复合式钢纤维混凝土路面研究

发布时间：2018-05-11 19:36

本文选题：复合式钢纤维混凝土 + 力学性能　；参考：《河南大学》2013年硕士论文

【摘要】：水泥混凝土路面在重载车轮重复荷载作用下，由于其弯拉强度和抗疲劳性能较低，断裂时的拉伸变形小，抗裂性和抗冲击韧性较差，易产生裂缝，并且混凝土板弹性模量及力学强度大大高于基层和土基的相应模量和强度，荷载在混凝土板内部沿深度消散快，致使混凝土路面板在车轮荷载作用下极易沿面板底部产生弯拉断裂破坏。本文基于水泥混凝土路面板分别在Winkler地基和弹性层状体系半空间地基上的受力特点的分析，结合钢纤维混凝土的工作特性，提出一种新型的复合式钢纤维混凝土路面结构。同时，对复合式钢纤维混凝土路面进行了模拟双轮轴载试验研究和成本分析，得出：（1）复合式钢纤维混凝土路面抗弯拉强度高于普通混凝土路面和层布式钢纤维混凝土路面，与传统钢纤维混凝土路面相近。同时，复合式钢纤维混凝土路面板破坏时相对于较普通混凝土路面具有较好的延性，从而可以有效缓解路基偏软、板底脱空等情况导致的路面底部的脆性断裂；（2）造价方面，复合式钢纤维混凝土路面与普通混凝土路面、层布式钢纤维混凝土相当，但成本远远低于传统的钢纤维混凝土路面；（3）复合式钢纤维混凝土路面相对于层布式钢纤维混凝土路面而言，更加机动灵活，可以针对不同的地质特点，对底部钢纤维混凝土层厚度以及钢纤维掺量进行合理调节，从而实现资源的合理利用。最后，分别从宏观和微观角度对复合式钢纤维混凝土路面结构进行增强和破坏机理分析，得出：（1）复合式钢纤维混凝土路面从其承受荷载开始到完全破坏，经历微裂缝产生阶段、微裂缝扩展阶段、微裂缝贯通阶段和板体破坏阶段。在四个阶段中，钢纤维对混凝土裂缝的产生和扩展起到了明显的制约作用，从而有效增强了板体的综合性能，在延缓板体破坏，提高承载能力的过程中发挥着至关重要的作用。（2）复合式钢纤维混凝土路面凝结初期，，由于集料泌水，板体收缩，细骨料下沉等原因，在水泥浆体和骨料的粘结界面会产生部分无法避免的细微裂缝，这些微裂缝的存在和混凝土徐变过程中所产生的收缩应力相互作用，从而影响到复合式钢纤维混凝土路面的抗疲劳强度和使用寿命。
[Abstract]:Due to the low flexural tensile strength and fatigue resistance of cement concrete pavement under the repeated load of heavy duty wheels, the tensile deformation is small, the crack resistance and impact toughness are poor, and cracks are easy to occur. And the elastic modulus and mechanical strength of concrete slabs are much higher than the corresponding modulus and strength of base and soil foundation, and the load dissipates quickly along the depth of concrete slabs. Under the wheel load, concrete pavement is prone to flexural fracture along the bottom of the slab. Based on the analysis of the mechanical characteristics of cement concrete pavement slab on Winkler foundation and elastic layered semi-space foundation, a new composite steel fiber reinforced concrete pavement structure is proposed in this paper, combining with the working characteristics of steel fiber reinforced concrete (SFRC). At the same time, the experimental study and cost analysis of composite steel fiber reinforced concrete pavement are carried out. It is concluded that the flexural tensile strength of composite steel fiber reinforced concrete pavement is higher than that of ordinary concrete pavement and layered steel fiber reinforced concrete pavement. It is close to the traditional steel fiber concrete pavement. At the same time, the composite steel fiber reinforced concrete pavement slab has better ductility than that of ordinary concrete pavement, which can effectively alleviate the brittle fracture of pavement bottom caused by soft subgrade and slab bottom void, etc. The composite steel-fiber concrete pavement is comparable to the ordinary concrete pavement and the layered steel-fiber concrete. However, the cost is far lower than that of the traditional steel fiber reinforced concrete pavement. The composite steel fiber concrete pavement is more flexible than the layered steel fiber concrete pavement, and can be adapted to different geological characteristics. The thickness of the bottom steel fiber concrete layer and the steel fiber content are adjusted reasonably, so as to realize the rational utilization of the resources. Finally, the strengthening and failure mechanism of composite steel fiber reinforced concrete pavement structure is analyzed from macro and micro angles, and it is concluded that the composite steel fiber reinforced concrete pavement has experienced micro-cracks from the beginning of the loading to the complete destruction. Microfracture propagation stage, microfracture through stage and slab failure stage. In the four stages, the steel fiber plays a significant role in restricting the production and expansion of concrete cracks, thus effectively enhancing the comprehensive performance of the slab body and delaying the destruction of the slab body. In the process of improving the bearing capacity, it plays an important role in the initial condensation of composite steel fiber concrete pavement, due to the reasons of bleeding of aggregate, shrinkage of slab, sinking of fine aggregate, and so on. At the bond interface between the cement paste and the aggregate, there are some unavoidable fine cracks that interact with the shrinkage stress generated during the creep of concrete. Thus, the fatigue strength and service life of composite steel fiber reinforced concrete pavement are affected.
【学位授予单位】：河南大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：U416.2

【参考文献】