Sulfate Freeze–Thaw Resistance of Magnesium Potassium Phosphate Cement Mortar
Concrete facilities in the severe-cold areas of western China (salt lake environments and heavy saline soils) are seriously damaged by the multiple corrosion effects of freeze–thaw cycles and sulfate corrosion. Magnesium phosphate cement (MPC) cement-based material has become an ideal concrete struc...
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MDPI AG
2022-05-01
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| Online Access: | https://www.mdpi.com/1996-1944/15/9/3342 |
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| author | Bin Yang Rong-Jian Ji Qian Lan Jian-Ming Yang Jun Xu |
| author_facet | Bin Yang Rong-Jian Ji Qian Lan Jian-Ming Yang Jun Xu |
| author_sort | Bin Yang |
| collection | DOAJ |
| description | Concrete facilities in the severe-cold areas of western China (salt lake environments and heavy saline soils) are seriously damaged by the multiple corrosion effects of freeze–thaw cycles and sulfate corrosion. Magnesium phosphate cement (MPC) cement-based material has become an ideal concrete structural component because of its superior performance. Because concrete structural repair materials are used in heavy-corrosion environments, their durability in those environments should also be considered. Regarding the salt-freezing resistance of MPC, the existing studies have all used a NaCl solution as the heat transfer medium. In addition to chlorine salt, sulfate, especially Na<sub>2</sub>SO<sub>4</sub>, is also common in typical use environments such as oceans, salt lakes, and groundwater. To evaluate the sulfate freeze–thaw resistance of potassium magnesium phosphate cement (MKPC) mortar, in this study the strength development, weight loss, and water absorption of MKPC mortar specimens subjected to different freeze–thaw cycles were tested and compared with those for Portland cement (P.O) mortar specimens of the same strength grade. The results showed that the P.O mortar specimen completely lost its strength after 75 cycles of rapid water freezing and thawing and 50 cycles of sodium sulfate solution (5%) freezing and thawing. However, the residual strength rating of the MKPC mortar specimen after 75 cycles of water freezing and thawing and 100 cycles of sodium sulfate solution freezing and thawing was higher than 75%. After 50 rapid freeze–thaw cycles in water and a 5% Na<sub>2</sub>SO<sub>4</sub> solution, the P.O mortar specimen’s mass loss exceeded the 5% failure standard, whereas the mass loss of the MKPC mortar specimens was much less than 5%. Before the freeze–thaw cycles, the water absorption of the P.O mortar specimen was close to 8 times that of the MKPC mortar specimen, and after 50 water freeze–thaw cycles and 25 sulfate solution freeze–thaw cycles, the water absorption reached 4.88% and 5.68%, respectively. However, after 225 freeze–thaw cycles in water and the sulfate solution, the water absorption rates of MKPC mortar specimens were 2.91% and 2.51% respectively. The test and analysis results show that the freeze–thaw resistance of MKPC mortar was much higher than that of Portland cement mortar specimens. Those results provide a prerequisite for applying and expanding the use of MKPC-based materials in severe-cold areas of western China (salt lake and heavily saline soil environments). |
| first_indexed | 2024-03-10T03:58:02Z |
| format | Article |
| id | doaj.art-ea2da76cc9124b76b0da912333d75f09 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T03:58:02Z |
| publishDate | 2022-05-01 |
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| series | Materials |
| spelling | doaj.art-ea2da76cc9124b76b0da912333d75f092023-11-23T08:42:00ZengMDPI AGMaterials1996-19442022-05-01159334210.3390/ma15093342Sulfate Freeze–Thaw Resistance of Magnesium Potassium Phosphate Cement MortarBin Yang0Rong-Jian Ji1Qian Lan2Jian-Ming Yang3Jun Xu4School of Architecture Engineering, Jiangsu Open University, Nanjing 210036, ChinaYangzhou Polytechnic Institute, College of Architecture Engineering, Yangzhou 225127, ChinaYangzhou Polytechnic Institute, College of Architecture Engineering, Yangzhou 225127, ChinaSchool of Civil Engineering, San Jiang University, Nanjing 210012, ChinaDepartment of Architecture and Civil Engineering, College of Civil Engineering and Architecture, Jiangsu University of Science and Technology, Zhenjiang 212000, ChinaConcrete facilities in the severe-cold areas of western China (salt lake environments and heavy saline soils) are seriously damaged by the multiple corrosion effects of freeze–thaw cycles and sulfate corrosion. Magnesium phosphate cement (MPC) cement-based material has become an ideal concrete structural component because of its superior performance. Because concrete structural repair materials are used in heavy-corrosion environments, their durability in those environments should also be considered. Regarding the salt-freezing resistance of MPC, the existing studies have all used a NaCl solution as the heat transfer medium. In addition to chlorine salt, sulfate, especially Na<sub>2</sub>SO<sub>4</sub>, is also common in typical use environments such as oceans, salt lakes, and groundwater. To evaluate the sulfate freeze–thaw resistance of potassium magnesium phosphate cement (MKPC) mortar, in this study the strength development, weight loss, and water absorption of MKPC mortar specimens subjected to different freeze–thaw cycles were tested and compared with those for Portland cement (P.O) mortar specimens of the same strength grade. The results showed that the P.O mortar specimen completely lost its strength after 75 cycles of rapid water freezing and thawing and 50 cycles of sodium sulfate solution (5%) freezing and thawing. However, the residual strength rating of the MKPC mortar specimen after 75 cycles of water freezing and thawing and 100 cycles of sodium sulfate solution freezing and thawing was higher than 75%. After 50 rapid freeze–thaw cycles in water and a 5% Na<sub>2</sub>SO<sub>4</sub> solution, the P.O mortar specimen’s mass loss exceeded the 5% failure standard, whereas the mass loss of the MKPC mortar specimens was much less than 5%. Before the freeze–thaw cycles, the water absorption of the P.O mortar specimen was close to 8 times that of the MKPC mortar specimen, and after 50 water freeze–thaw cycles and 25 sulfate solution freeze–thaw cycles, the water absorption reached 4.88% and 5.68%, respectively. However, after 225 freeze–thaw cycles in water and the sulfate solution, the water absorption rates of MKPC mortar specimens were 2.91% and 2.51% respectively. The test and analysis results show that the freeze–thaw resistance of MKPC mortar was much higher than that of Portland cement mortar specimens. Those results provide a prerequisite for applying and expanding the use of MKPC-based materials in severe-cold areas of western China (salt lake and heavily saline soil environments).https://www.mdpi.com/1996-1944/15/9/3342magnesium potassium phosphate cement mortarsulfate freeze–thaw resistancestrengthweight losswater absorption |
| spellingShingle | Bin Yang Rong-Jian Ji Qian Lan Jian-Ming Yang Jun Xu Sulfate Freeze–Thaw Resistance of Magnesium Potassium Phosphate Cement Mortar Materials magnesium potassium phosphate cement mortar sulfate freeze–thaw resistance strength weight loss water absorption |
| title | Sulfate Freeze–Thaw Resistance of Magnesium Potassium Phosphate Cement Mortar |
| title_full | Sulfate Freeze–Thaw Resistance of Magnesium Potassium Phosphate Cement Mortar |
| title_fullStr | Sulfate Freeze–Thaw Resistance of Magnesium Potassium Phosphate Cement Mortar |
| title_full_unstemmed | Sulfate Freeze–Thaw Resistance of Magnesium Potassium Phosphate Cement Mortar |
| title_short | Sulfate Freeze–Thaw Resistance of Magnesium Potassium Phosphate Cement Mortar |
| title_sort | sulfate freeze thaw resistance of magnesium potassium phosphate cement mortar |
| topic | magnesium potassium phosphate cement mortar sulfate freeze–thaw resistance strength weight loss water absorption |
| url | https://www.mdpi.com/1996-1944/15/9/3342 |
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