{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,22]],"date-time":"2026-07-22T18:17:18Z","timestamp":1784744238939,"version":"3.55.0"},"reference-count":36,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2025,10,30]],"date-time":"2025-10-30T00:00:00Z","timestamp":1761782400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004608","name":"Natural Science Foundation of Jiangsu Province, China","doi-asserted-by":"publisher","award":["BK20241483"],"award-info":[{"award-number":["BK20241483"]}],"id":[{"id":"10.13039\/501100004608","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["52378401"],"award-info":[{"award-number":["52378401"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["52422808"],"award-info":[{"award-number":["52422808"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012226","name":"Fundamental Research Funds for the Central Universities","doi-asserted-by":"publisher","award":["30924010946"],"award-info":[{"award-number":["30924010946"]}],"id":[{"id":"10.13039\/501100012226","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>This study explored the chloride binding characteristics and mechanisms of sulphoaluminate cement (SAC) by isolating its principal mineral component, anhydrous calcium sulphoaluminate (C4A3S-), as the research object. Chloride ingress was investigated under external penetration and internal incorporation conditions, with gypsum dosage varied at molar ratios of 1:0, 1:1, and 1:2 relative to \u00a0C4A3S-. Through chloride binding experiments and hydration product analysis performed by XRD and TG, the following findings were obtained: under external chloride exposure, the binding capacity increased with rising solution concentration and immersion time. External chloride binding was attributed to SO42\u2212\/Cl\u2212 ion exchange in AFm to generate Friedel\u2019s salt and was complemented by physical adsorption of chloride in AH3 gel. Under internal chloride incorporation, binding capacity increased progressively with curing age. Internal chloride binding involved the direct participation of Cl\u2212 in hydration reactions to form Friedel\u2019s salt in addition to the chemical reaction of AFm and the physical adsorption of AH3. Gypsum dosage critically regulates the AFm\/AFt ratio, which in turn governs chloride binding efficiency under both external and internal chloride scenarios (e.g., after immersion in 1 mol\/L NaCl solution, the bound chloride content for C4A3S-\/gypsum ratios of 1:0, 1:1, and 1:2 was 50.94, 27.28, and 13.47 mg\/g, respectively).<\/jats:p>","DOI":"10.3390\/ma18214949","type":"journal-article","created":{"date-parts":[[2025,10,30]],"date-time":"2025-10-30T03:44:39Z","timestamp":1761795879000},"page":"4949","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Exploration of the Chloride Binding Behavior of Anhydrous Calcium Sulfoaluminate Under Dual Chloride Ingress Modes"],"prefix":"10.3390","volume":"18","author":[{"given":"Zirui","family":"Cheng","sequence":"first","affiliation":[{"name":"School of Safety Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Luyan","family":"Ji","sequence":"additional","affiliation":[{"name":"School of Safety Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhen","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Linlin","family":"Gu","sequence":"additional","affiliation":[{"name":"School of Safety Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wenbin","family":"Tang","sequence":"additional","affiliation":[{"name":"School of Safety Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,10,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"102074","DOI":"10.1016\/j.jobe.2020.102074","article-title":"Durability deterioration of concrete under marine environment from material to structure: A critical review","volume":"35","author":"Qu","year":"2021","journal-title":"J. Build. Eng."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"126888","DOI":"10.1016\/j.jclepro.2021.126888","article-title":"Techno-economic assessment of calcium sulfoaluminate clinker production using elemental sulfur as raw material","volume":"301","author":"Chaliulina","year":"2021","journal-title":"J. Clean. Prod."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"152","DOI":"10.1016\/j.cemconres.2017.02.030","article-title":"Influence of fly ash on the hydration of calcium sulfoaluminate cement","volume":"95","author":"Martin","year":"2017","journal-title":"Cem. Concr. Res."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"116665","DOI":"10.1016\/j.conbuildmat.2019.08.046","article-title":"Effect of ground granulated blast furnace slag on the properties of calcium sulfoaluminate cement","volume":"227","author":"Gao","year":"2019","journal-title":"Constr. Build. Mater."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"126138","DOI":"10.1016\/j.conbuildmat.2021.126138","article-title":"Exploration of hydration and durability properties of ferroaluminate cement with compare to Portland cement","volume":"319","author":"Cheng","year":"2022","journal-title":"Constr. Build. Mater."