Gelation And Structure Evolution Mechanism Research Of Waterproof Grouting Material

Mine water disaster has become one of major disasters in mining engineering. It is the critical measure to cut the water disaster chain with grouting into mined areas and water passages. Managed mined areas and water passages are made water proofed. Cement slurry, and the quick-setting grout material has been widely used in the mine water treatment process. But studies on its condensation mechanism is still in the theoretical analysis level. A reliable basis for the actual project could not be found.Portland cement, mining tailings, sodium silicate were selected as experimental material. Firstly, the ratio tests were done and main performance parameters of different proportions of the slurry were obtained. Two major factors (coagulation time and compressive strength) of water disaster control grouting material were analyzed specially. Secondly, based on NMR technology,three grouting slurry’s NMR T2relaxation properties and porosity characteristics were studied. Finally, characteristics and changes in the microstructure of the three kinds of grouting slurry were exploredIt was found that the setting time of double liquid grouting material declined with increasing dosage of sodium silicate, and setting time stayed stable after reaching a certain level. Ratio in the test range, the minimum setting time was found when volume ratio of sodium silicate to slurry was0.5. Dosage of accelerator significantly improved the early strength of slurry, but at the expense of later strength development potential. The higher the accelerator dosage, the lower strength of grouting material.Considering NMR T2relaxation time of grouting material, it could be inferred from the variation trend that capillary pores gradually developed into smaller gel pore structure. This was caused by the new composition carried out with hydration reaction. The continuous growth of new composition filled original pores. pore size in cement slurry was the smallest. the trend that large pores changed to smaller pores are weakest in paste with accelerator. Effect of accelerator were weakened with dosage of taillings, but the active ingredients in tailings would play a role in the later hydration.There were a grid-like structure inside grouting slurry, but its grid structures were significantly different. Pure cement slurry structure formation is the most dense, micron pores among grid was about10um. Quick-setting cement, grid and the grid nodes are the largest size, up to100um. Dense degree of grouting material is associated with compressive strength, the structure of the pure cement paste developed gradually with hydration reaction, it was able to achieve high early strength with accelerator added into slurry. However, the growth of the structure caused by hydration reaction is hampered. Therefore, it was far better than the pure cement grouting material, considering the later strength.