Carbonation of Concretes with SCMs

Anya Vollpracht, Gregor J.G. Gluth, Bart Rogiers, I.D. Uwanuakwa, Quoc Tri Phung, Yury Villagran Zaccardi, Charlotte Thiel, Hanne Vanoutrive, Juan Manuel Etcheverry, Elke Gruyaert, Siham Kamali-Bernard, Antonios Kanellopoulos, Zengfeng Zhao, Isabel Milagre Martins, Sundar Rathnarajan, Nele De Belie

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Abstract

Due to the urgent need to reduce CO2 emissions, cement and concrete producers aim to substitute increasing proportions of Portland cement by supplementary cementitious materials (SCMs). However, lowering the clinker content can lead to an increasing risk of neutralisation of the concrete pore solution and reinforce-ment corrosion due to carbonation. Carbonation mechanisms and kinetics depend on hydrate phase assem-blage, pore solution chemistry and porous structure as well as the exposure conditions. To study the effects of mix-design, curing, preconditioning and storage conditions on carbonation resistance, the RILEM TC 281–CCC established a comprehensive database, consisting of 1044 concrete and mortar mixes with their associated carbonation depth data over time. The dataset comprises mix designs with a large variety of binders and includes information on chemical composition and physical properties of the raw materials, compressive strengths, curing and carbonation testing conditions. Both natural and accelerated carbonation with CO2 concentrations of up to10 vol.-% were considered. The analysis of the available data confirmed that the w/CaOreactive ratio is a decisive factor for carbonation resistance, but curing and exposure conditions also influence carbonation. Probabilistic inference suggests that both accelerated and natural carbonation processes follow a square-root-of-time behavior, but direct conversion between accelerated and natural carbonation by solely taking the CO2 concentration into account is not possible. Accelerated carbonation testing and application of the square-root-of-time law yield predicted natural carbonation depths that tend to be lower than the measured values. This effect was particularly noticeable for concretes with a higher SCM fraction (w/CaOreactive > ~1.1).
Original languageEnglish
Title of host publicationConcrete under Severe Conditions - Environment & Loading
Subtitle of host publicationProceedings of 10th International Conference (CONSEC24) Chennai, India
PublisherIIT Madras
Pages140-143
Number of pages4
StatePublished - 25 Sep 2024
Event2024 - CONSEC24: 10th international conference on CONcrete under SEvere Conditions - Environment and loading - IIT Madras Research park, Madras
Duration: 25 Sep 202427 Sep 2024
https://consec24.com/

Conference

Conference2024 - CONSEC24
Abbreviated titleCONSEC24
Country/TerritoryIndia
CityMadras
Period2024-09-252024-09-27
Internet address

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