Yield strength development of 3D printable concrete by the early age activation reactions plays a vital role in the printability of geopolymer concrete. This study presents a rheo-chemical approach to investigate the early age strength development due to alkali reactions for the formulation of suitable 3D printable one-part geopolymer concrete. The influence of design parameters, including activator content, thixotropic additive (Magnesium Alumino Silicate -MAS), and retarder (sucrose) dosage, on the rheological properties of concrete were assessed. The shear stresses of geopolymer concrete were measured with the aid of a rotational rheometer for various shearing protocols that represent the major stages of printing operation (pumping, extrusion and building). The measured rheological properties were related to reaction kinetics of geopolymer mixes using FT-IR spectroscopy and calorimetry. The results revealed that, with MAS, activator and sucrose content of 0.75 wt%, 10 wt% and 1.5 wt% of the binder respectively, the formulated one-part geopolymer showcased enhanced printing properties. This is further demonstrated by printing laboratory-scale specimens and evaluating the hardened properties.

通过早期活化反应开发3D可打印混凝土的屈服强度在地聚合物混凝土的可印刷性中起着至关重要的作用。这项研究提出了一种流变化学方法，以研究碱反应引起的早期强度发展，以配制合适的3D可打印的一件式地质聚合物混凝土。评估了包括活化剂含量，触变添加剂（铝硅酸镁-MAS）和缓凝剂（蔗糖）用量等设计参数对混凝土流变性能的影响。借助旋转流变仪针对各种剪切规程测量了地质聚合物混凝土的剪切应力，这些规程代表了印刷操作的主要阶段（泵送，挤出和建筑）。使用FT-IR光谱和量热法，测得的流变性质与地质聚合物混合物的反应动力学有关。结果表明，在MAS，活化剂和蔗糖含量分别为粘合剂的0.75wt％，10wt％和1.5wt％的情况下，配制的单组分地质聚合物显示出增强的印刷性能。通过印刷实验室规模的样品并评估其硬化性能，可以进一步证明这一点。