TY - JOUR A1 - Bernal, Susan A. A1 - Angst, Ueli M. A1 - Provis, John L. A1 - Thiel, Charlotte A1 - Gluth, Gregor J. G. A1 - Villagran-Zaccardi, Yury A1 - De Belie, Nele T1 - Recommendation of RILEM TC 281-CCC: RILEM CPC-18R1 - guideline for measuring the carbonation depth of hardened concrete using a pH indicator solution JF - Materials and Structures N2 - This recommendation provides a procedure for determining the carbonation depth on the surface of concrete by applying a pH indicator. This includes definitions of carbonation, carbonation depth and carbonation front, as well as descriptions of the different pH indicator solutions that can be used. Recommendations for testing laboratory-prepared specimens and those obtained from concrete structures are also given. This involves guidelines for sample preparation and/or extraction, CO2 exposure duration, carbonation depth determination and reporting of results. A section on data interpretation is also provided, as carbonation results are used for determining durability of concrete, as well as a criterion for materials selection or for carbon uptake calculations. The new Recommendation CPC-18R1 is intended to supersede the former RILEM recommendation CPC-18, particularly when prescribed as the preferred method for evaluating and reporting carbonation depths. KW - Carbonation KW - Carbonation depth KW - Carbonation front KW - pH indicator KW - RILEM CPC-18 KW - Test method Y1 - 2026 U6 - https://doi.org/10.1617/s11527-026-02966-0 SN - 1359-5997 VL - 59 PB - Springer ER - TY - RPRT A1 - Albrecht, Sophie A1 - Thiel, Charlotte T1 - Environmental life cycle assessment - determination of ecological sustainability potentials by AMC T2 - Research Summary Report of C09 2024 N2 - C09 aims to enhance the ecological sustainability of Additive Manufacturing in Construction (AMC) by quantifying and optimizing its environmental benefits through comprehensive Life Cycle Assessments (E-LCA) from cradle to cradle. This involves developing transparent Product Environmental Footprint Category Rules (PEFCR), identifying impactful reduction measures, and integrating circular design strategies to create durable, efficient, and reusable components. By incorporating these findings into Fabrication the environmental footprint of the building sector. Y1 - 2024 UR - https://amc-trr277.de/research-summary-report-of-c09/ PB - AMC ER - TY - RPRT A1 - Albrecht, Sophie A1 - Thiel, Charlotte T1 - Environmental life cycle assessment - determination of ecological sustainability potentials by AMC T2 - Research Summary Report of C09 2025 N2 - C09 aims to enhance the ecological sustainability of Additive Manufacturing in Construction (AMC) by quantifying and optimizing its environmental benefits through comprehensive Life Cycle Assessments (E-LCA) from cradle to cradle. This involves developing transparent Product Environmental Footprint Category Rules (PEFCR), identifying impactful reduction measures, and integrating circular design strategies to create durable, efficient, and reusable components. C09 enables early-stage, sustainability-focused decision-making, fostering material-efficient, low-impact construction practices and reducing the environmental footprint of the building sector. Y1 - 2025 UR - https://amc-trr277.de/research-summary-report-of-c09-2/ PB - AMC ER - TY - JOUR A1 - Schmid, Michael T. A1 - Thiel, Charlotte T1 - Is it worth it? Potential for reducing the environmental impact of bitumen roofing membrane production JF - Recycling N2 - Between 51% and 72% of a bituminous roofing membrane used for structural water-proofing consists of organic material, predominantly bitumen - a derivative of crude oil refining - highlighting the strong dependence of this product on fossil resources. Considering that several tonnes of these membranes must be replaced every 30 to 50 years, substantial potential exists for emission reduction through the establishment of circular material systems. This study investigates this potential by analysing 26 Environmental Product Declarations (EPDs) and life cycle datasets from across Europe covering the period from 2007 to 2023. To ensure comparability, all data were normalised to a declared unit of 1 kg of roofing membrane. The reinforcement layers were categorised into glass and polyester & glass composites, and their differences were examined using Welch’s t-tests. Correlative analyses and linear as well as multiple regression models were then applied to explore relationships between environmental indicators and the shares of organic and mineral mass fractions. The findings reveal that renewable energy sources, although currently representing only a small share of total production energy, provide a major lever for reducing nearly all environmental impact categories. The type of reinforcement layer was also found to influence the demand for fossil resources, both materially and energetically. For most environmental indicators, only multiple regression models can explain at least 30% of the variance based on the proportions of organic and mineral inputs. Overall, the study underscores the crucial importance of high-quality, transparently documented product data for accurately assessing the sustainability of building products. It further demonstrates that substituting fossil energy carriers with renewable sources and optimising material efficiency can substantially reduce environmental burdens, provided that methodological consistency and clarity of indicator definitions are maintained. KW - bitumen sealing KW - bitumen recycling KW - circular construction KW - correlation analysis KW - LCA Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-86873 N1 - Corresponding author der OTH Regensburg: Michael Schmid VL - 10 IS - 6 PB - MDPI ER - TY - RPRT A1 - Sigwarth, Tess A1 - Büchner, Johannes A1 - Wistuba, Michael A1 - Geiger, Lydia A1 - Knittlmayer, Christian A1 - Rädecke, Christoph A1 - Seelig, Karsten A1 - Schmid, Michael A1 - Thiel, Charlotte A1 - Tumakov, Konstantin A1 - Ditscherlein, Lisa A1 - Peuker, Urs Alexander T1 - Forschungsbericht REBIBA - Recycling von Bitumenbahnen für Bauwerksabdichtungen BT - Baustofftechnologische Grundlagen und