TY - CONF A1 - Schmidt, Wolfram A1 - Priebe, Nsesheye Susan A1 - Uzoegbo, H. C. A1 - Makunza, J. K. ED - Malhotra, V. M. ED - Gupta, P. R. ED - Holland, T. C. T1 - Admixture concepts for the Sub-Saharan African environment with indigenous raw materials N2 - The economic use of chemical admixtures depends on supply chains. Therefore, in most regions ins sub-Saharan Africa (SSA), the use of admixtures is not common practice. This amplifies the unfavorable framework for concrete construction such as fragmentary supply chains, high local cement prices, and unfavorable construction site facilities in this region significantly. The use of superplasticizer (SP) and stabilizing agents (STA) can enhance the concrete technology in SSA, since they can disassociate the concrete quality from external boundary influences. After providing a general overview of the peculiarities of the SSA boundary framework, economic concepts are provided, how existing material solutions can be significantly improved by the use of SPs and STAs based on locally available materials such as lignosulphonates and cassava starch. Finally a three step optimization process is described that helps developing flowable concrete based on materials that can be accessed in most locations in SSA. T2 - 11th International Conference on Superplasticizers and Other Chemical Admixtures in Concrete CY - Ottawa, Canada DA - 12.07.2015 KW - Lignosulfonate KW - Polycarboxylate ether KW - Robustness KW - Self-compacting concrete KW - Sub-Saharan Africa PY - 2015 SN - 9781942727224 N1 - Geburtsname von Priebe, Nsesheye Susan: Msinjili, N. S. - Birth name of Priebe, Nsesheye Susan: Msinjili, N. S. SP - SP-302-37, 491 EP - 505 AN - OPUS4-36860 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Schmidt, Wolfram A1 - Ramirez Caro, Alejandra A1 - Sojref, Regine A1 - Mota Gassó, Berta ED - Greim, M. ED - Kusterle, W. ED - Teubert, O. T1 - Contribution of the coarse aggregates to rheology - effects of flow coefficient, particle size distribution, and volume fraction N2 - In order to observe the effect of the aggregate phases between 2 mm and 16 mm without overlap with rheological effects induced by the cement hy-dration and without interactions with a threshold fine sand particle size that affects both, paste and aggregates, rheological experiments were conducted on a limestone filler based paste mixed with aggregates up to 16 mm. Vari-ous aggregate fractions were blended and mixed with the replacement paste in different volumetric ratios. The dry aggregates’ flow coefficients were determined and compared to yield stress and plastic viscosity values at different aggregate volume fractions. The results indicated that the flow coefficient is not a suitable parameter to predict the performance of the aggregates in the paste. It was shown that the yield stress of pastes is largely determined by the blend of different aggregate fractions, while the plastic viscosity to large extend depends upon the coars-est aggregate fraction. Based on the results, ideal aggregate composition ranges for minimised yield stress are presented. For the plastic viscosity no such grading curves to achieve minimum values could be found, but high viscosity curves are identified. KW - Rheology KW - Flow Coefficient KW - Particle Size Distribution KW - Volume Fraction KW - Cement KW - Concrete KW - Reference Material KW - Limestone Filler PY - 2018 SN - 978-3-7469-1878-5 SP - 96 EP - 108 PB - tredition GmbH CY - Hamburg AN - OPUS4-44434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten T1 - Wechselwirkungen zwischen Zusatzmitteln und mineralischen Komponenten in selbstverdichtendem Beton beim Betonieren in unterschiedlichen Temperaturen KW - Self-compacting concrete KW - Admixtures KW - Temperature KW - Rheology KW - Limestone filler KW - Selbstverdichtender Beton KW - Zusatzmittel KW - Temperatur KW - Rheologie KW - Kalksteinmehl PY - 2009 SN - 1439-7706 VL - 2 SP - 32 EP - 38 PB - ad-media-Verl. CY - Köln AN - OPUS4-19412 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bühler, M. M. A1 - Hollenbach, P. A1 - Michalski, A. A1 - Meyer, S. A1 - Birle, E. A1 - Off, R. A1 - Lang, Ch. A1 - Schmidt, Wolfram A1 - Cudmani, R. A1 - Fritz, O. A1 - Baltes, G. A1 - Kortmann, G. T1 - The Industrialisation of Sustainable Construction: A Transdisciplinary Approach to the Large-Scale Introduction of Compacted Mineral Mixtures (CMMs) into Building Construction N2 - Abstract: Increasing demand for sustainable, resilient, and low-carbon construction materials has highlighted the potential of Compacted Mineral Mixtures (CMMs), which are formulated from various soil types (sand, silt, clay) and recycled mineral waste. This paper presents a comprehensive inter- and transdisciplinary research concept that aims to industrialise and scale up the adoption of CMM-based construction materials and methods, thereby accelerating the construction industry’s systemic transition towards carbon neutrality. By drawing upon the latest advances in soil mechanics, rheology, and automation, we propose the development of a robust material properties database to inform the design and application of CMM-based materials, taking into account their complex, time-dependent behaviour. Advanced soil mechanical tests would be utilised to ensure optimal performance under various loading and ageing conditions. This research has also recognised the importance of context-specific strategies for CMM adoption. We have explored the implications and limitations of implementing the proposed framework in developing countries, particularly where resources may be constrained. We aim to shed light on socio-economic and regulatory aspects that could influence the adoption of