Study on the Rheological Properties of Calcium Oxide-Sodium Carbonate
Composite Activated Slag Based Grouting Material
(1. State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang 330013;2. School of Civil & Architectural Engineering, East China University of Technology, Nanchang 330013; 3. Jiangxi Geological Environment and Underground Space Engineering Research Center, East China University of Technology, Nanchang 330013)
Abstract：
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 prepared by using calcium oxide and sodium carbonate (amount of substance ratio is 1∶1) as activators. Next, the rheological 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-cement 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 and0.65 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 viscosity of Newtonian grout with water-cement ratio of 0.80, 0.90 and 1.00 changes slightly as the hydration time increases, but only slightly, so it is deemed that its viscosity is not time-varying.
2023, Vol. 60 