Comparative Analysis of Rheological Models for Cement-Based Grout

The filling and diffusion capacity of grout in engineering is significantly influenced by its rheological properties. To aid in selecting appropriate rheological models, the characteristics and applicability of existing models were compared and analyzed. Also, their suitability for different grout materials and ratios was summarized. The applicability of various rheological models to cement-based grouts was compared and ranked through rheological testing, leading to the identification of an optimal rheological equation. The influence of grout ratios on rheological behavior was analyzed, and the effects of these ratios on statistical parameters and rheological parameters were discussed. Results indicated that the Bingham model, Modified Bingham model, and Herschel–Bulkley model are the most commonly used rheological models. The Modified Bingham model is considered the most suitable for predicting the rheological behavior of cement-based grouts due to its ability to account for varying yield stresses. The bentonite-to-water ratio and water-to-binder ratio were found to have the most significant impact on rheological behavior and model prediction accuracy. Yield stress decreased with an increase in the water-to-binder ratio and binder-to-sand ratio, but it increased with a higher bentonite-to-water ratio and cement-to-fly ash ratio. Compared with other models, the Casson, De Kee–Casson, and Robertson–Stiff models tended to predict lower yield stresses.