Influence of Coupling Effects of Time and Water-to-Cement Ratio on Rheological Properties of Bingham Cement Grouts

Time and water-to-cement ratio have significant influences on rheology of cement grouts. In order to study effects of time and water-to-cement ratio on rheology of Bingham cement grouts, taking Bingham cement grouts widely used in practical engineering (cement grouts with water-to-cement ratio of 0.75-1.25) as research object, some rheological experiments of five cement grouts with water-to-cement ratio of 0.8, 0.9, 1.0, 1.1, and 1.25 were carried out at six moments of 0, 5, 10, 20, 30, and 60 minutes, respectively. Combining theoretical discussion with numerical analysis, influence of coupling effects of time and water-to-cement ratio on rheological properties of Bingham cement grouts was discussed. Results show that at the level of alpha = 0.05, time has a significant influence on plastic viscosity but has no significant influence on the yield stress of Bingham cement grouts. Water-tocement ratio has a significant influence on both plastic viscosity and yield stress. Exponential models obtained by comprehensive analysis from statistical theory, practical applicability, and accuracy are the optimal models to describe quantitative change in the relationship of coupling effects of time and water-to-cement ratio on plastic viscosity and yield stress of Bingham cement grouts. The rheological equation considering coupling effects of time and water-to-cement ratio of Bingham cement grouts is constructed. Research achievements not only have certain theoretical significance to the development and improvement of fluid mechanics and theoretical system of penetration grouting but also provide theoretical support and technical reference for practical grouting engineering and also have certain practical significance for solving or improving the practical engineering problems.