Voraussetzungen, Materialcharakterisierung, Verfahrenstechnik, Prozesssicherheit N2 - In Europa werden ca. 62 % aller neuen Flachdächer mit Bitumenbahnen abgedichtet (Das Dachdecker-Handwerk, 2023). Bitumenbahnen bestehen typischerweise aus einem Trägermaterial – einem Glas-moder Kunststoffvlies. Dieses ist beidseitig mit Bitumen(-massen) beschichtet. Diese Bitumenmassenbestehen zu einem großen Anteil aus erdölbasiertem Bitumen, dessen Herstellung viel Energieverbraucht und somit einen hohen Emissionsausstoß aufweist. Am Ende der Nutzungsdauer vonBitumenbahnen werden diese aufgrund ihres Heizwertes thermisch verwertet.Mit diesem Forschungsprojekt wurden die wissenschaftlichen und technischen Hindernisse für diestoffliche Verwertung und das kontinuierliche Recycling von bituminösem Abdichtungs- undDachbahnen-Abfall in Deutschland eruiert. Dazu wurden alle Verarbeitungsschritte zur Gewinnung undAufbereitung von wiedergewonnenen Bitumenbahnen aus Bauabfällen als wertvolle Ressource fürAnwendungen im Hochbau in Form neuer Bitumenbahnen betrachtet. Hierzu wurden zunächstunterschiedliche Aufbereitungstechniken erprobt, um die Bitumenmasse von den Trägereinlagenabzutrennen. Zur Charakterisierung der Bitumenmassen und deren Alterungsverhalten wurdenrheologische Prüfverfahren im Dynamischen Scherrheometer durchgeführt. Diese erlauben dieBeurteilung der viskoelastischen Eigenschaften und des Gebrauchsverhaltens bei Wärme und beiKälte. Anhand der rheologischen Prüfungen wurde das Alterungsverhalten von Bitumenmassenumfassend untersucht, um daraus die Grundlage für die Rezepturentwicklung von rezykliertenBitumenmassen zu erstellen.Aus den zerkleinerten Rezyklaten konnten Prototypen von Bitumenbahnen mit Recycling-Anteilen vonbis zu 37 % hergestellt werden. Für die großtechnische Umsetzung des Recyclingverfahrens ist dieAbtrennung der Trägereinlagen und möglichen mineralischen Abstreuungen anzustreben. Die begleitende Ökobilanzierung zeigte ein Einsparpotenzial bei den Treibhausemissionen (GWP) vonbis zu 33,0 %. Unter Einbindung erneuerbarer Energien ist eine Reduktion von bis zu 43,1 % denkbar. Im Bereich der nicht erneuerbaren Primärenergie (PENRT), die sich bei Bitumendachbahnen hauptsächlich aus materiellen und energetischen fossilen Stoffen zusammensetzt, kann etwa die Hälfte davon eingespart werden. Das ist den 80 % des Bitumenmaterials zuzuschreiben, die maximal prozesstechnisch substituiert werden können, was schließlich deutlich höher ausfällt, als die theoretischen Einsparpotentiale im Treibhauspotential. N2 - Around 62 % of all new flat roofs in Europe are waterproofed with bitumen membranes (Das Dachdecker-Handwerk, 2023). These membranes typically consist of a carrier material, such as glass or plastic fleece, coated on both sides with bitumen compounds. These compounds consist largely of petroleum-based bitumen, the production of which causes high emissions and consumes a lot of energy. After bitumen sheets reach the end of their useful life, they are thermally recycled due to their calorific value. This project aims to overcome the scientific and technical obstacles to recovering and continuously recycling bituminous waterproofing and roofing membrane waste in Germany. All processing steps for extracting and treating recovered bituminous membranes from construction waste will be considered valuable resources for applications in building construction, such as new bituminous membranes. Initially, different processing techniques were tested to separate the bitumen mass from the carrier layers. Rheological test methods using a dynamic shear rheometer were introduced to characterize the bitumen masses and their aging behavior. These tests allow us to assess the viscoelastic properties and service behavior in hot and cold conditions. Rheological tests were used to investigate the aging behavior of bituminous mixtures, creating a foundation for developing formulations for recycled bituminous mixtures. Shredded recyclates were used to produce prototypes of bitumen membranes containing up to 37 % recycled material. The goal for large-scale implementation of the recycling process is to separate the carrier layers and any mineral scattering. An accompanying life cycle assessment showed the potential for reducing greenhouse gas emissions (GWP) by up to 33.0 %. With the integration of renewable energies, a reduction of up to 43.1 % is possible. In the area of non-renewable primary energy (PENRT), around half of this can be saved, mainly by substituting material and energetic fossil substances in bitumen roofing membranes. This is due to the fact that 80 % of the bitumen material can be substituted by process technology, which is ultimately a significantly higher savings potential than that of global warming. With the integration of renewable energies, a reduction of up to 43.1 % is possible. Around half of this can be saved in the area of non-renewable primary energy (PENRT), which, in the case of bitumen roofing membranes, is mainly made up of material and energetic fossil substances. This is due to the fact that 80 % of the bitumen material can be substituted by process technology, which is ultimately significantly higher than the theoretical savings potential in terms of global warming potential. Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:084-2025103011147 N1 - Dieses Projekt wurde gefördert vom Bundesinstitut für Bau-, Stadt- und Raumforschung im Auftrag des Bundesministeriums für Wohnen, Stadtentwicklung und Bauwesen aus Mitteln der Zukunft Bau Forschungsförderung CY - Braunschweig ER - TY - CHAP A1 - Albrecht, Sophie Viktoria A1 - Thiel, Charlotte A1 - Karamara, Merve T1 - Decoding concrete’s environmental performance: A detailed analysis of global EPDs across the entire life cycle T2 - MATEC Web of Conferences N2 - Environmental Product Declarations (EPDs) for concrete are essential tools to quantify the environmental impact of this versatile building material throughout its life cycle, supporting sustainable choices in construction. Concrete is made up of raw materials like cement, water, aggregates, additives, and admixtures, which can be mixed in diverse ways. This variability often necessitates site-specific EPDs, as emissions and environmental impacts depend greatly on cement type, transport routes, and specific production processes. This study analyses various data sources, focusing on EPDs according to ISO 14025 and EN 15804. The life cycle phases A1-A3, B1-B7, C1-C4 and D are considered and compared. The results demonstrate that factors such as scenario assumptions, methodological choices, and allocation procedures significantly influence concrete’s environmental impact. Transparent EPDs improve assessment reliability, while allocation methods, especially in phases D and end-of-life, significantly influence reported benefits, underscoring the importance of careful allocation for accurate impact evaluations. Improved standardisation, transparency, and alignment with EN 16757 would enhance EPD comparability and reliability. Overall, the study identifies key parameters such as recycling potential, production stage and allocation methods as substantial factors in the environmental performance of concrete. Y1 - 2025 U6 - https://doi.org/10.1051/matecconf/202540913001 VL - 409 PB - EDP Sciences CY - Les Ulis ER - TY - CHAP A1 - Pfahler, Katharina A1 - Thiel, Charlotte A1 - Neidhart, Thomas T1 - Einfluss der Probengeometrie auf die Mechanischen Eigenschaften von Stampflehm - Eine Literaturrecherche T2 - ce/papers - Proceedings in Civil Engineering N2 - Der Klimawandel lenkt den Fokus im Bauwesen zunehmend auf die Reduktion von Treibhausgasen und die Förderung nachhaltiger Materialien. Baustoffe wie Lehm gewinnen dank ihrer ökologischen und bauphysikalischen Vorteile an Bedeutung. Eine zentrale Herausforderung stellt die Definition standardisierter Prüfmethoden für Stampflehm dar. Dieser Beitrag analysiert Forschungsergebnisse zur Geometrie von Stampflehmprobekörpern mittels Literaturrecherche und vergleicht experimentelle Untersuchungen sowie relevante Normen und Testmethoden. Die Auswertung zeigt, dass äußere Einflüsse wie Mischungszusammensetzung, Verdichtungsenergie, Gesteinskörnung und Tonminerale eine zentrale Rolle spielen. Eine Vereinheitlichung von Probengeometrie, Lagerung und Prüfverfahren ist essenziell, um reproduzierbare Ergebnisse zu erzielen und die mechanischen Kennwerte von Stampflehm vergleichbar zu machen. Ziel ist es, einheitliche Standards zu entwickeln, um die Stampflehmbauweise in der Praxis zu fördern. KW - Lehmbau KW - Stampflehm KW - Stampflehm Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-80291 SN - 2509-7075 N1 - Corresponding author der OTH Regensburg: Katharina Pfahler VL - 8 IS - 1 SP - 57 EP - 68 PB - Ernst & Sohn, a Wiley Brand ER - TY - CHAP A1 - Albrecht, Sophie Viktoria A1 - Thiel, Charlotte A1 - Hellerbrand, Stefan A1 - Weininger, Florian T1 - Possibilities for Reducing the Environmental Impact in the Construction Industry Using the Example of a 3D Printed Staircase T2 - Proceedings of the 4th International Conference on Sustainable Development in Civil, Urban and Transportation Engineering (CUTE 2024), 14–17 October, Wrocław, Poland N2 - The construction industry faces numerous challenges, including environmental sustainability, high material costs, and a shortage of skilled labor. Modern technologies enabling digital fabrication present opportunities to reduce raw material consumption and waste generation. Among these, 3D printing technologies offer distinct advantages over traditional construction methods, particularly in handling complex geometries. However, the significant environmental impact of cement in 3D printed concrete, due to its high rheological and printability requirements, remains a concern. This study introduces a novel application of 3D printed permanent formwork in the construction of a winder staircase, assessed through an environmental Life Cycle Assessment (LCA) from cradle to gate. By comparing the environmental impacts of various construction materials and processes, the study highlights the comparative advantages and disadvantages of conventional methods versus 3D printing. The LCA results reveal that traditional production methods, particularly those using plywood formwork, exhibit higher environmental impacts. In contrast, timber formwork performs better than most 3D printed mixtures in terms of Global Warming Potential (GWP), Acidification Potential (AP), and Abiotic Depletion Potential (ADP). The findings of this study underscore the potential of additive manufacturing for sustainable construction, particularly through the use of low clinker cement in 3D printed formwork, offering a promising pathway towards reducing the environmental footprint of construction activities. Y1 - 2025 SN - 978-981-97-9400-3 U6 - https://doi.org/10.1007/978-981-97-9400-3_6 SP - 55 EP - 64 PB - Springer Nature ER - TY - JOUR A1 - Albrecht, Sophie Viktoria A1 - Hellerbrand, Stefan A1 - Weininger, Florian A1 - Thiel, Charlotte T1 - Strategies for Minimizing Environmental Impact in Construction: A Case Study of a Cementitious 3D Printed Lost Formwork for a Staircase JF - materials N2 - The construction industry faces significant challenges, including environmental sustainability, rising material costs, and a shortage of skilled labor. Digital fabrication technologies offer innovative solutions to address these issues by reducing raw material consumption and waste generation. Among these, 3D printing technologies offer distinct advantages over traditional construction methods, particularly in handling complex geometries. However, the significant environmental impact of cement in 3D printed concrete, due to its high rheological and printability requirements, remains a concern. This study introduces a novel application of 3D printed permanent formwork in the construction of a winder staircase, assessed through an Environmental Life Cycle Assessment (LCA) from cradle to gate. By comparing the environmental impacts of various construction materials and processes, this study highlights the comparative advantages and disadvantages of conventional methods versus 3D printing. The LCA results reveal that traditional production methods, particularly those using plywood formwork, exhibit higher environmental impacts. In contrast, timber formwork