Evaluating the Effectiveness of CO₂ Curing Versus Conventional Water Curing in Fly Ash–Blended Concrete

Evaluating the Effectiveness of CO₂ Curing Versus Conventional Water Curing in Fly Ash–Blended Concrete | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Evaluating the Effectiveness of CO₂ Curing Versus Conventional Water Curing in Fly Ash–Blended Concrete Raghuvanshi Shubham, Patel Kumar Arun, Dangi Vishnu Prasad This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9015825/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This study evaluates the performance of carbon dioxide (CO₂) curing in comparison with conventional water curing for concrete embedding coal fly ash as a partial replacement of Ordinary Portland Cement. Cement mortar cubes were prepared with varying fly ash replacement ratios (0–25%) and subjected to CO₂ curing for 6, 12, and 24 hours, as well as conventional water curing for up to 28 days. Compressive strength development, carbonation depth, and durability-related characteristics were assessed. The results demonstrate that CO₂ curing significantly enhances early-age compressive strength by accelerating carbonation reactions and refining the pore structure. Specimens subjected to 24 hours of CO₂ curing achieved strength levels comparable to those obtained after several days of conventional curing. An optimum fly ash replacement level of approximately 5% yielded comparable or improved strength under both curing regimes. At higher fly ash contents (≥15%), a reduction in strength was observed due to dilution of cementitious phases, although CO₂ curing partially mitigated this loss. Phenolphthalein testing confirmed effective carbonation penetration, indicating successful CO₂ sequestration within the cement matrix. The study concludes that integrating CO₂ curing with partial cement replacement using coal fly ash offers a viable pathway toward sustainable, low-carbon concrete with enhanced early-age performance. CO₂ curing Carbonation curing Coal fly ash Sustainable concrete Accelerated carbonation Compressive strength CO₂ sequestration Full Text Additional Declarations The authors declare potential competing interests as follows: No, the authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this preprint submission. All authors are affiliated with RKDF University, Bhopal, India, and the research was conducted independently without any commercial or financial influence. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9015825","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":599704219,"identity":"fcd9cceb-6f59-4b78-bc83-3d86b498e684","order_by":0,"name":"Raghuvanshi Shubham","email":"data:image/png;base64,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","orcid":"https://orcid.org/0009-0004-9374-3969","institution":"Department of civil Engineering, RKDF, University Bhopal, India","correspondingAuthor":true,"prefix":"","firstName":"Raghuvanshi","middleName":"","lastName":"Shubham","suffix":""},{"id":599704220,"identity":"32fde562-aab2-46d5-a5a2-35c25cc271d1","order_by":1,"name":"Patel Kumar Arun","email":"","orcid":"https://orcid.org/0000-0002-2646-9806","institution":"Department of civil Engineering, RKDF, University Bhopal, India","correspondingAuthor":false,"prefix":"","firstName":"Patel","middleName":"Kumar","lastName":"Arun","suffix":""},{"id":599704221,"identity":"d83ac377-0cf6-428a-bb7b-c4ba6b747b81","order_by":2,"name":"Dangi Vishnu Prasad","email":"","orcid":"https://orcid.org/0009-0001-6758-6507","institution":"Department of civil Engineering, RKDF, University Bhopal, India","correspondingAuthor":false,"prefix":"","firstName":"Dangi","middleName":"Vishnu","lastName":"Prasad","suffix":""}],"badges":[],"createdAt":"2026-03-03 04:48:06","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":true,"conflictsOfInterestStatement":true,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":true},"doi":"10.21203/rs.3.rs-9015825/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9015825/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":103930744,"identity":"dbfa07f7-92c8-4e87-b67b-c9ab118f0cfb","added_by":"auto","created_at":"2026-03-04 16:29:04","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1066804,"visible":true,"origin":"","legend":"","description":"","filename":"FinalPaper.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9015825/v1_covered_338cba01-c2bd-40d6-88c1-a351b21fab5d.pdf"}],"financialInterests":"The authors declare potential competing interests as follows: No, the authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this preprint submission. 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Cement mortar cubes were prepared with varying fly ash replacement ratios (0–25%) and subjected to CO₂ curing for 6, 12, and 24 hours, as well as conventional water curing for up to 28 days. Compressive strength development, carbonation depth, and durability-related characteristics were assessed. The results demonstrate that CO₂ curing significantly enhances early-age compressive strength by accelerating carbonation reactions and refining the pore structure. Specimens subjected to 24 hours of CO₂ curing achieved strength levels comparable to those obtained after several days of conventional curing. An optimum fly ash replacement level of approximately 5% yielded comparable or improved strength under both curing regimes. At higher fly ash contents (≥15%), a reduction in strength was observed due to dilution of cementitious phases, although CO₂ curing partially mitigated this loss. 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