Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Rheology of fresh cement pastes modified with nanoclay-coated cements
Abstract Nanoclays (NC) can serve as thixotropy modifiers for fresh concretes, and show potential to meet the rheological demands of 3D concrete printing. Here, we propose a dry dispersion technique that produces NC-coated cement and compare to conventional methods of dispersion. Pastes incorporating NC were tested via shear rheology, scanning electron microscopy, and isothermal calorimetry. Dry dispersion was found to be the most effective method, where incorporating 4.0 wt% NC increased the static yield stress and storage modulus of cement paste by 1500% and 550%, respectively, with a minimal increase in viscosity of 90%. Results of small amplitude oscillatory shear and isothermal calorimetry indicated NC can enhance fresh-state stiffening through seeding, although shear rheology results of kerosene-based cement systems indicated the increase in static yield stress by NC is mainly due to ionic forces. Finally, we discuss how these properties translate to high buildability and stable layer deposition.
Rheology of fresh cement pastes modified with nanoclay-coated cements
Abstract Nanoclays (NC) can serve as thixotropy modifiers for fresh concretes, and show potential to meet the rheological demands of 3D concrete printing. Here, we propose a dry dispersion technique that produces NC-coated cement and compare to conventional methods of dispersion. Pastes incorporating NC were tested via shear rheology, scanning electron microscopy, and isothermal calorimetry. Dry dispersion was found to be the most effective method, where incorporating 4.0 wt% NC increased the static yield stress and storage modulus of cement paste by 1500% and 550%, respectively, with a minimal increase in viscosity of 90%. Results of small amplitude oscillatory shear and isothermal calorimetry indicated NC can enhance fresh-state stiffening through seeding, although shear rheology results of kerosene-based cement systems indicated the increase in static yield stress by NC is mainly due to ionic forces. Finally, we discuss how these properties translate to high buildability and stable layer deposition.
Rheology of fresh cement pastes modified with nanoclay-coated cements
Douba, AlaEddin (Autor:in) / Ma, Siwei (Autor:in) / Kawashima, Shiho (Autor:in)
07.10.2021
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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