Rheological parameters, thixotropy and creep of 3D-printed calcium sulfoaluminate cement composites modified by bentonite

By Mingxu Chen, Bo Liu, Laibo Li, Lidong Cao, Yongbo Huang, Shoude Wang, P. Zhao, Lingchao Lu, Xin Cheng. 2020

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Abstract The structural instability and poor thixotropy of three-dimensional (3D) printing of calcium sulfoaluminate (CSA) cement composites hinder their applicability in the construction field. In this study, the rheological parameters, thixotropy and creep of 3D-printed CSA cement composites containing bentonite are investigated based on shear-rate- and shear-stress-controlled protocols to achieve a stable three-dimensional structure and excellent thixotropy. Experimental results show that a stable 3D structure with excellent thixotropy can be achieved when the content of bentonite is 2%. In this case, the plastic viscosity and dynamic yield stress are lower than 2.50 Pa s and 645.54 Pa, respectively. The correlation between the rheological parameters and thixotropy of 3D-printed CSA cement composites suggests that the actual thixotropy can be predicted by the yield stress. Furthermore, the shear-stress-controlled protocol was implemented to simulate the effect of gravity and test different creep periods of 3D-printed CSA cement composites with bentonite. The improved static yield stress exhibited better effectiveness in resisting structural deformation over time.

Subfields: Automotive Engineering, Building and Construction, Civil and Structural Engineering

View Paper: https://www.semanticscholar.org/paper/9efe580f0e320fa848d91865f820d0dcab6a6397