Effect of Freeze–Thaw Cycles on Mechanical and Microstructural Properties of Tailings Reinforced with Cement-Based Material

Abstract

In China, more than 10,000 Tailings storage facilities (TSF) have been created on the ground surface through mineral mining processes, these TSF occupy a large amount of land. The strength of the tailings is too low to be able to stand on its own without strengthening. In order to save land resources and alleviate the damage to the environment caused by mineral mining, it is necessary to reinforce the TSF so that they can store more tailings. China is one of the countries with the largest area of permafrost and seasonal frozen regions, accounting for about 75% of the country’s total land area. The problem can be exacerbated in these regions where the freeze–thaw effect can further degrade the strength of tailings. A review of the literature suggests that there is little research on the mechanical and microstructural properties of tailings reinforced with cement-based materials under freeze–thaw conditions, especially when the tailings are to be discharged to land for sustainable development. This study investigates the effect of freeze–thaw cycles on the mechanical properties and microstructural changes of tailings reinforced with cement-based materials to mitigate environmental hazards. Unconfined compressive strength (UCS) tests, scanning electron microscopic images, X-Ray Diffraction tests, thermogravimetry tests and mercury intrusion porosimetry tests were conducted on samples of tailings. The results from this study show that freeze–thaw cycles reduce the UCS of all the tested samples eventually, but the frozen temperature does not significantly affect the UCS. The larger number of freeze–thaw cycles, the more damage is to the surface morphology and the matrix of the tailings. The results presented in the paper can help engineers and managers to effectively transport the TSF to other locations to minimize environmental hazards to achieve sustainable production of mineral mining processes.

Performance of a New Grouting Material under the Coupling Effects of Freeze–Thaw and Sulfate Erosion

“…As can be seen in Figure 7, the main hydration products of the specimens after freeze-thaw cycling in aqueous solution are Ca(OH) 2 , AFt (ettringite) crystals, C-S-H gel, CaCO 3 , etc. Ding et al investigated the effect of freeze-thaw cycling on the microscopic properties of new cementitious materials and came to the same conclusion [17]. The Ca(OH) 2 diffraction peaks of the samples in the aqueous solution increased with the number of freezethaw cycles compared to the pre-freeze-thaw period.…”

Mining Safety and Sustainability—An Overview

“…Reinforced TSFs are beneficial for saving land resources, reducing environmental damage caused by mineral extraction, and achieving sustainable production in the mineral extraction process. Ding et al [37] investigated the effects of freeze-thaw cycles on the mechanical properties and microstructural changes of cementitious material-reinforced tailings by performing unconfined compressive strength (UCS) tests, scanning electron microscope imagery, X-ray diffraction tests, and thermogravimetric tests. The results demonstrated that freeze-thaw cycles eventually reduce the UCS of all tested samples, and the higher the number of freeze-thaw cycles, the greater the damage to the surface morphology and matrix of the tailings.…”

Freeze–Thaw Damage Characterization of Cement-Stabilized Crushed Stone Base with Skeleton Dense Gradation

“…Ding et al revealed that freeze–thaw cycles degrade the mechanical properties of tailings reinforced with cement-based materials. However, the frozen temperature does not significantly affect the unconfined compressive strength [ 23 ]. Ying et al pointed out that marine shell powder can improve the mechanical properties of cement-solidified coastal clay to some extent, and the corresponding best marine shell powder content is 15%, which can enhance the compactness of coastal cement clay under freeze–thaw cycles [ 24 ].…”