performs better than most 3D printed mixtures in terms of Global Warming Potential (GWP), Acidification Potential (AP), and abiotic depletion potential (ADP). The findings of this study underscore the potential of additive manufacturing for sustainable construction, particularly through the use of low-clinker cement in 3D printed formwork, offering a promising pathway towards reducing the environmental footprint of construction activities KW - permanent formwork KW - selective cement activation (SCA) KW - 3D concrete printing (3DCP) KW - life cycle assessment (LCA) KW - additive manufacturing in construction (AMC) Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-79236 N1 - Corresponding author der OTHR: Sophie Viktoria Albrecht VL - 18 PB - MDPI ER - TY - GEN A1 - Pfahler, Katharina A1 - Neidhart, Thomas A1 - Hüttner, Susanne A1 - Thiel, Charlotte T1 - Vom Boden zur Wand - Stand der Technik und zukünftige Entwicklungen T2 - LEHM 2024, 9. Internationale Fachtagung für Lehmbau, 27.–29.9.2024, Weimar N2 - Lehm selbst ist ein Baustoff mit zahlreichen Vorteilen (diffusionsoffen, wiederverwendbar, hohe Verfügbarkeit, geringe graue Emissionen, guter Schallschutz und hohe Dauerhaftigkeit bei fachgerechtem Einsatz), aber auch Grenzen in der Anwendbarkeit, die sich aus Schwund, begrenzter Lastaufnahme und hoher Wärmeleitfähigkeit (und damit geringer Wärmedämmwirkung) ergeben. Aus Lehm und damit aus Boden Wandbaustoff zu fertigen, funktioniert sowohl im Bereich des Trockenausbaus (Lehmbauplatten, Lehmputz) als auch des tragendes Mauerwerks sehr gut und gewinnt durch die kürzlich eingeführten Normen an neuem Aufschwung. Die tragende Stampflehmbauweise mit lokal ausgehobenem Material ist bedingt durch den hohen handwerklichen Aufwand bei gleichzeitigem Fachkräftemangel und erforderlichen Zustimmung im Einzelfall oder vorhabensbezogener Bauartgenehmigung kosten- und zeitintensiv. Dabei bringt sie bauphysikalisch und ökologisch häufig signifikante Vorteile im Vergleich zu konventionellen Bauweisen mit sich. Dieser Beitrag stellt daher anhand einer ausführlichen Literaturrecherche und eigenen Versuchen den Stand der Technik industrieller Lehmbaustoffe dar. Fokus des Beitrags liegt auf Möglichkeiten, die Stampflehmbauweise zu neuer und wirtschaftlicher Leistungsfähigkeit zu bringen. KW - Lehmbau KW - Lehmbau Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-78400 SN - 978-3-00-079502-2 PB - Eigenverlag Dachverband Lehm e.V. CY - Weimar ER - TY - JOUR A1 - Vanoutrive, Hanne A1 - Alderete, Natalia A1 - De Belie, Nele A1 - Etxeberria, Miren A1 - Grengg, Cyrill A1 - Ignjatović, Ivan A1 - Ling, Tung-Chai A1 - Liu, Zhiyuan A1 - Garcia-Lodeiro, Inés A1 - Medina Martínez, César A1 - Sanchez, Javier A1 - Palomo, Angel A1 - Rebolledo, Nuria A1 - Sakoparnig, Marlene A1 - Sideris, Kosmas A1 - Thiel, Charlotte A1 - Van den Heede, Philip A1 - Vollpracht, Anya A1 - von Greve-Dierfeld, Stefanie A1 - Wei, Jinxin A1 - Zając, Maciej A1 - Gruyaert, Elke T1 - Report of RILEM TC 281-CCC: outcomes of a round robin on the resistance to natural carbonation of Portland, Portland-fly ash and blast-furnace cements and its relation to accelerated carbonation JF - Materials and Structures N2 - Numerous (inter)national standards are in place for assessing the resistance to carbonation of mortar and concrete. Within the framework of RILEM TC 281-CCC ‘Carbonation of Concrete with SCMs,’ an extensive interlaboratory test campaign (ILT) involving twenty-two participating laboratories worldwide was initiated to compare natural carbonation of concrete and mortar with three different cement types (Portland cement (CEM I), Portland-fly ash cement (CEM II/B-V) and blast-furnace cement (CEM III/B)) and investigate its relation to accelerated carbonation as reported in Vanoutrive et al. (Mater Struct 55:1–29, 2022). It could be concluded that ranking of cement types was analogous between accelerated and natural carbonation methods. Environmental parameters have an important effect on the carbonation rate, however, differences between the mean carbonation rates originating from indoor and sheltered outdoor natural exposure with different exposure conditions and curing regimes were insignificant for each considered cement type. This is caused by the scatter related to carbonation testing among different laboratories. Nevertheless, results showed that a natural exposure period of at least one year is essential to reach a constant carbonation rate over time. For both natural and accelerated carbonation, the carbonation rate increased by 18% when the aggregate-to-cement ratio increased by 1.79 (concrete versus mortar). This correlation seems insensitive to binder type and exposure method. Finally, the best correlation between natural and accelerated carbonation was found for EN 12390–10 (specifically natural indoor exposure) and EN 12390–12 (accelerated exposure) when only test methods performed by more than one laboratory were considered. Y1 - 2024 U6 - https://doi.org/10.1617/s11527-024-02464-1 SN - 1359-5997 VL - 57 IS - 9 PB - Springer Science and Business Media ER - TY - JOUR A1 - Vollpracht, A. A1 - Gluth, Gregor J. G. A1 - Rogiers, Bart A1 - Uwanuakwa, I. D. A1 - Phung, Quoc Tri A1 - Villagran Zaccardi, Y. A1 - Thiel, Charlotte A1 - Vanoutrive, H. A1 - Etcheverry, Juan Manuel A1 - Gruyaert, Elke A1 - Kamali-Bernard, Siham A1 - Kanellopoulos, Antonios A1 - Zhao, Zengfeng A1 - Milagre Martins, Isabel 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 JF - Materials and Structures 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. One approach to summerise the physical and chemical resistance in one parameter is the ratio of water content to content of carbonatable CaO (w/CaOreactive ratio). 