TY - JOUR A1 - Vanoutrive, Hanne A1 - van den Heede, Philip A1 - Alderete, Natalia A1 - Andrade, Carmen A1 - Bansal, Tushar A1 - Camões, Aires A1 - Cizer, Özlem A1 - de Belie, Nele A1 - Ducman, Vilma A1 - Etxeberria, Miren A1 - Frederickx, Lander A1 - Grengg, Cyrill A1 - Ignjatović, Ivan A1 - Ling, Tung-Chai A1 - Liu, Zhiyuan A1 - Garcia-Lodeiro, Inés A1 - Lothenbach, Barbara A1 - Medina Martinez, César A1 - Sanchez-Montero, Javier A1 - Olonade, Kolawole A1 - Palomo, Angel A1 - Phung, Quoc Tri A1 - Rebolledo, Nuria A1 - Sakoparnig, Marlene A1 - Sideris, Kosmas A1 - Thiel, Charlotte A1 - Visalakshi, Talakokula A1 - Vollpracht, Anya A1 - von Greve-Dierfeld, Stefanie A1 - Wei, Jinxin A1 - Wu, Bei A1 - Zając, Maciej A1 - Zhao, Zengfeng A1 - Gruyaert, Elke T1 - Report of RILEM TC 281-CCC: outcomes of a round robin on the resistance to accelerated carbonation of Portland, Portland-fly ash and blast-furnace blended cements JF - Materials and Structures N2 - Many (inter)national standards exist to evaluate the resistance of mortar and concrete to carbonation. When a carbonation coefficient is used for performance comparison of mixtures or service life prediction, the applied boundary conditions during curing, preconditioning and carbonation play a crucial role, specifically when using latent hydraulic or pozzolanic supplementary cementitious materials (SCMs). An extensive interlaboratory test (ILT) with twenty two participating laboratories was set up in the framework of RILEM TC 281-CCC 'Carbonation of Concrete with SCMs'. The carbonation depths and coefficients determined by following several (inter)national standards for three cement types (CEM I, CEM II/B-V, CEM III/B) both on mortar and concrete scale were statistically compared. The outcomes of this study showed that the carbonation rate based on the carbonation depths after 91 days exposure, compared to 56 days or less exposure duration, best approximates the slope of the linear regression and those 91 days carbonation depths can therefore be considered as a good estimate of the potential resistance to carbonation. All standards evaluated in this study ranked the three cement types in the same order of carbonation resistance. Unfortunately, large variations within and between laboratories complicate to draw clear conclusions regarding the effect of sample pre-conditioning and carbonation exposure conditions on the carbonation performance of the specimens tested. Nevertheless, it was identified that fresh and hardened state properties alone cannot be used to infer carbonation resistance of the mortars or concretes tested. It was also found that sealed curing results in larger carbonation depths compared to water curing. However, when water curing was reduced from 28 to 3 or 7 days, higher carbonation depths compared to sealed curing were observed. This increase is more pronounced for CEM I compared to CEM III mixes. The variation between laboratories is larger than the potential effect of raising the CO2 concentration from 1 to 4%. Finally, concrete, for which the aggregate-to-cement factor was increased by 1.79 in comparison with mortar, had a carbonation coefficient 1.18 times the one of mortar. Supplementary Information The online version contains supplementary material available at 10.1617/s11527-022-01927-7. Y1 - 2022 U6 - https://doi.org/10.1617/s11527-022-01927-7 VL - 55 IS - 3 SP - 1 EP - 29 PB - Springer ER - TY - JOUR A1 - van den Heede, Philip A1 - Thiel, Charlotte A1 - de Belie, Nele T1 - Natural and accelerated carbonation behaviour of high-volume fly ash (HVFA) mortar: Effects on internal moisture, microstructure and carbonated phase proportioning JF - Cement and Concrete Composites N2 - Binders with large portions of carbon-intensive Portland cement replaced by supplementary cementitious materials (e.g. fly ash) are more susceptible to carbonation mainly due to their lower CO2 buffering capacity. This conclusion is usually drawn from accelerated experiments at elevated CO2 levels involving processes that seriously differ from natural carbonation. The resulting presence of H2O reactant in the pore system and the carbonated microstructure itself may be very different. In this paper, these phenomena were investigated for High-Volume Fly Ash (HVFA) mortar via carbonation tests at ±0.04% CO2 (natural carbonation), 1% CO2 and 10% CO2. Internal humidity sensor monitoring and 1H NMR relaxometry revealed the highest water vapour and liquid water contents after carbonation at 10% CO2. Carbonation at 10% CO2 results in a coarser pore structure than carbonation at 1% CO2, and this probably due to a higher degree of C–S–H carbonation. KW - 1H NMR relaxometry KW - Carbonation KW - Mercury intrusion porosimetry KW - Moisture sensors KW - Multi-ring electrodes KW - Thermogravimetric analysis Y1 - 2020 U6 - https://doi.org/10.1016/j.cemconcomp.2020.103713 VL - 113 IS - October PB - Elsevier ER - TY - JOUR A1 - von Greve-Dierfeld, Stefanie A1 - Lothenbach, Barbara A1 - Vollpracht, Anya A1 - Wu, Bei A1 - Huet, Bruno A1 - Andrade, Carmen A1 - Medina, César A1 - Thiel, Charlotte A1 - Gruyaert, Elke A1 - Vanoutrive, Hanne A1 - Del Saéz Bosque, Isabel F. A1 - Ignjatovic, Ivan A1 - Elsen, Jan A1 - Provis, John L. A1 - Scrivener, Karen A1 - Thienel, Karl-Christian A1 - Sideris, Kosmas A1 - Zajac, Maciej A1 - Alderete, Natalia A1 - Cizer, Özlem A1 - van den Heede, Philip A1 - Hooton, Robert Douglas A1 - Kamali-Bernard, Siham A1 - Bernal, Susan A. A1 - Zhao, Zengfeng A1 - Shi, Zhenguo A1 - de Belie, Nele T1 - Understanding the carbonation of concrete with supplementary cementitious materials BT - a critical review by RILEM TC 281-CCC JF - Materials and Structures N2 - Blended cements, where Portland cement clinker is partially replaced by supplementary cementitious materials (SCMs), provide the most feasible route for reducing carbon dioxide emissions associated with concrete production. However, lowering the clinker content can lead to an increasing risk of neutralisation of the concrete pore solution and potential reinforcement corrosion due to carbonation. carbonation of concrete with SCMs differs from carbonation of concrete solely based on Portland cement (PC). This is a consequence of the differences in the hydrate phase assemblage and pore solution chemistry, as well as the pore structure and transport properties, when varying the binder composition, age and curing conditions of the concretes. The carbonation mechanism and kinetics also depend on the saturation degree of the concrete and CO2 partial pressure which in turn depends on exposure conditions (e.g. relative humidity, volume, and duration of water in contact with the concrete surface and temperature conditions). This in turn influence the microstructural changes identified upon carbonation. This literature review, prepared by members of RILEM technical committee 281-CCC carbonation of concrete with supplementary cementitious materials, working groups 1 and 2, elucidates the effect of numerous SCM characteristics, exposure environments and curing conditions on the carbonation mechanism, kinetics and structural alterations in cementitious systems containing SCMs. KW - Transport properties KW - Environmental impact KW - Aggregate KW - Supplementary cementitious materials KW - Carbonations Y1 - 2020 U6 - https://doi.org/10.1617/s11527-020-01558-w VL - 53 SP - 1 EP - 34 PB - Springer Nature ER - TY - INPR A1 - Vollpracht, Anya A1 - Gluth, Gregor J. G. A1 - Rogiers, Bart A1 - Uwanuakwa, Ikenna D. A1 - Phung, Quoc Tri A1 - Zaccardi, Yury Villagran A1 - Thiel, Charlotte A1 - Vanoutrive, Hanne A1 - Etcheverry, Juan Manuel A1 - Gruyaert, Elke A1 - Kamali-Bernard, Siham A1 - Kanellopoulos, Antonios A1 - Zhao, Zengfeng A1 - Martins, Isabel Milagre A1 - Rathnarajan, Sundar A1 - De Belie, Nele T1 - Report of RILEM TC 281-CCC: Insights into factors affecting the carbonation rate of concrete with SCMs revealed from data mining and machine learning approaches N2 - The RILEM TC 281–CCC ‘‘Carbonation of concrete with supplementary cementitious materials’’ conducted a study on the effects of supplementary cementitious materials (SCMs) on the carbonation rate of blended cement concretes and mortars. In this context, a comprehensive database has been established, 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 with up to 94% SCMs, collected from the literature as well as unpublished testing reports. The data includes chemical composition and physical properties of the raw materials, mix-designs, compressive strengths, curing and carbonation testing conditions. Natural carbonation was recorded for several years in many cases with both indoor and outdoor results. The database has been analysed to investigate the effects of binder composition and mix design, curing and preconditioning, and relative humidity on the carbonation rate. Furthermore, the accuracy of accelerated carbonation testing as well as possible correlations between compressive strength and carbonation resistance were evaluated. The analysis revealed that the w/CaOreactive ratio is a decisive factor for carbonation resistance, while curing and exposure conditions also influence carbonation. Under natural exposure conditions, the carbonation data exhibit significant variations. Nevertheless, probabilistic inference suggests that both accelerated and natural carbonation processes follow a square-root-of-time behavior, though accelerated and natural carbonation cannot be converted into each other without corrections. Additionally, a machine learning technique was employed to assess the influence of parameters governing the carbonation progress in concretes. KW - natural carbonation KW - accelerated carbonation KW - SCMs KW - database Y1 - 2024 U6 - https://doi.org/10.21203/rs.3.rs-4169492/v1 PB - Research Square Platform LLC ER -