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"305","DOI":"10.1016\/j.conbuildmat.2013.11.110","article-title":"Influences of freeze\u2013thaw cycle and curing time on chloride ion penetration resistance of Sulphoaluminate cement concrete","volume":"53","author":"Zhao","year":"2014","journal-title":"Constr. Build. Mater."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"124139","DOI":"10.1016\/j.conbuildmat.2021.124139","article-title":"Effects of cyclic seawater exposure on the mechanical performance and chloride penetration of calcium sulfoaluminate concrete","volume":"303","author":"Tang","year":"2021","journal-title":"Constr. Build. Mater."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Tang, X., Zhan, S., Xu, Q., and He, K. (2023). Mechanical Performance and Chloride Penetration of Calcium Sulfoaluminate Concrete in Marine Tidal Zone. Materials, 16.","DOI":"10.3390\/ma16072905"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"649","DOI":"10.1016\/j.conbuildmat.2017.12.064","article-title":"Prediction of chloride ingress into blended cement concrete: Evaluation of a combined short-term laboratory-numerical procedure","volume":"162","author":"Chari","year":"2018","journal-title":"Constr. Build. Mater."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"107318","DOI":"10.1016\/j.jobe.2023.107318","article-title":"Chloride binding behavior of calcium silicate hydrates and Friedel\u2019s salt of pastes","volume":"76","author":"Chang","year":"2023","journal-title":"J. Build. Eng."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1016\/j.cemconres.2018.03.001","article-title":"Influence of calcium ion in concrete pore solution on the passivation of galvanized steel bars","volume":"108","author":"Zheng","year":"2018","journal-title":"Cem. Concr. Res."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1016\/j.cemconcomp.2018.12.011","article-title":"Chloride binding of cement pastes with fly ash exposed to CaCl2 solutions at 5 and 23 \u00b0C","volume":"97","author":"Qiao","year":"2019","journal-title":"Cem. Concr. Compos."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"108978","DOI":"10.1016\/j.jobe.2024.108978","article-title":"Research progress in mechanisms, influence factors and improvement routes of chloride binding for cement composites","volume":"86","author":"He","year":"2024","journal-title":"J. Build. Eng."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"127929","DOI":"10.1016\/j.conbuildmat.2022.127929","article-title":"Effects of curing regimes on the chloride binding capacity of cementitious materials","volume":"342","author":"Chen","year":"2022","journal-title":"Constr. Build. Mater."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"131584","DOI":"10.1016\/j.conbuildmat.2023.131584","article-title":"Chloride binding and diffusion of slag blended concrete mixtures","volume":"388","author":"Mapa","year":"2023","journal-title":"Constr. Build. Mater."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"104603","DOI":"10.1016\/j.cemconcomp.2022.104603","article-title":"Investigation on chloride binding capacity and stability of Friedel\u2019s salt in graphene oxide reinforced cement paste","volume":"132","author":"Long","year":"2022","journal-title":"Cem. Concr. Compos."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"04021429","DOI":"10.1061\/(ASCE)MT.1943-5533.0004066","article-title":"Binding mechanism of CSA cement on premixed Cl\u2212 and its governing parameters","volume":"34","author":"Wang","year":"2022","journal-title":"J. Mater. Civ. Eng."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"04025246","DOI":"10.1061\/JMCEE7.MTENG-19536","article-title":"Effect of Temperature on the Hydration, Chloride Penetration Resistance, and Chloride-Binding Capacity of Ferric-Rich Sulfoaluminate Cement","volume":"37","author":"Cheng","year":"2025","journal-title":"J. Mater. Civ. Eng."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"107728","DOI":"10.1016\/j.jobe.2023.107728","article-title":"Chloride penetration resistance and chloride binding capacity under different application environments of ferroaluminate cement","volume":"78","author":"Cheng","year":"2023","journal-title":"J. Build. Eng."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"04023238","DOI":"10.1061\/JMCEE7.MTENG-15178","article-title":"Corrosion Resistance of Calcium Sulfoaluminate Cementitious Systems","volume":"35","author":"Shakouri","year":"2023","journal-title":"J. Mater. Civ. Eng."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"120852","DOI":"10.1016\/j.conbuildmat.2020.120852","article-title":"Behavior of blends of CSA and Portland cements in high chloride environment","volume":"262","author":"Bertola","year":"2020","journal-title":"Constr. Build. Mater."