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. Y1 - 2024 U6 - https://doi.org/10.1617/s11527-024-02465-0 SN - 1359-5997 VL - 57 IS - 9 PB - Springer Science and Business Media ER - TY - JOUR A1 - Bernal, Susan A. A1 - Dhandapani, Yuvaraj A1 - Elakneswaran, Yogarajah A1 - Gluth, Gregor J. G. A1 - Gruyaert, Elke A1 - Juenger, Maria C. G. A1 - Lothenbach, Barbara A1 - Olonade, Kolawole Adisa A1 - Sakoparnig, Marlene A1 - Shi, Zhenguo A1 - Thiel, Charlotte A1 - van den Heede, Philip A1 - Vanoutrive, Hanne A1 - Von Greve-Dierfeld, Stefanie A1 - De Belie, Nele A1 - Provis, John L. T1 - Report of RILEM TC 281-CCC: A critical review of the standardised testing methods to determine carbonation resistance of concrete JF - Materials and Structures N2 - The chemical reaction between CO2 and a blended Portland cement concrete, referred to as carbonation, can lead to reduced performance, particularly when concrete is exposed to elevated levels of CO2 (i.e., accelerated carbonation conditions). When slight changes in concrete mix designs or testing conditions are adopted, conflicting carbonation results are often reported. The RILEM TC 281-CCC ‘Carbonation of Concrete with Supplementary Cementitious Materials’ has conducted a critical analysis of the standardised testing methodologies that are currently applied to determine carbonation resistance of concrete in different regions. There are at least 17 different standards or recommendations being actively used for this purpose, with significant differences in sample curing, pre-conditioning, carbonation exposure conditions, and methods used for determination of carbonation depth after exposure. These differences strongly influence the carbonation depths recorded and the carbonation coefficient values calculated. Considering the importance of accurately determining carbonation potential of concrete, not just for predicting their durability performance, but also for determining the amount of CO2 that concrete can re-absorb during or after its service life, it is imperative to recognise the applicability and limitations of the results obtained from different tests. This will enable researchers and practitioners to adopt the most appropriate testing methodologies to evaluate carbonation resistance, depending on the purpose of the conclusions derived from such testing (e. g. materials selection, service life prediction, CO2 capture potential). Y1 - 2024 U6 - https://doi.org/10.1617/s11527-024-02424-9 SN - 0025-5432 SN - 1359-5997 VL - 57 IS - 8 PB - Springer ER - TY - CHAP A1 - Thiel, Charlotte A1 - Hechtl, C. Maximilian A1 - Gehlen, Christoph A1 - Kränkel, Thomas ED - Lowke, Dirk ED - Freund, Niklas ED - Böhler, David ED - Herding, Friedrich T1 - Sustainability Potential of Additive Manufactured Concrete Structures – Studies on the Life Cycle Assessment and Circularity of an Extruded Exterior Wall T2 - Fourth RILEM International Conference on Concrete and Digital Fabrication (DC 2024), Munich, Germany, September 2024 N2 - The Brundtland Report defined sustainable development as a development that meets the needs of the present without compromising the ability of future generations to meet their own needs. If this definition is applied to the construction sector, a new, circular approach to cementitious materials is required. Additive manufacturing (AM) enables to design material-efficient and monolithic structures that meet physical and chemical requirements of building standards while allowing reuse or high-quality recycling of concrete. Here, the environmental impact as well as the circularity potential of an additively manufactured exterior wall, produced by 3D concrete extrusion, are determined. To classify the results, the additively manufactured exterior wall is compared with a conventional concrete construction. Finally, various options for optimizing the printed wall are considered and evaluated. Additive manufacturing enabled significant material savings compared to conventional construction. The environmental impacts strongly depend on the used concrete composition. For example, greenhouse gas emissions could be reduced by 20% when changing the type of lightweight aggregate. The additively manufactured exterior wall exhibited advantages in terms of circularity. Through further development and research, additive manufacturing of concrete can promote a paradigm shift towards sustainable practices. Y1 - 2024 SN - 978-3-031-70030-9 U6 - https://doi.org/10.1007/978-3-031-70031-6_2 SP - 13 EP - 21 PB - SPRINGER INTERNATIONAL PU 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 - Milagre Martins, Isabel 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 N1 - Verörffenticht bei Springer Nature: https://opus4.kobv.de/opus4-oth-regensburg/frontdoor/index/index/docId/7776 PB - Research Square Platform LLC ER - TY - JOUR A1 - Haynack, Alexander A1 - Timothy, Jithender J. A1 - Kränkel, Thomas A1 - Gehlen, Christoph A1 - Thiel, Charlotte T1 - Analyse des Frost‐Tausalz‐Widerstands zementgebundener Baustoffe mittels 3D‐Laserscanning JF - ce/papers: Proceedings in Civil Engineering N2 - Eine Herausforderung performancebasierter Prüfverfahren zur Bewertung der Dauerhaftigkeit ist die Beschleunigung natürlicher Mechanismen. Dies ist notwendig, um innerhalb kurzer Zeit die Langzeit-Leistungsfähigkeit ermitteln zu können. Die Bestimmung der Frost-Tausalzbeständigkeit von Beton kann durch den CDF-Test erfolgen, welcher für Betone mit ausreichendem Frost-Tausalz-Widerstand sehr gut funktioniert. Bei Proben mit einer unzureichenden bzw. unbekannten Performance können erhöhte Randabwitterungen auftreten, welche durch das Ablösen des seitlichen Abdichtbands entstehen. Der zunehmende Randeinfluss führt so zu einer Verfälschung der Ergebnisse und zu einer Unterschätzung der tatsächlichen Performance des Bauteils. In diesem Beitrag werden Mörtel- und Betonprobekörper mit unterschiedlichen Abwitterungsraten in Anlehnung an das CDF-Verfahren untersucht. Zusätzlich wird die Oberflächenschädigung der Proben anhand einer neuartigen Messmethode mittels hochauflösendem 3D-Laserscanning ausgewertet. Die Ergebnisse zeigen, dass die Randeffekte mit der Laserscan-Methode umgangen und vergleichbare Ergebnisse zu den CDF-Untersuchungen erzielt werden können. Somit können Betone ohne Randeinflüsse charakterisiert und eine präzise Prognose der Langzeitbeständigkeit getroffen werden. KW - Beton KW - Mörtel KW - Frost-Tausalz-Widerstand KW - Dauerhaftigkeit KW - 3D-Laserscanning Y1 - 2023 U6 - https://doi.org/10.1002/cepa.2951 SN - 2509-7075 VL - 6 IS - 6 SP - 1189 EP - 1196 PB - Ernst & Sohn ER - TY - JOUR A1 - Grimm, Benedikt A1 - Thiel, Charlotte A1 - Kränkel, Thomas A1 - Gehlen, Christoph T1 - Einfluss der Permeation auf die Carbonatisierung von Beton JF - ce/papers: Proceedings in Civil Engineering N2 - Die Carbonatisierung von Beton kann einerseits zu Schäden bei Stahlbetonbauwerken führen, andererseits kann der Beton so CO2 speichern und damit seinen CO2-Fußabdruck verringern. In diesem Beitrag wird dargestellt, wie eine effiziente Beschleunigung der Carbonatisierung durch Anlegen eines geringen äußeren Drucks erreicht werden kann. Damit wird neben der Diffusion der wesentlich schneller ablaufende Transportmechanismus der Permeation ausgenutzt, der das CO2 tiefer in das Probeninnere transportiert und damit in kurzer Zeit die Bestimmung des Carbonatisierungswiderstand zementgebundener Materialien ermöglicht. Hierzu wurde eine Prüfeinrichtung entwickelt, die es ermöglicht, die CO2-Konzentration und in gewissen Grenzen auch relative Luftfeuchte sowie die Temperatur gezielt einzustellen und zu steuern, um so Mörtel- und Betonproben schnell und präzise zu carbonatisieren. Der Einfluss verschiedener Druckstufen und Wechselzyklen wird dargelegt und die resultierenden chemischen und physikalischen Veränderungen der Proben bestimmt. Als besonders effizient und gleichzeitig realitätsnah erwies sich die konstante CO2-Beaufschlagung mit 3 Vol.-% CO2 mit zusätzlichem, moderatem Gasdruck. Das hier entwickelte Verfahren kann daher genutzt werden, um Betone schnell und effizient in zeitraffenden Materialtests hinsichtlich Carbonatisierungswiderstand zu charakterisieren. KW - Beton KW - Carbonatisierung KW - Prüfverfahren KW - Gasdruck KW - Permeation Y1 - 2023 U6 - https://doi.org/10.1002/cepa.3005 SN - 2509-7075 VL - 6 IS - 6 SP - 1348 EP - 1357 PB - Ernst & Sohn CY - Berlin ER - TY - JOUR A1 - Haynack, Alexander A1 - Sekandar, Zadran A1 - Jithender, J. Timothy A1 - Gambarelli, Serena A1 - Kränkel, Thomas A1 - Thiel, Charlotte A1 - Ozbolt, Josko A1 - Gehlen, Christoph T1 - Can a Hend-Held 3D Scanner Capture Temperature-Induced Strain of Mortar Samples? Comparison between Experimental Measurements and Numerical Simulations JF - mathematics N2 - The expected lifespan of cement-based materials, particularly concrete, is at least 50 years. Changes in the pore structure of the material need to be considered due to external influences and associated transport processes. The expansion behaviour of concrete and mortar during freeze–thaw attacks, combined with de-icing salt agents, is crucial for both internal and external damage. It is essential to determine and simulate the expansion behaviour of these materials in the laboratory, as well as detect the slow, long-term expansion in real structures. This study measures the expansion of mortar samples during freeze–thaw loading using a high-resolution hand-held 3D laser scanner. The specimens are prepared with fully or partially saturated pore structures through water storage or drying. During freeze–thaw experiments, the specimens are exposed to pure water or a 3% sodium chloride solution (NaCl). Results show contraction during freezing and subsequent expansion during thawing. Both test solutions exhibit similar expansion behaviour, with differences primarily due to saturation levels. Further investigations are required to explore the changing expansion behaviour caused by increasing microcracking resulting from continuous freeze–thaw cycles. A numerical analysis using a 3D coupled hygro-thermo-mechanical (HTM) model is conducted to examine the freeze–thaw behaviour of the mortar. The model accurately represents the freezing deformation during the freeze–thaw cycle. KW - concrete KW - mortar KW - durability KW - freeze–thaw and de-icing salt resistance KW - strain KW - 3D laser scanning KW - numerical simulation KW - 3D FE numerical model KW - hygro-thermo-mechanical coupling Y1 - 2023 U6 - https://doi.org/10.3390/math11173672 VL - 11 IS - 17 PB - MDPI CY - Basel ER - TY - CHAP A1 - Grimm, Benedikt A1 - Münchmeyer, Sebastian A1 - Kränkel, Thomas A1 - Gehlen, Christoph A1 - Thiel, Charlotte T1 - Developing a New Rapid, Relevant, and Reliable (R3) Method for Accelerated Measurement of Carbonation Progress at Gas Overpressure T2 - International RILEM Conference on Synergising expertise towards sustainability and robustness of CBMs and concrete structures, SynerCrete’23 - Volume 1 N2 - The determination of durability-relevant material resistances of concrete is of great importance. They serve as input to engineering models to predict the durability of structures under real environmental conditions. The natural resistances have to be determined in time-consuming experiments, since the processes in nature are very slow. This is particularly important for new materials where long-term experience is not yet available. Thus, accelerated testing is required. Only that way new materials can be evaluated regarding their durability and subsequently be used in practical applications. For carbonation, a new R3 accelerated test method is presented in this contribution. An automated carbonation pressure chamber was developed. It consists of a pressure vessel, automated in such a way that it can apply gas overpressure of various intensities up to 8 bar to mortar and concrete samples. Simultaneously, it can control and regulate the ambient CO2 concentration from 0 to 99.5% in a fully automated and continuously variable procedure. Experiments were carried out with varying combinations of gas overpressure at CO2 concentrations of 3 vol.