坏形态和本构关系的影响。结果表明,钢纤维在试件裂缝失稳扩展阶段和破坏阶段增强增韧效果显著。由于试验机自身刚度较小,高强混凝土试件难以测得应力-应变曲线下降段。混凝土基体强度在C30/CF30~C60/CF60时,随钢纤维体积率在0%~2.0%范围内的增大,应力-应变曲线愈加饱满,峰值应力和峰值应变显著增大。而对于C80/CF80混凝土试件,峰值应力仍随钢纤维体积率增大而提高,峰值应变则有所降低。高强度钢纤维对高强混凝土增韧效果较好。针对钢纤维混凝土的特点,建立了钢纤维混凝土受压本构关系模型。(3)基于在试验机上增设刚性元件的情况下,通过90个150mm×150mm×300mm的钢纤维混凝土棱柱体单轴受压试验,研究了钢纤维体积率、混凝土基体强度和钢纤维类型对钢纤维混凝土单轴受压本构关系的影响。研究表明,混凝土基体强度在C30/CF30~C80/CF80时,钢纤维体积率在0%~2.0%范围内的增大,棱柱体试件的受压应力-应变曲线更加饱满,峰值应力、峰值应变和曲线下包面积均显著提高。随基体强度等级在C30/CF30~C80/CF80范围内的提高,试件的峰值应力提高,曲线上升段斜率增大,而曲线曲率和上升段的变形减小。高强度钢纤维对高强混凝土增韧效果较好。与基于试验机自身刚度的试验方法相比,增设刚性元件后可以稳定地量测到应力-应变曲线的下降段,并使曲线上升段参数有所增大,曲线下降段的规律性更加明显。建立的钢纤维受压本构关系模型仍适用于基于试验机自身机刚度情况下的钢纤维混凝土本构关系计算。
[Abstract]:Steel fiber can be added to concrete to enhance the toughening effect, although steel fiber reinforced concrete has been used in water conservancy and hydropower, coastal ocean, civil construction, road and bridge construction, etc. However, as a basis for structural design and numerical calculation of steel fiber reinforced concrete (SFRC), the research on the constitutive relationship of SFRC under compression is very limited. In this paper, the uniaxial compression test of steel fiber reinforced concrete (SFRC) is carried out. The compressive strength and compressive constitutive relationship of steel fiber reinforced concrete (SFRC) are studied in this paper. The main contents are as follows: (1) the compressive strength of 90 steel fiber reinforced concrete cube specimens with 150mm 脳 150mm 脳 150mm is studied under different concrete matrix strength. The effect of the volume ratio of steel fiber and the strength of steel fiber on the failure form and compressive strength of concrete cube specimen is studied. The results show that the failure mode of concrete is changed from brittle failure to plastic failure by steel fiber, and when the strength of concrete matrix is at C30/CF30~C60/CF60, the failure mode of concrete is changed from brittle failure to plastic failure. When the volume ratio of steel fiber increases in the range of 0% and 2%, the cube compressive strength can be increased by 2.5% and 41.66. The enhancement effect of high strength steel fiber on the compressive strength of concrete cube is better than that of low strength steel fiber. Through uniaxial compression tests of 90 steel fiber reinforced concrete prisms with 150mm 脳 150mm 脳 300mm, the effects of volume ratio of steel fiber, strength of matrix concrete and strength of steel fiber on the failure mode and constitutive relationship of steel fiber concrete under uniaxial compression were studied. The effect of strengthening and toughening of steel fiber in crack instability and failure stage is remarkable. Because of the small stiffness of the testing machine, it is difficult to measure the decrease of stress-strain curve of high strength concrete. When the strength of concrete matrix is in C30/CF30~C60/CF60, the strength of concrete matrix is in the condition of C30/CF30~C60/CF60. With the increase of steel fiber volume ratio in the range of 0% and 2.0%, the stress-strain curve becomes fuller, and the peak stress and peak strain increase significantly. However, for C80/CF80 concrete specimens, the peak stress increases with the increase of steel fiber volume ratio. The peak strain is reduced. The high strength steel fiber has better toughening effect on high strength concrete. According to the characteristics of steel fiber reinforced concrete, the constitutive relation model of steel fiber reinforced concrete under compression is established. The effects of volume ratio of steel fiber, strength of concrete matrix and type of steel fiber on the constitutive relationship of steel fiber reinforced concrete under uniaxial compression were studied by uniaxial compression tests of 90 150mm 脳 150mm 脳 300mm prisms. When the strength of concrete matrix is in C30/CF30~C80/CF80, the volume ratio of steel fiber increases in the range of 2.0%, the compressive stress-strain curve of the prism specimen becomes fuller and the peak stress is increased. The peak strain and the area under the curve increased significantly. With the increase of the matrix strength grade in the range of C30/CF30~C80/CF80, the peak stress of the specimen increased, and the slope of the rising section of the curve increased. The curvature of the curve and the deformation of the rising section decrease. The high strength steel fiber has better toughening effect on the high strength concrete. Compared with the test method based on the stiffness of the testing machine, With the addition of rigid elements, the descending section of stress-strain curve can be measured stably, and the parameters of rising section of the curve can be increased. The constitutive relation model of steel fiber under compression is still applicable to the calculation of the constitutive relation of steel fiber concrete based on the stiffness of the testing machine itself.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528.572

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