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/j.cemconres.2014.08.004","article-title":"Friedel\u2019s salt formation in sulfoaluminate cements: A combined XRD and 27Al MAS NMR study","volume":"67","author":"Paul","year":"2015","journal-title":"Cem. Concr. Res."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1016\/j.cemconres.2013.01.008","article-title":"C4A3\u0160 hydration in different alkaline media","volume":"46","author":"Palomo","year":"2013","journal-title":"Cem. Concr. Res."},{"key":"ref_24","first-page":"75","article-title":"Hydration of calcium sulphoaluminate at different water\/solid ratios","volume":"24","author":"Chang","year":"2016","journal-title":"Mater. Sci. Technol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"107216","DOI":"10.1016\/j.cemconres.2023.107216","article-title":"Nanostructure evolution of (A\/F) H3 phase with different alkali concentrations based on calcium sulfoaluminate cement","volume":"172","author":"Li","year":"2023","journal-title":"Cem. Concr. Res."},{"key":"ref_26","first-page":"e01440","article-title":"Study on properties and degradation mechanism of calcium sulphoaluminate cement-ordinary Portland cement binary repair material under seawater erosion","volume":"17","author":"Li","year":"2022","journal-title":"Case Stud. Constr. Mater."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"847","DOI":"10.1016\/j.conbuildmat.2017.10.086","article-title":"Influence of polycarboxylate superplasticizer on chloride binding in cement paste","volume":"158","author":"Feng","year":"2018","journal-title":"Constr. Build. Mater."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"102419","DOI":"10.1016\/j.jobe.2021.102419","article-title":"Chloride permeability and chloride binding capacity of nano-modified concrete","volume":"41","author":"Li","year":"2021","journal-title":"J. Build. Eng."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"421","DOI":"10.1016\/j.conbuildmat.2014.04.038","article-title":"Modelling of chloride binding related to hydration products in slag-blended cements","volume":"64","author":"Florea","year":"2014","journal-title":"Constr. Build. Mater."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"105945","DOI":"10.1016\/j.jobe.2023.105945","article-title":"Chloride binding of monosulfate hydrate (AFm) and its effect on steel corrosion in simulated concrete pore solution","volume":"67","author":"Zhang","year":"2023","journal-title":"J. Build. Eng."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"479","DOI":"10.1016\/j.commatsci.2018.07.021","article-title":"Insight on the sodium and chloride ions adsorption mechanism on the ettringite crystal: Structure, dynamics and interfacial interaction","volume":"153","author":"Hou","year":"2018","journal-title":"Comput. Mater. Sci."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"698","DOI":"10.4028\/www.scientific.net\/KEM.467-469.698","article-title":"Study on bonding characteristic of mixed-type chloride ion in sulphoaluminate cement","volume":"467","author":"Zhao","year":"2011","journal-title":"Key Eng. Mater."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"3749","DOI":"10.1007\/s10706-022-02123-8","article-title":"Study on the erosion mechanism of the solidified silt under sulphate\u2013chloride erosion","volume":"40","author":"Wu","year":"2022","journal-title":"Geotech. Geol. Eng."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1180","DOI":"10.1016\/j.cemconres.2009.08.003","article-title":"Hydration of calcium sulfoaluminate cement by a ZnCl2 solution: Investigation at early age","volume":"39","author":"Berger","year":"2009","journal-title":"Cem. Concr. Res."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Wei, Y., Cao, Z., Hou, J., Li, B., Jia, G., Chen, P., and Liu, P. (2024). Study on the chloride ion binding rate of sulfoaluminate cement mortars containing different mineral admixtures. Sci. Rep., 14.","DOI":"10.1038\/s41598-024-75171-0"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Deng, H., Wei, X., Liu, S., Li, S., and Cai, X. (2020). Influence of different lithium compounds on hydration and mechanical properties of calcium sulfoaluminate cement. Materials, 13.","DOI":"10.3390\/ma13163465"}],"container-title":["Materials"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1996-1944\/18\/21\/4949\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,30]],"date-time":"2025-10-30T03:49:12Z","timestamp":1761796152000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1996-1944\/18\/21\/4949"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,10,30]]},"references-count":36,"journal-issue":{"issue":"21","published-online":{"date-parts":[[2025,11]]}},"alternative-id":["ma18214949"],"URL":"https:\/\/doi.org\/10.3390\/ma18214949","relation":{},"ISSN":["1996-1944"],"issn-type":[{"value":"1996-1944","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,10,30]]}}}