氧化钙-碳酸钠复合激发矿渣灌浆材料流变特性研究

Study on the Rheological Properties of Calcium Oxide-Sodium Carbonate Composite Activated Slag Based Grouting Material

浆液流型及流变参数的时变规律是建立注浆扩散理论模型的前提。为探究氧化钙和碳酸钠复合激发矿渣灌浆材料流变特性,首先采用氧化钙和碳酸钠(物质的量比为1∶1)为激发剂制备出析水率和结石体抗压强度优于42.5号普通硅酸盐水泥浆的新型灌浆材料,接下来采用旋转黏度计对不同水胶比、不同水化时间灌浆材料的流变特性进行测试,基于测试结果探讨了水胶比、水化时间对灌浆材料流型及流变参数的影响规律。结果表明,水胶比对氧化钙-碳酸钠复合激发矿渣灌浆材料流变模式有较大影响,水胶比为0.60~1.00的灌浆材料流型不是某种单一流型,分属宾汉姆流体、牛顿流体。塑性黏度和屈服应力随水胶比增大呈幂函数关系减小。与水泥基注浆材料类似,氧化钙-碳酸钠复合激发矿渣灌浆材料在注浆过程中流型保持不变,只是流变参数随水化时间发生变化。灌浆材料水胶比越大,水化时间对剪切应力与剪切速率关系、流变参数量值影响越小。与水泥基注浆材料不同的是,新型灌浆材料塑性黏度随水化时间变化规律符合幂函数而非指数函数。水胶比为0.60、0.65的浆液屈服应力随水化时间增加呈线性增大,而水化时间对水胶比为0.70、0.75的浆液屈服应力影响不显著,可认为屈服应力无时变性。水胶比为0.80、0.90、1.00的牛顿型浆液的黏度随水化时间增加而略微增大,但是变化幅度较小,可认为黏度无时变性。

The prerequisite of building the theoretical model of grout diffusion is to determine the flow pattern of grout and time varying pattern of rheological parameters.In order to investigate the rheological properties of calcium oxide-sodium carbonate composite activated slag based grouting material,the new grouting material whose bleeding rate and concretion compressive strength are superior to those of the Grade 42.5 ordinary Portland cement is pre⁃pared by using calcium oxide and sodium carbonate(amount of substance ratio is 1∶1)as activators.Next,the rheo⁃logical properties of the grouting materials with different water-cement ratios and hydration times are tested by using the rotary viscometer.Based on the test results,it is feasible to examine how the water-cement ratio and hydration time will affect the flow pattern and rheological parameters of grouting material.According to the results,water-ce⁃ment ratio will significantly affect the rheological pattern of calcium oxide-sodium carbonate composite activated slag based grouting material.The grouting materials with water-cement ratio of 0.60~1.00 do not have a single flow pattern,but are classified as Bingham fluid and Newtonian fluid.The plastic viscosity and yield stress will decrease as the water-cement ratio increases,with the two being in a power functional relation.Similar to cement-based grouting material,calcium oxide-sodium carbonate composite activated slag based grouting material will maintain its flow pattern in the grouting process,while only the rheological parameter changes with the hydration time.The greater the water-cement ratio of grouting material,the less the hydration time will affect the relation between shear stress and shear rate and the value of rheological parameter.Unlike cement-based grouting material,the variation pattern of plastic viscosity of the new grouting material resulting from change of hydration time is represented by a power function instead of exponential function.The yield stress of the grout with water-cement ratio of 0.60 and 0.65 will increase linearly as the hydration time increases,while hydration time does not significantly affect the yield stress of the grout with water-cement ratio of 0.70 and 0.75,i.e.the yield stress is not time-varying.The vis⁃cosity of Newtonian grout with water-cement ratio of 0.80,0.90 and 1.00 changes slightly as the hydration time in⁃creases,but only slightly,so it is deemed that its viscosity is not time-varying.