Alkali activated materials applied in 3D printing construction: A review

This study aims to contribute to the promising field of alkali-activated materials (AAM) used in 3D printing for construction. Presented as a comprehensive review, the research provides valuable insights for researchers within and beyond the field. The study focuses on identifying prevalent research trends and accessing pertinent information on materials, methodologies, and parameters of interest. The study commenced with a bibliometric analysis of 55 carefully selected publications, followed by an in-depth review of these articles categorized into extrusion-based and powder-based systems. Emphasis was placed on the materials used, methodologies employed, and key findings from these studies. The bibliometric analysis unveiled prevalent keywords, their relevance in the field, highly cited articles, and collaborative networks among researchers. The most influential countries in terms of publications are Australia, China, and Singapore. The review highlighted commonly used materials and their potential impacts on large-scale applications of AAM, exploring how various precursors, activators, additives, aggregates, and reinforcements shape the properties of printed AAM, featuring innovative approaches with alternative materials. The methodologies employed in these studies and trends in characterization were outlined, due to the absence of standardized tests for materials in 3D printing applications. The study emphasized how material properties vary concerning production processes, printing parameters, curing methods, and post-treatment, outlining advancements in material characterization necessary for achieving a printable mix design. Through the analysis of these 55 articles, key scientific challenges and hurdles in large-scale applications were identified, suggesting potential focal points for further studies. In summary, AAMs exhibit substantial uniqueness and complexity due to their diverse material composition, resulting in varying properties in both fresh and hardened states. However, this diversity also signifies the adaptability of AAMs to diverse equipment, construction techniques, and desired specifications, showcasing their potential to revolutionize traditional construction by integrating technology and sustainability.