Evaluation of the mechanical behavior of 3DCP mixtures with partial replacement of cement by limestone filer and metakaolin in comparison with materials for structural masonry
3D concrete printing; 3DCP blocks; 3DCP masonry prisms; 3DCP mini-walls; Supplementary cementitious materials.
3D printing has generated changes in traditional processes, ensuring greater freedom of design with complex geometries and the possibility of using various materials. However, the cementitious mixtures 3D printing on concrete (3DCP) have high Portland cement contents to meet the printing parameters, so, in order to satisfy the more sustainable construction aspect, an alternative is to partially replace cement by supplementary cementitious materials (SCMs). As also, in view of the similarity of the 3D printing system with that of structural masonry, a comparative evaluation between the aforementioned methods is of importance. Based on this, the present study aims to develop 3DCP blocks, prisms and mini-walls with limestone filler and metakaolin in partial replacement of Portland cement, aiming to evaluate the mechanical behavior of these 3DCP elements in comparison to the structural masonry system; in addition to analyzing their performance in the fresh and hardened state. The results show that the lime filler increases the fluidity and the open time of the mixture, while the metakaolin increases the viscosity of the mixture. It was also found that the geometry of the 3DCP containing an internal lattice ensured greater stability to the material, being favorable to the buildability of the 3DCP. As well as, it was possible to prove the similarity of the mechanical behavior of the structural masonry system with 3DCP, with respect to the brittle failure mode and the compressive strength.