TY - JOUR A1 - Schmidt, Wolfram A1 - Alexander, Mark A1 - John, Vanderley T1 - Education for sustainable use of cement based materials N2 - Structural design and application have always been linked to the compressive strength of concrete as the main relevant criterion. This was justifiable in the past, where concrete consisted of water, ordinary Portland cement and aggregates, but this concept is no longer relevant for modern and more sustainable cement and concrete. Despite these new developments, existing standards, guidelines and academic curricula have not been much updated and are still used worldwide. There is a need to change this situation by proper education of the users. This overview describes the challenges that arise at a user Level from the higher complexity of modern concrete, and defines needs and requirements for enhanced applicability of sustainable concrete concepts. Furthermore, recommendations are given on how better concrete practice can be communicated to all the involved parties, from civil and design engineers to constructors and site-appliers on the construction site. KW - Cement KW - Concrete KW - Sustainability KW - Environment KW - Carbon footprint KW - Education KW - Climate PY - 2018 UR - https://www.sciencedirect.com/science/article/pii/S0008884616307189?via%3Dihub DO - https://doi.org/10.1016/j.cemconres.2017.08.009 SN - 0008-8846 SN - 1873-3948 VL - 114 SP - 103 EP - 114 PB - Elsevier AN - OPUS4-47673 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Priebe, Nsesheye Susan A1 - Schmidt, Wolfram A1 - Mota, Berta A1 - Leinitz, Sarah A1 - Kühne, Hans-Carsten A1 - Rogge, Andreas T1 - The effect of superplasticizers on rheology and early hydration kinetics of rice husk ash-blended cementitious systems N2 - Superplasticizers (SPs) have been employed in concrete technology for decades to improve the workability of concrete in its fresh state. The addition of SPs in cement-based systems affects the early properties. Although the interaction of the cement particles with various SPs has been extensively researched, there still exists limited research on the interaction of SPs with supplementary cementitious materials such as rice husk ash (RHA). This paper investigates the rheological properties and early hydration kinetics of RHA-blended systems with three types of SPs, a polycarboxylate ether (PCE) and two lignosulphonates (LS-acc and LS-ret). In rheological properties, the addition of SP causes an initial improvement of workability as the yield stress is significantly reduced. The pastes with PCE and LS-acc show a slight increase of yield stress over time whereas pastes with LS-ret tend to lower the yield stress slightly over time, further improving the workability. Without SP, pastes with RHA show a lower yield stress but an increase in plastic viscosity as cement is further replaced with RHA. The addition of the LS SPs is observed to lower the plastic viscosity but remains constant with further replacement of cement with RHA. This indicates that LS SPs further adsorbs on RHA particles and hydration products produced causing dispersion of the particles within the system. In early hydration kinetics, pastes with PCE retard hydration and the degree of retardation is further increased with LS SPs. In the presence of RHA, the retardation of LS SP systems is significantly reduced. The pastes with PCE show more ettringite in the SEM micrographs, but is observed to be shorter needles. This indicates an initial good workability for PCE. However, C-S-H and CH were observed to be low in quantity, whereby the pastes with LS show more nucleation sites for C-S-H and CH. The ettringite needles in the LS systems were similar in quantity and more elongated in some cases but not abundant as in the PCE systems. KW - Plastic viscosity KW - Cement KW - CO2 reduction KW - Supplementary cementitious materials KW - Rice husk ash KW - Superplasticizers KW - Hydration KW - Rheology KW - Yield stress KW - Slump flow PY - 2017 UR - http://www.sciencedirect.com/science/article/pii/S0950061817310978?via%3Dihub DO - https://doi.org/10.1016/j.conbuildmat.2017.05.197 SN - 0950-0618 SN - 1879-0526 N1 - Geburtsname von Priebe, Nsesheye Susan: Msinjili, N. S. - Birth name of Priebe, Nsesheye Susan: Msinjili, N. S. VL - 150 SP - 511 EP - 519 PB - Elsevier Ltd. AN - OPUS4-41036 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 - Lu, Z. C. A1 - Haist, M. A1 - Ivanov, D. A1 - Jakob, C. A1 - Jansen, D. A1 - Schmid, M. A1 - Kißling, P. A. A1 - Leinitz, Sarah A1 - Link, J. A1 - Mechtcherine, V. A1 - Neubauer, J. A1 - Plank, J. A1 - Schmidt, Wolfram A1 - Schilde, C. A1 - Schröfl, C. A1 - Sowoidnich, T. A1 - Stephan, D. T1 - Characterization data of reference cement CEM III/A 42.5N used for priority program DFG SPP 2005 "Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials" N2 - Two types of cements were selected as the reference cement in the priority program 2005 of the German Research Foundation (DFG SPP 2005). A thorough characterization of CEM I 