Rheological behaviors and structure build-up of 3D printed polypropylene and polyvinyl alcohol fiber-reinforced calcium sulphoaluminate cement composites

The uncontrollable printed structure and poor toughness of three dimensional (3D) printed cement composites hamper their application in buildings. In this study, the polypropylene (PP) and polyvinyl alcohol (PVA) fibers were introduced into the 3D printed calcium sulphoaluminate cement composites (CSACCs) to achieve the stable shape retention and high mechanical strength by controlling the rheological parameters. Experimental results show that the PP and PVA fibers enlarge the linear viscoelastic region (LVR) and increase the elastic modulus of CSACCs. Moreover, these two fibers clearly increase the yield stress and improve the thixotropy of CSACCs in the fiber content of 0.50-1.25%. The relationship between the rheological parameters and structure deformation is revealed by the radar map, and it indicates that the printed structure deformation is improved by controlling the coupling rheological parameters. Furthermore, both PP and PVA fibers are beneficial to the improvement of toughness in the 3D printed CSACCs, and the optimal contents are 0.75 and 1.00%, respectively. In conclusion, developing the 3D printed fiber-reinforced CSACCs with the controllable rheological parameters is significant for improving the printed structures and toughness, which shows a considerable potential in buildings. (C) 2021 The Authors. Published by Elsevier B.V.

Automated summary

In this study, PP and PVA fibers were introduced into 3D printed CSACCs to improve the stable shape retention and mechanical strength by controlling rheological parameters. The experimental results showed that the fibers enhanced the elastic modulus, yield stress, and thixotropy of CSACCs. The radar map revealed the relationship between rheological parameters and structure deformation.