Rheological performance regulation of solidified soil slurry for mine reclamation: Superplasticizer selection and structural characterization based on in-situ techniques
This paper focuses on the low cement content characteristic of soil slurry materials for mine reclamation, investigating the effects of three types of superplasticizers (polyester-based polycarboxylate (PCE), sodium lignosulfonate (SLS), and naphthalene-based (PNS)) on the flow properties of freshly mixed solidified soil slurry. It proposes a method combining shear rheology and micro-rheology experiments to complete the selection of superplasticizers. The rheological properties of the freshly mixed slurry were compared at different dosages of superplasticizers and various resting times. The results indicate that PCE at 0.4 % dosage exhibits the best dispersion effect in the solidified soil slurry. In-situ ATR FTIR, in-situ low-field NMR, and zeta-potential tests confirmed that PCE can effectively delay the solidification process of the soil slurry to maintain its fluidity. At a PCE dosage of 0.4 %, the spatial hindrance between slurry particles is reduced, increasing the proportion of free water in the solidified soil, with the zeta-potential not being the main factor affecting the rheological properties of the soil slurry. This study provides a theoretical foundation and solutions for regulating the early fluidity of solidified soil slurry materials used in the land reclamation of coal gangue in the Northwest mining areas of China.
