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Life Cycle Assessment (LCA) and Multi-Criteria Decision-Making (MCDM) analysis to determine the performance of 3D printed cement mortars and geopolymersA comparison between low-clinker cement and geopolymer mortars for their application in 3D printing is discussed in this paper. The mortars are composed of materials with low environmental impact, such as cements with low clinker content, by-products of the industry and recycled aggregates. The developed mortars were both mechanically and rheologically characterised. The environmental impact was studied by LCA. To select the most suitable dosages, MCDM analysis was applied based on cost of materials, printability and LCA.Compressive strength was considered as a normalising parameter for both the LCA and cost. The mortars showed good printability and suitable mechanical strength, being higher in the cement mortars. The LCA showed that the geopolymer mortars have a higher environmental impact due to the use of sodium hydroxide. Likewise, MCDM revealed that low-clinker cement mortars are at the top of the ranking, due to a lower environmental impact and lower cost of materials.

3D printing of concrete structures has had a strong development in recent years, enhanced by the advantages it presents over traditional construction.However, it currently still has some limitations. One of those limitations is to incorporate the reinforcements into the automated 3D printing process. The objective of this work is to present a review of the methods that have been used so far to reinforce the structures. The different methods used will be presented focusing on the reinforcement by the use of fibers. The properties of the fibers, lengths, percentages of the same used in the mixtures will be analyzed. The results of the different tests will be shown making a comparison between the values obtained from the tests carried out with the printed and molded materials. Finally, the increases in the results of the tests that these fibers provide with respect to the samples without them will be analyzed.

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