RESUMO
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.
RESUMO
Pelagic Sargassum, usually found at the Sargasso Sea and the Western portion of the North Atlantic and Gulf of Mexico, has been detected in many new locations through the tropical Atlantic. The huge biomass found from the African coast to the Caribbean was called the Great Atlantic Sargassum Belt and is responsible for the stranding of tons of algae on coastal regions. Despite the environmental, social, and economic impacts, sargassum is a valuable source for multiple uses at the industry, such as alginates, cosmetics, recycled paper and bioplastics, fertilizers, and as raw material for civil construction. This work presents a systematic literature review on the use of algae at the civil construction sector, with a focus on the valorization of the pelagic Sargassum spp. biomass, by identifying the potential applications related to the use of other algal species. The review considered other genera of marine algae and marine angiosperms, resulting in a total of 31 selected articles. The marine grass Posidonia oceanica was the most used species, found in eight published papers, followed by the red alga Kappaphycus alvarezii with four studies. Two articles were available on the use of pelagic Sargassum spp. (S. fluitans and S.natans) for construction materials (adobe and pavement), with potential good results. The literature presented results from the use of marine algae and sea grasses for particleboards, polymeric and cemented composites, adobe, pavement, facades, and roofs. This article provides a state-of-the-art review of algal application in the civil construction sector and points out the main directions for the potentialities on the insertion of the Sargassum spp. biomass into the production chain of the sector.