Development of sustainable mortars for application in 3D printing

Abstract

In the present work, corresponding to the current doctoral thesis, some results of mechanical and physical tests of different types of geopolymer and cement mortars will be announced, whose purpose is to be used as additive material in a 3D printer, contour crafting type. The geopolymer mortars used are composed of fly ash, as a precursor, alkaline solution, as an activator, limestone aggregate, crushed glass and seashells, such as aggregate and additives. Cement mortars, as the name implies, consist of cement, additions, additives and various aggregates (limestone sand, crushed glass and seashells). The mechanical tests correspond to flexion and compression in prismatic specimens of 4 x 4 x 16 cm. The geopolymer mortars were cured under different conditions (at room temperature, in water -sea and tap- and in a stove at 40 ° C) and were exposed to different environments (laboratory environment and immersed in water); while cement mortars were cured at room temperature and in water (sea and tap). Elements of different sizes, shapes and complexities were printed to prove their effectiveness as an additive material, obtaining satisfactory behaviors. Mechanical results show that mortars continue to gain resistance up to 90 days, for cement and 60 days for geopolymers; the latter have lower resistance compared to cements, which recorded values around 70 MPa for those containing limestone aggregate and crushed glass, cured in water.