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 JF - MRS Advances 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 - CONF A1 - Schmidt, Wolfram A1 - Olonade, K. A. A1 - Mbugua, R. N. A1 - Lenz, F. J. A1 - Tchetgnia Ngassam, I. T1 - Bio-Based Rheology Modifiers for High Performance Concrete – Possible Modes of Actions and Case Study for Cassava Starch in West Africa T2 - 3rd International Conference on the Application of Superabsorbent Polymers (SAP) and Other New Admixtures Towards Smart Concrete N2 - Polymers that help tailoring rheological properties during the casting process have become inevitable constituents for all kinds of high-performance concrete technologies. Due to lacking industries, these typically crude-oil based admixtures are not readily available in many parts of the world, which limits the implementation of more sustainable high-performance construction technologies in these regions. Alternative polymers, which often demand for less processing, can be derived from local plant-based resources. The paper provides experimental data of flow tests of cement pastes with polysaccharides from Triumfetta pendrata A. Rich, acacia gum and cassava without and in the presence of polycarboxylate ether superplasticizer. The flow tests are amended by observations of the zeta potentials and the hydrodynamic diameters in the presence of and without calcium ions in the dispersion medium. The results show that in the presence of and without calcium ions all polysaccharides provide negative zeta potentials, yet, they affect flowability and thixotropy in different ways. Cassava starch, acacia gum, and the gum of Triumfetta pendrata A. Rich qualified well for robustness improvement, strong stiffening, and additive manufacturing, respectively. The reason for the different effects can be found in their average sizes and size distribution. Due to the promising results, a flow chart for local value chains is derived on the example of yet unused cassava wastes, which can be converted in parallel. T2 - 3rd International Conference on the Application of Superabsorbent Polymers CY - Skukuza, South Africa KW - Admixtures KW - Polysaccharides KW - Rheology KW - Thixotropy KW - Concrete PY - 2020 SN - 978-3-030-33341-6 SN - 978-3-030-33342-3 DO - https://doi.org/10.1007/978-3-030-33342-3_17 SP - 158 EP - 166 PB - Springer AN - OPUS4-58404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lu, Z. A1 - Haist, M. A1 - Ivanov, D. A1 - Jakob, C. A1 - Jansen, D. 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 I 42.5 R used for Priority Program DFG SPP 2005 “Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials” JF - Data in Brief N2 - A thorough characterization of starting materials is the precondition for further research, especially for cement, which contains various phases and presents quite a complex material for fundamental scientific investigation. In the paper at hand, the characterization data of the reference cement CEM I 42.5 R used within the priority program 2005 of the German Research Foundation (DFG SPP 2005) are presented from the aspects of chemical and mineralogical compositions as well as physical and chemical properties. The data were collected based on tests conducted by nine research groups involved in this cooperative program. For all data received, the mean values and the corresponding errors were calculated. The results shall be used for the ongoing research within the priority program. KW - Portland cement KW - Characterization KW - DFG SPP 2005 PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500849 DO - https://doi.org/10.1016/j.dib.2019.104699 SN - 2352-3409 VL - 27 SP - 104699 PB - Elsevier Inc. AN - OPUS4-50084 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" JF - Data in brief 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 - Pott, U. A1 - Crasselt, Claudia A1 - Fobbe, N. A1 - Haist, M. A1 - Heinemann, M. A1 - Hellmann, S. A1 - Ivanov, D. A1 - Jakob, C. A1 - Jansen, D. A1 - Lei, L. A1 - Li, R. A1 - Link, J. A1 - Lowke, D. A1 - Mechtcherine, V. A1 - Neubauer, J. A1 - Nicia, D. A1 - Plank, J. A1 - Reißig, S. A1 - Schäfer, T. A1 - Schilde, C. A1 - Schmidt, Wolfram A1 - Schröfl, C. A1 - Sowoidnich, T. A1 - Strybny, B. A1 - Ukrainczyk, N. A1 - Wolf, J. A1 - Xiao, P. A1 - Stephan, D. T1 - Characterization data of reference materials used for phase II of the priority program DFG SPP 2005 “Opus Fluidum Futurum –Rheology of reactive, multiscale, multiphase construction materials” JF - Data in Brief N2 - A thorough characterization of base materials is the prereq- uisite for further research. In this paper, the characterization data of the reference materials (CEM I 42.5 R, limestone pow- der, calcined clay and a mixture of these three components) used in the second funding phase of the priority program 2005 of the German Research Foundation (DFG SPP 2005) are presented under the aspects of chemical and min- eralogical composition as well as physical and chemical properties. The data were collected based on tests performed by up to eleven research groups involved in this cooperative program. KW - Portland cement KW - Limestone powder KW - Calcined clay KW - Sustainable cement KW - DFG SPP 2005 PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569913 DO - https://doi.org/10.1016/j.dib.2023.108902 VL - 47 SP - 1 EP - 19 PB - Elsevier AN - OPUS4-56991 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, K. A1 - Mezhov, Alexander A1 - Schmidt, Wolfram T1 - Chemical and thixotropic contribution to the structural build-up of cementitious materials JF - Construction and Building Materials N2 - The structural build-up of fresh cement paste is often considered as a purely thixotropic phenomenon in literature even though cementitious materials undergo a non-reversible hydration process that can have an influence on the structuration process. In the current paper a method is proposed to validate the impact of the non-reversible structural build-up. It is shown that fresh cement paste samples lose their structural gain almost completely due to thixotropy while the structural build-up due to hydration can be observed but occurs in a significantly lower order of magnitude over the course of the first hours of hydration. In addition, it is shown, that the chemical component of the structural build-up accelerates with the onset of the acceleration period of hydration, while its contribution in the entire structural build-up remains constant. KW - Thixotropy KW - Structural build-up KW - Penetration test KW - Rheological properties PY - 2022 DO - https://doi.org/10.1016/j.conbuildmat.2022.128307 SN - 0950-0618 VL - 345 IS - 128307 SP - 1 EP - 10 PB - Elsevier Ltd. AN - OPUS4-58248 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Govin, A. A1 - Bartholin, M.-C. A1 - Schmidt, Wolfram A1 - Grosseau, P. T1 - Combination of superplasticizers with hydroxypropyl guar, effect on cement-paste properties JF - Construction and Building Materials N2 - Viscosity-modifying agent (VMA) are used in several applications of concrete, such as underwater concrete, Self-Compacting Concrete (SCC) or Self-Levelling Underlayments (SLU) in order to improve the washout resistance and the stability. The study focuses on the modifications of cement pastes properties implied when a VMA (hydroxypropyl guars or HPG) and a superplasticizer are introduced together. For reaching this objective, two chemically different polycarboxylate-based superplasticizers (PCE) and two HPGs exhibiting different molar substitution ratios (MSHP), were studied. A method, combining total organic carbon and size exclusion chromatography, was developed in order to quantify the adsorption of the both admixtures. The adsorption of HPGs appears being significantly lowered by the presence of PCE, while only the adsorption of the less charged PCE is slightly affected by the HPG. As consequence, strong modifications of the rheological properties of cement pastes were noticed when HPG and PCE are combined. The desorption of HPG leads to higher yield stress and residual viscosity than with PCE alone. KW - Pore solution KW - Admixture KW - Rheology KW - Adsorption KW - Polymers PY - 2019 DO - https://doi.org/10.1016/j.conbuildmat.2019.04.137 VL - 215 SP - 595 EP - 604 PB - Elsevier Ltd. AN - OPUS4-49298 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 JF - Cement and Concrete Research 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 - JOUR A1 - Schmidt, Wolfram A1 - Alexander, Mark A1 - John, Vanderley T1 - Education for sustainable use of cement based materials JF - Cement and Concrete Research 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 - Zhang, K. A1 - Mezhov, Alexander A1 - Schmidt, Wolfram T1 - Effect of Polycarboxylate Superplasticizer in Ordinary Portland Cement and Sulfate Resistant Cement JF - Journal of Materials in Civil Engineering N2 - Polycarboxylate superplasticizers (PCE) are the most widely used admixtures in today’s cementitious construction materials. The molecular structure has a decisive influence on the effectiveness of PCE, which also can be tailored to serve in a different cementitious system. The current study investigates the influence of the backbone charge density of PCE on the rheology, hydration kinetics, and adsorption behavior of ordinary Portland cement (OPC) and sulfate-resistant cement (SRC). The results indicate that regardless of the PCE type, OPC requires a higher amount of PCE to be adsorbed to induce changing of rheological parameters and hydration kinetics. Regardless of the cement type, the PCE with a higher charge density exhibits higher adsorption behavior, corresponding to lower viscosity measurement. Compared to OPC, SRC is more sensitive to the introduction of both PCEs and has a lower saturation dosage, indicating that SRC generally provides better workability properties regardless of the PCE. KW - Polycarboxylate superplasticizers (PCE) KW - Sulfate resistant cement (SRC) KW - Rheological KW - Adsorption KW - Cement hydration PY - 2023 DO - https://doi.org/10.1061/JMCEE7.MTENG-15033 SN - 0899-1561 VL - 35 IS - 6 SP - 1 EP - 12 PB - ASCE Libary AN - OPUS4-58244 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -