TY - CONF A1 - Manninger, Tanja T1 - Eco friendly stabilization of loam with calcined clay and potassium hydroxide – calorimetric background study N2 - The low calcination temperature for clays (600° C) and a low CO2 footprint compared to cement make them an interesting material. To find a stabilization method for loam using calcined clays, activation by alkalis was necessary. Therefore (and to keep the mixture environmentally friendly) KOH was used as alkali activator. It could be proven that the alkali activated polymer enhances water resistance of the loam mixture. T2 - First International RILEM Conference on Earthen Construction Fundamentals and Applications for a Circular Economy CY - Paris, France DA - 18.03.2022 KW - Loam KW - Alkali activation PY - 2022 SP - 44 EP - 47 CY - Paris AN - OPUS4-56393 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weise, Frank A1 - von Werder, Julia A1 - Manninger, Tanja A1 - Maier, Bärbel A1 - Fladt, Matthias A1 - Simon, Sebastian A1 - Gardei, Andre A1 - Höhnel, Desirée A1 - Pirskawetz, Stephan A1 - Meng, Birgit T1 - A multiscale and multimethod approach to assess and mitigate concrete damage due to alkali-silica reaction N2 - Alkali-silica reaction (ASR) is a chemical reaction within concrete which can lead over time to cracking and spalling. Due to the complexity of the problem, it still causes damage to concrete constructions worldwide. The publication aims to illustrate the interdisciplinary research of the German Federal Institute for Materials Research and Testing (BAM) within the last 20 years, considering all aspects of ASR topics from the macro to the micro level. First, methods for characterization and assessment of ASR risks and reaction products used at BAM are explained and classified in the international context. Subsequently the added value of the research approach by combining different, preferably nondestructive, methods across all scales is explained using specific examples from a variety of research projects. Aspects covered range from the development of new test-setups to assess aggregate reactivity, to analysis of microstructure and reaction products using microscopical, spectroscopical and X-ray methods, to the development of a testing methodology for existing concrete pavements including in-depth analysis of the visual damage indicator and the de-icing salt input using innovative testing techniques. Finally, research regarding a novel avoidance strategy that makes use of internal hydrophobization of the concrete mix is presented. KW - Mitigation strategies KW - Concrete KW - Damage analysis KW - Alkali silica reaction KW - Road pavement KW - Accelerated testing KW - Non-destructive testing KW - Microstructure PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:101:1-2022052515100075090235 DO - https://doi.org/10.1002/adem.202101346 SN - 1527-2648 VL - 24 IS - 6 SP - 1 EP - 36 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Manninger, Tanja A1 - Rübner, Katrin A1 - von Werder, Julia T1 - Eco friendly stabilization of loam with calcined clay and potassium hydroxide: a new approach to improve water resistance N2 - Earth buildings and adobe construction have been in use for thousands of years. Loam is locally available, environmentally friendly and has a small CO2 footprint mainly resulting from extraction and transport. Because of these reasons loam is one of the building materials of the future. Water resistance is an important aspect when using loam as a construction material. If the structural option of building protruding roofs cannot be implemented, the water resistance of clay can be improved by stabilization. Positive properties of the material should not be diminished by stabilization. For example, the desired regulation of air humidity, which however cannot be fully preserved by cement stabilization. For an alternative and more appropriate stabilisation, different mixtures with calcined clays with alkali activator were examined. The calcination temperature for clays is usually lower than for cement and starts at 600° C. The calcined clays therefore also have a lower CO2 footprint compared to cement. To keep the mixture environmentally friendly potassium was used as alkali ion. It could be proven that the alkali activated polymer enhances water resistance of the loam mixture. Provided some further optimization the material shows potential to replace cement without compromising on the positive properties of clay. T2 - International Conference on Regeneration and Conservation of Structures (ICRCS 2022) CY - Kyoto, Japan DA - 07.09.2022 KW - Loam KW - Alkali activation PY - 2022 SP - 1 EP - 4 AN - OPUS4-56396 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stohl, Leonie A1 - Tonon, Chiara A1 - Cook, Jake A1 - Gorbushina, Anna A1 - Dehn, Frank A1 - von Werder, Julia A1 - Manninger, Tanja T1 - Understanding bioreceptivity of concrete: material design and characterization N2 - The climate crisis is driving an increasing demand for ecologically oriented concepts. In the building sector, this demand includes not only the use of environmentally friendly materials but also the greening of urban areas. One promising approach is the development of bioreceptive concrete façades, which support the growth of green biofilms directly on their surfaces. These innovative façades are anticipated to deliver benefits comparable to those of macroscopically greened façades, such as enhanced biodiversity and improved air quality, while offering the advantages of being more self-sustaining and stable systems once fully established. However, the development of bioreceptive concrete presents substantial challenges. Due to the interdisciplinarity and novelty of this field, standardized methods for material characterization and bioreceptivity assessment are currently lacking. This study proposes an approach for evaluating surface properties crucial for bioreceptivity, developed on differently structured samples of ultra-high-performance concrete (UHPC). Existing methods and standards from concrete technology are critically reviewed and, where necessary, modified to meet the unique requirements of measuring bioreceptive material