Effects of Vinyl Acetate and Ethylene Copolymer on Printing and Mechanical Performances of 3D Printing Cementitious Materials

These days, 3D printing technology has become more widely applied in the field of building and construction, and the most common method is extruded-based 3D concrete printing (3DCP). During the printing process, cementitious materials are extruded layer by layer with any formwork; thus, it forms a series of interlayers which are considered weak points. Vinyl acetate and ethylene (VAE) copolymer, a re-dispersible polymer, is effective in enhancing adhesive behaviour for cast concrete; however, the studies on the effects of VAE on printing and mechanical performances for 3DCP cementitious materials are still limited. In this paper, rheological tests, printing tests, and mechanical tests were conducted to investigate the effects of VAE on rheological, printing, and mechanical performances, respectively. This paper revealed that VAE has negative effects on 3DCP buildability, while it can significantly benefit surface quality, reduction of cracks, flexural strengths, and interlayer bonding strengths for 3DCP cementitious materials.