42.5 R has been made in a recent publication. In this paper, the characterization data of the other reference cement CEM III/A 42.5 N are presented from the aspects of chemical and mineralogical compositions as well as physical and chemical properties. The characterization data of the slag, which is the second main constituent of this specific cement besides the clinker, are presented independently. For all data received, the mean values and the corresponding errors were calculated. The data shall be used for the ongoing research within the priority program. Also, researchers from outside this priority program can benefit from these data if the same materials are used. KW - Cement KW - Slag KW - Characterization KW - DFG SPP 2005 PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568980 DO - https://doi.org/10.1016/j.dib.2020.105524 SN - 2352-3409 VL - 30 SP - 1 EP - 14 PB - Elsevier CY - Amsterdam AN - OPUS4-56898 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Hirya, N.N.M. A1 - Bjegovic, D. A1 - Uzoegbo, H.C. A1 - Kumaran, S.G. T1 - Cement technology in sub-Saharan Africa-practical and scientific experiences N2 - Sub-Saharan Africa is populated by more than half a billion people, and rapid urbanization is creating challenges in the areas of housing, roads, railways, power supply, dams and water pipelines — aspects of nfrastructure that are critical to the well being of the population. This situation indicates that cement and concrete will play a major role in the future construction technology in Africa, despite the fact that it does not have a long-lasting tradition over most of the continent. Although the continent is rich in natural resources for the production of mineral binder systems, many sub-Saharan African countries exhibit challenging boundary conditions, that have to be well understood in order to use cement and concrete technologies in a sustainable and reasonable way. KW - Africa KW - Cement KW - Technology transfer KW - SPIN PY - 2012 SN - 0002-7812 VL - 91 IS - 5 SP - 52 EP - 56 PB - American Ceramic Society CY - Westerville, Ohio AN - OPUS4-26075 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Gluth, Gregor T1 - Knowledge transfer and quality assurance - key factors for the future prospects of building with cement in Africa / Wissentransfer und Qualitätssicherung - Schlüsselfaktoren für die Zukunftsperspektiven der Bauweise mit Zement in Afrika N2 - The SPIN Project included workshops for young academics and building materials laboratories of the cement and concrete sector. Within the framework of the SPIN Project, plans were discussed for the conference 'Advances in Cement and Concrete Technology in Africa' that will take place in January 2013. A lecture on application rules for shotcrete construction was given by Prof. Regina Stratmann-Albert who took part in the courses as guest speaker. A short lecture was given by Akindehinde Ayotunde on the use of starch in cement-bound systems. Renato Rajzer talked about standard regulations for quality assurance during site operation. A workshop for an interlaboratory comparison took place with participants from all regions of Africa to test cement according to the standard series EN 196. The Round Robin test comprises the determination of the tensile bending and compressive strengths according to EN 196-1, of the water demand, the initial and final set, and the soundness according to EN 196-3 as well as of the fineness according to EN 196-6. KW - Africa KW - Cement KW - Concrete KW - Proficiency testing KW - Round robin PY - 2012 SN - 0949-0205 N1 - Sprachen: Deutsch/Englisch - Languages: German/English VL - 65 IS - 9 SP - 34 EP - 38 PB - Bauverl. BV CY - Gütersloh AN - OPUS4-26535 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - The working mechanism of starch and diutan gum in cementitious and limestone dispersions in presence of polycarboxylate ether superplasticizers N2 - Polysaccharides provide high potential to be used as rheology modifying admixtures in mineral binder systems for the construction industry such as concrete or mortar. Since superplasticizers have become state of technology, today, concrete is more and more adjusted to flowable consistencies. This often goes along with the risk of segregation, which can be effectively avoided by adding stabilising agents supplementary to superplasticizers. Stabilising agents are typically based on polysaccharides such as cellulose, sphingan gum, or starch. Starch clearly distinguishes in its effect on rheology from other polysaccharides, mainly due to the strong influence of amylopectin on the dispersion and stabilisation of particles. Based on rheometric investigations on cementitious and limestone based dispersions with different volumetric water to solid ratios, the mode of operation of modified potato starch is explained in comparison to a sphingan gum. It is shown that the stabilising effect of starch in a coarsely dispersed system is mainly depending upon the water to solid ratio and that above a certain