Rheology, 3D printing, and particle interactions of xanthan gum-clay binder for earth concrete

This study investigates the potential of xanthan gum (XG) to serve as a biopolymer binder for improving the rheological, mechanical, and 3D printing properties of earth-based concrete, aligning with the pressing need for sustainable, low-carbon construction materials. Experimental results indicate that XG could disperse kaolinite clay particles, which likely arises from the highly negative charges of both kaolinite and XG. Rheological parameters display two trends with increasing XG concentration: initially decreasing yield stress, viscosity, and storage modulus owing to XG's dispersing effect, followed by an increase due to polymer overlapping. The same trend is observed in 3D printing experiments, where the kaolinite clay suspensions exhibited enhanced buildability with increasing XG concentration and eventually achieved a “Printable” state at 5 % XG. Additionally, compressive strength was observed to steadily increase with increasing XG content, for instance, nearly tenfold with 2.4 % XG compared to 0 % XG (0.34 MPa to 3.58 MPa). This exploration highlights the pivotal role of XG as a dual-functionality agent, acting as a robust binder and a promising rheology modifier.