无砟轨道充填层自密实混凝土流动过程能量耗散机制研究

To overcome the workability loss of self-compacting concrete used in the ballastless tracks filling layer through remote pumping and flowing on the geotextile flexible base. The multi-scale gradually approaching research method of "from paste to mortar and from mortar to concrete" will be propsosed . To find the correlation among the parameters of concrete mix proportion, rheological parameters and workability, the effect of water-binder ratio, volume fractions of aggregate, cementitious material composition, admixtures, and air content on the shear deformation behavior of self-compacting concrete and its paste have been researched by concrete rheologic-meter, workability test device and viscosity meter. Take example by colloid chemistry and electric double layer theory, the mechanism of shear deformation of self-compacting concrete will be disclosed based on order-disorder transformation theory and cluster formation theory. Simulate self-compacting concrete pumping and horizontal flow process, study on the friction coefficient and thermal loss between self-compacting concrete and steel plate with different roughness, geotextile with different friction coefficient by different friction test equipments (linear motion, rotary and ultrasonic reflection method) to reveal the main factors which influence the friction of self-compacting concrete. Judging for the energy balance between self-compacting concrete smart power and friction, based on building the model of self-properties, rheological properties and friction performance of self-compacting concrete, the mechanism of energy dissipation of self-compacting concrete in the process of flowing will be revealed.

为攻克无砟轨道充填层用自密实混凝土远程泵送及在土工布柔性基础上流动过程工作性能损失问题，拟采用"净浆-砂浆-混凝土"多尺度逐渐逼近研究方法，使用粘度计、流变仪、工作性能测试装置等，研究水粉比、骨料体积分数、胶凝组分、外加剂、含气量等对自密实混凝土及其浆体剪切变形行为影响规律，建立混凝土配合比参数、流变参数及工作性能间相关关系；借鉴胶体化学、双电层理论，基于簇形成理论、有序-无序转变理论等揭示自密实混凝土剪切变形机制。还原自密实混凝土泵送与水平流动过程，选择不同原理摩擦力测定仪（直线运动法、旋转法和超声波反射法），研究摩擦压力、滑动速度、温度对自密实混凝土与不同粗糙度钢板及土工布之间的摩擦性能与热损耗，揭示影响自密实混凝土摩擦性能的关键因素；以自密实混凝土自身智能动力与摩擦力之间能量平衡为判据，建立自密实混凝土自身性能、流变性能与摩擦性能之间的力学模型，揭示自密实混凝土流动过程能量耗散机制。

为攻克无砟轨道充填层用自密实混凝土远程泵送及在土工布柔性基础上流动过程工作性能损失问题，系统开展了自密实混凝土拌合物流变性能、稳定性能、摩擦性能等演变规律及能量耗散机制的研究，提出了适用于自密实混凝土剪切变形行为的表征方法，掌握了自密实混凝土流变行为的影响规律，揭示了自密实混凝土剪切变形行为形成机制，提出了自密实混凝土稳定性评价方法，揭示了变温条件下自密实混凝土流变行为的演变规律，探讨了自密实混凝土流动过程能量耗散机制。