properties. Special attention is given to the surface pH value and water retention characteristics, as these are essential for promoting microbial growth and ensuring the long-term stability of green biofilms. The observed surface characteristics vary according to the imprinted surface structures, offering a spectrum of material properties and enabling the evaluation of their impact on bioreceptivity. The findings presented form the foundation for subsequent laboratory weathering experiments, which will be discussed in a complementary publication. KW - Novel methods KW - Bioreceptivity testing PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655023 DO - https://doi.org/10.1617/s11527-025-02863-y SN - 1359-5997 VL - 58 SP - 1 EP - 18 PB - Springer Science and Business Media LLC AN - OPUS4-65502 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schraut, Katharina A1 - Adamczyk, Burkart A1 - Adam, Christian A1 - Stephan, Dietmar A1 - Meng, Birgit A1 - Simon, Sebastian A1 - von Werder, Julia A1 - Hirsch, Tamino A1 - Manninger, Tanja T1 - Effect of gypsum on the hydration of fused cement clinker from basic oxygen furnace slag N2 - Fused cement clinker can be produced from molten basic oxygen furnace slag (BOFS) by way of a reductive thermochemical treatment. During the thermochemical treatment, oxidic iron is reduced to metallic iron and separated. The resulting low-iron slag has a chemical and mineralogical composition similar to ordinary Portland cement (OPC) clinker. In this study, the hydraulic reactivity of the fused clinker from BOFS with and without gypsum was investigated using isothermal calorimetry, differential scanning calorimetry, in situ X-ray diffraction and powder X-ray diffraction. Furthermore, a synthetic fused clinker without foreign ions and fused clinker produced by a mixture of both materials was studied. The hydraulic reaction of the fused clinker from BOFS was considerably slower than that of OPC. However, the reaction can be accelerated by adding gypsum as a sulfate carrier. Furthermore, the results showed an increased reaction rate with decreasing content of foreign ions such as Fe, P or Mn. KW - General Materials Science KW - Building and Construction PY - 2024 DO - https://doi.org/10.1680/jadcr.23.00070 SN - 0951-7197 SP - 1 EP - 19 PB - Telford AN - OPUS4-59391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stohl, Leonie A1 - Manninger, Tanja A1 - von Werder, Julia A1 - Dehn, F. A1 - Gorbushina, Anna A1 - Meng, Birgit T1 - Bioreceptivity of concrete - A review N2 - Materials that support natural biodiversity on their surfaces can compensate for human activities that have a negative impact on nature and thus contribute to a carbon-neutral and nature-positive world. Specifically designing bioreceptive materials which favor the growth of biofilms on their surface is an approach complementing conventional, macroscopic green façades. But what exactly characterizes a bioreceptive substrate and how do biofilm and substrate interact? How and why does a spontaneous colonization and the formation of biofilms take place? What are biofilms and how can they be established in a laboratory setting? How can this existing knowledge be transferred to the artificial stone concrete so that this material can be tuned to increase (or decrease) its bioreceptivity? This review paper aims at summarizing the existing state of knowledge on bioreceptive concrete and pointing out inconsistencies and contradictions which can only be removed by more interdisciplinary research in the field. KW - Bioreceptivity KW - Biofilm KW - Green facades KW - Developing building materials KW - Surface interactions KW - Concrete PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581685 DO - https://doi.org/10.1016/j.jobe.2023.107201 SN - 2352-7102 VL - 76 SP - 1 EP - 17 PB - Elsevier AN - OPUS4-58168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stohl, Leonie A1 - Manninger, Tanja A1 - Dehn, Frank A1 - von Werder, Julia T1 - Understanding bioreceptivity of concrete: material design and characterization N2 - The climate crisis is driving an increasing demand for ecologically oriented concepts. In the building sector, this demand includes not only the use of environmentally friendly materials but also the greening of urban areas. One promising approach is the development of bioreceptive concrete façades, which support the growth of green biofilms directly on their surfaces. These innovative façades are anticipated to deliver benefits comparable to those of macroscopically greened façades, such as enhanced biodiversity and improved air quality, while offering the advantages of being more self-sustaining and stable systems once fully established. However, the development of bioreceptive concrete presents substantial challenges. Due to the interdisciplinarity and novelty of this field, standardized methods for material characterization and bioreceptivity assessment are currently lacking. This study proposes an approach for evaluating surface properties crucial for bioreceptivity, developed on differently structured samples of ultra-high-performance concrete (UHPC). Existing methods and standards from concrete technology are critically reviewed and, where necessary, modified to meet the unique requirements of measuring bioreceptive material properties. Special attention is given to the surface pH value and water retention characteristics, as these are essential for promoting microbial growth and ensuring the long-term stability of green biofilms. The observed surface characteristics vary according to the imprinted surface structures, offering a spectrum of material properties and enabling the evaluation of their impact on bioreceptivity. The findings presented form the foundation for subsequent laboratory weathering experiments, which will be discussed in a complementary publication. KW - Bioreceptivity KW - Concrete KW - Biofilm PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648180 DO - https://doi.org/10.1617/s11527-025-02863-y SN - 1359-5997 VL - 58 IS - 10 SP - 1 EP - 12 PB - Springer Science and Business Media LLC AN - OPUS4-64818 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -