超高韧性水泥基复合材料构件受剪性能试验研究

发布时间：2018-05-02 10:11

本文选题：超高韧性水泥基复合材料 + 简支梁　；参考：《合肥工业大学》2014年博士论文

【摘要】：超高韧性水泥基复合材料是以水泥作为基本粘结料,加上小粒径细骨料作为基体,再加入体积掺量2%左右的聚乙烯醇纤维作增强材料配制而成的新型建筑材料。这种材料的特点不同于以前的纤维增强材料,依靠通过增加大体积含量的纤维来获得高性能,而是基于材料微观结构设计的一种具有超高韧性的新型复合材料,这种材料在荷载作用下具有明显的应变硬化特征,在直接拉伸作用下可产生多条细微裂缝,稳定的拉应变能够达到3%左右。为了研究超高韧性水泥基复合材料的力学性质及构件受剪性能,本文围绕“一种材料、两种构件、三个重点”来进行研究,以获得超高韧性水泥基复合材料基本物理力学性能和构件的承载力及变形特性。一种材料为超高韧性水泥基复合材料；两种构件为超高韧性水泥基复合材料简支梁以及超高韧性水泥基复合材料连梁；三个重点主要包括以下内容： 1分析了超高韧性水泥基复合材料的配合比及搅拌工艺,对超高韧性水泥基复合材料进行了基本力学性能的试验。分别从超高韧性水泥基复合材料配制工艺、抗压强度试验和抗拉强度试验三个方面进行阐述,了解了超高韧性水泥基复合材料的基本力学性能,通过实验室配制浇筑不同类型的超高韧性水泥基复合材料试块,得到了单轴抗拉、单轴抗压的强度值及试件的应力应变曲线,为超高韧性水泥基复合材料构件的计算提供依据,并对应力应变曲线进行分析,为进一步的理论分析和数值模拟提供参考。 2通过9根超高韧性水泥基复合材料简支梁试验和1根混凝土对比试件试验,对集中荷载作用下的超高韧性水泥基复合材料梁的受剪性能进行了试验研究,讨论了不同配筋率、配箍率及剪跨比等主要因素对超高韧性水泥基复合材料梁剪切开裂强度和抗剪极限强度的影响；对梁在剪切破坏的变形特征和延性性能进行了分析；同时对超高韧性水泥基复合材料简支梁和普通混凝土简支梁的破坏特点及承载力进行了对比；最后对试件进行了基于修正压力场理论的构件抗剪承载力理论计算。 3通过10根超高韧性水泥基复合材料连梁和1根对比混凝土连梁的试验,详细研究了连梁在低周反复加载和静载作用下的破坏形态、抗剪承载力、荷载位移曲线、钢筋应变、连梁的轴向变形和剪切变形等性能；结合本次试验对超高韧性水泥基复合材料连梁的骨架曲线、位移延性、承载力退化及刚度退化和耗能性能进行了分析,同时对试件进行了抗剪承载力的分析,给出了计算建议公式；其次利用软化拉压杆模型对试件进行了抗剪承载力的理论计算,对超高韧性水泥基复合材料连梁的试验值和理论值进行了对比和分析；最后对部分连梁试件进行了ANYSY有限元分析,得到了试件的承载力、钢筋应变等性能,并与试验值进行对比分析。研究表明：超高韧性水泥基复合材料具有较好的强度和优越的韧性性能,超高韧性水泥基复合材料构件具有较好承载力和延性性能,超高韧性水泥基复合材料能够应用于实际工程中。
[Abstract]:Super high toughness cement-based composite material is a new type of building material made of cement as a basic binder, adding small size aggregate as a matrix, and adding a volume of about 2% of polyvinyl alcohol as a reinforced material. The characteristics of this material are different from the previous fiber reinforced material, depending on increasing the volume content. Fiber has high performance, but a new type of composite material based on material microstructure design. This material has obvious strain hardening characteristics under load. It can produce a number of fine cracks under direct tension, and the stable tensile strain can reach about 3%.
In order to study the mechanical properties of ultra-high toughness cementitious composites and the shear properties of components, this paper focuses on the study of "one material, two components, three key points" to obtain the basic physical and mechanical properties of ultra high toughness cementitious composites and the bearing capacity and deformation properties of the components. The two components are super high toughness cementitious composite beams and super high toughness cement-based composite beams; the three main points include the following:
1 the mixture ratio and mixing process of ultra-high toughness cementitious composites were analyzed, and the basic mechanical properties of ultra high toughness cementitious composites were tested. From three aspects of super high toughness cementitious composite material preparation process, compressive strength test and tensile strength test, the super high toughness cementitious composite was understood. The basic mechanical properties of the material are prepared by the preparation of different types of ultra-high toughness cementitious composite material by the laboratory preparation. The strength value of uniaxial tensile, uniaxial compression and stress strain curve of the specimen are obtained, which provide the basis for the calculation of the super high toughness cementitious composite component, and analyze the stress-strain curve. The theoretical analysis and numerical simulation of the step are provided for reference.
2 the shear behavior of ultra high toughness cementitious composite beams under concentrated load was tested by 9 super high toughness cementitious composite simple supported beam test and 1 concrete contrast test. The main factors such as different reinforcement ratio, stirrup rate and shear span ratio were discussed, and the super high toughness cementitious composite material Liang Jian was discussed. The influence of shear strength and shear strength, the deformation characteristics and ductility of the beam in shear failure are analyzed, and the failure characteristics and bearing capacity of the simple supported beam of super high toughness cementitious composite and the simple concrete beam are compared. Finally, the specimen is constructed based on the correction pressure field theory. Theoretical calculation of shear bearing capacity.
3 through the experiments of 10 super high toughness cementitious composite beams and 1 concrete continuous beams, the failure modes, shear bearing capacity, load displacement curves, steel strain, axial deformation and shear deformation of continuous beams were studied in detail. The skeleton curves, displacement ductility, load-bearing degeneracy, stiffness degradation and energy dissipation of the composite beams are analyzed. At the same time, the shear bearing capacity of the specimens is analyzed, and the calculation formula is given. Secondly, the theoretical calculation of the shear bearing capacity of the specimens is carried out by using the softened tension and tension bar model, and the super high toughness cement base is made. The test values and theoretical values of composite beams are compared and analyzed. Finally, the finite element analysis of some specimens of continuous beams is carried out by ANYSY finite element analysis. The bearing capacity of the specimen, the strain and other properties of the steel bar are obtained and compared with the test values.
The research shows that ultra high toughness cementitious composites have better strength and superior ductility, and the ultrahigh toughness cementitious composites have better bearing capacity and ductility, and ultra high toughness cementitious composites can be applied to practical engineering.

【学位授予单位】：合肥工业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU528

【参考文献】