these sustainable construction methods. The proposed concept explores how the automated production of CMM-based wall elements can become a fast, competitive, emission-free, and recyclable alternative to traditional masonry and concrete construction techniques. We advocate for the integration of open-source digital platform technologies to enhance data accessibility, processing, and knowledge acquisition; to boost confidence in CMM-based technologies; and to catalyse their widespread adoption. We believe that the transformative potential of this research necessitates a blend of basic and applied investigation using a comprehensive, holistic, and transfer-oriented methodology. Thus, this paper serves to highlight the viability and multiple benefits of CMMs in construction, emphasising their pivotal role in advancing sustainable development and resilience in the built environment. KW - Decarbonisation KW - Circular economy KW - Recycled materials KW - Demolition wastes KW - Low-carbon construction KW - Building with earth KW - Compressed earth KW - Rammed earth KW - Sustainable construction PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583260 DO - https://doi.org/10.3390/su151310677 VL - 15 IS - 13 SP - 1 EP - 25 PB - MDPI AN - OPUS4-58326 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Munsch, Sarah Mandy A1 - Schmidt, Wolfram A1 - Lorenzoni, Renata A1 - Telong, Melissa A1 - Grobla, Lili A1 - Lauinger, Robert A1 - Kruschwitz, Sabine T1 - Investigation of the hydration of clinker‑reduced cementitious binders by 1H NMR relaxometry N2 - In this paper, we demonstrate the value of 1 H NMR relaxometry for studying the hydration of clinker-reduced, climate-friendly cementitious binders. Our study includes white cement (WC), ordinary Portland cement (OPC), and samples incorporating reactive agro-waste based ashes and non-reactive biochars as supplementary cementitous materials (SCM). NMR measurements were performed over a period of up to 120 h during hydration with an echo time of 50 μ s and a relatively large sample size of 20 mL. The results were compared to heat flow calorimetry (HFC) data, and a detailed comparison with literature data was performed for pure OPC and WC. The results show that time-resolved NMR measurements, especially the analysis of individual NMR signal components assigned to defined 1 H reservoirs, are effective for studying hydration processes. They offer insights into the evolution of the microstrucure and specific chemical phases. NMR provides valuable information and serves as a good complement to HFC. The comparison with data obtained with shorter echo times (40 μs or around 15–45 μs with solid echo sequence) on much smaller samples showed almost identical developments with respect to the T2 distributions. For the SCM samples, NMR results indicated partially accelerated hydration processes compared to classical OPC hydration. One SCM sample acted as a highly reactive pozzolan, showing a similar hydration process to OPC with the strongest effect observed when superplasticizer was added. Adding biochar delayed C-S-H gel pore formation but significantly increased capillary pores and even free water, likely due to the sponge-like structure. KW - Nuclear magnetic resonance relaxometry KW - Heat flow calorimetry KW - Cement KW - Hydration KW - Clinker reduction KW - Carbon emission KW - Kinetics PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630284 DO - https://doi.org/10.1617/s11527-025-02632-x SN - 1871-6873 VL - 58 IS - 137 SP - 1 EP - 23 PB - Springer Nature AN - OPUS4-63028 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, K. A1 - Mezhov, Alexander A1 - Schmidt, Wolfram T1 - Effect of agitation during the early‑age hydration on thixotropy and morphology of cement paste N2 - The effect of agitation during the earlyage hydration on thixotropy and morphology of cement paste prepared with and without superplasticizers (SP) is investigated by applying penetration test, small amplitude oscillatory shear sweep test (SAOS), isothermal calorimetric test, scanning electron microscopy (SEM) and energy dispersive X-ray analyses (EDX). The results show that the agitation of cement paste during the induction period increases the heat flow rate and destroys existing structures of samples without changing the mineral composition of samples. Yet, if the agitation is applied during the acceleration period, the heat flow rate is significantly lowered and the morphology and mineral composition of samples undergo irreversible change, freshly formed syngenite is destroyed and no longer restored. The penetration force and the static yield stress grow linearly during the induction period and exponentially during the acceleration period. Agitation during the induction period destroys the structure, which causes the static yield stress and the penetration force values becoming nearly equal to zero. However, during the acceleration period, even after agitation the static yield stress and the penetration force exhibit high residual values, which indicates the impact of hydration to the structural build-up. KW - Hydration · Thixotropy KW - Agitation KW - Morphology KW - Structural build-up PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621189 DO - https://doi.org/10.1617/s11527-024-02504-w VL - 57 SP - 1 EP - 13 PB - Springer Nature Switzerland AG CY - Schweiz AN - OPUS4-62118 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mezhov, Alexander A1 - Bright, Asante A1 - Schmidt, Wolfram T1 - Increasing the Incorporation of CO2-Sequestering Materials in Concrete N2 - Concrete is the most widely used construction material accounting for approximately half of all human production throughout history. The production of