12. Rheology-active additives in OPC based formulations – From nano/micro-scale structures to macro scale properties

Principal investigator(s) – PI

    Researcher(s) in-charge- RI

    • M.Sc. Ursula Pott
      Technische Universität Dresden, Institut für Baustoffe

    Associated researcher(s) – AR

    • Dr. rer. nat. Daniel Jansen
      Geozentrum Nordbayern, Lehrstuhl für Mineralogie
    • Prof. Dr. Jürgen Neubauer
      Geozentrum Nordbayern, Lehrstuhl für Mineralogie

    Former members

    • M.Sc. Cordula Jakob
      Geozentrum Nordbayern, Lehrstuhl für Mineralogie
    • Uni.-Prof. Dr. rer. nat. Dietmar Stephan
      TU Berlin, Fachgebiet für Baustoffe und Bauchemie

    Subject Area

    Rheology; Cement hydration; Building material additives

    Term

    2018-2021

    Project identifier

    Deutsche Forschungsgemeinschaft (DFG) – Projekt number 386869775

    Project Description

    Two substantial goals are pursued in this proposal. Initially, the highly time-resolved (ca. 10min) evolution of the relevant rheology determining parameters during the early cement hydration will be traced and evaluated. Here the evolution of the morphology and the amount of the forming hydrate phases as well as the availability and amount of the residual unbound and rheology active water fraction play a significant role. These parameters and others will be traced and quantified by a combination of different physical, chemical, and rheological analytic methods. Beside calorimetry, quantitative X-ray diffraction, 1H-TD-NMR, rheometer, and ultra-sound measurements, a new developed penetration test method is used to observe the rheological behavior of cementitious materials. The combination of these methods will hold the information of a deeper understanding of the underlying mechanisms, which are determining the rheology of fresh cement pastes. Important to highlight that most of the proposed analytic methods provide overlapping information, allowing a cross validation in order to confirm the consistency of the measured results. In the second part the influence of rheology active additives on the above-mentioned parameters will be evaluated. Thereby important information on the effect of building additives and the fundamental working mechanisms of the superimposition of cement hydration and the development of rheological properties over time are expected. This information is compulsory for further in deep understanding of the rheology in fresh concretes.

    Linking the phase formation (alite and ettringite) and heat flow of a cement paste with its rheological properties measured by a rheological and a penetration test
    © TU Berlin, Geozentrum Nordbayern

    Publications

    1. Jakob, C.; Jansen, D.; Ukrainczyk, N.; Koenders, E.; Pott, U.; Stephan, D.; Neubauer, J.; Re-lating Ettringite Formation and Rheological Changes during the Initial Cement Hydration: A Comparative Study Applying XRD Analysis, Rheological Measurements and Modeling; Materi-als 12 (2019) 2957
    2. Jakob, C.; Jansen, D.; Pott, U.; Neubauer, J.; Comparing Phase Development and Rheological Properties of OPC Paste within the First hour of Hydration; Rheology and Processing of Con-struction Materials (2019) 219-227; RILEM Bookseries Springer
    3. Pott, U.; Jakob, C.; Jansen, D.; Neubauer, J.; Stephan, D.; Investigation of the incompatibilities of cement and superplasticizers and their influence on the rheological behavior; Materials 13 (2020) 977
    4. Pott, U.; Ehm, C.; Jakob, C.; Stephan, D.; Investigation of the early cement hydration with a new penetration test, rheometry and in situ XRD; Rheology and Processing of Construction Materials 12 (2020) 246-255; RILEM Bookseries Springer