Deformation characteristics of dense and foamed mortars based on cement and gypsum-to-cement binders for 3D printing

Abstract

Construction 3D printing is one of the revolutionary construction technologies, which involves the use of highly fluid cement and gypsum-to-cement mixes. However, this requires an additional study of the deformation characteristics of multicomponent materials. The article is devoted to the study of the own deformation characteristics of mortars based on cement and gypsum-to-cement binders, as well as fine-grained concrete for printing the contours of wall structures and foamed mortar for filling, monolithic and thermal insulation of their internal space. A wide range of cement and gypsum-to-cement materials has been studied, incl. foamed mortar. For these materials, comprehensive studies of deformation characteristics have been carried out, confirming the results obtained by X-ray diffraction analysis, SEM, heat of hydration, fresh and physical and mechanical properties. It has been established that in gypsum-to-cement materials, the revealed deformations of the expansion of gypsum overlap the negative deformations of air shrinkage. The resulting materials have a slump flow up to 226 cm, which allows the use of these materials for 3D printing of building structures. The high strength of the developed cement and gypsum-to-cement materials in all periods of hardening (above 50 MPa), as well as excellent thermal conductivity (0.10–0.13 W/(m·°C)), shows the promise of fine-grained mortars and foamed ones.