one ton of cement emits around 600 kg of CO2. With a global cement production estimate of 4.2 billion tons, this results in about 2.5 billion tons of CO2 emissions. This accounts for roughly 7.2% of the total global carbon emissions in 2021. Strategies to decrease carbon emissions in the cement and concrete industry include carbon capture and storage (CCS), reduced binders like ordinary Portland cement (OPC) clinker and optimizing material use through improved processes and structural design. This also means changing architectural vision [6], avoiding concrete where its structural performance is not required and use alternative materials instead, and optimizing the communication among the entire production value chain. T2 - 1st International Conference on Net-Zero Built Environment: Innovations in Materials, Structures, and Management Practices (Net-Zero Future 2024) CY - Oslo, Norway DA - 19.06.2025 KW - Concrete KW - CO2-Sequestering PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638531 DO - https://doi.org/10.1007/978-3-031-69626-8_4 VL - 237 SP - 39 EP - 48 PB - Springer Nature Switzerland AG CY - Schweiz AN - OPUS4-63853 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Leinitz, Sarah A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten T1 - Assessment of rheological effects in the binder on the rheology of mortar and concrete N2 - In the last years flowable concrete has become increasingly important in applications such as, for systems with highly reinforced concrete with a complicated formwork, or sprayed concrete and 3D-printing of concrete. For all these applications it is necessary to have tailored rheological properties. Rheology can be described by values of yield stress and plastic viscosity, which can be determined for example by evaluation of rheometer measurements. But for different materials various rheometers with different geometries and stirrers are being used. To see the effects from paste in concrete, it is necessary to investigate mixes of paste, mortar and concrete, stepwise. But currently there exists no device, which is calibrated for these different systems at once. Due to this fact, conventional tests such as V-funnel efflux-time and flow diameter were determined, as well as rheometer data in different cell sizes and geometries. In this study the assessment of rheological effects in the binder on the rheology of mortar and concrete was investigated by using combination of two rheometers. T2 - Rheologische Messungen an Baustoffen 2018, 27. Workshop und Kolloquium CY - Regensburg, Germany DA - 07.03.2018 KW - Rheology KW - Cement KW - Mortar KW - Upscaling KW - Superplasticizer PY - 2018 SN - 978-3-7469-1878-5 VL - 27 SP - 109 EP - 111 PB - tredition GmbH AN - OPUS4-44444 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram ED - Schmidt, Wolfram T1 - Engineering skill requirements to cope with the local and global challenges of the future N2 - In the 21st century, adequate habitat and functioning infrastructure are critical for global societal and economic stability. In addition, growing urbanisation and environmental pollution cause challenges to societies. With increasing velocity, humanity faces that the current way of living is not sustainable. Thus, habitat,infrastructure, urbanisation, environment and sustainability are definitively among the most striking challenges of the 21st century. By consulting, planning, building, maintaining, exploiting and processing of global resources, civil engineers contribute significantly to the existence of these challenges. This is a high responsibility, but due to the heavy involvement, together with adjacent disciplines such as architecture, geosciences, chemistry, physics, environmental sciences and economics, civil engineers also hold the key to mitigate these challenges and provide a brighter global future. Solutions towards greener, more sustainable and economically viable materials do exist, and there is ongoing research on how greener technologies can contribute to better livelihood and economic growth, but their level of implementation is limited, a major reason for which is that these approaches require more fundamental understanding rather than standard application. T2 - ISEE Africa - Innovation, Science, Engineering, Education CY - Nairobi, Kenya DA - 30.01.2019 KW - Civil Engineering KW - Education KW - Sustainability KW - Materials KW - Sciences PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484895 UR - http://isee-africa.com/wp-content/uploads/2019/07/Innovation-Science-Engineering-Education_High-Quality.pdf SN - 978-3-9818564-2-2 SP - 16 EP - 19 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-48489 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Barucker-Sturzenbecher, Meike A1 - Schmidt, Wolfram ED - Schmidt, Wolfram T1 - Learning from the future - How children of Mukuru fancy the city of tomorrow N2 - Sustainability means meeting the needs of today without compromising the needs of the next generations. How can we meet the needs of the next generations, if we do not even know what these needs are? If we do not listen to the next generation and learn from them? Do we even meet the needs of today for everyone on earth? T2 - ISEE Africa - Innovation, Science, Engineering, Education CY - Nairobi, Kenya DA - 30.01.2019 KW - Urban planning KW - Concrete KW - Mukuru KW - Africa KW - Sustainability PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484832 UR - http://isee-africa.com/wp-content/uploads/2019/07/Innovation-Science-Engineering-Education_High-Quality.pdf SN - 978-3-9818564-2-2 SP - 194 EP - 197 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-48483 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -