{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T17:13:32Z","timestamp":1782494012600,"version":"3.54.5"},"reference-count":31,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2024,6,6]],"date-time":"2024-06-06T00:00:00Z","timestamp":1717632000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Priority Academic Program Development of the Jiangsu Higher Education Institutions (PAPD)","award":["XCL-029"],"award-info":[{"award-number":["XCL-029"]}]},{"name":"Priority Academic Program Development of the Jiangsu Higher Education Institutions (PAPD)","award":["BK20140606"],"award-info":[{"award-number":["BK20140606"]}]},{"name":"Priority Academic Program Development of the Jiangsu Higher Education Institutions (PAPD)","award":["BK20180714"],"award-info":[{"award-number":["BK20180714"]}]},{"name":"Qing Lan Project, Six Talent Peaks Project in Jiangsu Province","award":["XCL-029"],"award-info":[{"award-number":["XCL-029"]}]},{"name":"Qing Lan Project, Six Talent Peaks Project in Jiangsu Province","award":["BK20140606"],"award-info":[{"award-number":["BK20140606"]}]},{"name":"Qing Lan Project, Six Talent Peaks Project in Jiangsu Province","award":["BK20180714"],"award-info":[{"award-number":["BK20180714"]}]},{"name":"Natural Science Foundation of Jiangsu Province","award":["XCL-029"],"award-info":[{"award-number":["XCL-029"]}]},{"name":"Natural Science Foundation of Jiangsu Province","award":["BK20140606"],"award-info":[{"award-number":["BK20140606"]}]},{"name":"Natural Science Foundation of Jiangsu Province","award":["BK20180714"],"award-info":[{"award-number":["BK20180714"]}]},{"name":"Natural Science Foundation of Jiangsu Province","award":["XCL-029"],"award-info":[{"award-number":["XCL-029"]}]},{"name":"Natural Science Foundation of Jiangsu Province","award":["BK20140606"],"award-info":[{"award-number":["BK20140606"]}]},{"name":"Natural Science Foundation of Jiangsu Province","award":["BK20180714"],"award-info":[{"award-number":["BK20180714"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>Immersion tests with 5 wt.% Na2SO4 solution were carried out to investigate the deterioration of calcium silicate hydrate (C-S-H) gel in a sulfate environment. C-S-H gels with different Ca\/(Si + Al) molar ratios were used for comparison. Particular attention was paid to the changes in element composition and Si-O-Si chain structure of the C-S-H gel. The results show that the C-S-H gels with a low Ca\/(Si + Al) ratio (0.8\u20131.0) and appropriate Si-O-Si chain length (14.8) presented better stability in a severe sulfate environment. The C-S-H gels with a higher Ca\/(Si + Al) ratio (&gt;2.0) were more sensitive to the attack of sulfate ions. Calcium ions dissolved rapidly during the immersion process, causing the loss of cohesive strength of the C-S-H gel, and then decomposed into fine particles. The C-S-H gel with a lower Ca\/(Si + Al) ratio (about 1.1) rarely leached out calcium ions and maintained good micromorphology. The 29Si MAS-NMR results indicate that the Si-O-Si chains with too short or too long chain lengths will break and recombine under the attack of sulfate ions. The Si-O-Si chains with an appropriate chain length (14.8) maintained the stability of the structure of the C-S-H gel in a sulfate environment. These changes are closely related to the asymmetric layered structure of amorphous C-S-H gel. Partial calcium ions between the layers of the main chain structure of Si-O-Si are easily taken away by sulfate ions, leading to the structural instability of the C-S-H gel.<\/jats:p>","DOI":"10.3390\/sym16060703","type":"journal-article","created":{"date-parts":[[2024,6,6]],"date-time":"2024-06-06T06:40:26Z","timestamp":1717656026000},"page":"703","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["The Deterioration of C-S-H Gel in a Severe Sulfate Environment"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8616-8909","authenticated-orcid":false,"given":"Wei","family":"Liao","sequence":"first","affiliation":[{"name":"State Key Laboratory of Materials-Oriented Chemical Engineering, College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chunhua","family":"Lu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Materials-Oriented Chemical Engineering, College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhongzi","family":"Xu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Materials-Oriented Chemical Engineering, College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,6,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"128","DOI":"10.1016\/j.conbuildmat.2016.04.147","article-title":"Durability of mortar and concrete made up of pozzolans as a partial replacement of cement: A review","volume":"116","author":"Hossain","year":"2016","journal-title":"Constr. 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