-% to achieve the most time-efficient carbonation of mortars and concretes. Mortars with different material compositions were used to evaluate the general suitability of the test procedure with the developed equipment. The automated carbonation pressure chamber enables reliable carbonation testing with a total duration under accelerated conditions of only 7 days. KW - Carbonation KW - concrete KW - durability KW - accelerated testing KW - gas overpressure Y1 - 2023 U6 - https://doi.org/10.1007/978-3-031-33211-1_30 SP - 336 EP - 346 PB - Springer ER - TY - CHAP A1 - Haynack, Alexander A1 - Schneider, Alexander A1 - Timothy, Jithender J. A1 - Kränkel, Thomas A1 - Gehlen, Christoph A1 - Thiel, Charlotte T1 - Effect of Chloride Concentration on the Freeze-Thaw Resistance of Concrete T2 - International RILEM Conference on Synergising expertise towards sustainability and robustness of CBMs and concrete structures, SynerCrete’23 - Volume 2 N2 - Performance test methods intend to provide a fast, accurate and precise determination of a particular building material property and thus determine the associated material performance. In concrete, various performance tests are used to classify existing or to approve new materials, to compare concrete compositions or to determine causes of damage in existing structures. The challenge of such test methods is to accelerate natural (very slow) mechanisms to determine the material performance precisely within a short time. However, the attack on the material must not be unrealistically intensive, but must represent reality, just in fast motion. The performance tests used to demonstrate the freeze-thaw resistance of concrete employ a 3% NaCl solution, with literature data ranging from 1% to 10% showing that low concentrations can result in higher surface scaling. In this paper, mortar and concrete specimens are tested at 0, 1, 3, 6, and 9% NaCl solution following the CDF procedure (DIN CEN/TS 12390-9:2017-05). The results are discussed against the background of the existing literature and show that the damage is critically dependent on the pore system and thus also on the effect of the micro-ice lens pump. With increasing freeze-thaw exposition, the pessimum in the external damage shifts towards a de-icing salt concentration of 6%. Furthermore, a novel test methodology based on 3D-laserscanning is presented to determine scaling accurately by eliminating side effects that are typically present in current standards. KW - Concrete KW - durability KW - freeze-thaw resistance KW - chloride concentration KW - 3D laser scanning Y1 - 2023 U6 - https://doi.org/10.1007/978-3-031-33187-9_83 SP - 911 EP - 921 PB - Springer CY - Cham ER - TY - JOUR A1 - Thiel, Charlotte A1 - Kratzer, Johanna A1 - Grimm, Benedikt A1 - Kränkel, Thomas A1 - Gehlen, Christoph T1 - Effect of Internal Moisture and Outer Relative Humidity on Concrete Carbonation JF - CivilEng N2 - With steadily rising CO2 concentrations in the ambient air and fast-changing concretecompositions with reduced clinker contents, the availability of reliable and accelerated concrete car-bonation tests is of crucial importance to design durable structures. This paper focuses on the effectsof moisture under accelerated conditions and the effects of different CO2 exposure conditions. Mor-tar prisms incorporating three different cement types were cured and stored at either 50% or 65%relative humidity (RH). Afterwards, the prisms were carbonated at different ambient humidities(50, 57 and 65%), different CO2 concentrations (0.04, 1 and 3 vol.%) and complemented by a seriesof tests at increased gas pressure (2 barg). High-resolution test methods were used to explain theunderlying carbonation mechanisms. The results show that pre-conditioning for two weeks—ascurrently suggested by the European Standard—seems to be too short because the initial inner mois-ture content severely affects the carbonation rate. Relative humidity during carbonation of 57% ledto higher carbonation rates compared to 50% and 65%. In addition, climate data needs to be period-ically (preferably permanently) recorded in research experiments and in laboratory testing to ensurefair interpretation of experimental results. KW - accelerated carbonation KW - concrete KW - moisture KW - durability KW - relative humidity Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-56091 N1 - Corresponding author: Charlotte Thiel VL - 4 IS - 3 SP - 1039 EP - 1052 PB - MDPI CY - Basel ER - TY - CHAP A1 - Thiel, Charlotte A1 - Keßler, Sylvia A1 - Chillé, R. A1 - Gehlen, Christoph T1 - Effect of internal freeze-thaw deterioration on chloride migration in concrete T2 - Life-Cycle and Sustainability of Civil Infrastructure Systems : proceedings of the third International Symposium on Life-Cycle Civil Engineering, Vienna, Austria, 3 - 6 October 2012 N2 - Depending on the specific exposure conditions, reinforced concrete structures (RCS) are simultaneously subjected to different physical and chemical loads. While in the field of reinforcement corrosion, service life prediction based on full-probabilistic models is well-established, the consequences of combined attack have been neglected until now. The most frequent “load” combination on RCS in cold climates are freeze-thaw attack which can lead to inner or outer damage and chloride ingress which can lead to reinforcement corrosion. In an experimental study four different concrete compositions are exposed either to a defined freeze-thaw attack or stored in moist environment. Afterwards, the chloride migration coefficient of the specimens which were both exposed to freeze-thaw-cycles and not, was determined with a modified rapid chloride migration test. The results clearly show an influence of freeze-thaw-induced internal damage on chloride ingress depending on concrete composition. Y1 - 2012 PB - CRC Press ER - TY - CHAP A1 - Thiel, Charlotte A1 - Lowke, Dirk A1 - Gehlen, Christoph T1 - Praxisgerechte Modellierung des Schädigungsverlaufs von Betonen unter Frost-Tausalz-Angriff -Einfluss der Austrocknung T2 - Tagungsbericht / IBAUSIL, 18. Internationale Baustofftagung : 12.-15. September 2012, Weimar, Band 2 Y1 - 2012 SN - 978-3-00-034075-8 PB - Bauhaus-Univ. ER - TY - CHAP A1 - Thiel, Charlotte A1 - Stengel, Thorsten T1 - Nachhaltigkeitsaspekte von Oberbauweisen aus Asphalt und Beton T2 - 10. Münchener Baustoffseminar GRIFFIG - LEISE - DAUERHAFT, Asphalt und Beton im Straßenbau, 10, 2012, München Y1 - 2012 ER - TY - CHAP A1 - Thiel, Charlotte A1 - Lowke, Dirk A1 - Gehlen, Christoph T1 - Effect of minimum temperature, salt and moisture content on concrete under freeze-thaw deicing salt attack T2 - ICDC 2012 : International Congress on Durability of Concrete; Trondheim, Norway, 18-21 June 2012 N2 - While in the field of reinforcement corrosion service life prediction is well-established, there is still need for a user-friendly design model in the field of freeze-thaw deicing salt attack. This attack is one of the major causes of damage to concrete structures in cold climates. The degree of moisture during the first freeze-thaw-cycles exceeds moisture saturation by capillary suction and diffusion. When a critical degree of saturation is reached before freezing damage occurs immediately. As a consequence, depending on the concrete resistance (e.g. pore structure of the concrete) and the severeness of the freeze-thaw load (e.g. minimum temperature, moisture offer and salt concentration), a certain number of freeze-thaw cycles is needed before damage occurs (initial phase). The main exposure parameters influencing the initial phase as well as the subsequent evolution of damage (deterioration phase) are the minimum temperature as well as the salt and moisture content. These factors were determined by single-sided NMR, gravimetry and mercury intrusion porosimetry respectively. Three different concrete compositions were exposed to freeze-thaw deicing salt load at different minimum temperatures. To investigate the influence of the initial moisture content concrete specimens were continuously exposed to freeze-thaw load while other specimens from the same batch were exposed to alternating freeze-thaw exposure with intermediate dry periods. It was found that the minimum temperature and intermediate dry periods had a significant influence on the initial phase as well as on the degradation phase. In addition, higher chloride content in the near-surface concrete reduced the scaling rate. The chloride content under freeze-thaw exposure with 3% NaCl solution in laboratory significantly exceeded typical contents due to capillary suction and diffusion. Increasing the minimum temperature increased the chloride content. The investigations form the basis for service life prediction of concrete towards freeze-thaw deicing salt attack. KW - freeze-thaw deicing salt attack KW - moisture movement Y1 - 2012 U6 - https://doi.org/10.13140/2.1.3243.9367 PB - Norwegian Concrete Association ER - TY - CHAP A1 - Thiel, Charlotte A1 - Lowke, Dirk A1 - Gehlen, Christoph T1 - Detection of Transport Processes during Freeze-Thaw Deicing Salt Attack Using Single-Sided NMR T2 - Microstructural-related durability of cementitious composites : Second International Conference on Microstructural-related Durability of Cementitious Composites, 11 - 13 April 2012, Amsterdam N2 - Damage of concrete structures exposed to a combined freeze-thaw deicing salt attack (FTDSA) is one of the major deterioration mechanisms in cold climates. Before damage occurs, concrete structures subjected to freeze-thaw cycles (FTC) in the presence of water or deicing salt solution exhibit fast moisture uptake known as frost suction. There is still need for research in describing and modelling the mechanisms that lead to freeze-thaw induced surface scaling of concrete. Therefore, the moisture transport under FTDSA was investigated using single-sided 1 H NMR. The technique enables the observation of dynamic transport processes of water inside the sample non-destructively. Furthermore, porosity and pore size distribution of water saturated samples can be determined. The method also provides information on the mobility of water, i.e. water in capillaries or in gel pores. Water redistribution in pores as well as changes in the pore structure inside the near surface concrete sample under FTDSA were observed with single-sided 1 H NMR. The measurements confirmed the additional saturation of gel pores during thawing previously described by the micro ice lens model. The results are discussed within the context of the mechanisms of freeze-thaw deicing salt attack of concrete and contribute to a deeper understanding of the mechanisms that lead to freeze-thaw deterioration of concrete. Y1 - 2012 PB - RILEM ER - TY - CHAP A1 - Thiel, Charlotte A1 - Stengel, T. A1 - Gehlen, Christoph T1 - Life cycle assessment (LCA) of road pavement materials T2 - Eco-efficient Construction and Building Materials N2 - At present the choice of materials and techniques in road construction is dictated by structural requirements and economic aspects. However, ecological factors have gained in importance due to environmental considerations in politics and society. To evaluate the environmental impact of motorways, a life cycle assessment (LCA) according to ISO 14040 was carried out for different pavement types. By investigating different case scenarios, the reduction potential of environmental impact was quantified. The biggest reduction in air pollution can be achieved by improving pavement properties (e.g., texture, stiffness and flatness) which would significantly reduce the fuel consumption of vehicles. KW - asphalt roads KW - concrete roads KW - life cycle assessment KW - pavement LCA Y1 - 2014 U6 - https://doi.org/10.1533/9780857097729.2.368 SP - 368 EP - 403 PB - Woodhead Publishing ER - TY - CHAP A1 - Franke, Wolfram A1 - Thiel, Charlotte A1 - Duran, F. A1 - Gehlen, Christoph T1 - Effect of Calcium Nitrate on the freeze-thaw-resistance of concrete T2 - Proceedings of the 2nd International Congress on Concrete Durability, 2, 2014, New Delhi N2 - Concrete in cold climates is not only exposed to cold weather while concreting but also to freeze-thaw cycles during its lifetime. Thus not only the concrete production needs to be adjusted to the environmental conditions but also the mixture has to be durable and resist the environmental impacts. Commonly an air entraining agent is used to interrupt the capillary pore system and to provide further space for the freezing water to expand. The downside of this approach is a loss in compressive strength. Within this paper the effect of simultaneous use of air entraining agent and calcium nitrate is discussed. It is shown that calcium nitrate can counteract strength loss due to the air entraining agent without reducing the durability gain in the same extent. A certain combination of calcium nitrate and air entraining agent can also be used to increase the freeze-thaw-resistance. KW - air entrainer KW - calcium nitrate KW - Durability KW - freeze-thaw-resistance Y1 - 2014 ER -