particle volume threshold starch mainly affects the dynamic yield stress of dispersions, while plastic viscosity is affected only to a minor degree. Sphingans operate more independent of the particle volume in a coarsely dispersed system and show significantly higher effect on the plastic viscosity than on the yield stress. In systems incorporating superplasticizers, influences of both stabilising agents on yield stress retreat into the background, while both observed polysaccharides maintain their effect on the plastic viscosity. KW - Cement KW - Limestone KW - Rheology KW - Stabilising agent KW - Coarsely dispersed systems KW - Diutan gum KW - Starch ether PY - 2013 DO - https://doi.org/10.3933/ApplRheol-23-52903 SN - 1430-6395 SN - 0939-5059 VL - 23 IS - 5 SP - 52903-1 EP - 52903-12 PB - Kerschensteiner CY - Lappersdorf AN - OPUS4-29932 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Kanjee, J. A1 - Motukwa, G. A1 - Olonade, K. A1 - Dodoo, A. T1 - A snapshot review of future‑oriented standards for cement, admixtures, and concrete: How Africa can spearhead the implementation of green urban construction materials N2 - The existing cement and concrete standards are not capable of making full use of the current technology capacity due to strong focus on conventional concrete and thus they are not fit for the current and future challenges of construction industry. The paper highlights shortcomings with regard to the implementation of the existing standards. It can be seen that future-oriented standards are generally required to contribute to a lower-carbon footprint of the industry. These changes are significantly more relevant in sub-Saharan Africa, due to the rapidly increasing urbanisation challenge and the enormous potentials to develop lower-carbon technologies than elsewhere in the world. KW - Future‑oriented standards KW - Green urban construction KW - Cement PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582563 DO - https://doi.org/10.1557/s43580-023-00563-9 SN - 2731-5894 VL - 4 IS - 8 SP - 557 EP - 565 PB - Springer International Publishing CY - Springer Nature Switzerland, Cham AN - OPUS4-58256 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cunningham, Patrick A1 - Schmidt, Wolfram T1 - Cement and clinker imports: embodied carbon, carbon costs, and the EU Carbon Border Adjustment Mechanism (CBAM) N2 - When the European Union (EU) Carbon Border Adjustment Mechanism (CBAM) comes into force, importers of Portland cement and clinker will be required to purchase carbon allowances for their goods. Herein, the trade flows into the EU are mapped by country and the equivalent carbon dioxide (CO2-eq) emissions from production is modeled. Using average allowance prices, the additional cost passed to the consumer if carbon allowances had been purchased for imports in the modeled years are estimated. Together, this retrospective analysis provides insights into CBAM and the potential implications of carbon allowances on the cost of imported goods. KW - Carbon border adjustment mechanism KW - Carbon allowances KW - Cost of carbon KW - Cement KW - Impact shifting PY - 2025 UR - https://www.zkg.de/en/artikel/cement-and-clinker-imports-embodied-carbon-carbon-costs-and-the-eu-carbon-border-adjustment-mechanism-cbam-4252088.html SN - 2748-8330 VL - 78 IS - 3 SP - 54 EP - 58 PB - Bauverlag BV GmbH CY - Gutersloh, Germany AN - OPUS4-63333 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ramirez Caro, Alejandra A1 - Pauli, Jutta A1 - Mota, Berta A1 - Simon, Sebastian A1 - Schmidt, Wolfram A1 - Resch-Genger, Ute T1 - C⁠3A passivation with gypsum and hemihydrate monitored by optical spectroscopy N2 - Tricalcium aluminate (C⁠3A) is found with less than 10% wt. of the total composition; however, during hydration, C⁠3A plays an important role in the early hydration of cement in the presence of gypsum as a set retarder. The aim of this investigation is to assess the suitability of optical spectroscopy and a dye-based optical probe to monitor early hydration of C⁠3A in the presence of gypsum and hemihydrate. Optical evaluation was performed using steady-state fluorescence and diffuses reflectance spectroscopy (UV-VisDR). Phase characterization during hydration was done with in-situ X-ray diffraction. UV-VisDR with a cyanine dye probe was used to monitor the formation of metastable phases and was employed together with fluorescence spectroscopy, to follow the Aggregation and disaggregation of the dye during hydration. In conclusion, for the first time, a cyanine dye was identified as a feasible and stable probe to monitor C⁠3A hydration changes in the presence of calcium sulfate. KW - Dye KW - Photoluminescence KW - Fluorescence KW - Reflection spectroscopy KW - Cement KW - Hydration KW - Method development PY - 2020 DO - https://doi.org/10.1016/j.cemconres.2020.106082 VL - 133 SP - 106082 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-50952 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Priebe, Nsesheye Susan A1 - Schmidt, Wolfram A1 - Gluth, Gregor A1 - Florea, M.V.A. A1 - Kumaran, G.S. A1 - Akindahunsi, A. A. A1 - Uzoegbo, H.C. A1 - Oslakovic, I.S. ED - Alexander, M. G. ED - Beushausen, H.