Experimental study on the strength deterioration of sulfidic paste backfill
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摘要: 高硫尾礦配制成的膏體表現出不同程度的強度劣化,高硫膏體強度劣化能引起充填體質量的巨大變化.通過不同硫含量的膏體強度劣化實驗,同時結合X射線衍射物相分析和環境掃描電鏡分析,對高硫膏體的劣化規律和劣化機理進行了分析.得出含硫尾礦在一定程度上能促進膏體早期強度增長,卻抑制了后期強度發育,硫含量越高,膏體后期強度劣化越顯著.硫化物氧化生成的硫酸鹽能促進膨脹性鈣礬石和石膏類物質的生成.同時酸性環境造成了C-S-H的脫鈣和CH的分解,已形成的膠凝體系遭到破壞,進一步促進了充填體的劣化.通過孔隙計算模型對晶體膨脹應變和裂紋發育過程進行了分析,闡述了膨脹性物質的線彈性應變發育機理.Abstract: Paste made from high-sulfur tailings shows strength deterioration to different degrees and this can cause great changes in the quality of the filling body. The deterioration and degradation mechanism of high-sulfur paste with different sulfur contents was analyzed using XRD (X-ray diffraction) phase analysis and an ESEM. The results showed that sulfur tailings promoted the growth of early strength to a certain extent, but inhibited the development of later strength, and the greater the sulfur content, the more obvious the effect. In addition, sulfate produced by sulfide oxidation can promote the formation of expansive ettringite and gypsum. Meanwhile, the acidic environment caused decalcification of C-S-H and dissolution of CH, destroys the cementitious system and further promotes the degradation of the filling body. The crystal expansion strain and crack development process were analyzed using a pore calculation model. The linear development of elastic strain in swelling material was clarified.
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Key words:
- paste backfill /
- sulfide tailings /
- strength degradation /
- microstructure /
- pyrite
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參考文獻
[2] Cihangir F, Ercikdi B, Kesimal A, et al. Paste backfill of highsulphide mill tailings using alkali-activated blast furnace slag:effect of activator nature, concentration and slag properties. Miner Eng, 2015, 83:117 [7] Ayora C, Chinchon S, Aguado A, et al. Weathering of iron sulfides and concrete alteration:thermodynamic model and observation in dams from Central Pyrenees, Spain. Cement Concrete Res, 1998, 28(4):591 [8] Fall M, Benzaazoua M. Modeling the effect of sulphate on strength development of paste backfill and binder mixture optimization. Cement Concrete Res, 2005, 35(2):301 [9] Klein K, Simon D. Effect of specimen composition on the strength development in cemented paste backfill. Can Geotech J, 2006, 43(3):310 [16] Benzaazoua M, Belem T, Bussiere B. Chemical factors that influence the performance of mine sulphidic paste backfill. Cement Concrete Res, 2002, 32(7):1133 [18] Hansen T C. Physical structure of hardened cement paste. A classical approach. Mater Struct, 1986, 19(6):423 [19] Ibrahim R E H, Rozière E, Grondin F, et al. Influence of sulphate solution concentration on the performance of cementitious materials during external sulphate attack. Meditsinskaia Sestra, 2009, 43(10):63 -
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