Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Effects of chloride salts on strength, hydration, and microstructure of cemented tailings backfill with one-part alkali-activated slag
https://orcid.org/0000-0002-1953-3208
https://orcid.org/0000-0002-2088-5905
https://orcid.org/0000-0001-9859-393X
Highlights Chloride salts’ effects on strength, hydration and microstructure of CTB were studied. The influence of chloride salts is highly dependent on their cation type. NaCl slightly weakens CTB’s strength due to the C-(A)-S-H decalcification. CaCl2 promotes slag hydration and thus improves the CTB’s microstructure and strength. MgCl2 inhibits slag dissolution due to the reaction between Mg2+ and OH–, markedly lowering CTB’s strength.
Abstract For mines located in saline areas, the use of mine water containing chloride salts to prepare cemented tailings backfill (CTB) for mined-out area treatment can realize the resource utilization of mine water and save a large amount of precious freshwater. However, the hydration behavior of binder and strength properties of CTB in the presence of chloride salts is still not well understood. This research investigates the effects of NaCl, CaCl2 and MgCl2 with different Cl- concentrations (0.50, 0.77 and 1.0 mol/L) on strength of CTB prepared with one-part alkali-activated slag binder. It analyzes the hydration process of binder and the microstructure of CTB. The results indicated that the decalcification of C-A-S-H (replaced by sodium to create N(C)-A-S-H at high Na+ concentrations) leads to numerous 0.01–0.1 μm micropores within the hardened backfill, increasing porosity while decreasing strength by 3.2–25.0%. Calcium ion (Ca2+) contributes to the formation of dense internal structures and high-strength backfill. Magnesium ion (Mg2+) reduces alkalinity by consuming Ca(OH)2, seriously impacts slag decomposition, but accelerates the dissolution of desulfurized gypsum. The study’s findings will help the application of chloride-containing mixing water in mines situated in saline regions.
Effects of chloride salts on strength, hydration, and microstructure of cemented tailings backfill with one-part alkali-activated slag
https://orcid.org/0000-0002-1953-3208
https://orcid.org/0000-0002-2088-5905
https://orcid.org/0000-0001-9859-393X
Highlights Chloride salts’ effects on strength, hydration and microstructure of CTB were studied. The influence of chloride salts is highly dependent on their cation type. NaCl slightly weakens CTB’s strength due to the C-(A)-S-H decalcification. CaCl2 promotes slag hydration and thus improves the CTB’s microstructure and strength. MgCl2 inhibits slag dissolution due to the reaction between Mg2+ and OH–, markedly lowering CTB’s strength.
Abstract For mines located in saline areas, the use of mine water containing chloride salts to prepare cemented tailings backfill (CTB) for mined-out area treatment can realize the resource utilization of mine water and save a large amount of precious freshwater. However, the hydration behavior of binder and strength properties of CTB in the presence of chloride salts is still not well understood. This research investigates the effects of NaCl, CaCl2 and MgCl2 with different Cl- concentrations (0.50, 0.77 and 1.0 mol/L) on strength of CTB prepared with one-part alkali-activated slag binder. It analyzes the hydration process of binder and the microstructure of CTB. The results indicated that the decalcification of C-A-S-H (replaced by sodium to create N(C)-A-S-H at high Na+ concentrations) leads to numerous 0.01–0.1 μm micropores within the hardened backfill, increasing porosity while decreasing strength by 3.2–25.0%. Calcium ion (Ca2+) contributes to the formation of dense internal structures and high-strength backfill. Magnesium ion (Mg2+) reduces alkalinity by consuming Ca(OH)2, seriously impacts slag decomposition, but accelerates the dissolution of desulfurized gypsum. The study’s findings will help the application of chloride-containing mixing water in mines situated in saline regions.
Effects of chloride salts on strength, hydration, and microstructure of cemented tailings backfill with one-part alkali-activated slag
https://orcid.org/0000-0002-1953-3208
https://orcid.org/0000-0002-2088-5905
https://orcid.org/0000-0001-9859-393X
Highlights Chloride salts’ effects on strength, hydration and microstructure of CTB were studied. The influence of chloride salts is highly dependent on their cation type. NaCl slightly weakens CTB’s strength due to the C-(A)-S-H decalcification. CaCl2 promotes slag hydration and thus improves the CTB’s microstructure and strength. MgCl2 inhibits slag dissolution due to the reaction between Mg2+ and OH–, markedly lowering CTB’s strength.
Abstract For mines located in saline areas, the use of mine water containing chloride salts to prepare cemented tailings backfill (CTB) for mined-out area treatment can realize the resource utilization of mine water and save a large amount of precious freshwater. However, the hydration behavior of binder and strength properties of CTB in the presence of chloride salts is still not well understood. This research investigates the effects of NaCl, CaCl2 and MgCl2 with different Cl- concentrations (0.50, 0.77 and 1.0 mol/L) on strength of CTB prepared with one-part alkali-activated slag binder. It analyzes the hydration process of binder and the microstructure of CTB. The results indicated that the decalcification of C-A-S-H (replaced by sodium to create N(C)-A-S-H at high Na+ concentrations) leads to numerous 0.01–0.1 μm micropores within the hardened backfill, increasing porosity while decreasing strength by 3.2–25.0%. Calcium ion (Ca2+) contributes to the formation of dense internal structures and high-strength backfill. Magnesium ion (Mg2+) reduces alkalinity by consuming Ca(OH)2, seriously impacts slag decomposition, but accelerates the dissolution of desulfurized gypsum. The study’s findings will help the application of chloride-containing mixing water in mines situated in saline regions.
Effects of chloride salts on strength, hydration, and microstructure of cemented tailings backfill with one-part alkali-activated slag
Zhu, Gengjie (Autor:in) / Zhu, Wancheng (Autor:in) / Fu, You (Autor:in) / Yan, Baoxu (Autor:in) / Jiang, Haiqiang (Autor:in)
05.03.2023
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
| British Library Online Contents | 2019