-D. ED - Dehn, F. ED - Moyo, P. T1 - Concrete knowledge improvement in sub-Saharan Africa N2 - The building situation in Africa is overwhelmed with high-priced materials and lack of adequate concrete technology, which provides a challenge in the concrete industry. Worldwide, cement and concrete experts are at the cutting-edge to sustainable, green and healthy but nonetheless high-performance concrete, which is more sustainable and safer than traditional methods of construction with clay and wood. Since concrete in Africa is rather a new construction material, this sustainability experience can offer the continent a unique opportunity to begin a constantly growing building sector with the newest state-of-the-art technology. This can be achieved without subordinating to existing standards by establishing a sustainable “African concrete technology”. The major challenge for most sub-Saharan countries is the deficiency of experts, which would be required to establish such state-of-the-art technology. Based on the examples of two African-European scientific networks—SPIN and LightSHIP—this paper presents possible solution strategies for the establishment of a scientific cooperation between Europe and Africa, with links to policy making bodies that can help accelerate the progress of cement and concrete industries in Africa. T2 - 3rd International conference on concrete repair, rehabilitation and retrofitting III CY - Cape Town, South Africa DA - 03.09.2012 KW - Education KW - Research sub-Sahara KW - Africa KW - Cement KW - Concrete PY - 2012 SN - 978-0-415-89952-9 N1 - Geburtsname von Priebe, Nsesheye Susan: Msinjili, N. S. - Birth name of Priebe, Nsesheye Susan: Msinjili, N. S. IS - Theme 5 SP - 1459 EP - 1465 PB - CRC Press CY - London, UK AN - OPUS4-26508 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kossatz, Philipp A1 - Mezhov, Alexander A1 - Andresen, Elina A1 - Prinz, Carsten A1 - Schmidt, Wolfram A1 - Resch-Genger, Ute T1 - Assessing the Applicability of Lanthanide-Based Upconverting Nanoparticles for Optically Monitoring Cement Hydration and Tagging Building Materials N2 - Chemically stable, lanthanide-based photon upconversion micro- and nanoparticles (UCNPs) with their characteristic multicolor emission bands in the ultraviolet (UV), visible (vis), near-infrared (NIR), and short-wave infrared (SWIR) arepromising optical reporters and barcoding tags. To assess the applicability of UCNPs for the monitoring of early stage cement hydration processes and as authentication tags for cementitious materials, we screened the evolution of the luminescence of Selfmade core-only NaYF4:Yb,Er UCNPs and commercial μm-sized Y2O2S:Yb,Er particles during the first stages of cement hydration, which largely determines the future properties of the hardened material. Parameters explored from the UCNP side included particle size, morphology, surface chemistry or coating, luminescence properties, and concentration in different cement mixtures. From the cement side, the influence of the mineral composition of the cement matrix was representatively examined for ordinary Portland cement (OPC) and its constituents tricalcium aluminate (C3A), tricalcium silicate (C3S), and gypsum at different water to cement ratios. Based on reflection and luminescence measurements, enabling online monitoring, which were complemented by XRD and isothermal heat-flow calorimetric measurements to determine whether the incorporation of these particles could impair cement hydration processes, well suited lanthanide particle reporters could be identified as well as application conditions. In addition, thereby the reporter influence on cement hydration kinetics could be minimized while still preserving a high level of information content. The best performance for the luminescence probing of changes during early stage cement hydration processes was observed for 25 nm-sized oleate (OA)-coated UCNPs added in a concentration of 0.1 wt %. Higher UCNP amounts of 1.0 wt % delayed cement hydration processes size- and surface coatingspecifically in the first 24 h. Subsequent luminescence stability screening studies performed over a period of about one year support the applicability of UCNPs as optical authentication tags for construction materials. KW - Quality assurance KW - Fluorescence KW - Nano KW - Particle KW - Synthesis KW - Quantum yield KW - NIR KW - Mechanism KW - Characterization KW - XRD KW - Calorimetry KW - Advanced material KW - Cement KW - Monitoring KW - Surface KW - Size KW - Lifetime KW - Barcode KW - Lanthanide KW - Upconversion KW - Encoding KW - Method PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638318 DO - https://doi.org/10.1021/acsomega.5c02236 SN - 2470-1343 VL - 10 IS - 29 SP - 31587 EP - 31599 PB - ACS Publications CY - Washington, DC AN - OPUS4-63831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -