Use of polysaccharides as a rheology modifying admixture for alkali activated materials for 3D printing

This paper presents a comprehensive rheological study on the incorporation of polysaccharides as a rheology modifying admixture in alkali activated materials (AAMs) for enhancing their suitability in 3D printing applications. AAMs have gained significant attention in the construction industry but challenges with printability and buildability hinder their successful integration into 3D printing processes. Existing rheological modifiers are often included prior to mixing and printing AAMs to allow buildability- but with undesirable consequences on material properties. In this research, Xanthan Gum (XG), is examined as potential modifier to address these challenges. The study focuses on a systematic investigation into the effects of XG concentration on rheological response, printability, and mechanical properties. The goal of the study is to ascertain if the inclusion of XG in AAM mixes improves rheological properties in relation to 3D printed buildability and investigate XG’s impact on mechanical performance and setting time. The findings from this research contribute valuable insights into the development of a rheology modifying admixture for AAMs, paving the way for enhanced 3D printing without a significant negative impact on setting times or compressive strength. The implications of this work extend beyond 3D printing, offering a promising avenue for improved rheological properties of AAMs applied to other construction methods i.e. spraying/shotcreting. • Xanthan gum improves the buildability of 3D printed alkali activated materials. • Xanthan gum causes a gelation and meshing mechanism in alkali activated materials. • A dramatic increase in geopolymer yield stress can be induced with a small volume of xanthan gum.