The Synergistic Effect of Ester-Ether Copolymerization Thixo-Tropic Superplasticizer and Nano-Clay on the Buildability of 3D Printable Cementitious Materials

Abstract

The shape retention ability of materials deposited layer by layer is called buildability, which is an indispensable performance parameter for successful 3D printable cementitious materials (3DPC). This study investigated the synergistic effect of nano-clay (NC) and thixotropic superplasticizer (TP) on the buildability of 3DPC. The rheological parameters and static yield stress are characterized by the rheology testing, the green strength is measured by a self-made pressure tester, and the fluidity is tested by flow table. Results indicate that NC significantly increases the growth rate of static yield stress and green strength and TP can improve the initial rheological parameters and fluidity, which ensures the initial stiffness and workability of printed materials. The mixture with 7‰ (by mass of cementitious materials) NC and 3‰ TP obtains excellent extrudability and buildability, due to the synergistic effect of NC and TP. Based on the rheology testing and specific printing experiments, a printable window with 1.0 Pa/s~2.0 Pa/s of the rate of static yield stress evolution over time (RST) or 170 mm~200 mm of fluidity is established. This work provides theorical support for the control and evaluation of rheological properties in 3DPC.

Clay as a Sustainable Binder for Concrete—A Review

“…This was similarly confirmed by Quanji et al (2014) [114]. In this field, Wang et al (2021) [119] reported that using nano attapulgite clay increases the static yield stress in 3D printable cementitious materials, warranting the strength improvement essential by the buildability of materials. As shown in Figure 7, Liu et al (2018) [120] confirmed these observations and showed that using nano-clay, as a viscosity modifier, significantly improves the plastic viscosity and yield stress of paste, especially for a lower w/c.…”

Influence of Nanoceramic-Plated Waste Carbon Fibers on Alkali-Activated Mortar Performance

“…The morphology of the ANC deposit was examined with the aid of the SEM technique and such observations were performed directly on the fiber surface after the nanoclay-based conditioning and drying of WCF bundles. From Figure 8, the first noticeable feature is the uniform nanoceramic coating along the entire length of the fibers, showing the typical needle-like morphology of ANC [26]. The fibers also exhibit a large number of longitudinal grooves indicative of partial oxidation on the fiber surface resulting from the pyrolysis treatment.…”